Core/shell nanocomposite based on the local polarization and its electrorheologi

2019-09-01 09:44:19

shell titanium oxide kaolinite

责任者: Wang, Baoxiang;Zhao, Xiaopeng 单位: Institute of Electrorheological Technology, Department of Applied Physics 141#, Northwestern Polytechnical University, Xian, 710072, China 来源出处: Langmuir,2005,21(14):6553-6559 摘要: Aimed at the increase of electrorheological effect, a novel core/shell material was prepared by the combination of mechanochemical activity and sol-gel technique. The structure analyses X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, and energy-dispersive spectrometry showed that a modified kaolinite/titanium oxide nanocomposite consisted of the mechanochemically activated kaolinite/NaCl complex coated by titanium oxide. A distinct enhancement of the electrorheological activity was found by using such particles dispersed in silicone oil than those of kaolinite or titanium oxide alone under a direct current electric field. Modified kaolinite/titanium oxide electrorheological fluid has a larger dielectric constant enhancement Δεe prime , and a strong interfacial polarization occurs with a clear dielectric loss peak around 2 kHz. Doping NaCl into the core (kaolinite) by the mechanochemical activation and limiting the transferring of the ions by the shell (titanium oxide) may increase the interfacial polarizability of particles and induce a high electrorheological effect. © 2005 American Chemical Society. 关键词: Nanostructured materials;Rheology;Polarization;X ray diffraction analysis;Fourier transform infrared spectroscopy;Titanium oxides;Energy dispersive spectroscopy;Electric field effects;Scanning electron microscopy;Sol-gels;Dielectric loss;Electrorheological effects;Kaolinites;Polarizability