Colloid-liquid-crystal composites: An unusual soft solid

Mixing model colloidal particles with a thermotropic nematic liquid crystal results in a soft solid with significant storage modulus (G' similar to 10(3) - 10(5) Pa). The soft solid comprises a network of particle aggregates, formed by the exclusion of particles from emergent nematic domains as the mixture is cooled below the isotropic-nematic transition. The unusually high storage modulus of the colloid-liquid-crystal composites may be due to the local frustration of nematic order within the particle aggregates. The birefringent soft solid is potentially important as a switchable electro-optical material that can be readily handled and processed.