Wettability of quartz by methanol and ethanol aqueous solutions

Abstract

Measurements of the contact angle were carried out in the systems: quartz — droplet of methanol in aqueous solution — air and quartz — droplet of ethanol in aqueous solution — air. The measured contact angle values were correlated with those calculated theoretically. For calculations the values of the dispersion and nondispersion components of surface free energy of quartz with monolayer water film, and values of surface tension and its dispersion and nondispersion components of methanol and ethanol aqueous solutions, taken from the literature were used. For these calculations, values of surface tension components of the above mentioned solutions determined theoretically on the assumption that the alcohol adsorption at the interface solution — air is negligible were also used. From the calculations it was shown that the contact angles calculated and measured would be compatible if it is assumed that adsorption of alcohol molecules from solution on a quartz surface is smaller than at a solution-air interface.