Dielectric spectroscopy of particle-based waterborne coatings

Antistatic layers (thin films) formulated with nanoparticulate antimony-doped tin oxide or with electrically conducting emulsion polymers provide robust electronic conductivity that survives aqueous and thermal processing. Dielectric spectroscopy of nanoparticulate-binder (antistatic) coatings reveal relaxation processes that depend on particle to binder ratios and on coating or film thickness. The frequency maxima of dielectric loss peaks inversely correlate with surface electrical resistance measurements. A simple model of a layered heterogeneous dielectric explains the relative position of dielectric loss peaks in terms of antistatic layer conductivity. An observation of apparent percolation induced by variations in coverage, at constant tin oxide to binder weight ratio, suggests that the coating conditions and drying processes appear to play a pivotal role in network formation and nanoparticulate aggregation.