Polymerization of cubosome and hexosome templates to produce complex microparticle shapes

Cubic and hexagonal liquid crystalline particles, or cubosomes and hexosomes, are used as templates to polymerize various monomers to produce particles with unique micron-scale geometric shapes. Emulsion droplets containing water, ethanol, and the lipid glyceryl monooleate are suspended in a yield stress fluid and used to produce shapes based on cubic and hexagonal symmetry by slow crystallization. The underlying liquid crystalline ordering of the aqueous lipid system drives symmetric shape formation, while its amphiphilicity allows incorporation of various organic monomers. Photopolymerization of monomers in the lipid templates creates polymeric particles shaped like polyhedra based on cubic symmetry as well as biconical cylinders based on hexagonal symmetry, and their shape is preserved after template removal. Product particle shapes are controlled by varying the structures and hydrophobicity of the monomers, as they control formation of different phases and microstructures. Monomer polarity determines whether the template can exhibit hexagonal phase, as when divinylbenzene is used, or cubic phase, when di(ethylene glycol) dimethacrylate is used. The monomers also control the microstructure of the final particles produced, forming rigid shapes composed of linked polymer nanospheres when divinylbenzene or di(ethylene glycol) dimethacrylate are used, and soft hydrogel particles when N,N'-methylenebisacrylamide is used.