In one embodiment, the present invention is a method for producing microfibers comprising the steps of: (a) providing a base material; (b) forming the base material in a ring; (c) gripping opposing ends of the ring; (d) flipping one of the opposing ends relative to the other of the opposing ends, forming an upper portion and a lower portion; (e) folding the upper portion onto the lower portion; (f) stretching the folded upper and lower portions; and (g) repeating steps (d)-(f) as desired.

In one embodiment, the present invention is a method for producing microfibers comprising the steps of: (a) providing a base material; (b) forming the base material in a ring; (c) gripping opposing ends of the ring; (d) flipping one of the opposing ends relative to the other of the opposing ends, forming an upper portion and a lower portion; (e) folding the upper portion onto the lower portion; (f) stretching the folded upper and lower portions; and (g) repeating steps (d)-(f) as desired.

In one embodiment, an electrospinning head has a nozzle unit and a control body. The nozzle unit is arranged opposite to a base material, is applied with a voltage, and thereby is capable of discharging a raw material liquid of fiber. The control body is arranged in the vicinity of the nozzle unit so as to extend to an outside of a spinning space between the base material and the nozzle unit. Further, the control body is applied with a voltage of the same polarity as the voltage to be applied to the nozzle unit, and thereby is capable of making an electric field to be generated at the periphery of the nozzle unit.

In one embodiment, an electrospinning head has a nozzle unit and a control body. The nozzle unit is arranged opposite to a base material, is applied with a voltage, and thereby is capable of discharging a raw material liquid of fiber. The control body is arranged in the vicinity of the nozzle unit so as to extend to an outside of a spinning space between the base material and the nozzle unit. Further, the control body is applied with a voltage of the same polarity as the voltage to be applied to the nozzle unit, and thereby is capable of making an electric field to be generated at the periphery of the nozzle unit.

Disclosed is a method for preparation and activation of a super hydrophobic electret nanofibrous filter material for cleaning PM2.5, comprising the steps as follows: (1) dissolving polymer powders and resin into a corresponding solvent so as to prepare a polymer solution, then stirring on a magnetic stirrer and standing for use; (2) in order to reinforce the electrostatic effect of the fiber, before preparing the polymer solution, adding in organic electret nanoparticles into the solvent, then oscillating with an ultrasonic oscillator; (3) in order to reinforce the super hydrophobic effect of the filter, spraying a low surface energy solution on the prepared nanofiber with a designed nozzle to carry out modification.

Provided is a polymer nanofiber sheet having high delamination resistance, a high mechanical strength, and a high specific surface area. Specifically, provided is a polymer nanofiber sheet, including polymer nanofibers, the polymer nanofibers being laminated and three-dimensionally entangled with each other, in which: at least part of the polymer nanofibers are crosslinked at a crosslinked part having crosslinking portions and a non-crosslinking portion; and the crosslinked part contains a low-molecular weight epoxy compound having a molecular weight of from 100 to 3,000.

In one embodiment, the present invention is a method for producing microfibers comprising the steps of: (a) providing a base material; (b) forming the base material in a ring; (c) gripping opposing ends of the ring; (d) flipping one of the opposing ends relative to the other of the opposing ends, forming an upper portion and a lower portion; (e) folding the upper portion onto the lower portion; (f) stretching the folded upper and lower portions; and (g) repeating steps (d)-(f) as desired.

In one embodiment, the present invention is a method for producing microfibers comprising the steps of: (a) providing a base material; (b) forming the base material in a ring; (c) gripping opposing ends of the ring; (d) flipping one of the opposing ends relative to the other of the opposing ends, forming an upper portion and a lower portion; (e) folding the upper portion onto the lower portion; (f) stretching the folded upper and lower portions; and (g) repeating steps (d)-(f) as desired.

A method for producing microfibers includes the steps of (a) providing a base material; (b) forming the base material in a ring; (c) gripping opposing ends of the ring; (d) flipping one of the opposing ends relative to the other of the opposing ends, forming an upper portion and a lower portion; (e) folding the upper portion onto the lower portion; (f) stretching the folded upper and lower portions; and repeating steps (d)-(f) as desired. Different apparatuses for performing the method are also provided.

A method for producing microfibers includes the steps of (a) providing a base material; (b) forming the base material in a ring; (c) gripping opposing ends of the ring; (d) flipping one of the opposing ends relative to the other of the opposing ends, forming an upper portion and a lower portion; (e) folding the upper portion onto the lower portion; (f) stretching the folded upper and lower portions; and repeating steps (d)-(f) as desired. Different apparatuses for performing the method are also provided.