Comparative Adsorption of Saturated and Unsaturated Fatty Acids at the Iron Oxide/Oil Interface

Mary H. Wood; M. T. Casford; R. Steitz; A. Zarbakhsh; R. J.L. Welbourn; Stuart M. Clarke

doi:10.1021/acs.langmuir.5b04435

Comparative Adsorption of Saturated and Unsaturated Fatty Acids at the Iron Oxide/Oil Interface

Mary H. Wood, M. T. Casford, R. Steitz, A. Zarbakhsh, R. J.L. Welbourn, Stuart M. Clarke

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82 Scopus citations

Abstract

A detailed comparison of the adsorption behavior of long straight chain saturated and unsaturated fatty acids at the iron oxide/oil interface has been considered using a combination of surface study techniques. Both depletion isotherms and polarized neutron reflectometry (PNR) show that the extent of adsorption decreases as the number of double bonds in the alkyl chains increases. Sum frequency generation spectroscopic measurements demonstrate that there is also an increase in chain disorder within the adsorbed layer as the unsaturation increases. However, for the unsaturated analogues, a decrease in peak intensity is seen for the double bond peak upon heating, which is thought to arise from isomerization in the surface-bound layer. The PNR study of oleic acid adsorption indicates chemisorbed monolayer adsorption, with a further diffuse reversible adsorbed layer formed at higher concentrations.

Original language	English
Pages (from-to)	534-540
Number of pages	7
Journal	Langmuir
Volume	32
Issue number	2
DOIs	https://doi.org/10.1021/acs.langmuir.5b04435
State	Published - Jan 19 2016
Externally published	Yes

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title = "Comparative Adsorption of Saturated and Unsaturated Fatty Acids at the Iron Oxide/Oil Interface",

abstract = "A detailed comparison of the adsorption behavior of long straight chain saturated and unsaturated fatty acids at the iron oxide/oil interface has been considered using a combination of surface study techniques. Both depletion isotherms and polarized neutron reflectometry (PNR) show that the extent of adsorption decreases as the number of double bonds in the alkyl chains increases. Sum frequency generation spectroscopic measurements demonstrate that there is also an increase in chain disorder within the adsorbed layer as the unsaturation increases. However, for the unsaturated analogues, a decrease in peak intensity is seen for the double bond peak upon heating, which is thought to arise from isomerization in the surface-bound layer. The PNR study of oleic acid adsorption indicates chemisorbed monolayer adsorption, with a further diffuse reversible adsorbed layer formed at higher concentrations.",

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AU - Welbourn, R. J.L.

AU - Clarke, Stuart M.

PY - 2016/1/19

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AB - A detailed comparison of the adsorption behavior of long straight chain saturated and unsaturated fatty acids at the iron oxide/oil interface has been considered using a combination of surface study techniques. Both depletion isotherms and polarized neutron reflectometry (PNR) show that the extent of adsorption decreases as the number of double bonds in the alkyl chains increases. Sum frequency generation spectroscopic measurements demonstrate that there is also an increase in chain disorder within the adsorbed layer as the unsaturation increases. However, for the unsaturated analogues, a decrease in peak intensity is seen for the double bond peak upon heating, which is thought to arise from isomerization in the surface-bound layer. The PNR study of oleic acid adsorption indicates chemisorbed monolayer adsorption, with a further diffuse reversible adsorbed layer formed at higher concentrations.

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Comparative Adsorption of Saturated and Unsaturated Fatty Acids at the Iron Oxide/Oil Interface

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