Centrifugal spinning

Centrifugal spinning, also known as centrifugal spinning or rotary jet spinning, employs centrifugal force to overcome the surface tension of a polymer solution and spin it into a variety of fibers with diameters ranging from microns to nanometers [62, 63]. The centrifugal spinning machine composes of a collector, a spinneret, a shaft, and a motor. The nanofiber preparation procedure begins with the insertion of polymer solution into the spinneret and is followed by a high-speed rotation. The polymer solution is ejected from the nozzle of the spinneret and stretched by centrifugal force. Finally, polymer nanofibers are obtained when the polymer solution is solidified on the collector [64]. The centrifugal spinning production process does not require high pressure and is more productive than other methods. Therefore, it is suitable for commercial production. However, the highly rotating bearings spinning will generate a large load, which will produce shaft bearing fracture phenomenon, affecting production efficiency and raising costs. Lu et al. [65] prepared superabsorbent sodium alginate/polyethylene oxide submicron fibers containing the hydrophilic model drug tetracycline hydrochloride by centrifugal spinning.

In addition, the discovery research of nozzle less centrifugal spinning provides a solution for the clogging of the nozzle of the spinneret in conventional centrifugal spinning, which can be done by adding spin coaters [66], rotating spinning discs with flow controllers [67], or using interchangeable spinnerets [68]. Chen et al. [67] prepared polyethylene terephthalate fibers and polyvinyl pyrrolidone fibers into nanofiber membranes by melt-needle-free centrifugal spinning technology. The preparation process begins with the injection of polymer liquid from the liquid controller to the inner wall of the disk and the formation of a film, and then the condensation of the film produces multiple jets, which are sprayed from the edge of the disk and finally sprayed onto the collector.