DYNAMIC MEASUREMENTS OF SURFACE-TENSION OF SOLUTIONS OF POLYISOBUTYLENE IN MIXTURES OF POLYBUTENE OIL AND DECALIN

The results of surface tension and of dynamic contact angle measuremen ts performed on a Cahn electrobalance for several solutions of polyiso butylene in mixtures of Decalin and polybutene oil are presented. The solid probe is submitted to cycles of immersion-emersion within the fl uid. The force exerted on the solid is recorded vs. the depth of immer sion for different values of the solid-liquid relative velocity. Sever al phenomena are discussed: formation, deformation, break of the menis cus, draining of the fluid. Different behaviours are observed for the polybutene oil and a polymer solution of the same zero-shear viscosity and same static surface tension. This indicates that, in the vicinity of the interfaces, the microscopic structure of the fluid has to be c onsidered.