Effects of doped polymers on the phase behaviors of lyotropic liquid crystals

Fabrication of polymer or polymer-modified nanomaterials templated by lyotropic liquid crystals (LLC) is a promising way to obtain expected nanostructured functional materials. However, the structures of LLC are easy to be changed by environmental conditions. Therefore, investigation on interactions between polymers (or monomers) and LLC templates is significant for better controlling the structures and properties of nanomaterials. In this paper, polymers are doped into lyotropic lamellar liquid crystals formed with different types of surfactants. Effects of doped components on the phase behaviors of the lamellae are investigated in detail by small angle X-ray scattering and polarized optical microscope. In LLC made of anionic surfactant, sodium bis(2-ethylhexyl) sulfosuccinate (AOT), and water, doped polymers induce a swelling lamellar phase and an increased periodic spacing. While in LLC made of nonionic surfactant, tetraethylene glycol monododecyl ether (C12EO4), and water, polymer doping results in more orderly phase and a reduced interlayer spacing, with an exception of a low molecular weight polymer (PEG400). Results show that interactions between doped polymers and LLC vary with types and sizes of polymer molecules and also doping concentrations, which strongly influence the phase structures. Obtained results are helpful for designing suitable LLC templates and controlling the structures of expected nanomaterials.