Some peculiarities of the kinetics of interaction of cationic hydrogels based on copolymers of vinyl esters of monoethanolamine and ethylene glycol with copper ions

Abstract

Over the past few decades, formation of polymer hydrogels complexes with metal ions, including transition ones, attracts the steady attention of researchers. The relevance of such study is due to the fact that the kinetics of swelling and contraction of hydrogels in various media has been studied in many works, however, this question remains insufficiently studied. Cationic hydrogels based on copolymer of vinyl ethers of monoethanolamine (VEMEA) and ethylene glycol (VEEG) as the study subject in the present work have been used. The kinetics of interaction cationic hydrogels based on copolymer of vinyl ethers of monoethanolamine and ethylene glycol with copper ions in aqueous solutions has been studied. It was shown that swelling behavior such hydrogel in this process is characterized two stages. At the initial stages of the interaction of the gel with the copper salt solution, the interaction in question is determined mainly by the displacement of water from the swollen mesh, due to the difference in osmotic pressures inside and outside the sample. At this stage, the kinetics of the gel contraction is described by the same laws as for polyelectrolyte hydrogel in the alkali metal solution. At the second stage, the network charge density increases due to the formation of a complex, and the degree of the gel swelling begins to increase with time. On the basis of the results obtained, it can be assumed that in systems of this kind, metastable states with differences in character from truly equilibrium states, persisting for a long time, can be formed.