REINFORCEMENT OF POLYMER-POLYMER INTERFAC E WITH COPOLYMER - STUDY OFINTERFACIAL-TENSION

We have studied rite effects of a graft copolymer poly(dimethylsiloxan e-g-polylethylene oxide) on the interfacial tension (gamma) between po ly(dimethylsiloxane) (PDMS) and poly(ethylene oxide) (PEO). The unexpe cted variation of gamma with time shows a drecrease corresponding to t he adsorption of the copolymer molecules at the interface, followed by a slow increase towards an equilibrium tension resulting from a pseud o-surface phase transition in the interfacial layer. The interfacial t ension decreases with the copolymer concentration The application of G ibb's law gives a specific area per copolymer molecule of 1.8 nm(2) an d an interfacial thickness of 1 nm.