Opposing charge bundling

Opposite charge bundling setup

Electrospinning may be initiated either using positive or negative charges and if there are two electrospinning jets carrying opposing charges, they are likely to attract each other. A bundle of fibers suspended in mid-flight will be formed by the colliding jet and this may be drawn onto a take-up roller. In one of the earliest experiments using this setup, the objective was to fabricate highly aligned nanofibers on a rotating collector [Pang et al 2006]. The chaotic collision between two electrospinning jets may pose a challenge to collect a continuous strand of yarn onto a bobbin. Nevertheless, this method has been reported to be capable of collecting continuous yarn [Yao et al 2009, Li et al 2008]. The same group has also reported the use of multiple pairs of opposing charged electrospinning jets for producing thicker yarn [Li et al 2008].

Polymer	Solvent	Take-up speed	Reference
Zein	Ethanol/water (70/30, v/v)	0.33 m/s	Yao et al 2009
Zein/PLLA	Dimethyl formamide	0.33 m/s	Yao et al 2009
poly(L-lactide)/n-TCP	Dimethyl formamide	0.75 m/s	Li et al 2008
Polyacrylonitrile	Dimethyl formamide	0.0016 m/s	Dabirian et al 2009

Pros

• Collected yarn is dry

Cons

• Difficult to control yarn density
• Difficult to control yarn take up speed
• May experience frequent stoppages

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Content [Yarn spinning setup]