Core–Shell-Structured Electrorheological Fluid with a Polarizability-Tunable Nanocarbon Shell for Enhanced Stimuli-Responsive Activity

The incorporation of nanocarbon-based materials into electrorheological fluids has been shown to be an effective means of improving the electrorheological (ER) response. However, the mechanism of the sp 2 /sp 3 -hybridized carbon structure and high ER response is still under investigation. Herein, barium titanate@nanocarbon shell (BTO@NCs) composites are proposed and prepared by introducing carbonized polydopamine (C-PDA) into a shell. When the polymerization time of dopamine is tuned, the shell thickness, surface polar functional groups, and sp 2 /sp 3 -hybridized carbon can be effectively controlled. The maximum yield stress of the BTO@NCs-24 h ER fluid reaches 2.5 kPa under an electric field of 4 kV mm –1, which is attributed to the increased content of sp 3 C–OH and oxygenous functional groups within the shell, resulting in a rapidly achievable polarization. Furthermore, the SiO 2 @NCs and TiO 2 @NCs ER fluids are also prepared with enhanced ER behavior in these phenomena, confirming an approach to high-performance ER fluids based on nanocarbon composites.