Stimuli-Responsive Colloidal Assembly Consisting of Imogolite, Inorganic Nanotube

Abstract

In this review, I describe stimuli-responsive colloidal assemblies prepared from a rigid rod-like clay mineral called imogolite, and relate them to their structural characteristics. When combined with dicarboxylic acids, imogolite formed gels that exhibited keen thixotropy, and physical anisotropy via orientation of the imogolite particles after flowing and subsequent standing. Robust hydrogels were also obtained by in-situ polymerization of vinyl monomers in imogolite aqueous dispersion. Under strain, these hydrogels showed a reversible isotropic–anisotropic structural transition.