| AVS 63rd International Symposium & Exhibition | |
| Manufacturing Science and Technology | Tuesday Sessions |
| Session MS-TuP |
| Session: | Aspects of Manufacturing Science and Technology Poster Session |
| Presenter: | Omar Ali, Fisk University |
| Authors: | O. Ali, Fisk University T. Grier, Fisk University A. Ueda, Fisk University C. Marvinney, Fisk University S. Avanesyan, Fisk University C.S. Carson, Fisk University W.E. Collins, Fisk University J. DeCoste, US Army Research, Development, and Engineering Command R. Mu, Fisk University |
| Correspondent: | Click to Email |
Polyvinylidene fluoride (PVDF) is a polymer which has important applications in insulation, sensors, and battery production. The thermal, electrical, elastic, and morphological behaviors and properties of PVDF, on which the applications depend, are intimately related to the structure of the polymer on various physical length scales. Retained PVDF solid structures on different scales are also related. For example, stretching and poling a PVDF membrane causes the PVDF monomer chain to change phase from the non-polar alpha phase to the polar beta phase, which imparts significant piezoelectric and pyroelectric properties. Controlling the properties of PVDF by tuning the solid structures is, therefore, of key importance for various applications. Efforts have been made by our team into electrospinning technology, which is a relatively simple and scalable method of nanofiber production, for energy storage and biomedical applications.
We have investigated the effect of varying the electrospinning conditions and polymer solution properties on the diameter size and uniformity, and the spatial distribution of the produced PVDF nanofibers. Experimentally, we varied both the concentration of PVDF in the initial solution, and the voltage applied during electrospinning. Using optical imaging and scanning electron microscopy (SEM), we obtained a set of images for several voltage-concentration parameter pairs. Based on the experimental data, we were able to examine the diameter and uniformity as functions of the concentration and applied voltage. Additionally, we simulated different electric field distributions in an effort to design a method for controlling fiber deposition area.
The results indicate that increased concertation can lead to a significant increase in average fiber diameter. Fibers produced at lower concentrations are not only thinner, but also had significantly less uniform diameters and a greater number of beads in the fibers. The effect of voltage on diameter size and uniformity was somewhat less clear. There does not appear to be any correlation between voltage and average diameter size. However, voltages around the middle of the range we studied seem to lead to slightly more uniform fibers. Further, COMSOL simulation has been conducted and showed that using conduction rings to manipulate the electric field lines can make the field diverge sufficiently at first to allow for the electrospinning process to take place and then converge to direct the fibers to a smaller area of the grounded substrate. Such control over where the fibers are distributed can be very useful when producing fibrous mats and other macro-structures from nanofibers.