Synthesis, characterization and electrorheological performance of polyaniline/organically modified titanium oxide hybrids

Abstract

A novel approach for synthesizing hybrid materials comprising polyaniline (PAni) and titanium dioxide (TiO₂) has been developed using ureasil-modified TiO₂ (U-TiO₂). Two distinct synthesis methods were explored, targeting at application in electrorheological (ER) fluids. The resulting hybrid particles were characterized using a comprehensive range of techniques, including thermal, structural, morphological, spectroscopic, and electrical analyses. ER fluids were formulated by dispersing the particles in silicone oil, and their rheological and dielectric behaviors were systematically evaluated. Among the methods studied, the in situ polymerization of aniline within a sol–gel emulsion containing U-TiO₂, without isolating the intermediate particles, yielded the U-TiO₂/PAni.C with superior results, including a maximum yield stress of 844 Pa under an applied electric field of 4 kV/mm. The ER fluids demonstrated excellent reversibility during repeated on–off electric field switching tests, highlighting their potential for practical applications. Comparative analysis with existing literature revealed that ER performance was significantly influenced by the concentrations of PAni and TiO₂, as well as particle morphology. Notably, the U-TiO₂/PAni.C hybrid developed in this study outperformed other reported PAni–TiO₂ systems, emphasizing its strong promise for advanced ER fluid applications. The great novelty of this research was the development of a high-performance, ureasil-modified TiO₂/polyaniline hybrid via an in situ polymerization route, resulting in unprecedented ER fluid performance, enhanced reversibility, and potential scalability.