Fabrication of high-kpoly(vinylidene fluoride)/Nylon 6/carbon nanotube nanocomposites through selective localization of carbon nanotubes in blends

The morphology, as well as the distribution of conductive fillers in conductive filler/polymer nanocomposites has a decisive effect on dielectric properties of blend composites. In this study, the relationship between morphology and properties are carefully investigated and the underlying mechanism was discussed based on the micro-capacitors model. Multiwalled carbon nanotubes (MWCNTs) were introduced into an immiscible poly(vinylidene fluoride) (PVDF)/polyamide 6 (Nylon 6) blend and the morphologies of PVDF/Nylon 6 were tailored by changing the weight ratio of PVDF to Nylon 6, varying from sea-island morphology to cocontinuous morphology. Interestingly, the CNTs are selectively localized in Nylon 6 phase in both sea-island and cocontinuous morphological blends, which are due to the finer interaction between Nylon 6 and CNTs. Only in sea-island morphological blend, a great increase of dielectric permittivity can be found when increasing the content of CNTs. It is surprised found that no effects of CNTs on dielectric properties can be found in cocontinuous morphological blend. In this case, the CNTs filled Nylon 6 domains in sea-island morphological blend act as a micro-capacitor with an improved charge accumulation and interfacial polarization, resulting in a great increase in dielectric permittivity.