Journal of Polymer Science Part B: Polymer Physics, Vol.37, No.16, 2039-2051, 1999
Low-rate dynamic contact angles on poly(methyl methacrylate/ethyl methacrylate, 30/70) and the determination of solid surface tensions
Low-rate dynamic contact angles of 12 liquids on a poly(methyl methacrylate/ethyl methacrylate, 30/70) P(MMA/EMA, 30/70) copolymer were measured by an automated axisymmetric drop shape analysis-profile (ADSA-P). It was found that five liquids yield nonconstant contact angles, and/or dissolve the polymer on contact. From the experimental contact angles of the remaining seven liquids, it is found that the liquid-vapor surface tension times cosine of the contact angle changes smoothly with the liquid-vapor surface tension (i.e., gamma(lv) cos theta depends only on gamma(lv) for a given solid surface or solid surface tension). This contact angle pattern is in harmony with those from other methacrylate polymer surfaces previously studied.(45,50) The solid-vapor surface tension calculated from the equation-of-state approach for solid-liquid interfacial tensions(14) is found to be 35.1 mJ/m(2), with a 95% confidence limit of +/- 0.3 mJ/m(2), from the experimental contact angles of the seven liquids.
Keywords:contact angle;dynamic;contact angle;equation of state;contact angle;drop shape;contact angle;complexity;surface tension;of solid;surface tension;from contact angle;surface tension;methacrylate polymer