Exploration of dielectric constant dependence on evolution of microstructure in nanotube/ferroelectric polymer nanocomposites

Multiwall carbon nanotube (MWNT) with high aspect ratio (AR=125–750) was dispersed into polyvinylidene fluoride (PVDF) to fabricate the MWNT/PVDF nanocomposites. Change of dielectric constant with increasing the length of tensile strain (LTS) was observed in the MWNT/PVDF composites with different mass concentration of MWNT (mMWNT=1.0% and mMWNT=2.0%). The results showed that an abrupt increase in dielectric constant appeared when the LTS was 4 and 2mm in the composites with mMWNT=1.0% and mMWNT=2.0%, respectively. By employing the evolutions of conductive pathway and microcapacitance structure during the tensile strain process, the increased dielectric constant could be explained well.