Flexible piezoelectric device directly assembled through the continuous electrospinning method

Abstract

Flexible piezoelectric devices could be widely used as important components in the future of electronic skin, foldable screens, robotics, and more. Herein, an integrated flexible piezoelectric device based on polyurethane/silver nanowire (PU/AgNW) electrodes and a piezoelectric polyurethane/polyvinylidene fluoride-trifluoroethylene [PU/P(VDF-TrFE)] layer was assembled directly through the continuous electrospinning method. The sheet resistance of the PU/AgNW electrode is 1.4 Ω sq−1 without tensile strain, and the integrated device exhibits high flexibility, high water-vapor permeability, and excellent work stability. Furthermore, both the PU/AgNW electrode and the piezoelectric device perform with excellent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), attributed to the incorporation of the silver nanowires. The cross-section SEM image shows a uniform structure of the device, which implies a good connection between electrode layers and the piezoelectric layer. The open-circuit output voltage, short-circuit output current and power density of the device can reach up to 47.9 V, 31.8 μA, and 35.3 μw cm−2, respectively. This study presents a fabrication strategy for both flexible conductive electrodes and piezoelectric devices, and it shows a promising application for monitoring human-activity and harvesting energy from ambient environments.

A review of silver nanowire-based composites for flexible electronic applications

“…The main reason is the interaction of silver ions (Ag + ) with microbial organisms, penetrating cell walls and inhibiting cell respiration [216]. Furthermore, silver can also bind to the DNA or RNA of bacteria and inhibit bacterial replication [217]. Ag NPs are commonly used for these applications due to the ease of preparation and large surface area (when compared to the bulk) which helps in the efficient release of Ag + .…”

“…The Ag NWs/GO composite electrodes exhibited good environmental stability as well, with only a minor increase in sheet resistance. A flexible piezoelectric device with antibacterial properties was devised by Xue et al wherein integrated flexible polyurethane/silver nanowire (PU/Ag NW) electrodes and piezoelectric polyurethane/polyvinylidene fluoride-trifluoroethylene (PU/P(VDF-TrFE)) layer were assembled using a continuous electrospinning method [217]. Both the composite electrode and the piezoelectric device were reported to demonstrate very good antibacterial activity against E. coli and S. aureus.…”

The Potential of Electrospinning to Enable the Realization of Energy-Autonomous Wearable Sensing Systems

“…The composite structure had high water vapor permeability under a constructed test method due to the porous nature of the electrospun membrane. A repeated (20 Hz) force with 32 N applied over the device (3 cm × 4 cm) could generate V OC of 47.9 V, I SC of 31.8 μA, and a maximum power density of 35.3 μW cm –3 through a 10 MΩ resistor and was stable for 20000 cycles …”

“…Layer 2 was prepared using PU/P(VDF-TRFE) electrospinning, while layer 3 was prepared by repeating the procedure for layer 1 (Figure 7c). The developed electrode resulted in 1.4 Ω sq −1 sheet resistance 145 Mechanical and chemical modification of the electrospun piezoelectric and conductive layers can significantly improve performance. For example, Diaz Sanchez et al used needleless electrospinning technology to produce a sponge-like 3D structured PENG piezoelectric layer with LiCl salt loaded P(VDF-TRFE)/poly(ethylene oxide) (Figure 7d).…”

A comprehensive review on branched nanofibers: Preparations, strategies, and applications

“…Since the late 1990s, the popularity of nanofibers has been rising as evident from expanding the number of publications. Nanofibers have unique properties (e.g., small diameter of fibers, 11,12 high specific surface area, 13,14 flexibility, 15,16 good pore structures, 17,18 ease of functionality, 19,20 low density, 21,22 excellent mechanical properties, 23,24 and exceptional adjustability 25,26 ). Therefore, they can be used in different areas such as energy harvesting, [27][28][29] antibacterial applications, 30,31 tissue engineering, 32,33 biomedical applications, [34][35][36][37] self-cleaning surfaces, 38,39 sensors, 40,41 catalyst, 42,43 filtrations, 44,45 and food packaging.…”