Maro Publications

Electrospinning

Notes

*11/11/2013 
from 5/20/2012

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Electro-Blown Spinning

Electrojetting

Electrostatic Explosion

Nanofibers

Spinning

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Notes

2. “Electrospinning uses an electrical charge to draw very fine (typically on the micro or nano scale) fibres from a liquid. Electrospinning shares characteristics of both electrospraying and conventional solution dry spinning of fibers. The process does not require the use of coagulation chemistry or high temperatures to produce solid threads from solution. This makes the process particularly suited to the production of fibers using large and complex molecules. Electrospinning from molten precursors is also practised; this method ensures that no solvent can be carried over into the final product.

When a sufficiently high voltage is applied to a liquid droplet, the body of the liquid becomes charged, and electrostatic repulsion counteracts the surface tension and the droplet is stretched; at a critical point a stream of liquid erupts from the surface. This point of eruption is known as the Taylor cone. If the molecular cohesion of the liquid is sufficiently high, stream breakup does not occur (if it does, droplets are electrosprayed) and a charged liquid jet is formed.

As the jet dries in flight, the mode of current flow changes from ohmic to convective as the charge migrates to the surface of the fiber. The jet is then elongated by a whipping process caused by electrostatic repulsion initiated at small bends in the fiber, until it is finally deposited on the grounded collector. The elongation and thinning of the fiber resulting from this bending instability leads to the formation of uniform fibers with nanometer-scale diameters.”

(Wikipedia, Electrospinning, 5/25/2012)

1. “The electrospinning technology is for manufacturing nanofibers. The principle of the electrospinning technology is to provide a driving force generated by an electrical field between a positive electrode and a negative electrode, so as to overcome surface tension and viscosity of a polymer solution. In addition, streams of polymer solution ejected from a nozzle are mutually repulsive because they carry the same charge; when the solvent evaporates, ultra-thin fibers are formed. The process is also called fiber electrospinning. Comparing with the fibers produced by the prior spinning technology in diameters of several micrometers (.mu.m), the polymeric fibrils produced by the electrospinning technology can achieve a purpose of fiber thinning, due to mechanical and electrostatic forces during the electrospinning process. Moreover, the fabric spun by the electrospinning method enjoys the advantages of having a more favored in higher porosity, larger surface area, and smaller pore size than those of conventional fabrics.” [Chang et al, US Patent 8,241,537 (8/14/2012)]

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Roger D. Corneliussen
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Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
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* Date of latest addition; date of first entry is 5/25/2012.