Processing and Fabrication of PVDF Sensors as a Dynamic Pressure Sensor

Poly (vinyl fluoride) (PVDF) is a piezoelectric polymer used in various transducer applications due to its good mechanical strength and electrical properties. In the current study, PVDF films have been processed and a pressure sensor has been fabricated. To accomplish this, the quality of PVDF granules was analysed first. High MW (Mw ~ 530,000) PVDF granules (PVDF1) and low MW (Mw ~ 180,000) PVDF granules (PVDF2) were taken and these granules were subjected to rotational and oscillatory motion using a dynamic mechanical analyser to analyse the viscoelastic properties and the flow behaviour of the material. After detailed studies, it was found that PVDF1 has required low viscosity compared to PVDF2. PVDF films were then processed using PVDF1 granules by hot press method and then thermo-mechanically stretched to get piezoelectric β- phase, required for sensor applications. Complete dynamic mechanical thermal analysis of β- phase film was also done and strain-stiffening behaviour was observed. Thereafter, PVDF piezoelectric films have been used to design and fabricate the sensors and their sensitivity as a pressure sensor was evaluated. Calibration of the PVDF sensor was done for pressure measurement in the frequency range 80–10 kHz at acoustic pressures ranging from 0 to 270 Pascal against reference dynamic pressure sensor (microphone). This indigenously developed and characterised pressure sensor are useful for various automotive and aerospace industries.