Processing polyvinylidene fluoride films for piezoelectric applications
Polyvinylidene Fluoride (PVDF) is a highly inert polymer with excellent piezoelectric properties and is hence used for sensors. The polymer has different crystal phases of which alpha phase is non-polar while beta phase is polar. The beta phase has high piezoelectricity while the alpha phase does not. Conversion of alpha phase to beta phase can be done by solid state stretching or by addition of nucleating agents. Both methods will be used to produce beta phase PVDF films. Further the films will be exposed to high electric fields at elevated temperatures to align the polar crystals and maximise the piezoelectric properties. Structure and properties of the films will be analysed to determine the optimal processing conditions. The mechanisms of the alpha to beta phase transition as well as the alignment of crystals by the electric field will be analysed.