Knowledge Bank

The adsorption of ethylene glycol onto the fused silica surface was studied by vibrational sum frequency generation spectroscopy. The clean silica/air SFG spectra shows that, in the OH stretch region $(3000-3800cm-1)$, there is only one dangling silanol OH stretch at $3760cm-1$ for 20relative humidity, whereas both silanol and broad OH stretching peaks (3200 and $3400cm-1$) were observed after the fused silica was immersed in neat water. At the air-silica interface, the adsorption of ethylene glycol was observed even after it was thoroughly rinsed with neat water for 30 minutes. The disappearance of the silanol OH stretching peak shows that the ethylene glycol molecules occupy most of the surface silanol sites.