Enhanced dielectric properties of polymer composite films induced by encapsulated MWCNTs with a one core-two shell structure

Multiwalled carbon nanotubes (MWCNTs) can endow high dielectric constant to polymer-based composites. However, the accompanying poor dispersion of MWCNTs and high dielectric loss for composites severely limit their application in dielectric field. Herein, a modified acid-treated MWCNTs encapsulated by the polyaniline/poly(sodium 4-styrenesulfonate) layers ( a MWCNTs@PANI-PSS) with a one core-two shell structure was fabricated by in situ polymerization followed by electrostatic self-assembly technique. Furthermore, the composite films based on a MWCNTs@PANI-PSS/poly(vinylidenefluoride-hexaflouropropylene) (PVDF-HFP) were fabricated by a solution-casting method. An ultrathin insulating PSS shell is wrapped onto a MWCNTs@PANI, resulting in the improvement of dispersibility for a MWCNTs@PANI and the decrease of dielectric loss for composite films. When the content of a MWCNTs@PANI-PSS is 5.0 wt %, the dielectric constant of a MWCNTs@PANI-PSS/PVDF-HFP reaches 430 (100 Hz), which is about 55 times of pure PVDF-HFP and 1.7 times of a MWCNTs@PANI/PVDF-HFP (247). Besides, the responding dielectric loss of a MWCNTs@PANI-PSS/PVDF-HFP composite film is only 0.67, much lower than that of a MWCNTs@PANI/PVDF-HFP (25) and a MWCNTs/PVDF-HFP (3185). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 948–956