Structural and Thermal Treatment Evaluation of Electrospun PVDF Nanofibers for Sensors

Polyvinylidene fluoride (PVDF) polymer has seen increased use in industrial, energy harvesting, and sensor applications due to its chemical inertness, durability, flexibility, and, more importantly,
its ferroelectric properties. Decreases in fabrication scale have increased PVDF sensor capabilities dramatically. Nanofibers fabricated by electro spinning provide an increased surface area over that of amorphous thin films, and thus have a greater sensitivity to measurements collected; analysis is required, however, to ascertain changes made in the sensor capabilities as temperatures increase. We have fabricated PVDF nanofibers by an electro-spinning process and annealed the samples at temperatures ranging from 40oC to 100oC. Scanning electron microscopy (SEM) imaging was performed before and after heat treatment, and confocal Raman analysis was also performed after treatment. Analysis of the SEM micrographs indicated no changes in morphology, while the Raman spectroscopy showed increases in both spectral intensity and beta to alpha phase ratio, which directly affects ferroelectric capabilities. Nanofibers showed greater stability than what has been achieved in PVDF thin films at similar temperatures.