Abstract

Silane films, their structure and stability, are of great interest in processes such as flow in porous media, mineral flotation, chromatography and corrosion. Here, the structure of octadecyl thriclorosilane (OTS) films on glass surfaces is studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), their adhesion properties by contact angle measurements and adhesion tests. Complete glass surface coverage by the silane is attained after an immersion time tc characteristic of the OTS compound. The time evolution of the OTS films regarding surface coverage is monitored by SEM with a BSE detector, by measuring the OTS film thicknesses from XPS data, by AFM and by contact angle measurement. At tc the structure of the films changes from micromolecular to macromolecular. Below tc the glass coverage has a fractal geometry and various degrees of hydrophobicity are possible. At t > tc the surface coverage is complete and the contact angle achieved a well defined constant value.