Structure and wettability of various silica surfaces: Evaluation on the nano and macro levels

Abstract

Microscopic and macroscopic wettabilities of various silica surfaces modified with trimethylsilyl groups were studied, focusing on the effect of their surface geometrical structures. Micro and macro geometrical structures were investigated by water vapor adsorption. Microscopic wettability was determined by water vapor adsorption, while macroscopic wettability was determined by measuring the contact angle. Microscopic wettability affects the continuous two-dimensional water layer, while macroscopic wettability is influenced by capillary condensation and surface roughness. Surface wettability is essentially governed by microscopic wettability, which is a primary property of various silica surfaces. Capillary condensation and surface roughness enhance wettability as a secondary effect which results from the primary property of microscopic wettability.