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Lowering the percolation threshold of conductive composites using particulate polymer microstructure
Author(s) -
Grunlan Jaime C.,
Gerberich William W.,
Francis Lorraine F.
Publication year - 2001
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 - 10.1002/1097-4628(20010425)80:4<692::aid-app1146>3.0.co;2-w
Subject(s) - percolation threshold , carbon black , materials science , composite material , microstructure , dispersity , polymer , percolation (cognitive psychology) , composite number , volume fraction , conductivity , electrical resistivity and conductivity , polymer chemistry , chemistry , natural rubber , neuroscience , electrical engineering , biology , engineering
The percolation thresholds of carbon black–polymer composites have been successfully lowered using particulate polymer starting materials (i.e., latex and water‐dispersible powder). Composites prepared using carbon black (CB) and commercial poly(vinyl acetate) (PVAc) latex exhibit a percolation threshold near 2.5 vol % CB. This threshold value is significantly lower than that of a comparable reference composite made from poly( N ‐vinylpyrrolidone) (PNVP) solution and the same CB, which exhibits a sharp rise in electrical conductivity near 15 vol % CB. This dramatic difference in critical CB concentration results from the segregated microstructure induced by the latex during composite film formation. Carbon black particles are forced into conductive pathways at low concentration because of their inability to occupy volume already claimed by the much larger latex particles. There appears to be good qualitative agreement between experimental findings and current models dealing with conductive behavior of composites with segregated microstructures. Lack of quantitative agreement with the models is attributed to the polydispersity of the polymer particles in the latex. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 692–705, 2001