One Pot Double Network Hydrogels: Progress Towards Synthesis of Applicable Crosslinking Agents

Abstract

Our work initially looked at the possibility of being able to synthesis a double network hydrogel in just one free radical polymerisation. We intended to carefully select three compounds based on their copolymerisation reactivity under free radical conditions. This reactivity would generate a tightly cross-linked network first, followed by a loosely cross-linked network in one process. The hypothesis was tested by a Monte-Carlo simulation which showed that this two network state was achievable with known reactivity ratios. This work primarily focuses on the synthesis of novel cross-linkers based on N-vinyl pyrrolidone (1). This monomer has the necessary copolymerisation ratios with methyl methacrylate for this project, so simple difunctional analogues of 1 were designed. The synthesis and purification of these analogues proved not to be straightforward, and in the end only very small amounts of a suitable material were obtained. While the idea has merit, new ways of synthesising the key cross-linker still need to be found.