DOI: https://doi.org/10.15368/theses.2018.142
Available at: https://digitalcommons.calpoly.edu/theses/2026
Date of Award
12-2018
Degree Name
MS in Polymers and Coatings
Department/Program
Chemistry & Biochemistry
Advisor
Raymond Fernando
Abstract
Piezoelectric nanogenerators (PNGs) are a new class of energy harvesting materials that show potential as a direct energy source for low powered electronics. Recently, piezoelectric polymers have been utilized for PNG technology due to low toxicity, high flexibility, and facile solution processing which provide manufacturing opportunities such as screen printing. Throughout the last decade, countless projects have focused on how to enhance the energy harvesting capabilities of these PNGs through the incorporation of nanoparticle fillers, which have been reported to enhance the piezoelectric properties of the film either directly through their intrinsic piezoelectric properties or through acting as surfaces for the interfacial nucleation of piezoelectric polymer crystals.
Herein, two systems of PNGs formed from piezoelectric copolymers poly(vinylidene fluoride-co-hexafluropropylene) or poly(vinylidene fluoride-co-trifluoroethylene) mixed with high aspect ratio zinc oxide nanowires, hydroxyl functionalized multi-walled carbon nanotubes, or carboxylic acid functionalized single walled carbon nanotubes were investigated. Variations of filler type and loading are tested to determine influences on film morphology and piezoelectric properties. Power harvesting tests are conducted to directly determine the effect of nanoparticle addition on the output power of the non-poled devices. Both copolymer systems are found to exhibit a non-linear increase in output power with the increase of nanoparticle filler loading. The crystal polymorph properties of both systems are investigated by Fourier transform infrared spectroscopy. The microstructure of the poly(vinylidene fluoride-co-trifluoroethylene) films are further examined using X-ray diffraction, differential scanning calorimetry, polarized optical microscopy, and atomic force microscopy to determine the mechanism behind the increased power harvesting capabilities. As well, explanations for perceived output power from “self-poled” films are briefly explored.