SURFACE MICELLES FORMATION BY ADSORPTION OF BLOCK COPOLYMERS

We discuss the adsorption of asymmetric diblock copolymers from a selective solvent onto an adsorbing surface, in the case when the block interacting unfavorably with the solvent only partially wets the surface. We calculate the wetting angle of an adsorbed droplet of copolymers, and we show that it differs only slightly from the contact angle given by the Young law. The main prediction of the model concerns the existence of a critical surface micellar concentration (csmc) different from the bulk one (cmc). When the contact angle, which characterizes the interfacial interactions between the copolymer, adsorbing surface, and solvent, is lower than some universal value theta-0c congruent-to 51-degrees, surface micelles appear at a lower copolymer concentration than bulk ones. The size distribution of these surface micelles is also studied.