Incorporating nanostructure in organic polymer materials encompasses a wide-range of kinetic, thermodynamic, and property relationships that differ greatly from classical polymer science. A promising method of controlling polymer network structure utilizes self-assembling lyotropic liquid crystals to direct polymer structure on the nanometer scale. The photopolymerization reaction in the ordered template of the LLC phase significantly influences the polymerization mechanism including dramatic changes in kinetic constants, overall polymerization rate, and polymerization rate fluctuations that coincide with structural changes during polymerization. Large differences in the mechanical and transport properties are also observed in the resulting nanoporous polymer network. In fact, a three-fold increase in the compressive modulus and a doubling of the equilibrium water uptake compared to isotropic polymers can be readily achieved as a result of the nanostructure as directed by the LLC templating process. The ordered pore structure has beneficial uses in stimuli-responsive polymer systems as well and can increase the deswelling rate of temperature sensitive poly(N-isopropylacrylamide) hydrogels by over an order of magnitude. Additionally, the water- and oil-soluble domains of the LLC phase provides a method of compatibilizing thermodynamically incompatible monomers to produce useful materials that incorporate properties inherent of the individual networks into the final polymer material. LLC templating provides a method of improving polymer properties for use in a growing number of advanced industrial and biomedical applications.

Polymer nanostructures through photopolymerization in lyotropic liquid crystalline templates

245th National Meeting (2013)

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