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

Polymer blends, which provide improved rheological and mechanical properties, are difficult to mix and leads to high energy interfaces between the components. This results in significant mechanical weakness but can be mediated by using compatibilizers. Here, we use molecular dynamics simulations to determine the effect of different types of compatibilizers on the interfacial behavior between two types of identical polymer chains. We investigate the effects of three types of copolymers (diblock, random and alternating) and compare its effect to inorganic sheet-like compatibilizers. 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 copolymers at equal volume fractions. We also show that sheet fillers reduce slip, thus providing for improved stress transfer across the interface, leading to a stronger blend. However, the localization of sheet fillers at the interface can be a possible limiting factor. Thus, we attempted to bracket the limits of sheet filler behavior by either allowing them to maximally localize at the interface or where the segregation at interface is kinetically limited. This step is highly dependent on sample preparation.