Preparation and Swelling Behaviour of Polyampholyte Hydrogels Composed of Acryloyloxyethyl-trimethyl Ammonium Chloride and Acrylic Acid

A series of poly(acryloyloxyethyl trimethyl ammonium choride-co-acrylic acid)hydrogels were synthesized by solution polymerization and the structure of hydrogel was characterized by FTIR and NMR.Meanwhile,the swelling behavior of hydrogels in distilled water with vairous pH values and the salt solutions with different concentrations were investigated.The results show that the hydrogel with equal molar negative charges and positive charges presented an antipolyelectrolyte effect.Ionic strength drastically affected the swelling behavior of hydrogels.At the same time,the swelling kinetic parameters of swelling process of hydrogels were also calculated in salt solutions with different concentrations and the results illuminated that the first 60% swelling process of hydrogels was governed by Fickian diffusion mechanism(n≤0.5)in the salt solution with a high ionic strength.With the increase of ionic strength,the swelling ratio of the hydrogels and diffusion coefficients increased.