title: Measurements of the thickness compressibility of an n-octadecyltriethoxysilane monolayer self-assembled on mica.
abstract: The surface forces apparatus technique and the Johnson-Kendall-Roberts theory were used to study the elastic properties of an n-octadecyltriethoxysilane self-assembled monolayer (OTE-SAM) on both untreated and plasma-treated mica. Our aim was to measure the thickness compressibilities of OTE monolayers on untreated and plasma-treated mica and to estimate their surface densities and phase-states from the film compressibility. The compressibility moduli of OTE are (0.96 +/- 0.02) x 10(8) N/m(2) on untreated mica and (1.24 +/- 0.06) x 10(8) N/m(2) on plasma-treated mica. This work suggests that the OTE phase-state is pseudocrystalline. In addition, the results from the compressibility measurements in water vapor suggest that the OTE-SAM on both untreated and plasma-treated mica is not homogeneous but rather contains both crystalline polymerized OTE domains and somewhat hydrophilic gaseous regions.
authors.affiliation: Department of Soil, Water and Environmental Science, The University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Sungsoo
authors.initials: S
authors.lastname: Kim
authors.forename: Kilwon
authors.initials: K
authors.lastname: Cho
authors.forename: Joan E
authors.initials: JE
authors.lastname: Curry