Bicontinuous hydrogel–hydrophobic polymer systems through emulsion templated simultaneous polymerizations

Polymerization in the external phase of a high internal phase emulsion (HIPE) yields an emulsion templated, porous polyHIPE. This work describes the synthesis of novel bicontinuous hydrogel–hydrophobic polymer systems through simultaneous polymerization and cross-linking reactions in the HIPE's external organic-phase (styrene or 2-ethylhexyl acrylate with divinylbenzene) and internal aqueous-phase (acrylamide with N,N-methylenebisacrylamide). The ability to reversibly dry and hydrate these materials demonstrates their potential for biomedical and separation applications. The unexpected and significant reduction in the hydrated polyHIPE modulus with increasing acrylamide content in the aqueous-phase indicated that the polymerizations were not mutually exclusive and that the acrylamide affected the molecular structure of the hydrophobic polymer synthesized in the external phase. The locus of initiation (which can be in the aqueous-phase, organic-phase, or both) was also shown to have a profound affect on the molecular structure, porous structure, and properties.