Observation of Dendritic Islands within Complete Octadecyltrichlorosilane Monolayers

Thin self-assembled monolayers of organosilanes are commonly used as surface-energy modifiers; adhesion promoters; or in nanotechnology applications, either as resists or as building blocks in multilayer systems. The ordering of individual molecules within such a monolayer is very important to its applications and its properties. Numerous studies of the formation mechanism of these monolayers have been reported; one such growth mechanism via the formation of dendritic islands was observed under certain preparation conditions. Here we report on the visualization of star-shaped or dendritic domains, even within a complete self-assembled monolayer of octadecyltrichlorosilane, by imaging these monolayers in liquid-mode atomic-force microscopy. Significant differences of the oxidation properties of the dendritic islands, in contrast to the surrounding areas, could be demonstrated by electrooxidative lithography, which suggests different properties of the island-like structures within the octadecyltrichlorosilane film.