Wearable piezoelectric device assembled by one-step continuous electrospinning

Abstract

A wearable piezoelectric membrane device of excellent flexibility, lightweight and air breathability is firstly intergrated by one step continuous electrospinning method. Piezoelectric membrane device displays a three-layer structure that PVDF nanofiber membrane is sandwiched between two PVDF-rGO electrode membranes. Since the whole piezoelectric device is prepared by elelctrospinning, both of active layer and electrode layer have high content of electroactive β-phase crystalline. The as-prepared device demonstrates high electric output. Open-circuit voltage, short-circuit current and power density can reach up to 46 V, 18 μA and 18.1 μW cm -2 , respectively. The electric output is remarkably affected by frequency and magnitude of exerted excitation force, especially the output present a linear relationship versus excitation force. Moreover, the piezoelelctric membrane device demonstrateds long time working stability of over 50, 000 circles and is capable to light LEDs directly. Fig. 2 Morphologies of PVDF-rGO electrode membrane (a, b) and PVDF nanofiber membrane (c, d); Schematic of piezoelectric device (e); Cross-sections of piezoelectric device assembled by continuous electrospinning (f).The piezoelectric membrane device integrated by one-step electrospinning has porous and uniform structure.

Smart Textile‐Integrated Microelectronic Systems for Wearable Applications

“…Besides polymer, other lead‐free solid materials such as lead zirconate titanate (PZT) particles and BaTiO 3 nanofibers, also have been utilized to make flexible piezoelectric nanogenerators, where the generator with BaTiO 3 nanofibers aligned vertically in the PDMS matrix achieved piezoelectric energy conversion output of 0.18 µW under a low mechanical stress of 2 kPa,162a and the maximum energy density of PZT composites under bending was found to be 14.3 J m −3 on a cotton textile . However, the electric output is remarkably affected by the frequency and magnitude of the exerted excitation force, specifically, the output demonstrates a linear relationship with the excitation force 159a. Thus, textile integrated microelectronic systems by using single piezoelectric effect are normally used for sensors (shown in Section ) not energy harvesters.…”

“…Comparing to piezoelectric generators made of uniform plane‐films, textile‐based or fiber‐based piezoelectric generators normally have higher conversion efficiency in wearable applications, due to high piezoelectric coefficient, flexibility, and ease of stress concentration. PVDF or PVDF composites made by electrospinning technologies are mostly utilized in wearable applications due to the merits of high piezoelectric coefficient, lightweight, and low stiffness (Figure b–e) . “3D spacer” technology was applied in the fabrication of all‐fiber piezoelectric fabrics, where the knitted single‐structure piezoelectric generator consists of spacers composed of piezoelectric PVDF monofilaments (with 80% β ‐phase) interconnected with two silver coated polyamide multifilament yarn layers serving as the top and bottom electrodes, can provide an output power density in the range of 1.10–5.10 µW cm −2 at applied impact pressures in the range of 0.02–0.10 MPa, showing superior performances over the existing 2D woven and nonwoven piezoelectric textiles .…”

Self-Polarization of PVDF Film Triggered by Hydrophilic Treatment for Pyroelectric Sensor with Ultra-Low Piezoelectric Noise

“…Recently, various methods have been developed to realize self-polarized PVDF films without undergoing thermal poling, including casting [21–25], spin coating [26, 27], Langmuir-Blodgett (LB) deposition [28], electrospinning [29–35], and depositing onto aqueous salt solution [36]. In general, self-polarization of the PVDF films can be observed through the above techniques due to different mechanisms, such as the salt-assisted [21–25], hydrogen-bonding interaction [21–25, 27, 36], built-in field [26] or strong electric field [29, 35] during deposition, and stretching during coating [26, 28, 36]. Yet, most of these methods only focused on the piezoelectric performance of PVDF films and neglected its pyroelectric property.…”

Polymer nanogenerators: Opportunities and challenges for large‐scale applications

“…Li et al . reported an interesting example of wearable piezoelectric device assembled by a one‐step continuous electrospinning method and where the PVDF nanofiber membrane is sandwiched between two PVDF‐rGO nanofibers electrode [Figure (b); (i)] . The device exhibits high flexibility, lightness, stretchability, and operational stability.…”