抄録
Gels exposed to stationary electric fields on the order of 0.1 to 1.0 V/cm were found to develop pH gradients. The development of these pH gradients appears to be a relevant phenomenon in explaining the phase transitions and volume changes of ionic gels induced by an electric field. It was also found that the occurrence of pH gradients is strongly affected by the type and concentration of the ions present in the gel. The ions in a gel could be classified into different categories, depending on whether they were counter-ions of the charged groups on the polymer network or free ions, and whether they would participate in electrochemical reactions or not. Using a simple theoretical consideration, which takes into account diffusion, ionic drift, dissociation equilibria and electroneutrality, the pH profiles of gels under stationary electric fields have been evaluated and compared with experimental results.
