Characterization and applications of piezoelectric polymers
Kim, Tae hoon
Arias, Ana Claudia
Technical Report Identifier: EECS-2015-253
December 18, 2015
Abstract: Mechanical and electrical properties characterization as well as some of applications for piezoelectric polymer polyvinylidene fluoride (PVDF) are reported here. A package level piezoelectric sensor with transient mode was designed as a main application of PVDF polymer as acoustic sensor. The PVDF sensor can detect acoustic signal outside of the package with acoustic sensitivity of -48.7 dBV/pa in our design. Upon triggering, both PVDF sensor and contents of package can be destroyed preventing reverse engineering of its content. For this application, a thermal transient condition and a footstep sound detection were studied. With the package temperature of 180°C, it takes around 300 seconds to destroy PVDF sensor on package. Maximum sound detection distance with footstep was about 20cm with gain of 100. X-ray diffraction (XRD) patterns were used to analyze the crystallinity of PVDF. Spin coated PVDF-TrFE, copolymer of PVDF, shows β-phase with XRD peak value of 20.2° which matches well with commercially purchased β-phase PVDF film without any poling process. XRD pattern of electrospun PVDF-TrFE sample is reported here. It shows XRD peak value of 20.47°. A heart rate of 67 bpm was measured using a commercial PVDF sensor that shows the possible biomedical application of piezoelectric polymer PVDF.