Studies of Transport Phenomena and Electrostatic Interactions in Polyacrylate Gels

Abstract

The transport of uncharged electroactive probes, 1,1‘-ferrocenedimethanol and 4-hydroxy-TEMPO, and electroactive cations, Tl+, was studied in polyacrylate hydrogels using steady-state voltammetry at platinum and mercury film microelectrodes. It was found that, for concentrations of polymer less than 1.5%, the diffusion coefficient of uncharged probes does not differ significantly from that observed in aqueous solutions without a polymeric network. For the probe cation, strong electrostatic interactions were observed between Tl+ and anionic polymeric networks; those interactions resulted in a significant decrease in the diffusivity of Tl+ cations. Experimental data for Tl+ transport in sodium polyacrylate gels were compared with predictions of Manning's theory for polyelectrolyte solutions. Electrostatic interactions between Tl+ and anionic polyacrylate three-dimensional gel network were found stronger than those predicted for solutions of an equivalent polyelectrolyte. Electrostatic effects for gels were ...