High-performance electrorheological elastomers enabled by rough-surfaced TiO 2 nanoparticles and a curing agent with a tuneable ratio of interfacial reinforcement

Abstract Rough-surfaced TiO 2 nanospheres were synthesized via a sol–gel method and employed as electro-responsive particulates in electrorheological (ER) elastomers. Their higher interfacial polarization capability compared with smooth counterparts was confirmed to enhance ER activity. The morphology, structure, crystallinity, and thermal stability of the nanospheres were characterized by Fourier transform infrared spectroscopy, x-ray diffraction, and thermogravimetric analysis. The ER performance of TiO 2 -based polydimethylsiloxane (PDMS) elastomers (30 vol%) was evaluated under various electric fields. At 4 kV mm –1 , the increase in storage modulus (Δ G ′) was found to be 5.85 MPa, demonstrating a linear dependence on field strength. Compared with the highest reported values of Δ G ′ for inorganic polarizable fillers, the present system exhibited performance that was up to four times higher, highlighting its superior electro-response. Furthermore, varying the PDMS prepolymer/curing agent ratio from 9:1 to 8:2 and 7:3 revealed an important difference: while pure PDMS loses modulus due to network imbalance when there is an excess of curing agent, ER elastomers gain strength through interfacial reinforcement via hydrogen bonding between the residual curing agent groups and the hydroxylated TiO 2 surfaces. These findings demonstrate tunable rheology and the potential for applications in adaptive damping, stiffness control and flexible smart devices.