Morphology-Dependent Behavior of PVDF/ZnO Composites: Their Fabrication and Application in Pressure Sensors

• Published in: Sensors (Basel, Switzerland) Vol. 25; no. 9; p. 2936
• Main Authors: Zhang, Binbin, Zhang, Wenhui, Luo, Wei, Liang, Zhijie, Hong, Yan, Li, Jianhui, Zhou, Guoyun, He, Wei
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 07.05.2025; MDPI
• Subjects: composite materials; Electric fields; Electrodes; Glass substrates; Morphology; Nanoparticles; Nitrates; Polyvinylidene fluoride; pressure sensors; Printing-ink; PVDF; Scanning electron microscopy; Sensors; Spectrum analysis; Zinc oxide; Zinc oxides; China; Japan; Shanghai China; PVDF; zinc oxide; pressure sensors; composite materials
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s25092936

This study investigated the impact of zinc oxide’s (ZnO’s) morphology on the piezoelectric performance of polyvinylidene fluoride (PVDF) composites for flexible sensors. Rod-like (NR) and sheet-like (NS) ZnO nanoparticles were synthesized via hydrothermal methods and incorporated into PVDF through direct ink writing (DIW). The structural analyses confirmed the successful formation of wurtzite ZnO and enhanced β-phase content in the PVDF/ZnO composites. At a degree of 15 wt% loading, the ZnO-NS nanoparticles achieved the highest β-phase fraction (81.3%) in PVDF due to their high specific surface area, facilitating dipole alignment and strain-induced crystallization. The optimized PVDF/ZnO-NS-15 sensor demonstrated superior piezoelectric outputs (4.75 V, 140 mV/N sensitivity) under a 27 N force, outperforming its ZnO-NR counterparts (3.84 V, 100 mV/N). The cyclic tests revealed exceptional durability (<5% signal attenuation after 1000 impacts) and a rapid response (<100 ms). The application trials validated their real-time motion-monitoring capabilities, including finger joint flexion detection. This work highlights the morphology-dependent interfacial polarization as a critical factor for high-performance flexible sensors, offering a scalable DIW-based strategy for wearable electronics.