Highly Sensitive Impact Sensor Based on PVDF-TrFE/Nano-ZnO Composite Thin Film

Abstract

A thin film of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) has good flexibility and simple preparation process. More importantly, compared with PVDF, its piezoelectric β-phase can be easily formed without mechanical stretching. However, its piezoelectricity is relatively lower. Therefore, at present, PVDF-TrFE is always compounded with other kinds of piezoelectric materials to solve this problem. The effect of nano-ZnO doping amount on the sensing characteristics of the piezoelectric films was studied. PVDF-TrFE/nano-ZnO films with different nano-ZnO contents were prepared by spin coating process and packaged. The dispersion of nano-ZnO dopants and the crystallinity of β-phase in piezoelectric films with different nano-ZnO contents were observed by scanning electron microscopy and X-ray diffraction, and the piezoelectric strain constants and dielectric constants were measured, respectively. The effect of different nano-ZnO contents on the output performance of the piezoelectric sensor was obtained by a series of impact experiments. The results show that the piezoelectric strain constant and dielectric constant can be increased by doping nano-ZnO in PVDF-TrFE. Moreover, the doping amount of nano-ZnO in PVDF-TrFE is of great significance for improving the piezoelectric properties of PVDF-TrFE/nano-ZnO thin films. Among the prepared piezoelectric films, the output voltage of PVDF-TrFE/nano-ZnO piezoelectric sensor with 7.5% nano-ZnO doping amount is about 5.5 times that of pure PVDF-TrFE. Thus, the optimal range of the doping amount for nano-ZnO is about 4–10%.

Materials as Machines

“…This is because steric‐driven effects lead to the spontaneous crystallization of the active polar β phase in the TrFE copolymer 87. Still, PVDF‐TrFE is outperformed by PVDF, and efforts to incorporate ZnO nanoinclusions have improved the copolymer's d 33 from 12 to 31 pCN −1 , but only at low applied electric field frequencies 88. Other semicrystalline polymers have also been explored as piezoelectrics, including polyamides,80,89 liquid crystalline polymers,90–93 and polyureas,80,94 each with their own processing, mechanical, and performance trade‐offs.…”

Acoustic–electric conversion and piezoelectric properties of electrospun polyvinylidene fluoride/silver nanofibrous membranes

“…The piezoelectric response (d 33 , YE2730, APC, USA) of the poled electrospun nanofibrous membranes was analyzed using a wide-range d 33 meter. This is a special instrument with a high compliance electrode mechanism ideally suited to thin films and polymers, and can directly measuring the d 33 values of piezoelectric materials [36]. For the d 33 characterization, circular specimens were prepared with a diameter of 10 mm and thickness of 0.15 mm for each test.…”

An Impact Location Method Based on Transmission Coefficient Weighted Impact Intensity

“…The resistance film method can locate the impact and leakage by arranging a large number of thin film sensors, to monitor the resistance or capacitance change caused by the shape change of the structure. Some researchers have developed this kind of sensor with PVDF material which can be applied to many structures with good sensitivity [7][8][9]. However, the system would be too complicate in large range applications.…”