Preparation and electrorheological properties of a squared chromium-ion-doped MOF-Ti/SiO2 composite.

Herein, a core–shell structured nanocomposite with excellent electrorheological (ER) properties was successfully prepared for studying ER fluids (ERFs). First, the material was prepared by using chromium (Cr)-ion-doped Ti-based metal–organic frameworks (MOF-Ti) as a template using the solvothermal method, followed by coating with SiO 2 via hydrolysis to form Cr-MOF-Ti/SiO 2 composite. In combination with the advantages of the MOF-Ti structure, such as more active sites and a high specific surface area, doping with transition metal ions and coating with SiO 2 can effectively enhance the interfacial polarisation of the obtained Cr-MOF-Ti/SiO 2 composite and thus improve its ER performance. Analyses were conducted on the morphology, elemental composition and functional groups of the materials using scanning electron microscopy, transmission electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller and dielectric analysis. The results indicate successful Cr-ion doping and SiO 2 coating. The ER performance of the composite particles was also evaluated. The results indicate that the SiO 2 -coated sample exhibits superior ER properties, including a smaller leakage current density and higher shear stress. Moreover, the SiO 2 coating enhanced the interfacial polarisation capability of Cr-MOF-Ti, as verified by the dielectric data. [ABSTRACT FROM AUTHOR]