SEGREGATION AT THE INTERFACE BETWEEN A HOMOPOLYMER AND A BINARY POLYMER BLEND

Low-energy forward-recoil spectrometry studies show that the interface between polystyrene (A) and a miscible blend of two poly(styrene-co-4- bromostyrene)s (B:C) has an interfacial excess of B, zB*, where B is the component with the lower bromostyrene level. At 170 °C, zB* increases with the bulk volume fraction of B, φB, has a maximum near 0.25, and then decreases. These results are in qualitative agreement with self-consistent field (SCF) calculations. SCF calculations of the interfacial tension and interfacial width predict that B has an optimum compatibilizing effect for φB∼0.25. © 1995 The American Physical Society.