Leung, Siu-Ning2018-11-212018-11-212018-08-292018-11-21http://hdl.handle.net/10315/35596Polyvinylidene fluoride (PVDF) has garnered interest due to its piezoelectric property and as a non-toxic, conformable, and low-cost alternative to the popular piezoelectric ceramic. A novel processing method through the combination of thermal and supercritical carbon dioxide (ScCO2) has been used to successfully promote the formation of electroactive phases (i.e., beta and gamma phases), as well as its piezoelectric property. In this report, the processing-to-structure properties and mechanisms that affect crystallization behaviors of electroactive phases were elucidated. It was revealed that gamma crystal formation was through thermal processing while beta phase was nucleated through fast cooling and physical foaming of CO2 bubbles. The results were comparable to common processing method and literature, with a maximum electroactive crystal phase of 72.2% and a corresponding piezoelectric coefficient of 7.7 pC/N. The findings in this study could provide insight to future research work on PVDF, advancing its development in piezoelectric applications.enAuthor owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Alternative energyElectronic Thesis or Dissertation2018-11-21PVDFPolyvinylidene fluoridePiezoelectricElectroactiveCrystalllinityCrystal structuresPiezoelectric propertyBetaGammaMorphologyBubble nucleationSupercriticalCarbon dioxideProcessingPhysical foamingIsothermalNon-isothermalFast coolingAlternative energy