Effects of Repulsion Parameter and Chain Length of Homopolymers on Interfacial Properties of An/Ax/2BxAx/2/Bm Blends: A DPD Simulation Study

Abstract

We explored the effects of the repulsion parameter (aAB) and chain length (NHA or NHB) of homopolymers on the interfacial properties of An/Ax/2BxAx/2/Bm ternary polymeric blends using dissipative particle dynamics (DPD) simulations. Our simulations show that: (i) The ternary blends exhibit the significant segregation at the repulsion parameter (aAB = 40). (ii) Both the interfacial tension and the density of triblock copolymer at the center of the interface increase to a plateau with increasing the homopolymer chain length, which indicates that the triblock copolymers with shorter chain length exhibit better performance as the compatibilizers for stabilizing the blends. (iii) For the case of NHA = 4 (chain length of homopolymers An) and NHB (chain length of homopolymers Bm) ranging from 16 to 64, the blends exhibit larger interfacial widths with a weakened correlation between bead An and Bm of homopolymers, which indicates that the triblock copolymer compatibilizers (Ax/2BxAx/2) show better performance in reducing the interfacial tension. The effectiveness of triblock copolymer compatibilizers is, thus, controlled by the regulation of repulsion parameters and the homopolymer chain length. This work raises important considerations concerning the use of the triblock copolymer as compatibilizers in the immiscible homopolymer blend systems.