Change search
CiteExportLink to record
Permanent link

Direct 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
Surface behavior of amphiphiles in aqueous solution: a comparison between different pentanol isomers
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
Show others and affiliations
2015 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 17, no 21, 14036-14044 p.Article in journal (Refereed) Published
Abstract [en]

Position isomerism is ubiquitous in atmospheric oxidation reactions. Therefore, we have compared surface-active oxygenated amphiphilic isomers (1- and 3-pentanol) at the aqueous surface with surface- and chemically sensitive X-ray photoelectron spectroscopy (XPS), which reveals information about the surface structure on a molecular level. The experimental data are complemented with molecular dynamics (MD) simulations. A concentration-dependent orientation and solvation of the amphiphiles at the aqueous surface is observed. At bulk concentrations as low as around 100 mM, a monolayer starts to form for both isomers, with the hydroxyl groups pointing towards the bulk water and the alkyl chains pointing towards the vacuum. The monolayer (ML) packing density of 3-pentanol is approx. 70% of the one observed for 1-pentanol, with a molar surface concentration that is approx. 90 times higher than the bulk concentration for both molecules. The molecular area at ML coverage (approximate to 100 mM) was calculated to be around 32 +/- 2 angstrom(2) per molecule for 1-pentanol and around 46 +/- 2 angstrom(2) per molecule for 3-pentanol, which results in a higher surface concentration (molecules per cm(2)) for the linear isomer. In general we conclude therefore that isomers - with comparable surface activities - that have smaller molecular areas will be more abundant at the interface in comparison to isomers with larger molecular areas, which might be of crucial importance for the understanding of key properties of aerosols, such as evaporation and uptake capabilities as well as their reactivity.

Place, publisher, year, edition, pages
2015. Vol. 17, no 21, 14036-14044 p.
National Category
Physical Chemistry Physical Sciences
Identifiers
URN: urn:nbn:se:uu:diva-256562DOI: 10.1039/c5cp01870fISI: 000354946200029PubMedID: 25953683OAI: oai:DiVA.org:uu-256562DiVA: diva2:825874
Available from: 2015-06-24 Created: 2015-06-24 Last updated: 2017-12-04Bibliographically approved
In thesis
1. Exploring the Surface of Aqueous Solutions: X-ray photoelectron spectroscopy studies using a liquid micro-jet
Open this publication in new window or tab >>Exploring the Surface of Aqueous Solutions: X-ray photoelectron spectroscopy studies using a liquid micro-jet
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The surface behavior of biologically or atmospherically relevant chemical compounds in aqueous solution has been studied using surface-sensitive X-ray photoelectron spectroscopy (XPS). The aim is to provide information on the molecular-scale composition and distribution of solutes in the surface region of aqueous solutions. In the first part, the distribution of solutes in the surface region is discussed, where in particular single molecular species are studied. Concentration-dependent studies on succinic acid and various alkyl-alcohols, where also parameters such as pH and branching are varied, are analyzed using different approaches that allow the quantification of surface concentrations. Furthermore, due to the sensitivity of XPS to the chemical state, reorientation of linear and branched alkyl-alcohols at the aqueous surface as a function of concentration is observed. The results are further discussed in terms of hydrophilic and hydrophobic interactions in the interfacial region, where the three-dimensional hydrogen bonded water structure terminates. In the second part, mixed solutions of compounds, both ionic and molecular, are inspected. Again concentration, but also co-dissolution of other chemical compounds, are varied and differences in the spatial distribution and composition of the surface region are discussed. It is found that the guanidinium ion has an increased propensity to reside at the surface, which is explained by strong hydration in only two dimensions and only weak interactions between the aromatic π-system and water. Ammonium ions, on the other hand, which require hydration in three dimensions, are depleted from the surface region. The presence of strongly hydrated electrolytes out-competes neutral molecules for hydrating water molecules leading to an enhanced abundance of molecules, such as succinic acid, in the interfacial region. The partitioning is quantified and discussed in the context of atmospheric science, where the impact of the presented results on organic loading of aerosol particles is emphasized.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. 88 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1313
Keyword
X-ray Photoelectron spectroscopy, liquid micro-jet, air-water interface, inorganic salt, carboxylic acid, alcohol, isomers, hydration.
National Category
Atom and Molecular Physics and Optics Condensed Matter Physics Chemical Sciences
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-265210 (URN)978-91-554-9399-8 (ISBN)
Public defence
2015-12-18, Häggsalen, Ångströmslaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2015-11-27 Created: 2015-10-25 Last updated: 2016-01-13

Open Access in DiVA

fulltext(1782 kB)34 downloads
File information
File name FULLTEXT01.pdfFile size 1782 kBChecksum SHA-512
2791c619d9bb3d4dd789fe27ad56b93f22b568656d146c9b11a866636d624f31077be2527095e4ba5785bdb79b514f2ef9fd604cc462c46e265653c2839ccff0
Type fulltextMimetype application/pdf

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Walz, Marie-MadeleineCaleman, CarlWerner, JosephinaEkholm, VictorBjörneholm, Olle
By organisation
Molecular and condensed matter physics
In the same journal
Physical Chemistry, Chemical Physics - PCCP
Physical ChemistryPhysical Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 34 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 714 hits
CiteExportLink to record
Permanent link

Direct 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