Hi John and Julian,
The notion of regarding a single spinneret electrospinning machine as a nanoscale rapid prototyping engine is very tempting. Especially if you consider that a matrix (maybe containing living cells) could be co-deposited by simultaneous electrospraying, and you can add to that the notion that your materials can be deposited at room temperature out of aqueous solution, and will solidify without recourse to coagulation chemistry. These conditions are ideal for coping with big biological molecules, and perhaps exploiting the self organising tendencies of the same. Difficulties arise in coping with the high speed of deposition (say 60-100m/s) for fibres spun from solution, and the so called "instability" - the point where the flight path of the nice straight strand forming jet turns to an expanding helix of fibre. To produce genuine precision deposition it will be necessary to gain understanding and control of the effect of the geometry of the driving electric field on the flight path of the fibre.
If you move to spinning from a melt, the instability is not such a problem, probably because the process of fibre freezing is faster than evaporation, and it is possible to produce controlled deposition patterns by physical manipulation of the target (see work by Paul Dalton on melt electrospinning).
Passive collector designs can produce simple 3-D structures, but the art is not yet well advanced.
What would be nice would be a combined technology - large scale deposition for large undifferentiated bits of material matched with nanoscale fine detail additions.
Regards,
Nick Tucker
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