Next Article in Journal
Exploring the Interactions of Physical, Chemical and Biological Variables of an Urban River Using Network Analysis
Next Article in Special Issue
Electrically Induced Liquid–Liquid Phase Transition in a Floating Water Bridge Identified by Refractive Index Variations
Previous Article in Journal
Relationship Between Aquifer Pumping Response and Quality of Water Extracted from Wells in an Active Hydrothermal System: The Case of the Island of Ischia (Southern Italy)
Open AccessFeature PaperArticle

A Molecular-Level Picture of Electrospinning

1
Department of Chemistry, Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, Pasteurova 3632/15, 400 96 Ústí nad Labem, Czech Republic
2
Department of Membrane Separation Processes, Institute of Chemical Process Fundamentals, Czech Academy of Sciences, Rozvojová 135/2, 165 02 Praha 6, Czech Republic
3
Department of Nonwovens and Nanofibrous Materials, Faculty of Textile Engineering, Technical University of Liberec, Studentská 1402/2, 461 17 Liberec 1, Czech Republic
*
Author to whom correspondence should be addressed.
Water 2020, 12(9), 2577; https://doi.org/10.3390/w12092577
Received: 14 August 2020 / Revised: 9 September 2020 / Accepted: 12 September 2020 / Published: 15 September 2020
(This article belongs to the Special Issue Experiments in a Floating Water Bridge and Electrified Water)
Electrospinning is a modern and versatile method of producing nanofibers from polymer solutions or melts by the action of strong electric fields. The complex, multiscale nature of the process hinders its theoretical understanding, especially at the molecular level. The present article aims to contribute to the fundamental picture of the process by the molecular modeling of its nanoscale analogue and complements the picture by laboratory experiments at macroscale. Special attention is given to how the process is influenced by ions. Molecular dynamics (MD) is employed to model the time evolution of a nanodroplet of aqueous poly(ethylene glycol) (PEG) solution on a solid surface in a strong electric field. Two molecular weights of PEG are used, each in 12 aqueous solutions differing by the weight fraction of the polymer and the concentration of added NaCl. Various structural and dynamic quantities are monitored in production trajectories to characterize important features of the process and the effect of ions on it. Complementary experiments are carried out with macroscopic droplets of compositions similar to those used in MD. The behavior of droplets in a strong electric field is monitored using an oscilloscopic method and high-speed camera recording. Oscilloscopic records of voltage and current are used to determine the characteristic onset times of the instability of the meniscus as the times of the first discharge. The results of simulations indicate that, at the molecular level, the process is primarily driven by polarization forces and the role of ionic charge is only minor. Ions enhance the evaporation of solvent and the transport of polymer into the jet. Experimentally measured instability onset times weakly decrease with increasing ionic concentration in solutions with low polymer content. High-speed photography coupled with oscilloscopic measurement shows that the measured instability onset corresponds to the formation of a sharp tip of the Taylor cone. Molecular-scale and macroscopic views of the process are confronted, and challenges for their reconciliation are presented as a route to a true understanding of electrospinning. View Full-Text
Keywords: electrospinning; polymer solution; molecular dynamics; ions; electric field; Taylor cone; liquid jet electrospinning; polymer solution; molecular dynamics; ions; electric field; Taylor cone; liquid jet
Show Figures

Graphical abstract

MDPI and ACS Style

Jirsák, J.; Pokorný, P.; Holec, P.; Dědičová, Š. A Molecular-Level Picture of Electrospinning. Water 2020, 12, 2577. https://doi.org/10.3390/w12092577

AMA Style

Jirsák J, Pokorný P, Holec P, Dědičová Š. A Molecular-Level Picture of Electrospinning. Water. 2020; 12(9):2577. https://doi.org/10.3390/w12092577

Chicago/Turabian Style

Jirsák, Jan; Pokorný, Pavel; Holec, Pavel; Dědičová, Šárka. 2020. "A Molecular-Level Picture of Electrospinning" Water 12, no. 9: 2577. https://doi.org/10.3390/w12092577

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop