Vivid-Colored Electrorheological fluids with simultaneous enhancements in color clarity and Electro-Responsivity

Surface modification of dielectric materials changes the dipole-dipole interactions under electric fields, thereby controlling the electrorheological (ER) response. The introduction of metal oxides onto mica templates and further coating of dyes is expected to simultaneously improve the color clarity and ER performance.

Dye-coated TiO₂ platelets on mica are synthesized for high-performance colorful ER fluids. A sol-gel method is utilized to grow TiO₂ on mica to prepare precursor light-colored mica/TiO₂ materials, which are coated with appropriate dyes to enhance the vividness as determined by the Commission Internationale de clairage L*a*b* color system. The color expression and color clarity improvement are explained via the light interference effect and the presence of chromophores.

The uniform TiO₂ layers can be obtained under low pH conditions with controlled nucleation kinetics. The addition of dyes to TiO₂ increases the surface area and porosity of ER materials and introduces heteroatoms that act as positive factors. In practical ER applications, dye-coated TiO₂-based ER fluids exhibit higher ER performances compared with the corresponding light-colored TiO₂-based ER fluids. The vivid-colored ER fluids could provide an easy selection for a wide range of rheological systems requiring a specific magnitude of stress by confirming the color.