Major role of process conditions in tuning the percolation behavior of polyvinylidene fluoride based polymer/metal composites

Abstract

The percolation behaviour of a polymer/metal composite (PMC), comprising polyvinylidene fluoride (PVDF)/nanocrystalline nickel (n-Ni) prepared by cold press and hot press methods, has been compared. Higher effective dielectric constants (εeff) with lower loss tangent (Tan δ) were observed for the cold pressed samples as compared to the hot pressed samples, which is attributed to better homogeneity and uniform distribution of n-Ni in the PVDF matrix. The percolation parameters [percolation threshold (fc) and critical exponents (s and s′)] are largely tuned due to the difference in process conditions. The non-universal fc, s, and s′ have been explained with the help of the percolation theory. PMC prepared though cold pressing would be a better candidate for static and low frequency dielectric applications.