Deionization-induced colorless transparency in physical gels formed by clay aqueous dispersions

Abstract

Physical gels formed by aqueous clay dispersion are typically turbid and have a milky appearance. The colorless and transparent nature of gels expands the potential for novel applications. In this study, we successfully produced a transparent gel by deionizing the gel as much as possible while maintaining its dynamic elastic modulus, akin to water. The aqueous clay suspensions exhibited specific sol-gel regions corresponding to the type of clay. According to images obtained through cryo-SEM, the three-dimensional network formed by clay became finer when deionization was carried out, and the aqueous dispersion exhibited Rayleigh scattering. The reduction in the extent of Mie scattering due to the suppression of clay aggregation through deionization results in its colorless transparency. This transparent gel will open up various potential applications, including 3D printing support structures, 3D cell culture, 3D art and displays with dispersed materials, educational materials with visual effects, enhancing traditional products, and innovative engineering applications.