Synthesis of nanomaterials in Highly Swollen Liquid Crystals

Highly Swollen Liquid Crystals (SLC) that exhibit hexagonal, cubic or lamellar symmetry have been demonstrated to form a new type of soft nanoreactors. These mesophases are formed by a quaternary mixture combining a surfactant, an aqueous solution of inorganic salt, cyclohexane as a hydrophobic swelling solvent and pentanol-1 as a co-surfactant. Unlike previous works that used a “nanocasting” approach in a binary liquid crystal, the composition of these SLC allows syntheses to be proceeded inside the aqueous and/or the organic phase. Therefore inorganic, metallic or organic materials can be prepared and the geometry of the SLC controls the final shape of the prepared by this approach. We will describe various materials that were obtained by different processes in these SLCs: rod-like nanoaggregates of metal nanoparticles were synthesized by chemical reduction in the aqueous part of the hexagonal mesophase, microrods of zirconia were obtained by slow crystallogenesis from hydrated zirconium oxychloride, mesoporous zirconia was prepared by a faster hydrolysis and polymer micro- and nano-fibers were obtained in the organic phase by photopolymerization or radiolysis. We will show how the changements in the SLC structure can modify the structure of the compounds synthesized inside and that this system constitutes a quite universal medium for the preparation of nanomaterials or nanostructured systems.