Stereocomplex formation in mixed polymers filled with two-dimensional nanofillers

The presence of nanofillers, such as graphene, can effectively promote stereocomplex formation in poly(l-lactide)/poly(d-lactide) blends. However, the detailed microscopic mechanism of the improved formation of stereocomplex crystallites (SCs) in filled polylactides is still unclear. Therefore, we performed dynamic Monte Carlo simulations to reveal the underlying mechanism of the effect of two-dimensional nanofillers on the formation of SCs in polymer blends. It was observed that the nanofillers can lead to the occurrence of heterogeneous nucleation of mixed polymer chains. On one hand, the miscibility of mixed polymers is improved in the interfacial regions, attributed to attractive interactions between polymers and nanofillers. On the other hand, for the heterogeneous nucleation process, chains prefer to crystallize by means of intermolecular packing alignment. Both phenomena contribute to the promotion of SCs.