Relaxation spectra of polymers and phenomena of electrical and hydrophobic recovery: Interplay between bulk and surface properties of polymers

Low-density polyethylene, polypropylene, and polycarbonate were exposed to cold air plasma treatment. The decay of electret response, hydrophobic recovery, and mechanical relaxation of polymers were studied experimentally. The three-exponential decay kinetic model was used for the treatment of mechanical and electret responses. The characteristic time scales of mechanical and electret responses turned out to be very close. The “longest” relaxation time, extracted from the experimental study of the hydrophobic recovery, was also close to the corresponding characteristic time spans of electret and mechanical responses. The kinetics of surface processes taking place in polymers is controlled by the mobility of their functional groups, represented by the bulk relaxation spectra.