Change search
Refine search result
1 - 30 of 30
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Abdel-Rehim, M.
    et al.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Bielenstein, M.
    Arvidsson, T.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Evaluation of Solid-Phase microextraction (SPME) for Study of the protein Binding in Human Plasma Samples,2000In: J. Chromatogr. Sci., 38 (2000) 458-464Article in journal (Refereed)
  • 2.
    Bohlin, Maria
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Johannesson, Ida
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Heegaard, Nils H H
    Department of Clinical Biochemistry and Immunology, Statens Serum Institut, Copenhagen, Denmark.
    Blomberg, Lars G.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Estimation of the amount of β2-glycoprotein I adsorbed at the inner surface of fused silica capillaries after acidic, neutral and alkaline pretreatment2012In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 33, no 12, p. 1695-1702Article in journal (Refereed)
    Abstract [en]

    Sample adsorption to the inner surface of fused silica capillaries is a common problem in

    CE when analyzingmacromolecules and is harmful to the analysis. We previously utilized

    the pH hysteresis effect of fused silica to facilitate electrophoresis of the strongly adsorbing

    protein β2gpI in plain-fused silica capillaries at neutral pH. In the present paper, the

    effect of different pretreatments of the capillary on the adsorption of the β2-glycoprotein

    I has been investigated using electroosmosis markers, SDS mobilization, and imaging

    based on indirect immunofluorescence microscopy for direct visualization. The amount

    of β2gpI adsorbed on the surface was probed using all these independent techniques after

    electrophoresis at neutral pH on capillaries pretreated with HCl, background electrolyte

    (BGE), and NaOH. BGE pretreatment was included as a positive control. We found that

    80% or more of the starting material was adsorbed to the inner surface of the silica

    capillaries during electrophoresis after pretreatment with only BGE or with NaOH, but

    after acidic pretreatment the loss was consistently less than 20%. NaOH most efficiently

    removes adsorbed protein between runs. A theoretical calculation of the pH change of

    the BGE showed that electrolysis affects the pH more than the deprotonation of silanols

    during electrophoresis. We conclude that acidic pretreatment of fused silica capillaries

    diminishes adsorption of β2gpI by decreasing charge-dependent wall adsorption.

     

  • 3.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Fluorescence Microscopy Applied to the Dynamics of Latex Colloids2003Licentiate thesis, monograph (Other academic)
  • 4.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Kursvärdering av examensarbeten för en kandidatexamen2011Conference paper (Refereed)
  • 5.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Latex Colloid Dynamics in Complex Dispersions2004Doctoral thesis, monograph (Other academic)
  • 6.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Programutvärdering av det Naturvetenskapliga programmet 2009-20102010Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Rapporten är en del av kvalitetsarbetet vid Fakulteten för teknik- och naturvetenskap.

    Rapporten innehåller resultaten från två enkätundersökningar av det naturvetenskapliga programmet, en till alumner och en till programstudenter.

    Enkätundersökningen som vände sig till alumner visade att:

    -         Magisterexamen var den vanligaste examen bland alumnerna.

    -         De flesta studenter fick ett arbete som var direkt relevant för de studier de bedrivit.

    -         10 % hade gått vidare till forskarutbildning.

    -         Det visade sig att det alumnerna saknade mest i sin utbildning var informationssökning, projektplanering samt muntlig presentation.

    Intervjuer av alumner gav information om vad som bidragit till deras första jobb efter utbildningen. Det visade sig att examensarbetet var oerhört viktigt för första jobbet.

    Enkätundersökningen som vände sig till programstudenter visade att:

    -         Studenterna tror att de inte kommer att få tillräckliga kunskaper i informationssökning och projektplanering, och att de kommer att sakna laborationsvana samt vana från att tolka experimentella resultat i sin utbildning.

    Intervjuer av studenter som avbrutit sina studier på det Naturvetenskapliga programmet vid Karlstads universitet visade att många av dem upplevde studierna för krävande. Andra orsaker till avbrott var byte av studieort, byte av studieinriktning eller att man helt enkelt hellre ville ut i arbetslivet.

    En jämförelse mellan de två enkätundersökningarna visade att det som alumnerna ansåg sig sakna i sin utbildning är det som dagens studenter befarar att de kommer att sakna när de kommer ut i arbetslivet. Projektplanering samt informationssökning var moment som lyftes fram.

  • 7.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Programutvärdering av det Naturvetenskapliga programmet 2009-2010: förberedelser, resultat och uppföljning2011Conference paper (Refereed)
  • 8.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Axrup, Lars
    Stora Enso, Karlstad Res Ctr, SE-65009 Karlstad, Sweden.
    Ljungqvist, Carl-Henrik
    Stora Enso, Karlstad Res Ctr, SE-65009 Karlstad, Sweden..
    Nyflott, Asa
    Stora Enso, Karlstad Res Ctr, SE-65009 Karlstad, Sweden.;Karlstad Univ, SE-65188 Karlstad, Sweden..
    The use of fluorescence microscopy and image analysis to characterize the porous structure in micro fibrillar cellulose gel - Part I: Brownian motion2013In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 28, no 2, p. 190-197Article in journal (Refereed)
    Abstract [en]

    The porous structure of a micro fibrilar cellulose, MFC, gel was studied by fluorescence microscopy and image analysis. The Brownian motion of fluorescent labelled carboxylated latex spheres, probes, was investigated at both high, 0.1-5 wt%, and low, 0-20 ppm, concentrations of MFC. The developed tracking program provides trajectories for probes. The trajectories can be studied according to either the individual approach or the ensemble approach to give complementary information regarding the fibrilar system. The Brownian motion can be used in the range 0 to 1.0 wt% MFC and the percentage of idle probes can be used when the concentrations exceeds 1.0 wt% MFC. The Brownian motion was found to be pH dependent both for the low and the high concentration regimes.

  • 9.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Heidkamp, Hannah
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Fluorescence microscopy – the most versatile tool for in situ investigation of colloids?2011Conference paper (Refereed)
  • 10.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Järnström, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Latex Diffusion at High Volume Fractions Studied by Fluorescence Microscopy2006In: J. Colloid Interface Sci. 298(1), 162-171 (2006)Article in journal (Refereed)
  • 11.
    Carlsson, Gunilla
    et al.
    Karlstad University, Division for Chemistry.
    Järnström, Lars
    Karlstad University, Division for Chemistry.
    van Stam, Jan
    Karlstad University, Division for Chemistry.
    Latex Diffusion at High Volume Fractions Studied by Fluorescence Microscopy2006In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 298, no 1, p. 162-171Article in journal (Refereed)
  • 12.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Ljungqvist, Carl-Henrik
    Stora Enso, Karlstad Research Center.
    Nyflött, Åsa
    Karlstad University, Faculty of Technology and Science, Materials Science.
    Axrup, Lars
    Stora Enso, Karlstad Research Center.
    Characterization of Micro Fibrillated Cellulose using fluorescence microscopy: Evaluation of pretreatments of Micro Fibrillated Cellulose using fluorescence microscopy2011Conference paper (Refereed)
    Abstract [en]

    The paper making process is well known but the underlying mechanisms are not fully understood. Paper builds up from cellulose fibers and many additives are needed in the process. The interactions between components in the furnish are important. Pulp fibers have a wide size distribution and the finest particle fraction is called fines. The fines used in this study are Micro Fibrillated Cellulose (MFC) from bleached craft pulp.

     

    A model system containing fibers and latex was used together with fluorescence microscopy and image analysis. By studying the motion of a labeled latex particle more can be understood about the internal structure of the system. The system consists of:

    • A water suspension of MFC. At the concentrations used the fines are interacting with each other, forming a gel like structure.
    • Negatively charged labeled latex particles (probes), with radius 0,1 µm.
    • Two types of electrolytes (NaCl and CaCl2). The electrolytes were used for altering the electrical double layer of the charged surfaces in the system.

    Different pretreatments of the MFC has been investigated and evaluated using the movements of the probe in the network of fibers.

  • 13.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Polymer film formation studied with fluorescence microscopy2009Conference paper (Refereed)
    Abstract [en]

    One problem with water-based film-forming systems is the high heat of evaporation, yielding long drying times. Short drying times are commonly important, and solvents with high vapour pressures must be used. This fluorescence microscopy method has successfully been used for studies of low and high volume latex fractions, even for particles with a diameter as small as 100 nm. It is possible to perform statistical analyses from single particles traces, yielding information on interactions with other compounds, as well as changes in the environment of the particle. For fast-drying systems, film formation often occurs under non-equilibrium conditions. The microstructure, frequently due to uncompleted phase separation, is decisive for the film properties. Such microstructures have been found in polymer thin films for optoelectronic devices. Of special interest is the recognition of arrested states and so-called Levy walk diffusion at elevated concentrations, the concentration gradient being a consequence of the drying process

  • 14.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Rådberg, Weronica
    Ljungqvist, Carl-Henrik
    Axrup, Lars
    Determination of Distribution of Fines in a Paper Structure using Fluorescence Microscopy and Image Analysis2010Conference paper (Refereed)
    Abstract

    When making paper a sheet is formed by draining a specific amount of dilute water suspension of pulp through a wire-cloth. The procedure is well known but the underlying mechanisms are not fully understood. The different particles such as fines, fibers, retention aids and other additives interact with each other during the process. These interactions are important since they impact the properties of the formed paper. The fibers have different sizes and the finest particle fraction is called fines. The fines used in this study are from bleached kraft pulp and are therefore oxidized to some extent.

    By labelling the fines with a fluorophore the movements of individual fines can be followed with video-based fluorescence microscopy even if the size of the fines is below the microscopes resolution limit. [1-3] The fluorophores that has been used are N-Methylisatoic anhydride and fluorescein-5-thiosemicarbazide. N-Methylisatoic anhydride reacts directly with hydroxyl groups on the cellulose chain. Fluorescein-5-thiosemicarbazide reacts with groups like aldehydes and ketones in the cellulose chain, so the chain has to be oxidized before the labeling process. These two fluorephores have different absorption and emission wavelengths. [4]

    The methods for labeling the fibers are easy to perform. The labeled fiber can be seen in the microscope. One problem is that the fibers aggregate, probably due to the method used for labeling. Another problem can be the fading of the flourophores. Both problems will be further investigated. [5]

    The elevated drying process in the paper machine makes it difficult to understand the mechanisms involved. Within this project the understanding will be built up in many steps. The first step is to study the labeled fibers in water. A model system containing fibers and latex will be used to study the behavior in different environments such as different electrolyte concentration and pH.



    References

    [1] Carlsson G., Warszynski P., van Stam J., J. Colloid Interface Sci., 2003, 267, 500-508

    [2] Carlsson G., van Stam J., Nord. Pulp Pap. Res. J., 2005, 20, 192-199

    [3] Carlsson G., Järnström L., van Stam J., J. Colloid Interface Sci., 2006, 298, 162-171

    [4] DeAngelis P. L., Analytical Biochemistry, 2000, 284, 167-169

    [5] Rådberg W., Bsc thesis, Karlstad university, 2010

  • 15.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Rådberg, Weronika
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Ljungqvist, Carl-Henrik
    Stora Enso, Karlstad Research Center.
    Axrup, Lars
    Stora Enso, Karlstad Research Center.
    A model system for understanding the distribution of fines in a paper structure using fluorescence microscopy2011Conference paper (Refereed)
    Abstract [en]

    When making paper a sheet is formed by draining a specific amount of dilute water suspension of pulp and wet end additives through a wire-cloth. The procedure is well known but the underlying mechanisms are not fully understood. The pulp stock is composed by different particles such as fines, fibers, retention aids and other additives that interact with each other during the papermaking process. These interactions are important since they influence the properties of the formed paper. Pulp fibers have different sizes and the finest particle fraction is referred to as fines. In this study fines from bleached Kraft pulp were used.

    The fines were oxidized to some extent as a consequence of the Kraft pulp process.A model system containing fibers and latex was used together with fluorescence microscopyand image analysis to study the Brownian motion of a probe in different electrolyte concentrations. The model system was built up of:

    • A water suspension of 1 % fines, negatively charged. At this concentration the fines are interacting with each other, forming a gel like structure.

    • Negatively charged probes with three different sizes (radii 50, 100 and 500 nm).

    • Two types of electrolytes (NaCl and CaCl2). The electrolytes were used for altering the electrical double layer of the charged surfaces in the system.

    By studying the Brownian motion of the probes with different sizes in the network of fines more can be understood about this model system. The knowledge obtained from this model system can be used for further understanding of the paper chemistry mechanisms.

    References

    Carlsson G., Warszynski P., van Stam J., J. Colloid Interface Sci., 2003, 267, 500-508

    Carlsson G., van Stam J., Nord. Pulp Pap. Res. J., 2005, 20, 192-199

    Carlsson G.,  Järnström L., van Stam J., J. Colloid Interface Sci., 2006, 298, 162-171

    Rådberg W., Bachelor thesis, Karlstad University, 2010

  • 16.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Interactions between Charged Latex Colloids and Starch Polyelectrolytes Studied by Fluorescence Microscopy with Image Analysis2005In: Nordic Pulp Pap. Res. J., 2005, 20, 192-199Article in journal (Refereed)
  • 17.
    Carlsson, Gunilla
    et al.
    Karlstad University, Division for Chemistry.
    van Stam, Jan
    Karlstad University, Division for Chemistry.
    Interactions between Charged Latex Colloids and Starch Polyelectrolytes Studied with Fluorescence  Microscopy with Image Analysis2005In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 20, no 2, p. 192-199Article in journal (Refereed)
    Abstract [en]

    The interactions between carboxylated polystyrene latex probe particles and ionically substituted starches have been investi-gated by fluorescence microscopy with image analysis. The degree of substitution of the starches was varied, as was also thepolyelectrolyte molecular weight and the probe size. 

  • 18.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Fredriksson, Lars
    Normal and anomalous diffusion2010Conference paper (Refereed)
    Abstract

    Brownian motion is perhaps best described as the never-ceasing phenomenon responsible for

    self-diffusion occurring although there is no temperature or concentration gradients. The

    distribution of the steps P(r) is vital in order to see the underlying mechanism of diffusion.

    Normal diffusion is characterised by having Gaussian distributions of the step lengths.

    Diffusion can be classified as either normal or anomalous depending on how the mean square

    displacement is related to time:



    If a = 1, diffusion is classified as normal diffusion. With a > 1 , there is superdiffusion. When

    a < 1 , subdiffusion takes place. In order to replace normal diffusion by anomalous diffusion,

    pathologies must be present. Most anomalous diffusion takes the shape of subdiffusion

    [1, 2].

    Video-based fluorescence microscopy is the basis for all experimental work and has

    successfully been used earlier [3-5]. For each concentration the trajectories of 60 probes were

    determined using the built-in Particle Analysis function in Aquacosmos 2.6. The 6000 data

    points collected were used to extract both the coefficient G and the exponenta .

    Relatively few studies have been devoted to tell normal diffusion from anomalous diffusion in

    real chemical systems. In this study the probe is a fluorescent labeled latex particle, the matrix

    was changed in different ways. Unlabelled latex particles, DoTAB (a cationic surfactant),

    cationic starch of different molecular weight were all used to alter the sample.

    The conclusion is that it is safe to assume a = 1 in all cases except for very high

    concentrations of starch, where diffusion is hindered by the viscous matrix, which gives rise

    to subdiffusion. Moreover, all distributions are Gaussian except for the highest concentrations

    of starch and latex. In these latter cases, distributions appear as truncated normal distributions

    [6,7].

    References

    [1] Klafter J., Blumen A., Zumofen g. Shlesinger M.f., Physica A., 1990, 168, 637-645

    [2] Ott A., Bouchaud J.P., Langevin D., Urbach W., Phys. Rev. Lett., 1990, 65, 2201-2204

    [3] Carlsson G., Warszynski P., van Stam J., J. Colloid Interface Sci., 2003, 267, 500-508

    [4] Carlsson G., van Stam J., Nord. Pulp Pap. Res. J., 2005, 20, 192-199

    [5] Carlsson G., Järnström L., van Stam J., J. Colloid Interface Sci., 2006, 298, 162-171

    [6] Fredriksson L., Bsc thesis, Karlstad university, 2010

    [7] Fredriksson L., Msc thesis, Karlstad university, 2010

  • 19.
    Heidkamp, Hannah
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Polymer film formation studied with fluorescence microscopy and AFM2010In: Molecular Processes at Solid Surfaces: 10th Annual Surface and Colloid Symposium, 2010, p. 49-Conference paper (Refereed)
    Abstract [en]

    Thin polymer films are used in many applications such as paint, paper coatings and electronic devices. For these applications, it is important to have knowledge about the film formation process, since it affect the film morphology and the morphology is important for the applications.One method for studying film formation in situ is fluorescence microscopy. By labeling a target molecule or particle with a fluorophore, the targets movements can be traced as the solvent evaporates [1-3]. If information gained from studies of particle movements during film formation and wet state behavior are combined, information about the film formation process can be obtained. Examination of the final film surfaces with regular light microscopy and AFM gives additional information about the film formation.These methods have been used for studying the formation of negatively charged latex films. It was shown that the films are greatly affected by adding positively charged surfactants [4-5]. Since latex is a water-based system it has relatively long drying times. Systems based on high-vapor pressure organic solvents have much shorter drying times and the film formation occurs under non-equilibrium conditions. This results in incomplete phase separation, which in turn gives microstructures in the film. These microstructures are of great interest since they affect the properties of the film and its function [6-7]. Our aim is to develop the methods used for latex studies in order to be able to apply them to study film formation of polymer blends used for photovoltaic applications. The goal is to get more knowledge about the film forming process and a deeper understanding about the mechanisms behind the formation of microstructures.[1] Carlsson G., Warszynski P., van Stam J., J. Colloid Interface Sci., 2003, 267, 500-508[2] Carlsson G., van Stam J., Nord. Pulp Pap. Res. J., 2005, 20, 192-199[3] Carlsson G., Järnström L., van Stam J., J. Colloid Interface Sci., 2006, 298, 162-171[4] Heidkamp H., Master thesis, Karlstad University 2009.[5] Paakkonen, J., Master thesis, Karlstad University 2010.[6] Björström C.M., Magnusson K.O., Moons E., Synth. Metals, 2005, 152, 109-112[7] Moons E., J. Phys.: Condens. Matter, 2002, 14, 12235-12260

  • 20.
    Heidkamp, Hannah
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Latex particle behavior studied in the wet state with fluorescence microscopy2010Conference paper (Refereed)
    Abstract

    Dispersions of latex are often used as model systems due to the well known properties of the latex particles. They can be made with a monodisperse distribution, different extent of cross linking and different surface charges. The behavior of latex particles in the wet state is important for both film formation and understanding what happens in the system when different additives are introduced. Latex is used in many different blends and one common additive is surfactants, both for stabilization during manufacturing and for adjusting the system features in different applications. A suitable method for studying latex dispersions in wet state is fluorescence microscopy. By adding latex particles with similar size and charge, marked with a fluorophore, particle movements can be followed even if the particle radius is below microscope resolution limit. This can be used for studying particle behavior in dispersions with different additives, in order to see how the additives affect the latex particles.



    By measuring the latex particles displacement, diffusion coefficients can be determined. This has been successfully used for both high and low latex volume fractions [1-3]. Since surfactants are a common additive, the focus in our studies lies on interactions between surfactants and negatively charged latex. When DoTAB (dodecyl trimethyl ammonium bromide), a cationic surfactant, is added to the latex dispersion, an interesting behavior can be seen. Both diffusion coefficients and conductivity measurements show that at a certain concentration, when DoTAB has neutralized the latex particles, aggregates are formed. When the DoTAB concentration is raised even more, the aggregates dissolve. Light scattering measurements give the same indications.



    Combined with other studies, such as film formation, the particle behavior gives important information about what happens in the system when different concentration of both latex and additives are used.



    [1] Carlsson G., Warszynski P. and van Stam J., J. Colloid Interface Sci., 2003, 267, 500-508 [2] Carlsson G., Järnström L. and van Stam J., J. Colloid Interface Sci., 2006, 298, 162-171

    [3] Carlsson G. and van Stam J., Nord. Pulp Pap. Res. J., 2005, 20, 192-199

  • 21.
    Heidkamp, Hannah
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Rogowski, Rafal
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Dzwilewski, Andrzej
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Morphology of polymer blends in films made by dip-coating2011Conference paper (Refereed)
    Abstract [en]

    Thin spincoated polymer films are used in various applications and there has been anincreasing demand to understand and get precise control over the film formation process. One of the most exciting applications is organic solar cells which have an active layer made of a polymer based blend. The film morphology has a strong effect on the efficiency of solar cells and therefore it is crucial to understand the film formation process in order to tailor thedesired morphology [1].

    In this study we are combining and comparing results from three different deposition processes: drop-casting, sphere-on-flat arrangement and dip-coating. We are using dip-coating to produce thin films of polymer blends with different morphologies under controlled conditions. The main goal is to gain a deeper insight into the processes that occur while solvent evaporates and to understand why certain structures are formed.

    Drop-casting allows for little control of the structure formation. In the sphere-on-flat arrangement a droplet of a solution is constrained between a half-sphere and the substrate, which provides more controllable conditions for the deposition process. For more precise control, dip-coating can be used, where a substrate is withdrawn from a solution at a constant speed.

    In this study we have used the polymer poly(3-hexylthiophene) (P3HT) and the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) dissolved in toluene. These components are the model system for studies on organic solar cells [1]. The dip-coated films show a wide variety of morphologies depending on the coating speed. This dependence can be rationalized by the different mechanisms occurring at low and high speeds: At low speeds, evaporation is dominant, [2] resulting in well ordered patterns. At high speeds, viscous forces become dominant, [2] yielding optically homogeneous films.

    [1] G. Dennler, M. C. Scharber, C. J. Brabec, Adv. Mat. 21, 1323-1338 (2009)

    [2] R. Z. Rogowski and A. A. Darhuber, Langmuir 26, 11485-93 (2010)

  • 22.
    Heidkamp, Hannah
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Dzwilewski, Andrzej
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Rogowski, Rafal
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Morphology of P3HT and PCBM blends in thin films obtained with different deposition methods2011Conference paper (Refereed)
    Abstract [en]

    Patterns and structures, formed when a semiconducting polymer blend in solution is subject to controlled evaporation, have been of great interest due to their influence on the performance of organic devices. By controlling the processes of pattern formation, function properties of organic semiconductor structures can be tailored, allowing for facile manufacturing of the active layers in organic devices, e.g. solar cells.

    By analyzing the morphologies of polymer blends resulting from different deposition methods, a deeper insight into the pattern formation process can be acquired. In this study, we have analyzed the morphology of blends of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) formed upon solvent evaporation. We used the following deposition methods: dip-coating, droplet evaporation within a constrained geometry and drop-casting. Dip-coated films revealed various types of morphology depending on the coating speed. At low coating speeds, where evaporation is the dominant factor, well-ordered patterns were obtained. When increasing the coating speed, viscous forces become dominant over evaporation yielding optically homogenous films [2]. Morphologically similar structures to those observed at low coating speeds, were also obtained with spatially constrained droplets. The blend morphologies were analyzed with polarized, fluorescence and atomic force microscopy [1].

    References:

    [1] C. M. Björström Svanström, J. Rysz, A. Bernasik, A. Budkowski, F. Zhang, O. Inganäs, M. R. Andersson, K. O. Magnusson, J. J. Benson-Smith, J. Nelson, and E. Moons, Adv. Mat. 21, 4398-4403 (2009)

    [2] R. Z. Rogowski and A. A. Darhuber, Langmuir 26, 11485-93 (2010)

  • 23.
    Heidkamp, Hannah
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Rogowski, Rafal
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Morphology of PCBM and P3HT blends in films made by dip-coating on homogeneous and chemically patterned surfaces,2011Conference paper (Refereed)
  • 24.
    Lestelius, Magnus
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013), Paper Surface Centre.
    Nyflött, Åsa
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Moons, Ellen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    Järnström, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013), Paper Surface Centre.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Bonnerup, Chris
    Govindarajan, Venkatesh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Oxygen permeabilityand economic-environmental impact studies of some polyvinyl alcohol dispersionbarrier coatings for packaging applications2017Conference paper (Other academic)
    Abstract [en]

    Purposes of employing barrier coatings in packaging, and in particular food packaging, can be to increase the shelf life, preserve colour, odour, and taste, and to protect from a harmful environment in general. Barrier coatings can thus help to reduce food waste along the value chain until end use. Including both materials choice for packaging and the possible fates of the used package, even further steps to provide greater knowledge for decisions on choices of packaging solutions. To that end, we have conducted several experimental and transport modeling studies on oxygen barrier coatings performance. The coating system of choice    has been dispersion coatings of poly vinyl alcohol (PVOH), with additions of kaolin. Physical and chemical features of the coatings were characterized to obtain information on polymer crystallinity, free volume and filler orientation as these characteristics are influential to the oxygen mass transport performance. In turn, the oxygen mass transport was also measured, both in steady state and dynamically. In so doing, we obtained information    useful for developing a general model to describe the oxygen permeability taking into account the physical and chemical features, described above, of the coating layer. Attempts on describing the interdependence and impact, for instance between crystalline and amorphous polymer regions and moisture, was added to the model. The model showed agreement to experimental data for PVOH-kaolin coating in this particular case. However, the basic permeability model has been applied to  many different polymers.

    To further explore the potential of these types of coating, which are technically possible to    produce in paperboard production, an economic-environmental impact comparison to other existing material solutions was made. Four barrier material alternatives – starch, polyethylene, ethyl vinyl alcohol (chosen as an alternative for PVOH, where data was difficult to obtain) and kaolin, and latex and kaolin, were analyzed with respect to cost and global warming potential. Weighting and comparing cost to environmental aspect, weighting    factors based on interviews with experts in the packaging value chain, starch emerges as the most sustainable alternative. However, previous coating and mass transport studies also shows how these renewable materials require some further technical development to be competitive.

    The mass transport model can serve as a tool for customizing barrier coatings and to predict the barrier performance, as permeability is obtained and thus shelf-life estimation is    possible. The overall concept, the combination of assessment of structural performance and the environmental studies, can be employed to find sustainable food packaging solutions.

  • 25.
    Nyflött, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Axrup, Lars
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Lestelius, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Effects of dispersion barrier coating structure on oxygen barrier performance2014Conference paper (Other academic)
  • 26.
    Nyflött, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Axrup, Lars
    Stora Enso.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Wahlström, Torbjörn
    Stora Enso.
    Influence of kaolin addition on the dynamics of oxygen mass transport in polyvinyl alcohol dispersion coatings2015In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 30, no 3, p. 385-392Article in journal (Refereed)
    Abstract [en]

    The permeability of dispersion barriers produced from polyvinyl alcohol (PVOH) and kaolin clay blends coated onto polymeric supports has been studied by employing two different measurement methods: the oxygen transmission rate (OTR) and the ambient oxygen ingress rate (AOIR). Coatings with different thicknesses and kaolin contents were studied. Structural information of the dispersion-barrier coatings was obtained by Fourier transform infrared spectroscopy (FTIR) spectroscopy and scanning electron microscopy (SEM). These results showed that the kaolin content influences both the orientation of the kaolin and the degree of crystallinity of the PVOH coating. Increased kaolin content increased the alignment of the kaolin platelets to the basal plane of the coating. Higher kaolin content was accompanied by higher degree of crystallinity of the PVOH. The barrier thickness proved to be less important in the early stages of the mass transport process, whereas it had a significant influence on the steady-state permeability. The results from this study demonstrate the need for better understanding of how permeability is influenced by (chemical and physical) structure.

  • 27.
    Nyflött, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Bonnerup, Chris
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences, Paper Surface Centre.
    Modeling of oxygen diffusion in flake-filled polymer system2014In: , 2014Conference paper (Other academic)
  • 28.
    Nyflött, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Bonnerup, Chris
    Stora Enso.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    The influence of clay orientation and crystallinity on oxygen permeation in dispersion barrier coatings2016In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 126, p. 17-24Article in journal (Refereed)
    Abstract [en]

    In this study oxygen permeability in dispersion barriers produced from poly(vinyl alcohol) (PVOH) and kaolin clay blends coated onto polymeric supports was investigated. To determine the oxygen permeability, two measurement methods were used: the oxygen transmission rate (OTR) and the ambient oxygen ingress rate (AOIR). It was found that with increasing kaolin content the oxygen permeability increased, up to about 5 wt% kaolin, whereafter the oxygen permeability decreased, as was expected. The increased (> 5%) kaolin loading lowered the diffusion because of an increased tortuosity. Structural information about the dispersion-barrier coatings, such as kaolin orientation and polymer crystallinity, was obtained from Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Kaolin orientation was influenced by the drying temperature, the thickness of the samples, and the kaolin concentration. The polymer crystallinity increased in thicker samples. The drying temperature did not show any clear effect on the crystallinity of thin samples, while for the thicker barriers, combined with a kaolin concentration lower than 20 wt%, a higher crystallinity was achieved at lower drying temperatures. This study demonstrates the strong influence of chemical and physical structures on the permeability of the investigated coatings.

  • 29.
    Nyflött, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Bonnerup, Chris
    Stora Enso.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Gunilla, Carlsson
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Lestelius, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Modeling of oxygen diffusion through flake-filled polymeric layers applied to barrier coatings2014Manuscript (preprint) (Other academic)
  • 30.
    Nyflött, Åsa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Petkova-Olsson, Yana
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Moons, Ellen
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    Bonnerup, Chris
    Stora Enso.
    Järnström, Lars
    Karlstad University, Faculty of Technology and Science, Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Lestelius, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science.
    Minelli, Matteo
    Bologna University.
    Modelling of oxygen permeation through filled polymeric layers for barrier coatings2017In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 134, no 20, article id 44834Article in journal (Refereed)
1 - 30 of 30
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf