Spinneret electrode

Deitzel et al. [78] placed electrically charged rings in front of the spinneret electrode which could reduce the space of fiber formation and focus the jet. 

There are several patents and methods describing modified electrospinning setups that make it possible to electrospin other materials or other formats for specific applications or to achieve better productivity. Some kind of rule of thumb is that modified spinneret electrodes should be used for higher output and modified collector systems developed have been to change the shape of the output material. A few of these inventions have begun to work on an industrial scale. 

Coating can be done before product preparation and pattern making when the reinforcement is available in roll or in tow formats. In this case the reinforcement material is rewound between two rollers and electrospinning takes place in between by using stationary spinneret electrode(s). Therefore, there is some technological flexibUity the production of nanofibrous interlayers can be accomplished by both the fiber manufacturer and the composite product manufacturer. 

Tantalum is now made into spinnerets for the manufacture of rayon, into electrodes for the neon signs that give our Great White Ways a... 

Platinum and palladium are useful in catalysis. Many of the elements are resistant to corrosion platinum is employed for electrodes and crucibles and extensively for spinnerets to extrude rayon, and rhodium provides a surfacing material for searchlight mirrors. Palladium is used for purifying hydrogen which diffuses rapidly and selectively through the warm metal. 

Electrospinning based on the application of a static electric field on a polymer solution or melt through a spinneret appears to be a simple and well-controllable technique able to produce polymeric nanofibers. A typical experimental setup is based on a capillary injection tip, a high-voltage source able to apply electric fields of 100-500 KVm , and a metallic collector, or counter electrode. Electric current in electrospinning experiments is usually in the order of a few milliamperes. ... 

Varabhas et al. [87] used a piece of poly-tetrafluoroethylene (PTFE) tube and drilled capillary holes axially in one line at every 10 mm and then placed a customized grid-like metal electrode inside. The collector was a moving belt, therefore, nanofibers could be continuously collected on a substrate material. The solution flow rate can be easily adjusted by increasing the pressure within the tube electrode and the spinneret can be cleaned or exchanged, therefore, maintenance seems to be easy. A tubular spinneret was also applied by Heikkila and Harlin [88], who simply placed a linear wire electrode along the tube. 

Figure 10.12. Scheme of rotating capillary spinneret [89], 1 power supply, 2 solution feed conduit, 3 spinneret, 4 charged electrode, 5 capillaries along the superficies of the tube, 6 collector electrode... 

Also related to the use of secondary electrodes, focused electrospinning can be implemented even of single jets by means of electrostatic lenses put along the path of the jet from the spinneret to the grounded collector, with the aim of controlling and limiting the area where nanofibers are deposited. 

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