Hidden ordered structure of clay nanosheets in binary colloids of niobate and clay nanosheets disclosed by small-angle neutron scattering

Abstract

Binary colloids of two different nanosheet species are promising systems for novel integrated materials because of their multicomponent and multiphase coexistence utilizable in novel smart materials. Among the binary colloids, niobate–clay binary nanosheet colloids are characterized by unusual photochemical functions and phase separation at a mesoscopic (∼several tens of micrometers) scale. The present study clarifies the colloidal state of the clay nanosheets in the mesostructured aqueous binary colloid of hexaniobate and fluorohectorite clay nanosheets by using small-angle neutron scattering (SANS) with the contrast variation technique. Compared to small-angle X-ray scattering (SAXS) that preferentially detects the niobate nanosheets, contrast variation SANS measurements can match out each nanosheet species to detect liquid crystalline ordering of each nanosheet species. The SANS results demonstrate the coexistence of two liquid crystalline phases induced by niobate and clay nanosheets, respectively, in the niobate–clay binary nanosheet colloids.