Investigation of the impact of cross-polymerization on the structural and frictional properties of alkylsilane monolayers using molecular simulation

Abstract

Cross-linked chemisorbed n-alkylsilane (CH 3 (CH 2 )n -1 Si(OH) 3 ) monolayers on amorphous silica surfaces have been studied and their structural properties and frictional performance were compared to those of equivalent monolayers without cross-linkages. The simulations isolated for the first time the effects of both siloxane cross-linkages and the fraction of chains chemisorbed to the surface, providing insight into a longstanding fundamental question in the literature regarding molecular-level structure. The results demonstrate that both cross-linkages and the fraction of chemisorbed chains affect monolayer structure in small but measurable ways, particularly for monolayers constructed from short chains; however, these changes do not appear to have a significant impact on frictional performance.