Very different structures and properies result from the preparation of polymer networks from the same weakly charged polyurethane acrylate anionomer (UAA) dissolved in two different solvents, water and dioxane, during cross-linking. The UAA polymer readily dissolved in organic solvent such as dioxane but forms dispersions with water. Networks prepared in water (UAAG networks) and then dried show much higher hydrophilicity (swelling in water of pH11) than their counterparts (UADG network), which are cross-linked in dioxane and the dried. The different thermodynamic equilibrium structure achieved in the two polymer/solvent mixtures are locked into diferent network structures by the cross-linking reaction.