Anomalies in Contact Angle Behaviour for Ethyl Alcohol–Water Mixtures

MEASUREMENTS of static contact angles for alcohol/water mixtures on pretreated copper surfaces are presented in Fig. 1. The results indicate that, for ethyl alcohol concentrations up to 8 per cent by weight, a constant contact angle of 72° is attained. Analogous behaviour has been, observed by Franke1 when measuring mutual diffusivities where a minimum value was reported at 10 per cent concentration. Hoffman et al.2 have shown a maximum value of the temperature coefficient of the surface tension of ethyl alcohol/water mixtures at 8 per cent weight.