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Micro-and-Nanostructuring of Polyvinylidene Fluoride with Tailored Crystal Polymorphs and Enhanced Piezoelectric Property

Micro-and-Nanostructuring of Polyvinylidene Fluoride with Tailored Crystal Polymorphs and Enhanced Piezoelectric Property

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Title: Micro-and-Nanostructuring of Polyvinylidene Fluoride with Tailored Crystal Polymorphs and Enhanced Piezoelectric Property
Author: Lee, Ji Eun
Abstract: Polyvinylidene 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.
Subject: Alternative energy
Keywords: PVDF
Polyvinylidene fluoride
Piezoelectric
Electroactive
Crystalllinity
Crystal structures
Piezoelectric property
Beta
Gamma
Morphology
Bubble nucleation
Supercritical
Carbon dioxide
Processing
Physical foaming
Isothermal
Non-isothermal
Fast cooling
Alternative energy
Type: Electronic Thesis or Dissertation
Rights: Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.
URI: http://hdl.handle.net/10315/35596
Supervisor: Leung, Siu-Ning
Degree: MASc - Master of Applied Science
Program: Mechanical Engineering
Exam date: 2018-08-29
Publish on: 2018-11-21

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