Coupling between voltage and tip-to-collector distance in polymer electrospinning: Insights from analysis of regimes, transitions and cone/jet features

In this study, we shed light on the coupling between voltage (V) and tip-to-collector distance (T) in polymer electrospinning. First, an operating map in the V-T plane - with the potential to facilitate real-time control - reveals four electrospinning regimes including a newly identified rotational regime that serves as a transition from the cone-jet to the multi-jet regime. Next, across experiments in which V and T are independently varied, we image and comprehensively investigate regime-specific cone and jet dynamics using quantifiable and universally recognizable features. Our results demonstrate for the first time that theoretical potential drop (V/T) although crucial in determining electrospinning outcomes is not a fundamental V-T coupling parameter. Further, the nature of coupling is shown to dynamically vary with specific V and T combinations, with correlations indicating stronger dependence of cone/jet features on V than on T. Significantly, small changes to the collector position orchestrates regime transitions at the needle tip despite the large separation distance, although the effects of V dominate at large T values. Supporting simulations implicate the combined roles of effective field strength, charge density and field line distribution near the cone apex as critical factors influencing V-T coupling. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study examines the coupling between voltage and tip-to-collector distance in polymer electrospinning, revealing different regimes in the V-T plane and the dynamic nature of the coupling with specific voltage and distance combinations. The results show that theoretical potential drop is not a fundamental V-T coupling parameter, and the dependence of cone/jet features on voltage is stronger than on tip-to-collector distance. Small changes to the collector position can orchestrate regime transitions at the needle tip, while the effects of voltage dominate at large distance values.