Fluorosilane modification on BaTiO 3 particles: A facile method to fabricate PVDF dielectric composites with desirable mechanical properties

Abstract Dielectric capacitors have attracted much attention due to their excellent power density and long service life. Its development trend is mainly towards miniaturization, lightweight, and integration. In this work, barium titanate (BaTiO 3 , BT) particles were modified by four different coupling agents and then were introduced in polyvinylidene fluoride (PVDF) matrix to prepare PVDF/BT dielectric composites. Thermodynamic, dielectric, mechanical, and rheological properties were researched. After the combination of the surface‐modified BT and PVDF, the dielectric constant ( ≈ 33) of the composites increased by 4–5 times compared to PVDF ( = 7.8), and the dielectric loss also was obviously reduced. One remarkable thing was that modification of 1H,1H,2H,2H‐perfluorooctyltriethoxysilane (F8261) could improve the mechanical properties of composites significantly, especially in toughness. For example, the impact strength of PVDF/F8261‐BT (12.8 kJ/m 2 ) was 103.1% higher than that of PVDF/KH550‐BT (6.3 kJ/m 2 ), and even 13.3% higher than that of PVDF (11.3 kJ/m 2 ). This simple preparation method is a good grafting tactic and has a positive effect on the dielectric properties and toughness of the composites. Highlights A method for enhancing the dielectric and mechanical properties of composites. Comparing the effects of four coupling agents on the properties of composites. F8261 can significantly improve the impact toughness of PVDF/BT. PVDF/F8261‐BT with 30 vol% filler has a dielectric constant of 34.5 at 10 2 Hz.