Electrorheological activity of a composite of titania-coated montmorillonite

A new kind of composite of montmorillonite coated by titania (MMT/TiO₂) nanocrystallites was synthesized by the means of the sol-gel technique for use as an electrorheological (ER) active material. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) measurements showed that TiO₂ was deposited on the surface of the montmorillonite particles as anatase nanocrystallites. The MMT/TiO₂ composites were used as an ER fluid by dispersing them in silicone oil. It was found that the MMT/TiO₂ ER fluid had a notable ER effect under a DC electric field and the coating content of TiO₂ was demonstrated to have an important influence on the ER effect. When the coating content of TiO₂ was about 22.7 wt%, the yield stress of the MMT/TiO₂ ER fluid reached its maximum, which was about 4 times that of a pure MMT ER fluid and 20 times that of a pure TiO₂ ER fluid.