Guiding Electrode

A sharp guiding electrode has been shown to be very effective in guiding the electrospinning jet as it accelerate towards the collector. The polarity of the guiding electrode (s) behind the collector may be of like- or opposing polarity to the spinning jet. A single opposing guiding electrode in the form of a sharp pin place behind the collector been used successfully to guide and control fiber deposition by several researchers [Sundaray et al 2004 , Baede 2009, Solberg 2007]. Others have used multiple counter electrodes behind the collector to construct membrane or tubes with better aligned fibers [Teo et al 2005; Carnell et al 2009] and patterned fibers. Patterned fibers that has been constructed include cross-aligned fibers and tube with diagonally aligned nanofibers [Teo et al 2005]. Mutliple guiding electrodes placed behind the collector can be used to exert greater influence on the electric field profile so that greater control of the spinning jet can be achieved. A study by Wu et al showed that greater fiber alignment can be achieved using multiple guiding electrodes with positive and negative polarity compared with just a single guiding electrode [Wu et al 2007].

Another method of guiding the electrospinning jet is to use parallel electrodes on the side of the collector. Electrospinning jet is known to deposit fibers across a gap and this can be used to encourage electrospinning jet to move in the direction of a rotation of a rotating collector [Haseeb 2011]. An AC voltage may be applied to the parallel electrodes where at lower frequency, the fibers will span across the electrodes [Kim 2006; Lee et al 2009] and at high frequency, the electrospinning jet will be focused between the electrodes without contacting either [Kim 2006].

Pin in cylinder to guide electrospinning jet [Sundaray et al 2004]	Guiding electrode to construct diagonally aligned fibers [Teo et al 2005]
Guiding electrode for more aligned fibers [Teo et al 2005; Carnell et al 2009]	Guiding electrode in the form of parallel bars [Haseeb 2011]
Multiple guiding electrodes [Wu et al 2007]	AC guiding electrode [Lee et al 2009]