Effect of Compatibilizers on the Structure and Dynamics at Polymer Blend Interfaces

We use coarse grained Molecular Dynamics simulations to determine the effect of diblock copolymers and inorganic sheet like compatibilizers at polymer blend interfaces. Previous studies have shown that the interfacial region is prone to slip if an external shear force is applied to the polymer blend. While a number of theoretical and computational studies have examined the effect of copolymer compatibilizers, the effect of adding sheet-like compatilibilizers (for e.g. nanoclay) has not been investigated computationally. Thus, while experiments have shown that sheet-like filler are effective, the exact mechanisms are unknown. Our results indicate that sheet like fillers that have equal affinity to either polymer in a binary blend can produce a larger reduction of interfacial tension when compared to diblock copolymers at equal volume fractions. However, the localization of sheet fillers at the interface can be a possible limiting factor. We also show that sheet fillers reduce slip, thus providing for improved stress transfer across the interface, leading to a stronger blend.