Ultrathin Epidermal P(VDF-TrFE) Piezoelectric Film for Wearable Electronics

Abstract

Ultrathin epidermal piezoelectric sensors are essential in the next generation of wearable flexible electronics due to their conformal contact with the skin. However, the fabrication and peeling of ultrathin film still face great challenges, and there is an urgent need to develop a facile and effective process. Here, we propose a method of combing spin-coating and aqueous phase exfoliating to prepare the ultrathin poly(vinylidene fluoride-ran-trifluoroethylene) (P(VDF-TrFE)) piezoelectric film with a thickness of about 3 μm. And the thermal treatment is employed to improve its crystallinity and piezoelectricity, resulting in the piezoelectric coefficient of 11.67 pC N −1 and fine sensitivity of 4.56 mV kPa −1 . The ultrathin device is successfully applied to monitor the signals of arterial pulse and interactive force, which is expected to provide references for medical diagnosis and robot design. Notably, this work might motivate design principles and methods of ultrathin epidermal devices and promote its applications in wearable flexible electronics.

Liquid Electrolyte-Assisted Electrospinning for Boosting Piezoelectricity of Poly (vinylidene Fluoride) Fiber Mats

“…In addition, the hysteresis loops of amplitude (butterfly curve) and the phase of ferroelectric PVDF indicate ferroelectric property of P15−W fibers, which is in line with other piezoelectric PVDF films reported in the literature. 34,77,78 Generally, there is a good linear relationship between V OC signals and the dynamic pressure applied to piezoelectric materials, and the slope of the V OC −pressure fitting curve indicates pressure sensitivity as well as the piezoelectric properties of the materials correspondingly. The piezoelectric output properties of PVDF fiber mats prepared by waterassisted electrospinning with different concentrations of PVDF solution are similar, yet they have a slope of V OC −pressure much larger than that of the P15-A fiber mat (Figure 4f and Table S1).…”

“…The generated electrical signals are completely reversed when swapping the electrodes connected to the sensor sample (Figure e), indicating piezoelectric signal response to impact force in the P15–W fiber mat. , Furthermore, there is a distinct phase change angle between the PVDF fiber and silicon wafer base under applied electric voltage (Figure g), indicating piezoelectric response of the P15–W fiber revealed by a piezoelectric force microscope (PFM). In addition, the hysteresis loops of amplitude (butterfly curve) and the phase of ferroelectric PVDF indicate ferroelectric property of P15–W fibers, which is in line with other piezoelectric PVDF films reported in the literature. ,, …”

Smart materials for sustainable energy

“…These windows offer energy savings, cost efficiency, and affordability. The increasing architectural trend toward using more glass, coupled with the demand for energy conservation, presents a unique opportunity for smart windows [20][21][22][23][24][25]. Smart shades: Smart shades, composed of zinc and steel, utilize shape memory alloy wires to monitor sunlight entering structures and regulate CO2 levels.…”

Multilayer stacked ultra-wideband perfect solar absorber and thermal emitter based on SiO2-InAs-TiN nanofilm structure

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