Poly(amide acid)-mediated glass fiber fabric/Pb(Zr,Ti)O3 piezoelectric composites with high flexibility and sensitivity

Poly (amide acid) acts as an interfacial mediator via hydrogen bonding. • PZT content is increased by 2.8 times with an optimized PAA concentration of 8 wt%. • Sintered flexible GFF/PZT composite forms a continuous piezoelectric ceramic network. • The flexible sensor achieves high sensitivity and excellent durability. Flexible piezoelectric composites have attracted increasing interest for sensor applications. However, for flexible fiber-based piezoelectric composites, constructing a continuous ceramic network with high loading and robust interfacial bonding on the fiber fabric remains challenging. In this study, we fabricated flexible glass fiber fabric (GFF)/PZT piezoelectric composites. Poly (amide acid) (PAA) was introduced as a molecular mediator on the GFF, where PAA forms hydrogen bonds with the hydroxyl group and acetate groups of the PZT sol, enabling a 2.8-fold increase in PZT loading at an optimized PAA concentration of 8 wt%. The resulting GFF/PZT composite exhibits a continuous ceramic phase and retains good flexibility with a minimum bending radius of 15 mm. After encapsulation with interdigitated electrodes via epoxy resin (Ep), the GFF/PZT/Ep sensor achieves a minimum bending radius as low as 2.5 mm and exhibits enhanced electrical properties: a dielectric constant of 147, a low dielectric loss of 0.01 at 10 3  Hz, and an inverse piezoelectric coefficient of 119.5 p.m./V. As a bending sensor, it delivers a high sensitivity of 7.52 V per unit flexural strain and excellent durability over 1000 cycles. As a vibration sensor, it attains a sensitivity of 211.16 mV/g at 10 Hz and maintains stable output over 10,000 cycles. This work offers a promising strategy for developing flexible piezoelectric composites for energy conversion applications. Download: Download high-res image (1MB) Download: Download full-size image