Swelling and mechanical behavior of ionized poly(acrylamide-co-N,N’-diethylacrylamide) gels in water/acetone mixtures and in water at various temperatures

Ionized networks of random copolymers of acrylamide (AAm) and N,N’-diethylacrylamide (DEAAm) (mole ratios of xAAm/xDEAAm=1/0,0.75/0.25,0.5/0.5,0.30/70,0.15/0.85,0/1) with various amounts of ionic comonomer-sodium methacrylate (MNa) (mole ratios to all monomers xMNa=0.0,0.025,0.05) and crosslinker – N,N’-methylenbisacrylamide (MBAAm) were prepared at high dilution in water. Their swelling and mechanical behavior was investigated in water at various temperatures (from 10 to 90 °C) and in water/acetone (w/a) mixtures at room temperature. For some copolymers the transition region from expanded to collapsed state was observed at critical concentration of acetone, ac, in w/a mixtures or at critical temperature, Tc, in water. It was found that with increasing content of DEAAm component in copolymers the ac values increase; the similar increase was observed with increasing xMNa. Neat PDEAAm and copolymers with the highest DEAAm content exhibit temperature transition; both increasing amount of AAm and charges bound on the chains (xMNa) in copolymers shifts the Tc temperatures to higher values very efficiently (for more than 20 °C).