Novel electro-rheological nanocrystalline dielectric particles modified with or embedded in organics

Inorganic-organic materials consisting of dielectric particles and organics were synthesized through in-situ processing of metalorganic precursors. BaTiO3 precursor was synthesized from barium metal, titanium isopropoxide and 4-octyloxyphenol (OP). The modified Ba-Ti alkoxide could successfully afford OP-modified BaTiO3 nano-particles below 100 degreesC. KNbO3 precursor was synthesized by the reaction control of potassium ethoxide, niobium ethoxide and acetoacetoxyethyl methacrylate. The organic matrix included nanometer-sized crystalline particles depending upon the hydrolysis conditions. The nanocrystalline particles were identified by XRD, electron diffraction and energy dispersive X-ray analysis. The hybrid nanocomposites revealed an interesting electrorheological (ER) behavior on applying DC field. The yield stress increased with increasing applied voltage and volume ratio of nano-particles. The hybridization of nanocrystalline particles and organic matrix was found to give a pronounced effect on ER properties. (C) 2003 Elsevier Ltd. All rights reserved.