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  • 1.
    Adam, Rania E.
    et al.
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Chalangar, Ebrahim
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Pirhashemi, Mahsa
    Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
    Pozina, Galia
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Liu, Xianjie
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Palisaitis, Justinas
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden & Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Willander, Magnus
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Nur, Omer
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 52, p. 30585-30598Article in journal (Refereed)
    Abstract [en]

    High-efficiency photocatalysts are crucial for the removal of organic pollutants and environmental sustainability. In the present work, we report on a new low-temperature hydrothermal chemical method, assisted by ultrasonication, to synthesize disruptive plasmonic ZnO/graphene/Ag/AgI nanocomposites for solar-driven photocatalysis. The plasmonic nanocomposites were investigated by a wide range of characterization techniques, confirming successful formation of photocatalysts with excellent degradation efficiency. Using Congo red as a model dye molecule, our experimental results demonstrated a photocatalytic reactivity exceeding 90% efficiency after one hour simulated solar irradiation. The significantly enhanced degradation efficiency is attributed to improved electronic properties of the nanocomposites by hybridization of the graphene and to the addition of Ag/AgI which generates a strong surface plasmon resonance effect in the metallic silver further improving the photocatalytic activity and stability under solar irradiation. Scavenger experiments suggest that superoxide and hydroxyl radicals are responsible for the photodegradation of Congo red. Our findings are important for the fundamental understanding of the photocatalytic mechanism of ZnO/graphene/Ag/AgI nanocomposites and can lead to further development of novel efficient photocatalyst materials. © 2019 Elsevier B.V.

  • 2.
    Adam, Rania Elhadi
    et al.
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Chalangar, Ebrahim
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering. School of Information Technology, Halmstad University, Halmstad, Sweden.
    Pirhashemi, Mahsa
    Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Pettersson, Håkan
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering. School of Information Technology, Halmstad University, Halmstad, Sweden; Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Willander, Magnus
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 52, p. 30585-30598Article in journal (Refereed)
    Abstract [en]

    High-efficiency photocatalysts are crucial for the removal of organic pollutants and environmental sustainability. In the present work, we report on a new low-temperature hydrothermal chemical method, assisted by ultrasonication, to synthesize disruptive plasmonic ZnO/graphene/Ag/AgI nanocomposites for solar-driven photocatalysis. The plasmonic nanocomposites were investigated by a wide range of characterization techniques, confirming successful formation of photocatalysts with excellent degradation efficiency. Using Congo red as a model dye molecule, our experimental results demonstrated a photocatalytic reactivity exceeding 90% efficiency after one hour simulated solar irradiation. The significantly enhanced degradation efficiency is attributed to improved electronic properties of the nanocomposites by hybridization of the graphene and to the addition of Ag/AgI which generates a strong surface plasmon resonance effect in the metallic silver further improving the photocatalytic activity and stability under solar irradiation. Scavenger experiments suggest that superoxide and hydroxyl radicals are responsible for the photodegradation of Congo red. Our findings are important for the fundamental understanding of the photocatalytic mechanism of ZnO/graphene/Ag/AgI nanocomposites and can lead to further development of novel efficient photocatalyst materials.

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  • 3.
    Adolfsson, Karin H.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hassanzadeh, Salman
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Valorization of cellulose and waste paper to graphene oxide quantum dots2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 34, p. 26550-26558Article in journal (Refereed)
    Abstract [en]

    Biobased graphene oxide quantum dots (GOQD) were derived from cellulose via carbon nanospheres (CN) as intermediate products. Solid CN were synthesized from cellulose through microwave-assisted hydrothermal degradation of alpha-cellulose with H2SO4 as a catalyst at 160 degrees C. The obtained CN were further utilized for the synthesis of GOQD by a two-step reaction including 30 minutes of sonication followed by heating at 90 degrees C under O-rich acidic conditions (HNO3). This process broke down the 3D CN to 2D GOQD. The size of the synthesized GOQD was controlled by the heating time, reaching a dot diameter of 3.3 nm and 1.2 nm after 30 and 60 minutes of heating, respectively. The synthesis process and products were characterized by multiple analytical techniques including FTIR, TGA, SEM, TEM, XPS, XRD, BET, DLS and AFM. Interesting optical properties in aqueous solutions were demonstrated by UV/Vis and fluorescence spectroscopy. Finally we demonstrated that corresponding GOQD can be synthesized from waste paper. This production route thus uses renewable and cheap starting materials and relatively mild synthesis procedures leads to instant nanometric production of 2D dots. In addition it enables recycling of low quality waste to value-added products.

  • 4.
    Ahlgren, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Fondell, Amelie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Gedda, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science. Swedish Radiat Safety Author, Res Unit, Solna Strandvag 96, SE-17116 Stockholm, Sweden.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 36, p. 22178-22186Article in journal (Refereed)
    Abstract [en]

    Concerns regarding poor aqueous solubility, high toxicity and lack of specificity impede the translation of many hydrophobic anticancer agents into safe and effective anticancer drugs. The application of colloidal drug delivery systems, and in particular the use of lipid-based nanocarriers, has been identified as a promising means to overcome these issues. PEG-stabilized lipid nanodisks (lipodisks) have lately emerged as a novel type of biocompatible, nontoxic and adaptable drug nanocarrier. In this study we have explored the potential of lipodisks as a platform for formulation and tumour targeted delivery of hydrophobic anticancer agents. Using curcumin as a model compound, we show that lipodisks can be loaded with substantial amounts of hydrophobic drugs (curcumin/lipid molar ratio 0.15). We demonstrate moreover that by deliberate choice of preparation protocols the lipodisks can be provided with relevant amounts of targeting proteins, such as epidermal growth factor (EGF). Data from in vitro cell studies verify that such EGF-decorated curcumin-loaded lipodisks are capable of EGF-receptor specific targeting of human A-431 tumour cells, and strongly suggest that the interaction between the lipodisks and the tumour cells results in receptor-mediated internalization of the disks and their cargo.

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  • 5.
    Ahlinder, Linnea
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Henych, Jiří
    Wiklund Lindström, Susanne
    Ekstrand-Hammarström, Barbro
    Stengl, Václav
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Graphene oxide nanoparticle attachment and its toxicity on living lung epithelial cells2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 73, p. 59447-59457Article in journal (Refereed)
    Abstract [en]

    Since its discovery, graphene and its oxidized form, graphene oxide (GO), have attracted interest in a wide range of technical applications. Concerns about their potential toxicity calls for scrutinized studies, but hitherto conflicting results have been reported which partly may be due to variations of synthesis and exposure procedures. Here we report on the attachment and toxicity of contamination-free graphene oxide nanoparticles (GONP) in living lung epithelial cells. The synthesis of chemically pure GONP was made by an improvement of the Hummer's method based on graphene exfoliated from graphite using high-intensity ultrasonication, resulting in two dimensional sheets with a lateral dimension in the range 200 nm to 3 mu m and thickness of 0.9 nm. Confocal Raman spectroscopy combined with multivariate analysis was used to study the interaction of GONP and living cells. It is shown that overlapping Raman bands due to GONPs and biomolecules in the cells can clearly be separated with this approach. Orthogonal partial least squares discriminant analysis was used to compare spectral data collected from cells exposed to GONP with spectral data collected from non-exposed control cells, and spectral data from cells exposed to a surfactant known to induce apoptosis. Our analyses show that GONP readily attach to the cells, forming sheets which cover a large fraction of the cell surfaces, and induce small chemical changes. In particular, chemical modifications of proteins and lipids in lung epithelial cells are inferred. GONPs do not, however, decrease cell viability. In contrast, enhanced cell proliferation is observed. Our results shed new light on the interactions of GO, and in contrast to some previous reports, suggest that GO is not toxic. The hyperspectral Raman spectroscopy analysis employed here should be applicable for other fields in nanomedicine as a label-free non-perturbing analytical method.

  • 6.
    Akan, Rabia
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Parfeniukas, Karolis
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Vogt, Carmen
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Toprak, M. S.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Vogt, Ulrich
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures2018In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, no 23, p. 12628-12634Article in journal (Refereed)
    Abstract [en]

    Metal-assisted chemical etching (MACE) reaction parameters were investigated for the fabrication of specially designed silicon-based X-ray zone plate nanostructures using a gold catalyst pattern and etching solutions composed of HF and H2O2. Etching depth, zone verticality and zone roughness were studied as a function of etching solution composition, temperature and processing time. Homogeneous, vertical etching with increasing depth is observed at increasing H2O2 concentrations and elevated processing temperatures, implying a balance in the hole injection and silica dissolution kinetics at the gold-silicon interface. The etching depth decreases and zone roughness increases at the highest investigated H2O2 concentration and temperature. Possible reasons for these observations are discussed based on reaction chemistry and zone plate design. Optimum MACE conditions are found at HFH2O2 concentrations of 4.7 M:0.68 M and room temperature with an etching rate of ≈0.7 μm min-1, which is about an order of magnitude higher than previous reports. Moreover, our results show that a grid catalyst design is important for successful fabrication of vertical high aspect ratio silicon nanostructures. 

  • 7.
    Akhtar, Farid
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Luleå University of Technology, Sweden.
    Keshavarzi, Neda
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Shakarova, Dilshod
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Cheung, Ocean
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hedin, Niklas
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Aluminophosphate monoliths with high CO2-over-N2 selectivity and CO2 capture capacity2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 99, p. 55877-55883Article in journal (Refereed)
    Abstract [en]

    Monoliths of microporous aluminophosphates (AlPO4-17 and AlPO4-53) were structured by binder-freepulsed current processing. Such monoliths could be important for carbon capture from flue gas. TheAlPO4-17 and AlPO4-53 monoliths exhibited a tensile strength of 1.0 MPa and a CO2 adsorption capacityof 2.5 mmol g1 and 1.6 mmol g1, respectively at 101 kPa and 0 C. Analyses of single component CO2and N2 adsorption data indicated that the AlPO4-53 monoliths had an extraordinarily high CO2-over-N2selectivity from a binary gas mixture of 15 mol% CO2 and 85 mol% N2. The estimated CO2 capturecapacity of AlPO4-17 and AlPO4-53 monoliths in a typical pressure swing adsorption (PSA) process at 20C was higher than that of the commonly used zeolite 13X granules. Under cyclic sorption conditions,AlPO4-17 and AlPO4-53 monoliths were regenerated by lowering the pressure of CO2. Regeneration wasdone without application of heat, which would regenerate them to their full capacity for CO2 adsorption.

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    Aluminophosphate monoliths with high CO2-over- N2 selectivity and CO2 capture capacity
  • 8.
    Akhtar, Farid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Keshavarzi, Neda
    Department of Materials and Environmental Chemistry, Stockholm University.
    Shakarova, Dilshod
    Department of Materials and Environmental Chemistry, Stockholm University.
    Cheung, Ocean
    Department of Materials and Environmental Chemistry, Stockholm University.
    Hedin, Niklas
    Department of Materials and Environmental Chemistry, Stockholm University.
    Bergström, L.M.
    Department of Materials and Environmental Chemistry, Stockholm University.
    Aluminophosphate monoliths with high CO2-over-N2 selectivity and CO2 capture capacity2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 99, p. 55877-55883Article in journal (Refereed)
    Abstract [en]

    Monoliths of microporous aluminophosphates (AlPO4-17 and AlPO4-53) were structured by binder-free pulsed current processing. Such monoliths could be important for carbon capture from flue gas. The AlPO4-17 and AlPO4-53 monoliths exhibited a tensile strength of 1.0 MPa and a CO2 adsorption capacity of 2.5 mmol g-1 and 1.6 mmol g-1, respectively at 101 kPa and 0°C. Analyses of single component CO2 and N2 adsorption data indicated that the AlPO4-53 monoliths had an extraordinarily high CO2-over-N2 selectivity from a binary gas mixture of 15 mol% CO2 and 85 mol% N2. The estimated CO2 capture capacity of AlPO4-17 and AlPO4-53 monoliths in a typical pressure swing adsorption (PSA) process at 20°C was higher than that of the commonly used zeolite 13X granules. Under cyclic sorption conditions, AlPO4-17 and AlPO4-53 monoliths were regenerated by lowering the pressure of CO2. Regeneration was done without application of heat, which would regenerate them to their full capacity for CO2 adsorption.

  • 9. Alanis, Andrés
    et al.
    Hernández Valdés, Josué
    Maria Guadalupe, Neira-Velázquez
    Lopez, Ricardo
    Mendoza, Ricardo
    Mathew, Aji P.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Diaz de León, Ramón
    Valencia, Luis
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Plasma surface-modification of cellulose nanocrystals: a green alternative towards mechanical reinforcement of ABS2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 30, p. 17417-17424Article in journal (Refereed)
    Abstract [en]

    This article proposes a strategy to functionalize cellulose nanocrystals by means of plasma-surface modification utilizing monomers of different nature: caprolactone, styrene and farnesene. The surface characteristics of the nanocrystals were studied by different techniques including XPS, FTIR and STEM, demonstrating that this technique allows a successful functionalization, yielding homogenous functionalization which does not alter the rod-like shape of the nanocrystals, and therefore their anisotropic behavior. We have furthermore studied the employment of the modified nanocrystals as reinforcement additive of ABS, which significantly enhanced the impact resistance of the thermoplastic, which could have great implications for industrial applications.

  • 10.
    Ali Soomro, Razium
    et al.
    University of Bristol, England; University of Sindh, Pakistan.
    Richard Hallam, Keith
    University of Bristol, England.
    Hussain Ibupoto, Zafar
    University of Sindh, Pakistan.
    Tahira, Aneela
    University of Sindh, Pakistan.
    Jawaid, Sana
    University of Sindh, Pakistan.
    Tufail Hussain Sherazi, Syed
    University of Sindh, Pakistan.
    Sirajjuddin,
    Univ Sindh, Natl Ctr Excellence Analyt Chem, Jamshoro 76080, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    A highly selective and sensitive electrochemical determination of melamine based on succinic acid functionalized copper oxide nanostructures2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 127, p. 105090-105097Article in journal (Refereed)
    Abstract [en]

    This study presents the development of a highly selective and sensitive electrochemical sensor for the determination of melamine from aqueous environments. The sensor system is based on functionalised marigold-like CuO nanostructures fabricated using a controlled hydrothermal process, where the utilised succinic acid is considered to play a dual role as a functionalising and growth controlling agent (modifier). The fabricated nanostructures exhibit sharp and well-ordered structural features with dimensions (thickness) in the range of 10-50 nm. The sensor system exhibits strong linearity within the concentration range of 0.1 x 10(-9) to 5.6 x 10(-9) M and demonstrates an excellent limit of detection up to 0.1 x 10(-10) M. The extreme selectivity and sensing capability of the developed sensor is attributed to the synergy of selective interaction between succinic acid and melamine moieties, and the high surface area of marigold-like CuO nanostructures. In addition to this, the developed sensor was also utilised for the determination of melamine from real milk samples collected from different regions of Hyderabad, Pakistan. The obtained excellent recoveries proved the feasibility of the sensor for real life applications. The sensor system offers an operative measure for detecting extremely low melamine content with high selectivity in food contents.

  • 11.
    Alvarez-Asencio, Ruben
    et al.
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Corkery, Robert
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Solventless synthesis of cerium oxide nanoparticles and their application in UV protective clear coatings2020In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 10, no 25, p. 14818-14825Article in journal (Refereed)
    Abstract [en]

    Colloidal dispersions of cerium oxide nanoparticles are of importance for numerous applications including as catalysts, chemical mechanical polishing agents and additives for UV protective and anticorrosion coatings. Here, concentrated oleate-coated cerium oxide nanoparticles (CeO2 NPs) with a uniform size have been produced by solventless thermolysis of cerium-oleate powder under low pressure at 320 degrees C and subsequently dispersed in hexane. Unlike any previously reported colloidal synthesis process for ceria nanoparticles, this process does not involve any toxic high boiling point organic solvent that requires subsequent removal at high cost. Although the process is very simple, highly concentrated cerium oxide nanoparticles with more than 17 wt% solid content and 70% of the theoretical yield can be easily obtained. Moreover, the size, shape and crystallinity of cerium oxide nanoparticles can be tailored by changing the thermal decomposition temperature and reaction time. Moreover, the new synthesis route developed in this study allows the synthesis of clean and dispersible ceria nanoparticles at a relatively low cost in a single step. The prepared ceria nanoparticles have an excellent UV absorption property and remain transparent to visible light, thus having the potential to replace potentially hazardous organic compounds in UV absorbing clear coatings. As a proof of concept, the prepared dispersions of cerium oxide nanoparticles in hexane were formulated into a solvent borne binder base to develop clear UV protecting coatings for light sensitive substrates. The general synthesis strategy presented in this study is generally applicable for the low-cost production of a concentrated dispersion of metal oxide nanoparticles with minimal environmental impact.

  • 12.
    Alvarez-Asencio, Ruben
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials.
    Corkery, Robert W.
    KTH Royal Institute of Technology, Sweden.
    Ahniyaz, Anwar
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials.
    Solventless synthesis of cerium oxide nanoparticles and their application in UV protective clear coatings2020In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 10, no 25, p. 14818-14825Article in journal (Refereed)
    Abstract [en]

    Colloidal dispersions of cerium oxide nanoparticles are of importance for numerous applications including as catalysts, chemical mechanical polishing agents and additives for UV protective and anticorrosion coatings. Here, concentrated oleate-coated cerium oxide nanoparticles (CeO2 NPs) with a uniform size have been produced by solventless thermolysis of cerium-oleate powder under low pressure at 320 °C and subsequently dispersed in hexane. Unlike any previously reported colloidal synthesis process for ceria nanoparticles, this process does not involve any toxic high boiling point organic solvent that requires subsequent removal at high cost. Although the process is very simple, highly concentrated cerium oxide nanoparticles with more than 17 wt% solid content and 70% of the theoretical yield can be easily obtained. Moreover, the size, shape and crystallinity of cerium oxide nanoparticles can be tailored by changing the thermal decomposition temperature and reaction time. Moreover, the new synthesis route developed in this study allows the synthesis of clean and dispersible ceria nanoparticles at a relatively low cost in a single step. The prepared ceria nanoparticles have an excellent UV absorption property and remain transparent to visible light, thus having the potential to replace potentially hazardous organic compounds in UV absorbing clear coatings. As a proof of concept, the prepared dispersions of cerium oxide nanoparticles in hexane were formulated into a solvent borne binder base to develop clear UV protecting coatings for light sensitive substrates. The general synthesis strategy presented in this study is generally applicable for the low-cost production of a concentrated dispersion of metal oxide nanoparticles with minimal environmental impact.

  • 13.
    Amin, Sidra
    et al.
    Lulea Univ Technol, Sweden; Shaheed Benazir Bhutto Univ, Pakistan.
    Tahira, Aneela
    Lulea Univ Technol, Sweden.
    Solangi, Amber
    Univ Sindh, Pakistan.
    Beni, Valerio
    Res Inst Sweden, Sweden.
    Morante, J. R.
    Catalonia Inst Energy Res IREC, Spain.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Mazzaro, Raffaello
    Lulea Univ Technol, Sweden.
    Ibupoto, Zafar Hussain
    Lulea Univ Technol, Sweden; Univ Sindh, Pakistan.
    Vomiero, Alberto
    Lulea Univ Technol, Sweden.
    A practical non-enzymatic urea sensor based on NiCo2O4 nanoneedles2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 25, p. 14443-14451Article in journal (Refereed)
    Abstract [en]

    We propose a new facile electrochemical sensing platform for determination of urea, based on a glassy carbon electrode (GCE) modified with nickel cobalt oxide (NiCo2O4) nanoneedles. These nanoneedles are used for the first time for highly sensitive determination of urea with the lowest detection limit (1 mu M) ever reported for the non-enzymatic approach. The nanoneedles were grown through a simple and low-temperature aqueous chemical method. We characterized the structural and morphological properties of the NiCo2O4 nanoneedles by TEM, SEM, XPS and XRD. The bimetallic nickel cobalt oxide exhibits nanoneedle morphology, which results from the self-assembly of nanoparticles. The NiCo2O4 nanoneedles are exclusively composed of Ni, Co, and O and exhibit a cubic crystalline phase. Cyclic voltammetry was used to study the enhanced electrochemical properties of a NiCo2O4 nanoneedle-modified GCE by overcoming the typical poor conductivity of bare NiO and Co3O4. The GCE-modified electrode is highly sensitive towards urea, with a linear response (R-2 = 0.99) over the concentration range 0.01-5 mM and with a detection limit of 1.0 mu M. The proposed non-enzymatic urea sensor is highly selective even in the presence of common interferents such as glucose, uric acid, and ascorbic acid. This new urea sensor has good viability for urea analysis in urine samples and can represent a significant advancement in the field, owing to the simple and cost-effective fabrication of electrodes, which can be used as a promising analytical tool for urea estimation.

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  • 14.
    Amin, Sidra
    et al.
    Luleå University of Technology, Sweden; University of Sindh, Pakistan´; Shaheed Benazir Bhutto University, Pakistan .
    Tahira, Aneela
    Luleå University of Technology, Sweden .
    Solangi, Amber
    University of Sindh, Pakistan.
    Beni, Valerio
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Morante, JR
    Catalonia Institute for Energy Research, Spain.
    Liu, Xianjie
    Linköping University, Sweden.
    Falhman, Mats
    Linköping University, Sweden.
    Mazzaro, Raffaello
    Luleå University of Technology, Sweden .
    Ibupoto, Zafar
    Luleå University of Technology, Sweden .
    Vomiero, Alberto
    Luleå University of Technology, Sweden .
    A practical non-enzymatic urea sensor based on NiCo 2 O 4 nanoneedles2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 25, p. 14443-14451Article in journal (Refereed)
    Abstract [en]

    We propose a new facile electrochemical sensing platform for determination of urea, based on a glassy carbon electrode (GCE) modified with nickel cobalt oxide (NiCo 2 O 4 ) nanoneedles. These nanoneedles are used for the first time for highly sensitive determination of urea with the lowest detection limit (1 μM) ever reported for the non-enzymatic approach. The nanoneedles were grown through a simple and low-temperature aqueous chemical method. We characterized the structural and morphological properties of the NiCo 2 O 4 nanoneedles by TEM, SEM, XPS and XRD. The bimetallic nickel cobalt oxide exhibits nanoneedle morphology, which results from the self-assembly of nanoparticles. The NiCo 2 O 4 nanoneedles are exclusively composed of Ni, Co, and O and exhibit a cubic crystalline phase. Cyclic voltammetry was used to study the enhanced electrochemical properties of a NiCo 2 O 4 nanoneedle-modified GCE by overcoming the typical poor conductivity of bare NiO and Co 3 O 4 . The GCE-modified electrode is highly sensitive towards urea, with a linear response (R 2 = 0.99) over the concentration range 0.01-5 mM and with a detection limit of 1.0 μM. The proposed non-enzymatic urea sensor is highly selective even in the presence of common interferents such as glucose, uric acid, and ascorbic acid. This new urea sensor has good viability for urea analysis in urine samples and can represent a significant advancement in the field, owing to the simple and cost-effective fabrication of electrodes, which can be used as a promising analytical tool for urea estimation.

  • 15.
    Amin, Sidra
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.Department of Chemistry, Shaheed Benazir Bhutto University, Shaheed Benazirabad, Pakistan.
    Tahira, Aneela
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Solangi, Amber
    National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.
    Beni, Valerio
    RISE Acreo, Research Institute of Sweden, Norrköping, Sweden.
    Morante, J.R
    Catalonia Institute for Energy Research (IREC), Barcelona, Spain.
    Liu, Xianjie
    Department of Physics, Chemistry and Biology, Surface Physics and Chemistry, Linköping University, Faculty of Science & Engineering, Sweden.
    Falhman, Mats
    Department of Physics, Chemistry and Biology, Surface Physics and Chemistry, Linköping University, Faculty of Science & Engineering, Sweden.
    Mazzaro, Raffaello
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Ibupoto, Zafar
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Institute of Chemistry, University of Sindh, Jamshoro, Pakistan.
    Vomiero, Alberto
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    A practical non-enzymatic urea sensor based on NiCo2O4 nanoneedles2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 25, p. 14443-14451Article in journal (Refereed)
    Abstract [en]

    We propose a new facile electrochemical sensing platform for determination of urea, based on a glassy carbon electrode (GCE) modified with nickel cobalt oxide (NiCo2O4) nanoneedles. These nanoneedles are used for the first time for highly sensitive determination of urea with the lowest detection limit (1 μM) ever reported for the non-enzymatic approach. The nanoneedles were grown through a simple and low-temperature aqueous chemical method. We characterized the structural and morphological properties of the NiCo2O4 nanoneedles by TEM, SEM, XPS and XRD. The bimetallic nickel cobalt oxide exhibits nanoneedle morphology, which results from the self-assembly of nanoparticles. The NiCo2O4 nanoneedles are exclusively composed of Ni, Co, and O and exhibit a cubic crystalline phase. Cyclic voltammetry was used to study the enhanced electrochemical properties of a NiCo2O4 nanoneedle-modified GCE by overcoming the typical poor conductivity of bare NiO and Co3O4. The GCE-modified electrode is highly sensitive towards urea, with a linear response (R2 = 0.99) over the concentration range 0.01–5 mM and with a detection limit of 1.0 μM. The proposed non-enzymatic urea sensor is highly selective even in the presence of common interferents such as glucose, uric acid, and ascorbic acid. This new urea sensor has good viability for urea analysis in urine samples and can represent a significant advancement in the field, owing to the simple and cost-effective fabrication of electrodes, which can be used as a promising analytical tool for urea estimation.

  • 16.
    Andersson, Richard
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Cabedo, L.
    Hedenqvist, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Olsson, Richard
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Ström, Valter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Superparamagnetic [sic] nanofibers by electrospinning2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 26, p. 21413-21422Article in journal (Refereed)
    Abstract [en]

    The preparation of superparamagnetic thin fibers by electrospinning dispersions of nanosized magnetite (Fe3O4, SPIO/USPIO) in a PMMA/PEO polymer solution is reported. The saturation magnetization and coercivity were not affected by the concentration (0, 1, 10, 20 wt%) or fiber orientation, showing hysteresis loops with high magnetization (64 A m(2) kg(-1) @ 500 kA m(-1)) and record low coercivity (20 A m(-1)). AC susceptibility measurements vs. temperature at frequencies from 60 to 2 kHz confirmed superparamagnetism. The mechanical properties were only slightly dependent on the particle concentration because the nanoparticles were separately encapsulated by the polymer. A uniform fibre fracture cross section was found at all the investigated particle contents, which suggests a strong interaction at the polymer/particle interface. A theoretical value of the magnetic low field susceptibility was calculated from the Langevin function and compared with measured values. The results show a distinct but concentration-independent anisotropy, favoring magnetization along the fiber orientation with no sign of exchange interaction, explained by complete nanoparticle separation. Superparamagnetism cannot be inferred from particle size alone, so a relevant interpretation and criterion for superparamagnetism is presented, in accordance with Neel's original definition. From the measurements, it can be concluded that magnetic characterization can be used to elucidate the material morphology beyond the resolution of available microscopy techniques (TEM and SEM).

  • 17.
    Arain, Munazza
    et al.
    University of Sindh, Pakistan.
    Nafady, Ayman
    King Saud University, Saudi Arabia; Sohag University, Egypt.
    Sirajuddin,
    Univ Sindh, Pakistan.
    Ibupoto, ZH
    Univ Sindh, Pakistan.
    Sherazi, Syed Tufail Hussain
    University of Sindh, Pakistan.
    Shaikh, Tayyaba
    University of Sindh, Pakistan.
    Khan, Hamayun
    Islamia Coll University, Pakistan.
    Alsalme, Ali
    King Saud University, Saudi Arabia.
    Niaz, Abdul
    Bannu University of Science and Technology, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Simpler and highly sensitive enzyme-free sensing of urea via NiO nanostructures modified electrode2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 45, p. 39001-39006Article in journal (Refereed)
    Abstract [en]

    In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid as doping agent in the presence of ammonia. As prepared nanostructures were characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) specific surface area analysis, and thermogravimetric analysis (TGA). These analyses showed that these nanostructures are in the form of cotton-like porous material and crystalline in nature. Furthermore, the average size of these NiO crystallites was estimated to be 3.8 nm. These nanostructures were investigated for their potential to be a highly sensitive and selective enzyme-free sensor for detection of urea after immobilizing on a glassy carbon electrode (GCE) using 0.1% Nafion as binder. The response of this as developed amperometric sensor was linear in the range of 100-1100 mu M urea with a R-2 value of 0.990 and limit of detection (LOD) of 10 mu M. The sensor responded negligibly to various interfering species including glucose, uric acid, and ascorbic acid. This sensor was applied successfully for determining urea in real water samples such as mineral water, tap water, and river water with acceptable recovery.

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  • 18.
    Arrhenius, Karine
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Fischer, Andreas
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Büker, Oliver
    RISE Research Institutes of Sweden, Safety and Transport, Measurement Technology.
    Adrien, Herve
    INERIS Parc Alata, France.
    El Masri, Ahmad
    INERIS Parc Alata, France.
    Lestremau, Francois
    INERIS Parc Alata, France.
    Robinson, Tim
    Waverton Analytics Ltd, UK.
    Analytical methods for the determination of oil carryover from CNG/biomethane refueling stations recovered in a solvent2020In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 10, no 20, p. 11907-11917Article in journal (Refereed)
    Abstract [en]

    Vehicle gas is often compressed to about 200 bar at the refueling station prior to charging to the vehicle's tank. If a high amount of oil is carried over to the gas, it may cause damage to the vehicles; it is therefore necessary to accurately measure oil carryover. In this paper, three analytical methods for accurate quantification of the oil content are presented whereby two methods are based on gas chromatography and one on FTIR. To better evaluate the level of complexity of the matrix, 10 different compressor oils in use at different refueling stations were initially collected and analysed with GC and FTIR to identify their analytical traces. The GC traces could be divided into three different profiles: oils exhibiting some well resolved peaks, oils exhibiting globally unresolved peaks with some dominant peaks on top of the hump and oils exhibiting globally unresolved peaks. After selection of three oils; one oil from each type, the three methods were evaluated with regards to the detection and quantification limits, the working range, precision, trueness and robustness. The evaluation of the three measurement methods demonstrated that any of these three methods presented were suitable for the quantification of compressor oil for samples. The FTIR method and the GC/MS method both resulted in measurement uncertainties close to 20% rel. while the GC/FID method resulted in a higher measurement uncertainty (U = 30% rel.).

  • 19.
    Assarsson, A.
    et al.
    Lund University.
    Nasir, I.
    Lund University.
    Lundqvist, M.
    Lund University.
    Cabaleiro-Lago, Celia
    Lund Univeristy.
    Kinetic and thermodynamic study of the interactions between human carbonic anhydrase variants and polystyrene nanoparticles of different size2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 42, p. 35868-35874Article in journal (Refereed)
    Abstract [en]

    The activity and adsorption of three variants of human carbonic anhydrase (HCA) with similar topology but variation in charge and stability were studied in the presence of carboxyl-modified polystyrene nanoparticles of different sizes ranging from 25 nm to 114 nm. The balance of forces driving the adsorption of carbonic anhydrase variants is affected by the physicochemical properties of the protein and the nanoparticle size. All enzymes are totally inhibited upon adsorption due to the transition towards a molten globule like state that lacks enzymatic activity. The size of the particle affects the adsorption of human carbonic anhydrase I and N-terminal truncated human carbonic anhydrase II. Investigations on pH effects indicate that the size of the particle modulates the lateral interactions at the protein layer for these particular variants whose adsorption is mainly driven by electrostatic forces. A third variant, human carbonic anhydrase II, instead shows no strong influence of nanoparticle size which supports an adsorption process mainly driven by the hydrophobic effect.

  • 20.
    Attard, Thohmas. M.
    et al.
    University of York, UK.
    Theeuwes, Elke
    Ecover Co-ordination Center NV, Belgium.
    Gomez, Leonardo D.
    University of York, UK.
    Johansson, Emma
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Processum.
    Dimitriou, Ioanna
    University of Sheffield, UK.
    Wright, Phillip C.
    University of Sheffield, UK.
    Clark, James H.
    University of Sheffield, UK.
    McQueen-Mason, Simon J.
    University of York, UK.
    Hunt, Andrew J.
    University of York, UK.
    Supercritical extraction as an effective first-step in a maize stover biorefinery2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 54, p. 43831-43838Article in journal (Refereed)
    Abstract [en]

    Supercritical carbon dioxide (scCO<inf>2</inf>) has been investigated for the generation of valuable waxy compounds and as an added-value technology in a holistic maize stover biorefinery. ScCO<inf>2</inf> extraction and fractionation was carried out prior to hydrolysis and fermentation of maize stover. Fractionation of the crude extracts by scCO<inf>2</inf> resulted in wax extracts having different compositions and melting temperatures, enabling their utilisation in different applications. One such fraction demonstrated significant potential as a renewable defoaming agent in washing machine detergent formulations. Furthermore, scCO<inf>2</inf> extraction has been shown to have a positive effect on the downstream processing of the maize stover. Fermentation of the scCO<inf>2</inf> extracted maize stover hydrolysates exhibited a higher glucose consumption and greater potential growth for surfactant (in comparison with non-scCO<inf>2</inf> treated stover) axnd ethanol production (a 40% increase in overall ethanol production after scCO<inf>2</inf> pre-treatment). This work represents an important development in the extraction of high value components from low value wastes and demonstrates the benefits of using scCO<inf>2</inf> extraction as a first-step in biomass processing, including enhancing downstream processing of the biomass for the production of 2nd generation biofuels as part of an integrated holistic biorefinery.

  • 21.
    Bai, Sai
    et al.
    Zhejiang University, Peoples R China.
    He, Shasha
    Zhejiang University, Peoples R China.
    Jin, Yizheng
    Zhejiang University, Peoples R China.
    Wu, Zhongwei
    Soochow University, Peoples R China.
    Xia, Zhouhui
    Soochow University, Peoples R China.
    Sun, Baoquan
    Soochow University, Peoples R China.
    Wang, Xin
    Zhejiang University, Peoples R China.
    Ye, Zhizhen
    Zhejiang University, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Shao, Shuyan
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Electrophoretic deposited oxide thin films as charge transporting interlayers for solution-processed optoelectronic devices: the case of ZnO nanocrystals2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 11, p. 8216-8222Article in journal (Refereed)
    Abstract [en]

    A promising fabrication method of electron transporting interlayers for solution-processed optoelectronic devices by electrophoretic deposition (EPD) of colloidal zinc oxide (ZnO) nanocrystals was demonstrated. A low voltage of 3-5 V and a short deposition time of 40 s at room temperature were found to be sufficient to generate dense and uniform ZnO thin films. The EPD ZnO nanocrystal films were applied as ETLs for inverted organic solar cell and polymer light emitting diodes (PLEDs). By optimizing the EPD processing of ZnO nanocrystal electron transporting layers (ETLs), inverted organic solar cells based on [3,4-b]-thiophene/benzodithiophene (PTB7): [6-6]-phenyl-C71-butyric acid methyl ester (PC71BM) and poly(3-hexylthiophene) (P3HT): [6-6]-phenyl-C-61-butyric acid methyl ester (PC61BM) with an average PCE of 8.4% and 4.0% were fabricated. In combination with the PLEDs and flexible devices results, we conclude that the EPD processed ZnOnanocrystal thin films can serve as high quality ETLs for solution-processed optoelectronic devices.

  • 22. Banerjee, Chandrima
    et al.
    Pal, Semanti
    Ahlberg, Martina
    Nguyen, T. N. Anh
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Vietnam Acad Sci & Technol, Vietnam.
    Åkerman, Johan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Univ Gothenburg, Sweden.
    Barman, Anjan
    All-optical study of tunable ultrafast spin dynamics in [Co/Pd]/NiFe systems: the role of spin-twist structure on Gilbert damping2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 83, p. 80168-80173Article in journal (Refereed)
    Abstract [en]

    We investigate optically induced ultrafast magnetization dynamics in [Co(0.5 nm)/Pd(1 nm)](5)/NiFe(t) exchange-spring samples with tilted perpendicular magnetic anisotropy using a time-resolved magneto-optical Kerr effect magnetometer. The competition between the out-of-plane anisotropy of the hard layer, the in-plane anisotropy of the soft layer and the applied bias field reorganizes the spins in the soft layer, which are modified further with the variation in t. The spin-wave spectrum, the ultrafast demagnetization time, and the extracted damping coefficients - all depend on the spin distribution in the soft layer, while the latter two also depend on the spin-orbit coupling between the Co and Pd layers. The spin-wave spectra change from multimode to single-mode as t decreases. At the maximum field reached in this study, H = 2.5 kOe, the damping shows a nonmonotonic dependence on t with a minimum at t = 7.5 nm. For t < 7.5 nm, intrinsic effects dominate, whereas for t > 7.5 nm, extrinsic effects govern the damping mechanisms.

  • 23.
    Banerjee, Indradumna
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Salih, Tagrid
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Ramachandraiah, Harisha
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Erlandsson, Johan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Araújo, A. C.
    Karlsson, M.
    Russom, Aman
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Slipdisc: A versatile sample preparation platform for point of care diagnostics2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 56, p. 35048-35054Article in journal (Refereed)
    Abstract [en]

    We report a microfluidic sample preparation platform called "Slipdisc" based on slipchip technology. Slipdisc is a rotational slipchip that uses a unique hand-wound clockwork mechanism for precise movement of specially fabricated polycarbonate discs. In operation, the microchannels and microchambers carved on the closely aligned microfluidic discs convert from continuous filled paths to defined compartments using the slip movement. The clockwork mechanism introduced here is characterised by a food dye experiment and a conventional HRP TMB reaction before measuring lactate dehydrogenase (LDH) enzyme levels, which is a crucial biomarker for neonatal diagnostics. The colorimetry based detection of LDH was performed with an unmodified camera and an image analysis procedure based on normalising images and observing changes in red channel intensity. The analysis showed a close to unity coefficient of determination (R2 = 0.96) in detecting the LDH concentration when compared with a standard Chemical Analyser, demonstrating the excellent performance of the slipdisc platform with colorimetric detection. The versatile point of care sample preparation platform should ideally be suited for a multitude of applications at resource-limited settings.

  • 24. Barman, Jharna
    et al.
    Gurav, Deepanjali
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Oommen, Oommen Podiyan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Varghese, Oommen P.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    2 '-N-Guanidino, 4 '-C-ethylene bridged thymidine (GENA-T) modified oligonucleotide exhibits triplex formation with excellent enzymatic stability2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 16, p. 12257-12260Article in journal (Refereed)
    Abstract [en]

    Here we present the synthesis and characterization of a new 2'-N-Guanidino, 4'-C-ethylene bridged thymidine (GENA-T) modified oligonucleotide possessing North-locked sugar conformation. Incorporation of GENA-T nucleotide though did not change the thermal stability of the oligonucleotides toward the complementary RNA; it significantly increased the stability of the parallel triplex at pH 7. The melting temperature of the triplex was increased by +9.5 degrees C as compared to that of the isosequential unmodified sequence. Moreover this modification imparted exceptional nuclease stability to the oligonucleotides for over 33 h. This study clearly demonstrates that GENA-T modified oligonucleotides could improve triplex formation with phenomenal enzymatic stability and could be used for various biomedical applications.

  • 25. Bassyouni, Fatma A.
    et al.
    Abu-Baker, Sherifa M.
    Mahmoud, Khaled
    Moharam, Maysa
    El-Nakkady, Sally S.
    Rehim, Mohamed Abdel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Synthesis and biological evaluation of some new triazolo[1,5-a]quinoline derivatives as anticancer and antimicrobial agents2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 46, p. 24131-24141Article in journal (Refereed)
    Abstract [en]

    In the present study, versatile multifunctional unreported triazolo[1,5-a]quinoline derivatives were prepared. Compounds 1-19 were synthesized by adopting appropriate synthetic routes and were pharmacologically evaluated for their in vitro anticancer activity against human cancer cell lines: hepatocellular liver carcinoma (HEPG2) and Caucasian breast adenocarcinoma (MCF-7), in addition to their antibacterial and antifungal activities. Compound 4 demonstrated strong inhibitory effects against breast cancer (MCF-7), whereas compounds 8 and 19 exhibited moderate activity against breast carcinoma cell line MCF-7. Compounds 16 and 19 gave moderate activity against liver carcinoma cell line HEPG2. The antimicrobial activity of the prepared compounds was tested against bacteria and fungi. Among them, the results of antimicrobial activity indicated that compounds 4, 9, 11, 13, 15, 17, 18 and 19 were the most active compounds. Compound 4 exhibited strong activity against Fusarium sp., whereas compounds 9, 11, 15, 17, 18 and 19 showed high activity against Escherichia coli. More specifically, compound 17 displayed a high inhibitory effect against Bacillus cereus, Escherichia coli and Rhizoctonia sp.

  • 26.
    Behera, Nilamani
    et al.
    Indian Inst Technol Delhi, Dept Phys, Thin Film Lab, New Delhi 110016, India..
    Kumar, Ankit
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Indian Inst Technol Delhi, Dept Phys, Thin Film Lab, New Delhi 110016, India..
    Chaudhary, Sujeet
    Indian Inst Technol Delhi, Dept Phys, Thin Film Lab, New Delhi 110016, India..
    Pandya, Dinesh K.
    Indian Inst Technol Delhi, Dept Phys, Thin Film Lab, New Delhi 110016, India..
    Two magnon scattering and anti-damping behavior in a two-dimensional epitaxial TiN/Py(t(Py))/beta-Ta(t(Ta)) system2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 14, p. 8106-8117Article in journal (Refereed)
    Abstract [en]

    The prime requirements for the spin transfer torque based ferromagnetic (FM)/nonmagnetic (NM) bilayer spin devices are (i) the absence of two-magnon scattering (TMS) noise, (ii) minimum energy dissipation and (iii) fast switching. To realize these objectives we have studied the thickness, Py (permalloy) thicknesses (t(Py)) and beta-Ta thicknesses (t(Ta)), dependent magnetization dynamics behaviour of the epitaxial Py (t(Py) = 3-20 nm)/beta-Ta (t(Ta) = 1.5-15 nm) system. The t(Py) dependence of TMS in epitaxial Py nanolayers (t(Py) = 3-20 nm) grown on a Si(400)/TiN(200) (8 nm) substrate is explored in terms of uniform and non-uniform magnetization precession regimes by employing ferromagnetic resonance field (H-r), linewidth (Delta H), and Gilbert damping constant (alpha) behaviour. It is found that in Py, t(Py) < 10 nm, layers TMS is dominating due to non-uniform precession of the magnetization. However in Py, t(Py) >= 10 nm, layers the uniform magnetization precession dominates, therefore Py layers, t(Py) >= 10 nm, are almost free from TMS. Furthermore, a nearly TMS free 12 nm epitaxial Py(200) layer is capped with beta-Ta (t(Ta) = 1.5-15 nm) layers to explore the t(Ta) dependent magnetization precession of epitaxial Py (12 nm) in terms of change in effective Gilbert damping constant (alpha(eff)). An anomalous decrease in alpha(eff) from 0.0087 at t(Ta) = 0 to a minimum value of 0.0077 at t(Ta) = 6 nm, and its subsequent increase for t(Ta) > 6 nm are observed in the epitaxial Py (12 nm)/beta-Ta(t(Ta)) system. Therefore the Si(400)/TiN(200) (8 nm)/Py(200) (12 nm)/beta-Ta(200) (6 nm) epitaxial system with nearly uniform magnetic precession and minimum effective Gilbert damping is suitable for low energy loss and ultrafast switching applications in spin transfer torque devices.

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  • 27.
    Bergfelt, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    Lacey, Matthew J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Hedman, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Sångeland, Christofer
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Bowden, Tim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Polymer Chemistry.
    ε-Caprolactone-based solid polymer electrolytes for lithium-ion batteries: synthesis, electrochemical characterization and mechanical stabilization by block copolymerization2018In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, no 30, p. 16716-16725Article in journal (Refereed)
    Abstract [en]

    In this work, three types of polymers based on epsilon-caprolactone have been synthesized: poly(epsilon-caprolactone), polystyrene-poly(epsilon-caprolactone), and polystyrene-poly(epsilon-caprolactone-r-trimethylene carbonate) (SCT), where the polystyrene block was introduced to improve the electrochemical and mechanical performance of the material. Solid polymer electrolytes (SPEs) were produced by blending the polymers with 10-40 wt% lithium bis(trifluoromethane) sulfonimide (LiTFSI). Battery devices were thereafter constructed to evaluate the cycling performance. The best performing battery half-cell utilized an SPE consisting of SCT and 17 wt% LiTFSI as both binder and electrolyte; a Li vertical bar SPE vertical bar LiFePO4 cell that cycled at 40 degrees C gave a discharge capacity of about 140 mA h g(-1) at C/5 for 100 cycles, which was superior to the other investigated electrolytes. Dynamic mechanical analysis (DMA) showed that the storage modulus E' was about 5 MPa for this electrolyte.

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  • 28.
    Berglund, Linn
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Forsberg, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Jonoobi, Mehdi
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Wood and Paper Science and Technology, Faculty of Natural Resources, University of Tehran, Karaj, Iran.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Fibre and Particle Engineering, University of Oulu, Oulu, Finland.
    Promoted hydrogel formation of lignin-containing arabinoxylan aerogel using cellulose nanofibers as a functional biomaterial2018In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, no 67, p. 38219-38228Article in journal (Refereed)
    Abstract [en]

    In this work, three-dimensional (3D) aerogels and hydrogels based on lignin-containing arabinoxylan (AX) and cellulose nanofibers (CNF) were prepared. The effects of the CNF and the crosslinking with citric acid (CA) of various contents (1, 3, 5 wt%) were evaluated. All the aerogels possessed highly porous (above 98%) and lightweight structures. The AX-CNF hydrogel with a CA content of 1 wt% revealed a favorable network structure with respect to the swelling ratio; nanofiber addition resulted in a five-fold increase in the degree of swelling (68 g of water per g). The compressive properties were improved when the higher CA content (5 wt%) was used; when combined with CNF, there was a seven-fold enhancement in the compressive strength. The AX-CNF hydrogels were prepared using a green and straightforward method that utilizes sustainable resources efficiently. Therefore, such natural hydrogels could find application potential, for example in the field of soft tissue engineering.

  • 29.
    Bermejo Gómez, Antonio
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Holmberg, Pär
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martin-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Transition metal-catalyzed redox isomerization of codeine and morphine in water2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 74, p. 39519-39522Article in journal (Refereed)
    Abstract [en]

    A water-soluble rhodium complex formed from commercially available [Rh(COD)(CH3CN)(2)]BF4 and 1,3,5-triaza-7-phosphaadamantane (PTA) catalyzes the isomerization of both codeine and morphine into hydrocodone and hydromorphone with very high efficiency. The reaction is performed in water, allowing isolation of the final products by simple filtration, which results in very high isolated yields. The reactions can be easily scaled up to 100 g.

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  • 30.
    Bhattacharyya, Shubhankar
    et al.
    Synthetic Chemistry Division, Defense R and D Establishment.
    Hatua, Kaushik
    Department of Chemistry, Bengal Engineering and Science University.
    Computational insight of the mechanism of Algar-Flynn-Oyamada (AFO) reaction2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 36, p. 18702-18709Article in journal (Refereed)
    Abstract [en]

    The present DFT investigation supports a previous conclusion of Dean et al. that hydroxylation occurs without epoxide intermediate at room temperature due to a strong electrostatic interaction of peroxide ions with π electrons of CC bonds of chalcone, and 3-hydroxyflavone has been found to be the major product. The calculated activation energy difference (ΔG#) of initial enolization followed by hydroxylation or simultaneous cyclization and hydroxylation has been found to be negligible (∼4 kcal mol-1). On the other hand, epoxide formation requires significant activation energy, which is supposed to occur at high temperatures. In addition, if epoxide is formed, the ring opens by an attack of phenolic oxygen, occurring preferentially at α position via a five-member transition state due to a low activation barrier height (19.82 kcal mol-1 in the gas phase and 19.55 kcal mol-1 in ethanol) compared to that of a six-member transition state (44.41 kcal mol-1 at B3LYP in the gas phase and 38.55 kcal mol -1 in ethanol). It is also observed that the solvation study does not affect the main conclusion of the paper. These findings also support the previous observation of Dean et al. Predicted ΔG# in different DFT functionals are consistent, although the total energy is significantly different

  • 31.
    Bhattacharyya, Shubhankar
    et al.
    Synthetic Chemistry Division, Defence R and D Establishment.
    Pathak, Uma
    Synthetic Chemistry Division, Defence R and D Establishment.
    Mathur, Sweta
    Synthetic Chemistry Division, Defence R and D Establishment.
    Vishnoi, Subodh
    Synthetic Chemistry Division, Defence R and D Establishment.
    Jain, Rajeev
    School of Studies in Chemistry, Jiwaji University.
    Selective N-alkylation of primary amines with R-NH2·HBr and alkyl bromides using a competitive deprotonation/protonation strategy2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 35, p. 18229-18233Article in journal (Refereed)
    Abstract [en]

    Monoalkylation of primary amines using amine hydrobromides and alkyl bromides has been carried out. Under controlled reaction conditions the reactant primary amine was selectively deprotonated and made available for reaction, while the newly generated secondary amine remained protonated, and did not participate in alkylation further. Reaction was carried out under mild reaction conditions and was applicable to a wide range of primary amines and alkyl bromides.

  • 32.
    Bhatti, Adeel Liaquat
    et al.
    Univ Sindh, Pakistan.
    Aftab, Umair
    Mehran Univ Engn and Technol, Pakistan.
    Tahira, Aneela
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Abro, Muhammad Ishaq
    Mehran Univ Engn and Technol, Pakistan.
    Samoon, Muhammad Kashif
    Ctr Pure and Appl Geol Univ Sindh, Pakistan.
    Aghem, Muhammad Hassan
    Ctr Pure and Appl Geol Univ Sindh, Pakistan.
    Bhatti, Muhamad Ali
    Ctr Environm Sci, Pakistan.
    HussainIbupoto, Zafar
    Univ Sindh, Pakistan.
    Facile doping of nickel into Co3O4 nanostructures to make them efficient for catalyzing the oxygen evolution reaction2020In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, RSC ADVANCES, Vol. 10, no 22, p. 12962-12969Article in journal (Refereed)
    Abstract [en]

    Designing a facile and low-cost methodology to fabricate earth-abundant catalysts is very much needed for a wide range of applications. Herein, a simple and straightforward approach was developed to tune the electronic properties of cobalt oxide nanostructures by doping them with nickel and then using them to catalyze the oxygen evolution reaction (OER) in an aqueous solution of 1.0 M KOH. The addition of a nickel impurity improved the conductivity of the cobalt oxide, and further increased its activity towards the OER. Analytical techniques such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and powder X-ray diffraction (XRD) were used to investigate, respectively, the morphology, composition and crystalline structure of the materials used. The nickel-doped cobalt oxide material showed randomly oriented nanowires and a high density of nanoparticles, exhibited the cubic phase, and contained cobalt, nickel and oxygen as its main elements. The nickel-doped cobalt oxide also yielded a Tafel slope of 82 mV dec(-1) and required an overpotential of 300 mV to reach a current density of 10 mA cm(-2). As an OER catalyst, it was shown to be durable for 40 h. Electrochemical impedance spectroscopy (EIS) analysis showed a low charge-transfer resistance of 177.5 ohms for the nickel-doped cobalt oxide, which provided a further example of its excellent OER performance. These results taken together indicated that nickel doping of cobalt oxide can be accomplished via a facile approach and that the product of this doping can be used for energy and environmental applications.

  • 33.
    Bi, Dongqin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Moon, Soo-Jin
    Häggman, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Yang, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Erik M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Nazeeruddin, Mohammad K.
    Graetzel, Michael
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Using a two-step deposition technique to prepare perovskite (CH3NH3PbI3) for thin film solar cells based on ZrO2 and TiO2 mesostructures2013In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, no 41, p. 18762-18766Article in journal (Refereed)
    Abstract [en]

    A two-step deposition technique is used for preparing CH3NH3PbI3 perovskite solar cells. Using ZrO2 and TiO2 as a mesoporous layer, we obtain an efficiency of 10.8% and 9.5%, respectively, under 1000 W m(-2) illumination. The ZrO2 based solar cell shows higher photovoltage and longer electron lifetime than the TiO2 based solar cell.

  • 34.
    Biundo, Antonino
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science. KTH, Centres, Science for Life Laboratory, SciLifeLab. ACIB, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria.
    Subagia, Raditya
    Univ Nat Resources & Life Sci BOKU, Inst Environm Biotechnol, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria..
    Maurer, Michael
    Univ Appl Sci, Dept Bioengn, Mauerbachstr 43, A-1140 Vienna, Austria..
    Ribitsch, Doris
    ACIB, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria.;Univ Nat Resources & Life Sci BOKU, Inst Environm Biotechnol, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria..
    Syrén, Per-Olof
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Guebitz, Georg M.
    ACIB, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria.;Univ Nat Resources & Life Sci BOKU, Inst Environm Biotechnol, Konrad Lorenz Str 20, A-3430 Tulln An Der Donau, Austria..
    Switched reaction specificity in polyesterases towards amide bond hydrolysis by enzyme engineering2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 62, p. 36217-36226Article in journal (Refereed)
    Abstract [en]

    The recalcitrance of plastics like nylon and other polyamides contributes to environmental problems (e.g. microplastics in oceans) and restricts possibilities for recycling. The fact that hitherto discovered amidases (EC 3.5.1. and 3.5.2.) only show no, or low, activity on polyamides currently obstructs biotechnological-assisted depolymerization of man-made materials. In this work, we capitalized on enzyme engineering to enhance the promiscuous amidase activity of polyesterases. Through enzyme design we created a reallocated water network adapted for hydrogen bond formation to synthetic amide backbones for enhanced transition state stabilization in the polyester-hydrolyzing biocatalysts Humicola insolens cutinase and Thermobifida cellulosilytica cutinase 1. This novel concept enabled increased catalytic efficiency towards amide-containing soluble substrates. The afforded enhanced hydrolysis of the amide bond-containing insoluble substrate 3PA 6,6 by designed variants was aligned with improved transition state stabilization identified by molecular dynamics (MD) simulations. Furthermore, the presence of a favorable water-molecule network that interacted with synthetic amides in the variants resulted in a reduced activity on polyethylene terephthalate (PET). Our data demonstrate the potential of using enzyme engineering to improve the amidase activity for polyesterases to act on synthetic amide-containing polymers.

  • 35.
    Björk, Emma
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering. Univ Ulm, Germany.
    Baumann, Bernhard
    Univ Ulm, Germany.
    Hausladen, Florian
    Ulm Univ, Germany.
    Wittig, Rainer
    Ulm Univ, Germany.
    Linden, Mika
    Univ Ulm, Germany.
    Cell adherence and drug delivery from particle based mesoporous silica films2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 31, p. 17745-17753Article in journal (Refereed)
    Abstract [en]

    Spatially and temporally controlled drug delivery is important for implant and tissue engineering applications, as the efficacy and bioavailability of the drug can be enhanced, and can also allow for drugging stem cells at different stages of development. Long-term drug delivery over weeks to months is however difficult to achieve, and coating of 3D surfaces or creating patterned surfaces is a challenge using coating techniques like spin- and dip-coating. In this study, mesoporous films consisting of SBA-15 particles grown onto silicon wafers using wet processing were evaluated as a scaffold for drug delivery. Films with various particle sizes (100-900 nm) and hence thicknesses were grown onto trichloro(octadecyl)silane-functionalized silicon wafers using a direct growth method. Precise patterning of the areas for film growth could be obtained by local removal of the OTS functionalization through laser ablation. The films were incubated with the drug model 3,3 -dioctadecyloxacarbocyanine perchlorate (DiO), and murine myoblast cells (C2C12 cells) were seeded onto films with different particle sizes. Confocal laser scanning microscopy (CLSM) was used to study the cell growth, and a vinculin-mediated adherence of C2C12 cells on all films was verified. The successful loading of DiO into the films was confirmed by UV-vis and CLSM. It was observed that the drugs did not desorb from the particles during 24 hours in cell culture. During adherent growth on the films for 4 h, small amounts of DiO and separate particles were observed inside single cells. After 24 h, a larger number of particles and a strong DiO signal were recorded in the cells, indicating a particle mediated drug uptake. The vast majority of the DiO-loaded particles remained attached to the substrate also after 24 h of incubation, making the films attractive as longer-term reservoirs for drugs on e.g. medical implants.

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  • 36. Bodvik, Rasmus
    et al.
    Thormann, Esben
    Karlsson, Leif
    Claesson, Per M
    YKI – Ytkemiska institutet.
    Temperature-dependent adsorption of cellulose ethers on silica and hydrophobized silica immersed in aqueous polymer solution2011In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 1, no 2, p. 305-314Article in journal (Refereed)
    Abstract [en]

    The influence of temperature on adsorption and the adsorbed layer properties of methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) were investigated on silica and hydrophobized silica surfaces immersed in aqueous polymer solution. To achieve a concise understanding a quartz crystal microbalance with dissipation, ellipsometry, and atomic force microscopy imaging were employed. These techniques provide complimentary information on the structure, mass and viscoelastic properties of the polymer layers. Adsorption was first allowed at 25 degrees C. Next, the temperature was increased step-wise up to 50 degrees C and then decreased again. This procedure highlights the temperature dependence of the adsorbed material, as well as the hysteresis in the adsorption due to temperature cycling. A change in temperature not only affects the adsorbed amount, but also the properties of the layer as illustrated by measurements of its water content, thickness and viscoelasticity.

  • 37.
    Bondarchuk, Sergey V.
    et al.
    Bogdan Khmelnitsky Cherkasy National University, Ukraine.
    Minaev, Boris F.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bogdan Khmelnitsky Cherkasy National University, Ukraine.
    Thermally accessible triplet state of pi-nucleophiles does exist. Evidence from first principles study of ethylene interaction with copper species2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 15, p. 11558-11569Article in journal (Refereed)
    Abstract [en]

    Three different models of ethylene interaction with copper species, namely, the Cu(100) surface, odd-numbered copper clusters C2H4/Cu-n (where n = 3, 7, 11, 15, 17, 19, 21, 25 and 27) and atomic copper C2H4/Cu were studied theoretically. It was found that the ethylene molecule possesses three different types of bonding depending on the presence of the unpaired spin on the reacting copper atom. These bonding structures demonstrate different types of band gap (bulk) or SOMO-LUMO gaps (cluster/atom), where SOMO stands for the singly occupied and LUMO means the lowest unoccupied molecular orbitals of the copper species. The obtained results are in good agreement with the previous experimental and computational results on the structural, spectral and energetic properties of the studied species. The bulk copper and sub-nanosized clusters (n > 7) build up the mono-pi-bonded ground state complexes with ethylene where the latter species possesses the C-2v symmetry. The single-atom complex C2H4/Cu forms the CS-symmetrical ground state (X) over tilde (2)A' and the excited B-2(2) and B-4 state complexes of the C-2v and C-2 symmetry, respectively. The (X) over tilde (2)A' state complex is mono-sigma-bonded and involves the singlet ethylene moiety. The more tightly bound excited B-2(2) complex has the di-sigma-bonded structure and corresponds to the triplet ethylene. The adiabatic energy difference between the B-2(2) and (X) over tilde (2)A' states is equal to 10.8 kcal mol(-1) and can be ascribed to the singlet-triplet splitting of the ethylene moiety interacting with copper. The QTAIM analysis supports the coordination type of the Cu-C bonds in all the studied complexes. Formation of the C2H4/Cu(100), C2H4/Cu-n and C2H4/Cu species is in accord with the well-known Dewar-Chatt-Duncanson model, in such a way that the opposing sigma-donation step yields the ground state complex ((X) over tilde (2)A'), while the subsequent more expensive supporting pi*-back donation step provides the excited B-2(2) state complex. In the present paper we have developed a computational procedure to optimize the latter complex.

  • 38.
    Bruce, Carl
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Javakhishvili, Irakli
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Hvilsted, Søren
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Well-defined ABA- and BAB-type block copolymers of PDMAEMA and PCL2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 49, p. 25809-25818Article in journal (Refereed)
    Abstract [en]

    Triblock copolymers of ABA- and BAB-type consisting of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, A) and poly(epsilon-caprolactone) (PCL, B) have successfully been prepared. PDMAEMA-b-PCL-b-PDMAEMA (ABA) and PCL-b-PDMAEMA-b-PCL (BAB) were synthesised by a combination of ring-opening polymerisation of epsilon-CL, atom transfer radical polymerisation of DMAEMA and end-group conversion, performed through either acylation or azide-alkyne "click" chemistry. All samples were analysed by size exclusion chromatography where it was found that the evaluation of PDMAEMA-containing polymers was difficult due to the thermoresponsivity of PDMAEMA, affecting the solubility of the polymer in the temperature range at which the SEC was operated. From differential scanning calorimetry measurements it was shown that the crystallinity could be altered by changing the order of the blocks; with PDMAEMA as the outer block (ABA), the inherent crystallinity of PCL was destroyed while with PCL as the outer block (BAB), the degree of crystallinity was in the same proximity as for a PCL homopolymer.

  • 39.
    Bu, Junfu
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jönsson, Pär Göran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Zhao, Zhe
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The effect of NiO on the conductivity of BaZr0.5Ce0.3Y0.2O3-delta based electrolytes2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 67, p. 62368-62377Article in journal (Refereed)
    Abstract [en]

    The effects of NiO on the sintering behaviors, morphologies and conductivities of BaZr0.5Ce0.3Y0.2O3-delta (BZCY532) based electrolytes were systematically investigated. 1 wt% NiO powder was added by different methods during the sample preparation: (i) added during ball-milling before a powder mixture calcination (named BZCY(Ni) 532), (ii) no NiO addition in the whole preparation procedure (named BZCY532) and (iii) added after a powder mixture calcination (named BZCY532(Ni)). The conductivities of these three kinds of dense BZCY532 ceramics were investigated in dry air, wet N-2 and wet H-2 atmospheres, respectively. Moreover, the electronic contributions to the total conductivities were also identified in a broad oxygen partial pressure range. According to the achieved results, it can be concluded that the dense BZCY(Ni) 532 ceramics showed the best enhanced oxygen and proton conductivities, followed by the BZCY532(Ni) and BZCY532 ceramics. Furthermore, the BZCY(Ni) 532 and BZCY532 ceramics showed a tiny electronic conductivity, when the testing temperatures were lower than 800 degrees C. However, the BZCY532(Ni) ceramics revealed an obvious electronic conduction when they were tested at temperatures of 600-800 degrees C. Therefore, it is preferable to add the NiO during powder preparation, which can lower the sintering temperature and also increase the conductivity of BZCY532-based electrolytes.

  • 40.
    Cai, Yanling
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Zhang, Peng
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Welch, Ken
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Photocatalysis induces bioactivity of an organic polymer based material2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 101, p. 57715-57723Article in journal (Refereed)
    Abstract [en]

    Several materials, like bioglasses, sintered hydroxyapatite and Ti metals and alloys, have the ability to bond to living bone in vivo, which is a desirable property of biomaterials called bioactivity. In this work, we present a novel strategy to develop bioactivity on the non-bioactive surface of a resin-TiO2 nanocomposite through photocatalysis. The results show that UV irradiation (365 nm, 10 mW cm(-2)) for 8 to 16 h on the resin-TiO2 nanocomposite immersed in water induces bioactivity as indicated by hydroxyapatite growth following immersion of the samples in Dulbecco's phosphate buffered saline for 7 days at 37 degrees C. While a nonirradiated resin-TiO2 surface did not show any hydroxyapatite deposition, a surface after 16 h of UV irradiation was fully covered by hydroxyapatite. In vitro cell adhesion of osteoblast-like MG63 cells confirmed the biocompatibility and bioactivity of the resin-TiO2 surfaces with a hydroxyapatite deposition layer, while the non-irradiated resin-TiO2 surface showed no cell adhesion. Resin-TiO2 nanocomposites, with or without UV irradiation, proved to be nontoxic to two human cell lines, human dermal fibroblasts (hDF) and MG63 cells. It was also shown that an increased dose of UV irradiation decreased bacterial adhesion, which is an additional benefit of the UV treatment and a favourable property for biomedical applications. The combined benefits of biocompatibility, bioactivity, decreased bacterial adhesion and the highly efficient disinfection property of TiO2 photocatalysis under UV light make this resin-TiO2 material an interesting candidate for implant and biomedical device applications.

  • 41.
    Cai, Yixiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Chen, Song
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    McMaster Univ, Dept Mat Sci & Engn, Hamilton, ON, Canada..
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Fabrication of translucent nanoceramics via a simple filtration method2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 121, p. 99848-99855Article in journal (Refereed)
    Abstract [en]

    Generally, particle packing density, grain size and morphology are the important factors that affect the transparency of ceramics. In order to achieve better transparency of ceramics, efforts should be developed to eliminate or minimize light scattering or absorption. Therefore the porosity and size of crystals in a ceramic body should be strictly controlled. Typical transparent ceramics are fabricated by pressure-assisted sintering techniques such as hot isostatic pressing (HIP), spark plasma sintering (SPS), and pressure-less sintering (PLS). However, a simple energy efficient production method remains a challenge. In this study, we describe a simple fabrication process via a facile filtration system that can fabricate translucent hydroxyapatite based ceramics. The translucent pieces yielded from filtration exhibit optical transmittance that was confirmed by UV spectroscopy. Briefly, the morphology and size of ceramic nanoparticles, filtration pressure and filtration time are important parameters to be discussed. Compared with different hydroxyapatite nanoparticles, spherical nanoparticles easily form a densely packed structure, followed by sintered ceramics. When the strontium content in HA increases, the morphology of HA changes from nano-spheres to nano-rods, following a decrease in transparency. A pressure filtration model combining Darcy's law and the Kozeny-Carman relation has been discussed to simulate and explain why the translucent ceramics can be fabricated via such a simple process. This method could be further applied to prepare other translucent functional ceramics by controlling the size and morphology of ceramic particles.

  • 42.
    Cai, Yixiao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Li, Hu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Biomineralization on Single Crystalline Rutile: The Modulated Growth of Hydroxyapatite by Fibronectin in a Simulated Body Fluid2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, p. 35507-35516Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to probe the complex interaction between surface bioactivity and protein adsorption on single crystalline rutile. Our previous studies have shown that single crystalline rutile possessed in vitro bioactivity and the crystalline faces affected the hydroxyapatite (HA) formation. However, upon implantation, a fast adsorption of proteins, from the biological fluids, is intermediated by a water layer towards the biomaterial interface. Thus the effect of protein on the bioactivity must be addressed. In this study, the HA growth dynamics on (001), (100) and (110) faces was investigated in a simulated body fluid with the presence of fibronectin (FN) by two different processes. The surface adhesion of each face before and after FN adsorption, as revealed by direct numerical values, was determined by atomic force microscopy (AFM) based peak force quantitative nanomechanical mapping (PF-QNM) for the first time. The findings suggest the surface energies of FN pre-adsorbed (001), (100) and (110) faces have been enhanced, leading to the subsequent accelerated HA formation. Furthermore, (001) and (100) faces were found to have larger coverage of HA crystals than (110) face at an early stage. In addition, various characterizations were performed to probe the chemical and crystal structures of as-grown biomimetic HA crystals, and in particular, the Ca/P ratio variations at different soaking time points.

  • 43.
    Carboni, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Naylor, Andrew J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Unlocking high capacities of graphite anodes for potassium-ion batteries2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 36, p. 21070-21074Article in journal (Refereed)
    Abstract [en]

    Graphite is considered a promising candidate as the anode for potassium-ion batteries (KIBs). Here, we demonstrate a significant improvement in performance through the ball-milling of graphite. Electrochemical techniques show reversible K-intercalation into graphitic layers, with 65% capacity retention after 100 cycles from initial capacities and extended cycling beyond 200 cycles. Such an affinity of the graphite towards storage of K-ions is explained by means of SEM and Raman analyses. Graphite ball-milling results in a gentle mechanical exfoliation of the graphene layers and simultaneous defect formation, leading to enhanced electrochemical performance.

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  • 44.
    Carlsson, Daniel O.
    et al.
    Nanotechnology and Functional Materials, Department of Engineering Sciences, Box 534, Uppsala University, Uppsala University, Department of Engineering Science.
    Lindh, Jonas
    Nanotechnology and Functional Materials, Department of Engineering Sciences, Box 534, Uppsala University.
    Nyholm, Leif
    Uppsala University, Department of Chemistry, Angstrom Lab.
    Mattsson, Maria Stromme
    Uppsala University, Department of Engineering Science.
    Mihranyan, Albert
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Cooxidant-free TEMPO-mediated oxidation of highly crystalline nanocellulose in water2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 94, p. 52289-52298Article in journal (Refereed)
    Abstract [en]

    Selective oxidation of C6 hydroxyls to carboxyls through 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, where the oxidizing species (TEMPO+) is generated by cooxidants, such as NaBrO, NaClO or NaClO2, has become a popular way to modify the surfaces of nanocellulose fibrils in aqueous solutions. Employing highly crystalline nanocellulose from Cladophora sp. algae we demonstrate that the same degree of oxidation (D.O.) can be achieved within approximately the same time by replacing the cooxidants with electrogeneration of TEMPO+ in a bulk electrolysis setup. The D.O. is controlled by the oxidation time and the maximum D.O. achieved (D.O. 9.8%, 0.60 mmol g-1 of carboxylic acids and 0 mmol g-1 aldehydes) corresponds to complete oxidation of the surface-confined C6. This shows that TEMPO+ is not sterically hindered from completely oxidizing the fibril surface of Cladophora nanocellulose, in contrast to earlier hypotheses that were based on results with wood-derived nanocellulose. The oxidation does not significantly affect the morphology, the specific surface area (>115 m2 g-1) or the pore characteristics of the water-insoluble fibrous particles that were obtained after drying, but depolymerization corresponding to ∼20% was observed. For extensive oxidation times, the product recovery of water-insoluble fibrils decreased significantly while significant amounts of charge passed through the system. This could indicate that the oxidation proceeds beyond the fibril surface, in contrast to the current view that TEMPO-mediated oxidation is confined only to the surface.

  • 45.
    Carlsson, Daniel O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Cooxidant-free TEMPO-mediated oxidation of highly crystalline nanocellulose in water2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 94, p. 52289-52298Article in journal (Refereed)
    Abstract [en]

    Selective oxidation of C6 hydroxyls to carboxyls through 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, where the oxidizing species (TEMPO+) is generated by cooxidants, such as NaBrO, NaClO or NaClO2, has become a popular way to modify the surfaces of nanocellulose fibrils in aqueous solutions. Employing highly crystalline nanocellulose from Cladophora sp. algae we demonstrate that the same degree of oxidation (D.O.) can be achieved within approximately the same time by replacing the cooxidants with electrogeneration of TEMPO+ in a bulk electrolysis setup. The D.O. is controlled by the oxidation time and the maximum D.O. achieved (D.O. 9.8%, 0.60 mmol g-1 of carboxylic acids and 0 mmol g-1 aldehydes) corresponds to complete oxidation of the surface-confined C6. This shows that TEMPO+ is not sterically hindered from completely oxidizing the fibril surface of Cladophora nanocellulose, in contrast to earlier hypotheses that were based on results with wood-derived nanocellulose. The oxidation does not significantly affect the morphology, the specific surface area (>115 m2 g-1) or the pore characteristics of the water-insoluble fibrous particles that were obtained after drying, but depolymerization corresponding to [similar]20% was observed. For extensive oxidation times, the product recovery of water-insoluble fibrils decreased significantly while significant amounts of charge passed through the system. This could indicate that the oxidation proceeds beyond the fibril surface, in contrast to the current view that TEMPO-mediated oxidation is confined only to the surface.

  • 46.
    Carlsson, Daniel O
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Strømme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Electrochemical TEMPO-mediated Oxidation of Highly Crystalline Nanocellulose in Water2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, p. 52289-52298Article in journal (Refereed)
  • 47.
    Carlsson, Daniel O.
    et al.
    Uppsala University, Department of Engineering Science.
    Mihranyan, Albert
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Stromme, Maria
    Uppsala University, Department of Engineering Science.
    Nyholm, Leif
    Uppsala University, Department of Chemistry, Angstrom Lab.
    Tailoring porosities and electrochemical properties of composites composed of microfibrillated cellulose and polypyrrole2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 17, p. 8489-8497Article in journal (Refereed)
    Abstract [en]

    Composites of polypyrrole and nanocellulose (PPy/nanocellulose) have a high potential as electrodes in energy-storage devices and as membranes for electrochemically controlled ion-exchange systems. In the present work, it is demonstrated that such composites with 42-72% porosity can be produced by using microfibrillated cellulose (MFC) prepared through enzymatic pretreatment or carboxymethylation, or by using different amounts of MFC in the composite synthesis. Together with previous work, this shows that the porosity of PPy/nanocellulose composites can be tailored from 30 to 98% with increments of similar to 10%. Employing the full porosity range of the composites, it is demonstrated that the electrochemical oxidation rate of the materials depends on their porosity due to limitations in the counter ion diffusion process. By tailoring the porosities of PPy/nanocellulose composites, the electrochemical properties can consequently be controlled. The latter provides new possibilities for the manufacturing of electrochemically controlled ion-extraction

  • 48.
    Carlsson, Daniel O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Mihranyan, Albert
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Tailoring porosities and electrochemical properties of composites composed of microfibrillated cellulose and polypyrrole2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 17, p. 8489-8497Article in journal (Refereed)
    Abstract [en]

    Composites of polypyrrole and nanocellulose (PPy/nanocellulose) have a high potential as electrodes in energy-storage devices and as membranes for electrochemically controlled ion-exchange systems. In the present work, it is demonstrated that such composites with 42-72% porosity can be produced by using microfibrillated cellulose (MFC) prepared through enzymatic pretreatment or carboxymethylation, or by using different amounts of MFC in the composite synthesis. Together with previous work, this shows that the porosity of PPy/nanocellulose composites can be tailored from 30 to 98% with increments of similar to 10%. Employing the full porosity range of the composites, it is demonstrated that the electrochemical oxidation rate of the materials depends on their porosity due to limitations in the counter ion diffusion process. By tailoring the porosities of PPy/nanocellulose composites, the electrochemical properties can consequently be controlled. The latter provides new possibilities for the manufacturing of electrochemically controlled ion-extraction and energy storage devices with optimized volumetric energy and power densities.

  • 49.
    Carrick, Christopher
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Larsson, Per A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Aidun, Cyrus
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Native and functionalized micrometre-sized cellulose capsules prepared by microfluidic flow focusing2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 37, p. 19061-19067Article in journal (Refereed)
    Abstract [en]

    Cellulose capsules with average outer and inner radii of approximately 44 mu m and 29 mm respectively were prepared from cellulose dissolved in a mixture of lithium chloride and dimethylacetamide using a microfluidic flow focusing device (MFFD). The MFFD had three inlets where octane oil in a cellulose solution in silicone oil was used to produce a double emulsion containing a cellulose capsule. This technique enables the formation of capsules with a narrow size distribution which can be beneficial for drug delivery or controlled release capsules. In this respect, cellulose is a highly interesting material since it is known to cause no autoimmune reactions when used in contact with human tissue. Furthermore, by controlling the chemical properties of the cellulose, it is possible to trigger a swelling of the capsules and consequentially the release of an encapsulated substance, e. g. a model drug, when the capsule becomes exposed to an external stimulus. To demonstrate this, capsules were functionalized by carboxymethylation to be pH- responsive and to expand approximately 10% when subjected to a change in pH from 3 to 10. The diffusion constant of a model drug, a 4 kDa fluorescently labelled dextran, through the native capsule wall was estimated to be 6.5 X 10(-14) m(2) s(-1) by fitting fluorescence intensity data to Fick's second law.

  • 50. Chen, Bin
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Wu, Wenjun
    Zha, Quanzheng
    Xie, Yongshu
    A novel trigeminal zinc porphyrin and corresponding porphyrin monomers for dye-sensitized solar cells2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 21, p. 10439-10449Article in journal (Refereed)
    Abstract [en]

    A novel trigeminal zinc porphyrin sensitizer (T) and two zinc porphyrin monomers (M1 and M2) were successfully designed and synthesized. The spectral, electrochemical, and photovoltaic properties of the porphyrin dyes were investigated. Compared with M1, the molecule of M2 has an additional aliphatic n-hexyloxyl chain at the meso-position of the porphyrin framework, and such a structure is favorable for the formation of a compact hydrophobic layer at the TiO2 surface and the retardation of the diffusion of I-3(-) ions into the nanoporous TiO2 electrode, resulting in more effective suppression of the charge recombination process and a higher V-oc. Meanwhile, M2 has larger IPCE values than those of M1, leading to the higher J(sc) value. Thus, the DSSC devices based on M2 demonstrated a relatively high power conversion efficiency of 5.77%, with the J(sc), V-oc and ff values of 13.93 mA cm(-2), 732 mV, and 0.566, respectively. Even though dye T has the highest molar absorption coefficients and multiple binding moieties, the corresponding power conversion efficiency is 2.30%, which is lower than those for M1 and M2. These observations may be ascribed to the low efficiency of the electron injection process caused by the isolation of the LUMOs from the anchoring carboxyl groups in addition to the lowest adsorption amount.

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