Study on the doping and interactions of metal nanoparticles in the lyotropic liquid crystals

The hydrophilic silver and hydrophobic gold nanoparticles are doped simultaneously or seperately into different regions of a lyotropic liquid crystal (LLC) with long-range structural order built with the AOT/isooctane/water ternary system. A stable lamellar hybrid is produced under suitable conditions. Polarized optical microscopy and small angle X-ray scattering are used to compare the phase changes upon various doping manners; The interactions between doped particles and surfactant bilayers are analyzed and compared in detail. Factors affecting the stability of inorganic/organic hybrids are also discussed. The doped hydrophobic particles affect the equilibrium of van der Waals and Helfrich interactions between them and the membranes. When hydrophilic particles are incorporated into LLC aqueous region, electrostatic force will be dominant. The results suggest that it is the balance of electrostatic, van der Waals, and Helfrich forces in the lyotropic liquid crystal that determine the hybrid structure.