We present results of equilibrium swelling studies of the ionizable copolymer gel, methyl methacrylate/N,N-dimethylaminoethyl methacrylate 70/30 mol%, in buffered and unbuffered electrolyte solutions. The experimental conditions were designed to demonstrate the sensitivity of swelling in ionized gels to the electrolyte composition of the external solution. In general, gel swelling as a function of solution ionic strength is shown to be highly nonmonotonic and is particularly sensitive to the valence and concentrations of ions present in solution. A rigorous test of ideal Donnan equilibrium theory shows that the latter is unable to explain all the data in a self-consistent manner. However, a heuristic procedure based on the ideal Donnan theory can predict qualitatively the observed trends. While not quantitative, this heuristic approach provides considerable insight into the mechanisms underlying the swelling behavior under various solution conditions. Possible causes of nonideal behavior are discussed, and some observed specific ion effects are reported and discussed.
|Original language||English (US)|
|Number of pages||18|
|Journal||Journal of Biomaterials Science, Polymer Edition|
|State||Published - 1994|
Bibliographical noteFunding Information:
part by a predoctoral NIH training grant to BAF 38035, and a grant from the Whitaker Foundation.
This work was funded in (GM07174), NIH grant DK
- Donnan equilibrium
- ion exchange
- ionizable gels