Titanium oxide nanoparticle modified with chromium ion and its giant electrorheological activity

Titanium oxide nanoparticles modified with chromium ion are fabricated via a modified hydrolysis methods. The X-ray diffraction analyses, Fourier transform-infrared spectrometry, transmitting electron microscopy, etc., are used to determine the structure of the nanoparticles. The results show that modified titanium oxide nanoparticles possess small size distribution. The average particle size is 120 nm. The electrorheological (ER) activity was studied by the rheological curve and yield stress under an electric field. An excellent ER effect is found with the suspension of modified titanium oxide nanoparticles dispersed in silicone oil. At the DC electric field, modified titanium oxide nanoparticles ER fluid not only possess high static yield stress, but also have good dynamic shear stress. The large Δε′ and proper polarization response in this nanoparticles ER fluid induces a strong and stable interaction among the particles. These may be the intrinsic reason for the huge enhancement of ER effect. Furthermore good sedimentation property of its electrorheological suspension is observed.