Development of Novel Colorful Electrorheological Fluids.

Herein, the electrorheological (ER) performances of ER fluids were correlated with their colors to allow for the visual selection of the appropriate fluid for a specific application using naked eyes. A series of TiO 2 -coated synthetic mica materials colored white, yellow, red, violet, blue, and green (referred to as color mica/TiO 2 materials) were fabricated via a facile sol-gel method. The colors were controlled by varying the thickness of the TiO 2 coating layer, as the coatings with different thicknesses exhibited different light interference effects. The synthesized color mica/TiO 2 materials were mixed with silicone oil to prepare colored ER fluids. The ER performances of the fluids decreased with increasing thickness of the TiO 2 layer in the order of white, yellow, red, violet, blue, and green materials. The ER performance of differently colored ER fluids was also affected by the electrical conductivity, dispersion stability, and concentrations of Na + and Ca 2+ ions. This pioneering study may provide a practical strategy for developing new ER fluid systems in future.