The structure of n-alkane binary mixtures adsorbed on graphite

Philippe Espeau; John W. White; Robert J. Papoular

doi:10.1016/j.apsusc.2005.02.091

The structure of n-alkane binary mixtures adsorbed on graphite

Philippe Espeau^*, John W. White, Robert J. Papoular

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

11 Citations (Scopus)

Abstract

The thermodynamics and structure of the surface adsorbed phase in binary C15-C16 and C15-C17 n-alkane mixtures confined in graphite pores have been studied by differential scanning calorimetry and small-angle X-ray scattering. The previously observed selective adsorption of the longer alkane for chain length differences greater than five carbon atoms is verified but reduced for chain length differences less than or equal to two. With a difference in chain length of one carbon atom, Vegard's law is followed for the melting points of the adsorbed mixture and the (0 2) d-spacing is a continuous function of the mole fraction x. With a two-carbon atom difference, samples aged for 1 week have a lamellar structure for which the entities A _1-x B _x try to be commensurate with the substrate. The same samples aged for 1 month show a continuous parabolic x-dependence for both the melting points and the d-spacings. An explanation in terms of selective probability of adsorption is proposed based on crystallographic considerations.

Original language	English
Pages (from-to)	1350-1359
Number of pages	10
Journal	Applied Surface Science
Volume	252
Issue number	5
DOIs	https://doi.org/10.1016/j.apsusc.2005.02.091
Publication status	Published - 15 Dec 2005

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10.1016/j.apsusc.2005.02.091

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title = "The structure of n-alkane binary mixtures adsorbed on graphite",

abstract = " The thermodynamics and structure of the surface adsorbed phase in binary C15-C16 and C15-C17 n-alkane mixtures confined in graphite pores have been studied by differential scanning calorimetry and small-angle X-ray scattering. The previously observed selective adsorption of the longer alkane for chain length differences greater than five carbon atoms is verified but reduced for chain length differences less than or equal to two. With a difference in chain length of one carbon atom, Vegard's law is followed for the melting points of the adsorbed mixture and the (0 2) d-spacing is a continuous function of the mole fraction x. With a two-carbon atom difference, samples aged for 1 week have a lamellar structure for which the entities A 1-x B x try to be commensurate with the substrate. The same samples aged for 1 month show a continuous parabolic x-dependence for both the melting points and the d-spacings. An explanation in terms of selective probability of adsorption is proposed based on crystallographic considerations.",

keywords = "Adsorbed phase, Alkanes, Binary mixtures, DSC, Graphite, X-ray diffraction",

author = "Philippe Espeau and White, {John W.} and Papoular, {Robert J.}",

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T1 - The structure of n-alkane binary mixtures adsorbed on graphite

AU - Espeau, Philippe

AU - White, John W.

AU - Papoular, Robert J.

PY - 2005/12/15

Y1 - 2005/12/15

N2 - The thermodynamics and structure of the surface adsorbed phase in binary C15-C16 and C15-C17 n-alkane mixtures confined in graphite pores have been studied by differential scanning calorimetry and small-angle X-ray scattering. The previously observed selective adsorption of the longer alkane for chain length differences greater than five carbon atoms is verified but reduced for chain length differences less than or equal to two. With a difference in chain length of one carbon atom, Vegard's law is followed for the melting points of the adsorbed mixture and the (0 2) d-spacing is a continuous function of the mole fraction x. With a two-carbon atom difference, samples aged for 1 week have a lamellar structure for which the entities A 1-x B x try to be commensurate with the substrate. The same samples aged for 1 month show a continuous parabolic x-dependence for both the melting points and the d-spacings. An explanation in terms of selective probability of adsorption is proposed based on crystallographic considerations.

AB - The thermodynamics and structure of the surface adsorbed phase in binary C15-C16 and C15-C17 n-alkane mixtures confined in graphite pores have been studied by differential scanning calorimetry and small-angle X-ray scattering. The previously observed selective adsorption of the longer alkane for chain length differences greater than five carbon atoms is verified but reduced for chain length differences less than or equal to two. With a difference in chain length of one carbon atom, Vegard's law is followed for the melting points of the adsorbed mixture and the (0 2) d-spacing is a continuous function of the mole fraction x. With a two-carbon atom difference, samples aged for 1 week have a lamellar structure for which the entities A 1-x B x try to be commensurate with the substrate. The same samples aged for 1 month show a continuous parabolic x-dependence for both the melting points and the d-spacings. An explanation in terms of selective probability of adsorption is proposed based on crystallographic considerations.

KW - Adsorbed phase

KW - Alkanes

KW - Binary mixtures

KW - DSC

KW - Graphite

KW - X-ray diffraction

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U2 - 10.1016/j.apsusc.2005.02.091

DO - 10.1016/j.apsusc.2005.02.091

M3 - Article

SN - 0169-4332

VL - 252

SP - 1350

EP - 1359

JO - Applied Surface Science

JF - Applied Surface Science

IS - 5

ER -

The structure of n-alkane binary mixtures adsorbed on graphite

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