In-flight charge loss from electrospinning jets

Nick Tucker 1Jon J. Stanger 1Nigel G. Larsen 1Mark Staiger 2Roger J. Reeves 3Kerry Kirwan 4

1. The New Zealand Institute for Crop and Food Research Ltd (CFR), Private Bag 4704, Christchurch 8140, New Zealand
2. Dept. mechanical Engineering, University Canterbury (ME-UOC), Private Bag 4800, Christchurch 8140, New Zealand
3. Department of Physics and Astronomy, The MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, New Zealand, Christchurch, New Zealand
4. University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom

Abstract

Due to the difficulty of measuring the electric current being drawn from the high voltage power supply to the high voltage electrode in the electrospinning process the electric current typically observed is the current flowing from the opposite electrode to ground.  This current can then be used to infer details about the electrostatic environment such as the charge density on the fluid jet.  It has been shown in literature that assuming initially the current is conducted in an ohmic mode and a reasonable conductivity for the polymer solution an electric current with the same order of magnitude to that observed.  As conductivity is directly related to ionic concentration it was possible to add a known amount of ionic salt and measure the electric current while electrospinning fibre.  This measured current was then compared to the expected electric current calculated from the ionic concentration.  It was found that as the ionic concentration increased the observed electric current increased but at a slower rate than the calculated electric current increased.  This suggests that a significant portion of the charge on the jet may be lost during flight.  This further implies that in order to increase the charge density where the bending instability occurs (driving force proportional to charge density) the initial charge density must be drastically increased to compensate for the losses in flight.  This may be limited as the effects of increased charge density may be detrimental to the formation of the Taylor cone.

 

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Presentation: Poster at E-MRS Fall Meeting 2008, Symposium F, by Nick Tucker
See On-line Journal of E-MRS Fall Meeting 2008

Submitted: 2008-05-29 05:24
Revised:   2009-06-07 00:48