(The) preparation and electric field-responsive behavior of sodium polyacrylate hydrogel particles

Abstract

The electric field responsive behaviors of hydrogel micro- and nanoparticles of sodium polyacrylate, prepared by an inverse emulsion polymerization, were investigated, which follows the swelling transition under a DC electric field. Sodium polyacrylate was polymerized with N,N’-methylenebisacrylamide using a radical initiator in heptane containing emulsifiers and microparticles were prepared with different concentrations of crosslinking agents. While, the hydrogel nanoparticles were obtained by controlling emulsion droplet sizes using two emulsifiers, Span80 and Tween80. The micro and nanoparticles were characterized with various techniques such as fourier transform infrared spectroscopy, dynamic light scattering measurement, particle size analyzer and scanning electron microscopy. The electric field responsive behavior of the prepared hydrogel particles with different crosslinker concentration were measured with particles inserted in ITO electrodes cell by in-situ video monitoring. A significant reduction of electric field responsiveness of hydrogel particles was observed at a high crosslinker concentration. In fact, the electro-responsive swelling ratio of hydrogel particles could be reduced when crosslinking density increases.