Contact angle measurements by axisymmetric drop shape analysis and an automated polynomial fit program

Low-rate dynamic contact angles of eight liquids on an inert (non-polar) FC -722 surface and a non-inert (polar) poly(propene-alt-N-methylmaleimide) co polymer are reported using two different contact angle methods: axisymmetri c drop shape analysis (ADSA) and an automated polynomial fit (APF) scheme. The latter technique was found to be more sensitive to minute surface heter ogeneity and/or roughness of the surface. For the non-inert solid-liquid sy stems, very complex contact angle responses were observed with both methods . If one omits these inconclusive contact angle measurements, the values of gamma(1v) cos theta change smoothly with gamma(1v) for these polymers, ind ependent of which of the two methods is used. When comparing with previousl y studied maleimide copolymer surfaces, a consistent change in the wettabil ity was observed as the length of the side chains decreases from hexyl to m ethyl groups. (C) 1998 Elsevier Science B.V. All rights reserved.