Emulsifying effects of block copolymers in incompatible polymer blends

Abstract

Abstract We discuss some theoretical aspects of interfacial and emulsifying activity of block copolymers A‐B in incompatible blends of homopolymers A and B. We predict the reduction in interfacial tension due to equilibrium adsorption of copolymers at the interface. It is shown that for an appropriate choice of block copolymer composition and molecular weight a very low interfacial tension can be achieved. This suggests a possible existence of a thermodynamically controlled stable droplet phase in which minority homopolymer particles protected by an interfacial film are suspended in a majority homopolymer matrix. The size distribution of the droplets depends on the rigidity and spontaneous radius of curvature of the interfacial film which, as we show, can be controlled by molecular parameters of copolymers.