. caused to try to have this kind of shape have been 22 and spiral turning capabilitiesin soft robots 21, spiral-like electrodesfor energy harvesting 20, spiral molds tospecify the action of polymers injected on fabrics 19microarrays with spiral channels for numeroushybridization rates . spiral patterns are detectedwidely in nature and art.
Benefits of this type of shape such as 18. Near fieldelectrospinning (NFES) has been used to achieve a nanofiber instead of randomlynanofibers by decreasing spinneret to collector distance in electrospinning 17. the width of deposite nanofibersdistribution area is changed by varying the collector material and this area ofthe silicon surface is smaller than that on SiO2 surface 16. different methods areapplied to fabricate hollow needles such as the combination of deep etching ofsilicon substrates and rotating small angle deposition 15.
Electrospinningprocess is done by micromachining spinneret to form the nanofibers 14 and stimulate thenervous signals 13, three-dimensionalmeasurement 12, blood extraction 11, transfer of DNAsolution to the core 10. So needle with thesmall diameter is beneficial to electrospun nanofibers. Micro-electromechanicalsystems (MEMS) technology has been applied to many types of research. Microneedlearray has been fabricated by using this technology. Microneedles have foundsome applications in cancer treatment 9. Also, a lesser needlediameter is conduced to have the bead free fibers and the beads are produceddue to instability of the jet initiation8 effect on the electrospinningprocess. The smaller diameter of fibers is created by the minor diametercapillaries 2.
many parameters suchas polymer concentration, solution viscosity and conductivity, the appliedvoltage, needle to collector distance, solution flow rate, needle diameter andtemperature and humidity of environment 7. conventionalelectrospinning process acts at high voltages above the tens of kilo-volts andprovides randomly coiled fibers because of the turning instability of fiber jet6 and MEMS device 5, bio-scaffolds 4, optical tools 3Such as filtrationmembranes 2. nanofibers have greatcharacteristics such as smaller diameter, high surface-to-volume ratio and longlength that use in various industrial and scientific fields1Electrospinning is a beneficial process to fabricatenanofibers of which the diameter ranging from tens to hundreds of nanometersfrom polymer solutions at circumstance temperature and atmospheric pressure