Piezoelectric Polymer Films for Application in Monitoring Devices.

摘要

To develop Army applications based on the pronounced piezoelectric effect noted for polyvinylidene fluoride (PVF2), this laboratory has conducted a systematic investigation of factors responsible for this remarkable behavior of an organic polymer. Commercial PVF2 homopolymer and copolymer films were oriented by uniaxial stretching, biaxial stretching, or rolling. The oriented films were characterized by means of infrared spectroscopy, density, birefringence, sonic modulus, and X-ray diffraction. The oriented films were then poled at various electric field strengths and temperatures for various times. Trends have been noted between draw ratio and the resulting physical properties; the piezoelectric activity has been correlated with draw ratio and poling conditions. The piezoelectric activity has also been investigated after accelerated temperature aging and isothermal aging. Prototype devices have been fabricated at AMMRC with these films to demonstrate their potential utility in microphones, vibration sensors, and strain gages. Further development efforts have been conducted jointly with industrial firms to produce more refined prototype devices, including a remarkable medical sensor. It is concluded that piezoelectric polymer films can provide unique and advantageous solutions to a number of Army problems requiring monitoring and communication devices. (Author)