Unexpected Resistance of Polyelectrolyte Brushes Formed via Surface-Initiated Polymerization on Glass and Sitall

Poly(dimethylaminoethyl methacrylate) and poly(2-carboxyethyl acrylate) brushes, including enriched with Li+ cations, were grafted to the glass and glass-ceramic via radical polymerization initiated by immobilized low molecular weight 4,4'-azobis (4-cyanopentanoic acid) and multi-site oligoperoxide metal complex initiators. The atomic force microscopy method was used to characterize and determine the thickness of polymer layers. Surface tension and contact angle of modified substrates were studied using contact angle measurements. It was revealed that resistance properties of grafted brushes studied in the frequency range 10(-3)-10(6) Hz by impedance spectroscopy depend on the initiator, substrate, and polymer natures and can be explained by the formation of polymer brushes of different packing densities on the substrates. It was assumed that 4-6 orders falling values of resistance observed for "grafting from" polyelectrolyte brushes initiated by 4,4'-azobis (4-cyanopentanoic acid) on glass substrate was caused by proton conductivity.