ZnO–PTFE-based antimicrobial, anti-reflective display coatings and high-sensitivity touch sensors

Abstract

Due to the rapid transmission of bacterial infections via microbial-contaminated interactive touch devices, functional coatings that can eradicate microbial contamination are in high demand. Furthermore, flexible and transparent antimicrobial touch/tactile sensors have received considerable attention on account of their wider applicability in personal electronic devices. Herein, anti-reflective, hydrophobic, antimicrobial zinc oxide-polytetrafluoroethylene (ZnO–PTFE) composite thin films with sensorial capabilities are developed via a sputtering technique. The ZnO–PTFE exhibits a significantly low refractive-index, high transmittance, and excellent hydrophobic properties, along with outstanding antibacterial activities of ∼6.2 and ∼4.7 for E. coli and S. aureus, respectively. Importantly, the major issue of zinc dissolution in water from the ZnO material is controlled in this study by compositing with PTFE to realize long-term water-stability and mechanical durability of ZnO films. Further, a triboelectric nanogenerator (TENG) based antimicrobial self-powered touch sensor that delivered recordable pressure/touch sensitivity is developed based on ZnO–PTFE composite films. In which, the ZnO–PTFE composite-based TENG is shown to provide a high triboelectric output voltage of ∼224 V, a current density of ∼21.4 μA cm⁻², and a power density of 1.65 mW cm⁻². Furthermore, the linear response of the TENG to driven pressure indicates its excellent pressure-sensing ability, with an unprecedented sensitivity of 75.31 V kPa⁻¹ and a touch sensitivity of 31.36 V kPa⁻¹. Further, the real-time application of ZnO–PTFE as a display coating and self-powered touch sensor is demonstrated. This work demonstrates a simple route towards the design of smart antimicrobial coatings with multifunctional capabilities for a wide range of applications in interactive devices for a safer experience.