Nanoscale Analysis of Surface Modifications on Silanized Glass: Wettability Alteration and Long-Term Stability

TL;DR

This study analyzes nanoscale surface modifications on silanized glass beads, revealing decreased hydrophilicity and increased stability against water-induced changes, with implications for wettability control in porous media applications.

Contribution

It provides detailed nanoscale insights into chemical and structural changes of silanized glass surfaces and evaluates their long-term stability under humidity exposure.

Findings

Silanization reduces surface energy and polar groups.

Silanized surfaces become smoother with increased treatment.

Water exposure causes minimal changes in silanized samples.

Abstract

To investigate the effect of wettability on multiphase flow in porous media, hydrophilic glass surfaces are typically modified through a silanization process. This study examines the nanoscale chemical and structural modifications of glass bead surfaces treated with Surfasil, using inverse gas chromatography and atomic force microscopy. The results show that silanization reduces both specific and dispersive components of surface energy, indicating fewer polar groups and lower total energy, leading to decreased hydrophilicity compared to untreated glass beads. BET surface area measurements and AFM images reveal that the surface becomes progressively smoother with increased silanization. Subsequently, this study assessed the stability and extent of surface modifications in silanized samples caused by adsorbed water during storage, using untreated glass beads as a reference. Untreated samples exhibit increases in surface roughness and polar groups, leading to marginal increase in surface energy and hydrophilicity. In contrast, the silanized samples show resistance to water adsorption, with only minor alterations in surface energy and structure, likely occurring in areas where the silanization coating was incomplete. The results suggest that humidity control is crucial during extended storage, as prolonged moisture exposure could still lead to surface modifications, even in silanized samples, potentially affecting wettability consistency in repeated experiments.