Amplifying Touch Using 3D ZnO Tetrapods for Tactile and Haptic Intelligence

Small. 2025 Apr;21(16):e2408414. doi: 10.1002/smll.202408414. Epub 2025 Mar 17.

Abstract

Advances in tactile and haptic intelligence are driven by development of advanced funtional materials capable of translating subtle physical interactions into precise electrical signals. This study presents an innovative approach to enhancing touch sensitivity by incorporating 3D Zinc Oxide (ZnO) tetrapods into a piezoelectric polymer matrix. The distinctive 3D architecture of the ZnO tetrapods significantly improves the mechanical-to-electrical conversion efficiency, thereby amplifying the material's ability to detect fine tactile forces. We optimized the loading of ZnO tetrapods within a Polyvinylidene fluoride (PVDF) matrix, resulting in a highly responsive composite material for tactile sensing. It exhibited exceptional performance in detecting minute pressure variations, with just 4 wt.% tetrapods in the polymer matrix. Output voltage and current of the composite matrix increased from 4 V, 0.5µA to 19 V, 2.5µA respectively when the concentration of the ZnO tetrapods is gradually increased from 0-4 wt.% and decreased with further increase in tetrapod concentration. Comprehensive analysis and applications of this piezoelectrical materialconfirmed its robustness across a range of pressure conditions. The amplification of touch sensitivity and signal responsiveness underscores the potential of 3D ZnO tetrapods for tactile and haptic technologies.

Keywords: 3D piezoelectric; ZnO; force detection; tactile sensor; tetrapods.