Adhesion force behaviors between two silica surfaces with varied water thin film due to substrate temperature studied by AFM

The adhesion force between two silica surfaces was measured to investigate the effect of substrate temperature using an atomic force microscope (AFM) at various relative humidities (RH). Results show that the adhesion force behavior largely depends on the thickness of water thin film and surface conditions. At different RHs, the adhesion force decreases with the increase of substrate temperature, which was attributed to the decrease of water film thickness on surfaces due to dehydration and/or dehydroxylation. However, a hysteresis of adhesion force was observed by increasing and decreasing substrate temperature. When the substrate temperature returns back to a low value, the adhesion force becomes abnormally large, which was attributed to rehydroxylation, rehydration, and the evaporation of organic contaminants. At low RH (5 +/- 1 %), the adhesion force also becomes abnormally large after cooling, which was attributed to the formation of siloxane bonds between the cantilever and sample surfaces. These results may help facilitate the anti-adhesion design of small-scale silicon-based systems under different conditions.