Compact, energy efficient charge injection electrostatic atomizers are capable of operating at arbitrarily high throughput levels. One version of this class of devices, the paper clip sized, cold-cathode, field-emitter, submerged electron gun SPRAY TRIODE atomizer is capable of electrospinning fibers at a gram per second and higher throughput levels. Micron sized fiber battings of molten polyethylene terephthalate (PET), and methylene chloride/Lexan and tetrahydrofuran (THF)/Pellethane solutions have been electrospun from solution to form nanofiber webs using milliwatts of input electrical power. Applicability for field use has been demonstrated by the approximately ten hour operation of a handheld SPRAY TRIODE based applicator using two (2) 9V transistor batteries for power. Building on this science/technology base, the Phase I effort will investigate the influence of charge density, operating and fluid parameters on fiber development for polymeric materials to be specified. Work will be undertaken to use the S'tron electron gun charging process for electrospinning polar solutions. Phase II will focus on S'tron development for field and large scale industrial applications requiring liter per minute throughputs. Charge injection permits the energy efficient electrospinning at the throughput levels required for high volume production of non-woven sieve materials. In addition to being applicable to battery operated hand-held field repair applicators, charge injection electrospinning can be used for the large scale production of charged (electret) and uncharged nanofiber polymeric films. Such sieve materials can be used for film barriers, surgical dressings, vascular grafts, catheters, surgical pads, scaffolding for tissue engineering, reinforcing meshes for surgical usage, sanitary barrier products, sieve non-woven fabrics for clothing including chemical and biological warfare suits, surgical gloves, face masks, and tentage. This technology is an energy efficient replacement for melt blown fiber generation. In addition, it is an inexpensive means to manufacture ultra-suede, and enables the direct spray formation of clothing either on mandrels or directly on the body. The same technology is applicable to the in-situ generation of high efficiency, electret ultra-filters for air and liquid purification.
