Surface behavior of amphiphiles in aqueous solution: a comparison between different pentanol isomers
Walz, M. -M. ; Caleman, C. ; Werner, J. ; Ekholm, V. ; Lundberg, D. ; Prisle, N. L. ; Öhrwall, Gunnar LU
and Bjorneholm, O.
(2015)
In Physical Chemistry Chemical Physics
17(21).
p.14036-14044
- Abstract
- 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)... (More)
- 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. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/7422560
- author
- Walz, M. -M.
; Caleman, C.
; Werner, J.
; Ekholm, V.
; Lundberg, D.
; Prisle, N. L.
; Öhrwall, Gunnar
LU
and Bjorneholm, O.
- organization
- publishing date
- 2015
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 17
- issue
- 21
- pages
- 14036 - 14044
- publisher
- Royal Society of Chemistry
- external identifiers
-
- wos:000354946200029
- scopus:84930221637
- pmid:25953683
- ISSN
- 1463-9084
- DOI
- 10.1039/c5cp01870f
- language
- English
- LU publication?
- yes
- id
- 04f3cd20-ac93-4d59-b823-46e52a423850 (old id 7422560)
- date added to LUP
- 2016-04-01 13:10:23
- date last changed
- 2022-04-06 02:56:01
@article{04f3cd20-ac93-4d59-b823-46e52a423850,
abstract = {{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.}},
author = {{Walz, M. -M. and Caleman, C. and Werner, J. and Ekholm, V. and Lundberg, D. and Prisle, N. L. and Öhrwall, Gunnar and Bjorneholm, O.}},
issn = {{1463-9084}},
language = {{eng}},
number = {{21}},
pages = {{14036--14044}},
publisher = {{Royal Society of Chemistry}},
series = {{Physical Chemistry Chemical Physics}},
title = {{Surface behavior of amphiphiles in aqueous solution: a comparison between different pentanol isomers}},
url = {{http://dx.doi.org/10.1039/c5cp01870f}},
doi = {{10.1039/c5cp01870f}},
volume = {{17}},
year = {{2015}},
}