Phase-dependent shear-induced order of nanorods in isotropic and nematic wormlike micelle solutions.

摘要: Small angle X-ray scattering with in situ shear was employed to study the assembly and ordering of dispersions gold nanorods within wormlike micelle solutions formed by surfactant cetylpyridinium chloride (CPyCl) counter-ion sodium salicylate (NaSal). Above a threshold CPyCl concentration but below isotropic-to-nematic transition micelles, self-assembled under quiescent conditions into isotropically oriented domains hexagonal order. Under steady at rates between 0.5 7.5 s−1, nanorod assemblies acquired macroscopic orientational order which planes were coincident flow-vorticity plane. The could be re-dispersed strong re-assembled following cessation shear. In nematic phase micelles higher concentration, did not acquire instead smectic-like layers gradient–vorticity plane Finally, still where form phase, showed no translational nematic-like due alignment flow. Depletion forces mediated are identified as driving mechanism for this sequence behaviors, suggesting novel controlled, reconfigurable nanoparticles solution.