Wettability of quartz in presence of nonionic surfactants and short chain alcohols mixtures

Abstract

Measurements of advancing contact angles for aqueous solution of Triton X-100 (TX-100) with methanol, ethanol and propanol mixtures and Triton X-165 (TX-165) with the same alcohols on quartz surface were carried out. From the obtained results it appeared that the wettability of quartz depends on Triton’s and alcohol concentrations and that there is a linear dependence between the adhesional and surface tension of aqueous solution of Triton’s and alcohols mixtures. This dependence can be described by linear equations which constants depend somewhat on the Triton’s and alchohols concentration. The slope of all linear dependencies between the adhesional and surface tension is positive. The critical surface tension of quartz wetting determined from these dependencies by extrapolating the adhesional tension to a value equal to the surface tension (for contact angle equal zero) depends on the assumption whether the concentration of Triton or alcohols was constant. The average value at constant Triton’s concentration was equal to 27.1 mN/m and was lower than that evaluated at constant alcohol concentration (29.5 mN/m). The critical surface tension of quartz wetting at constant alcohol concentration was nearly the same as the apolar component of the surface tension of quartz covered with water monolayer film. The positive slope of the adhesional-surface tension curves and the work of water adhesion, Triton’s and alcohols to quartz surface indicates that the interaction between water molecules and quartz surface might be stronger than that between quartz and surface active agents molecules. So, the concentration excess of surfactants at quartz–water interface is probably negative, and the possibility of the surface active agents to adsorb at quartz/water film–water interface is higher than that at the quartz–water. However, at alcohol concentration above that of its aggregation the molecules of the surface active agents probably destroy the strongly ordered film of water.