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Thermal effects on the percolation behavior of polyvinylidene fluoride/nickel composites
Author(s) -
Panda M.,
Thakur A. K.,
Srinivas V.
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.31223
Subject(s) - materials science , composite material , polyvinylidene fluoride , percolation threshold , dielectric , percolation (cognitive psychology) , wetting , polymer , permittivity , electrical resistivity and conductivity , biology , optoelectronics , engineering , neuroscience , electrical engineering
Percolation theory predicts the ideal percolation threshold ( P C ) for insulator/conductor composites (ICC) to be at 0.16 of the conductor volume fraction in the composite. In this article, we have investigated the percolation behavior in polyvinylidene fluoride/nickel (Ni) composites by varying the Ni concentration. It is observed that the thermal effect/time of heat treatment play a crucial role in changing the value of P C in a simple random continuum percolative ICC. The effect is attributed to decrease in: (i) intercluster distance, (ii) viscosity of the polymer, and (iii) wetting of the polymer to metal. The heat energy helps the polymer matrix to be melted as a result the metal particles/clusters come closure, that causes an increase in the cluster size of the metal particles. The overall effect is lowering of P C mainly due to decrease in intercluster distance. A drastic enhancement in the dielectric permittivity with increase of metal content is explained using boundary layer capacitive effect arising due to Maxwell–Wagner–Sillars interfacial polarization of accumulated charges at the metal–polymer interfaces and blocking of charge carriers at the insulating boundary. The substantial enhancement of ac conductivity at the P C is attributed to leakage of charge carriers across the insulating barrier. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010