Polarization treatments of electrospun PVDF fiber mats

Nanostructured materials such as electrospun fibers are used as filters in many applications. Functionalization techniques can affect the filter performance characteristics such as fiber diameter, pore size, thickness and surface charge. Polyvinylidene fluoride (PVDF) is well known for its piezoelectric properties and its alpha, beta, gamma, delta, and epsilon crystalline phases. The beta crystalline phase exhibits the most polar phase and has higher dipole moment upon mechanically stretching of the polymer. This paper uses a custom-made heat-stretch-poling method to polarize electrospun PVDF fibers. Effects of various polarization -treatments such as stretching, heating and electrical poling on filter characteristics as well as on beta-phase were studied individually and as a combination of treatments. As-spun and polarized samples were characterized for pore size distribution, charge, and mat thickness respectively. It was observed that most of the treatments had a significant impact on filter performance but little to no impact on beta-phase content as electm-spinning alone resulted in relatively high 83% beta-phase content.

Automated summary

This paper focuses on the polarization of electrospun PVDF fibers using a custom-made heat-stretch-poling method and studies the effects of stretching, heating, and electrical poling on filter characteristics and the beta phase. The results show that most treatments have a significant impact on filter performance, but little impact on the beta phase content.