Wearable Pressure/Touch Sensors Based on Hybrid Dielectric Composites of Zinc Oxide Nanowires/Poly(dimethylsiloxane) and Flexible Electrodes of Immobilized Carbon Nanotube Random Networks

• Published in: ACS applied materials & interfaces Vol. 13; no. 35; pp. 42014 - 42023
• Main Authors: Kang, Byeong-Cheol, Park, Sang-Joon, Ha, Tae-Jun
• Format: Journal Article
• Language: English
• Published: American Chemical Society 08.09.2021
• Subjects: Applications of Polymer, Composite, and Coating Materials; hybrid dielectric composite; capacitive-type; wearable pressure/touch sensor; flexible electrode; effective dielectric constant
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c10961

Capacitive-type physical sensors based on hybrid dielectric composites of zinc oxide nanowires/poly­(dimethylsiloxane) (ZnO NWs@PDMS) and flexible electrodes of immobilized carbon nanotube (CNT) random networks, which are highly sensitive to pressure and touch stimuli, are demonstrated. Immobilized CNT random networks densely entangled in a Nafion matrix improve the electrical stability of wearable pressure sensors against mechanical stress with a bending radius of 5 mm. The effect of ZnO NW incorporation into PDMS on the sensing performance of pressure sensors is investigated, which results in a significantly enhanced sensitivity of 8.77 × 10–4 Pa–1 in low-pressure regions, compared to pristine PDMS (1.32 × 10–4 Pa–1). This improvement is attributed to the increase in the effective dielectric constant (εr) of the hybrid dielectric composites with their piezoelectric properties. In addition, wearable pressure/touch sensor arrays capable of detecting ultralow pressures (down to 20 Pa) and the real-time identification of touch and pressure stimuli via different sensing mechanisms are demonstrated. We believe that the multifunctionality introduced by the proposed sensors can extend the potential of physical sensor applications, while they are suitable for integration with wearable electronics based on hybrid nanocomposites and interfaces.