Tailoring Actuated Performance of Ti ₃ C ₂ T x MXene /Fluorosilicone Rubber Composites via Controlling BaTiO ₃ Particle Size and Content

Fluorosilicone rubber (FSR) has emerged as a promising matrix for actuator composites, while the trade‐off between dielectric performance and mechanical robustness restricts its practical applications. Herein, we report a series of FSR/Ti 3 C 2 T x MXene composites modified with nano‐sized BaTiO 3 (nBT) and micro‐sized BaTiO 3 (μBT) to investigate the size‐dependent effects of BaTiO 3 on composite performance. Owing to the coordination effect between MXene and BaTiO 3 , uniform dispersion of fillers was achieved, and the composites exhibited thermal stability exceeding 400°C. The FSR/MXene composite with 8 phr (parts per hundred rubber) nBT showed a tensile strength of 486 kPa, elongation at break of 194%, and elastic modulus of 356 kPa, superior to the μBT‐modified composite. It also possessed a higher dielectric constant (12.85 at 10 3 Hz) and lower dielectric loss (0.00522) than μBT‐modified counterparts, attributed to stronger interfacial polarization and less particle agglomeration. Notably, an actuated strain of 19.58% at 45 kV mm −1 was achieved, 35.7% higher than the μBT‐modified composite. This work reveals that BaTiO 3 particle size significantly regulates the synergistic interaction between ceramic particles and conductive MXene, providing a feasible strategy for designing high‐performance FSR‐based composites toward soft actuator and sensor applications.