Structural relaxation and dielectric response of PVDF/PMMA blend in the presence of graphene oxide

Structural relaxation of polymer chains exhibits high correlation to the macroscopic performance of polymers, and it has been well investigated and analyzed in the polymer systems. However, it is still challenging to accurately describe the structural relaxation of some complex systems, such as the nanomaterials incorporated blends. In this work, structural relaxations in the poly (vinylidene fluoride)/poly (methyl methacrylate) (PVDF/PMMA) blends in the presence of graphene oxide (GO) were systematically investigated via revealing the cooperativity concerning about segmental relaxation, chain relaxation relating to the crystallization behaviors using the broadband dielectric spectroscopy (DRS). In the presence of GO, the cooperative volume was enlarged and dynamic heterogeneity was weakened. And the chain relaxation αcmoved to higher frequency; while the αm relaxation associated with molecular motion in miscible amorphous region of PVDF/PMMA blends can be well resolved. Thus, the structure relaxations confirmed that GO could hinder the crystallization of PVDF but enhance the miscibility in the PVDF/PMMA amorphous phase. On the basis of structure relaxations, the dielectric properties as function of temperature and frequency were accordingly studied, and at room temperature PVDF/PMMA blends in the presence of GO exhibited higher constant and lower loss at low frequency regions.