Self-Assembled Monolayers of Vinyltriethoxysilane and Vinyltrichlorosilane Deposited on Silicon Dioxide Surfaces

Abstract

This study was aimed at deposition of self-assembled monolayers (SAMs) using vinyltriethoxysilane (VTES) and vinyltrichlorosilane (VTCS) molecules chemisorbed on silicon dioxide surfaces. The kinetics of SAM formation on planar glass substrates and silicon wafers was characterized by contact angle measurements. The surface free energy and its dispersion and polar components enabled to estimate the time of immersion required to deposit compact SAMs. Adsorption of organosilane molecules as a function of immersion time was characterized by X-ray photoelectron spectroscopy. The SAM thickness was evaluated by spectroscopic ellipsometry. Surface topography of deposited layers was investigated by atomic force microscopy (AFM). The VTCS/glass combination exhibited the fastest kinetics but the deposit was not uniform and included local agglomerates. The hydrophobic vinyl groups at deposit surface resulted in a surface free energy of 32 mJ/m².