Alternating current electrospinning: The impacts of various high-voltage signal shapes and frequencies on the spinnability and productivity of polycaprolactone nanofibers

Abstract

This study describes the application of a new technological parameter in the alternating-current (AC) electrospinning process for enhancing the electrospinnability and productivity of polycaprolactone (PCL) electrospun nanofibers (ENF). High-voltage AC is influenced via changes in both the waveform and the frequency; however, the overall contribution to PCL electrospinnability remains unclear. This study hypothesizes that the electrospinnability, morphology, diameter and productivity of PCL ENF are dependent on both the waveform and the frequency of the AC high-voltage signal. Thus, the paper demonstrates that both the waveform and the frequency significantly affect the formation of a stable fibrous plume and the PCL ENF morphology. Consequently, trimodal- (beads, spindles and helical), bimodal- (beads and spindles) and unimodal-structured ENF morphologies were attained for square, sine and triangle waveforms, respectively. Moreover, the frequency of the waveform directly influences the number of beads and/or spindles per unitary length. The square waveform reflects higher productivity (23.6 ± 0.4 g/h) than the sine (16.5 ± 0.3 g/h) and triangle waveforms (6.9 ± 0.2 g/h). This study presents a simple approach to the industrial-scale fabrication of PCL ENF via the tuning of the AC high-voltage signal shape and/or frequency with the added advantage of the potential for obtaining a range of PCL ENF morphologies.