Effects of monomer organization on the photopolymerization kinetics of acrylamide in lyotropic liquid crystalline phases

The synthesis of nanostructured polymer gels via polymerization of hydrophilic monomers in lyotropic liquid crystal (LLC) phases has recently been of great interest. This work describes the effects of monomer organization on the photopolymerization kinetics of acrylamide in various LLC phases of surfactant/water systems. Resulting polymer morphology is reported as well. The polymerization rate of acrylamide is significantly enhanced when performed in the presence of various LLC phases. An unprecedented 10-fold increase in polymerization rate is observed in bicontinuous cubic and hexagonal phases as compared to polymerizations in water. This significant increase in polymerization rate is a result of diffusional limitations on the propagating polymer as well as segregation and ordering phenomena induced by the LLC phase. C-13 T-1 relaxation times and N-14 NMR spectra show that the monomer strongly associates with the interface of the surfactant/water assemblies and assumes the orientational order of the LLC phases to some degree. When formed using photopolymerization, the resulting polymer morphology appears to be a direct template of the parent LLC phase.