Electrical response of open tubular piezoelectrets exposed to low pressures stimulations
When foamed thin electret films are electrically charged, a highly piezoelectric structure known as piezoelectret is obtained. This flexible and lightweight material is very much desired for sensors and transducer applications. Recently, this piezoelectric behavior was obtained with fluoropolymer films assembled in multi-layer systems. This approach led to piezoelectrets with improved thermal stability. However, since this kind of piezoelectret was developed, not much has been done regarding its electro-mechanical behavior under low pressure (< 40 kPa) stimulation. Therefore, in this work we present the first results obtained with an open-tubular structure made of FEP films that was prepared according to the lamination process and submitted to a low-pressure stimulation. This was performed with a dual-chamber system, one previous pressurized (A) and the other containing the piezoelectret sensor (B). The relation between applied pressure and sensor response was then obtained and it was fitted with an exponential curve providing a good approximation for the piezoelectret behavior in this condition.