Effect of Copolymer Architecture on the Efficiency of Compatibilizers

We use analytical arguments and numerical self-consistent field (SCF) calculations to calculate the interfacial tension, γ, for a system of AB copolymers localized at the interface between two immiscible homopolymers, A and B. In particular, we fix the molecular weights of the copolymers but vary their architecture from diblock, star, and various comb copolymers. The results from both methods show that diblock copolymers are the most efficient at reducing γ. We also observe that at fixed molecular weight (N), as the number of teeth (n) is increased, the comb becomes significantly less efficient and the disparity between combs and diblocks grows larger. However, when we compare combs and diblocks with different molecular weights, we observe a trade-off between N and n. In particular, long combs with multiple teeth are more efficient than short diblocks. These studies allow us to predict the reduction in interfacial tension produced by a wide variety of copolymers and thereby permit a rational design of effective compatibilizers.