关键词: 静电纺丝, 阵列圆盘式纺丝头, 电场强度, 有限元分析

Abstract: Electrospinning is mainly used to prepare nanofibers from polymers. Nanofibers have high porosity, high specific surface area, good mechanical properties and excellent biocompatibility. Therefore, nanofibers are widely used in drug delivery, wound dressing, tissue engineering and other fields, and have become one of the research hotspots. 
At present, electrospinning technology for large-scale preparation of nanofibers is mainly divided into multi-needle electrospinning and needleless electrospinning. Multi-needle electrospinning can accurately feed the liquid, and the required voltage is low, but the pinhole is easy to block and difficult to clean, and there is a edge effect, resulting in uneven preparation of nanofibers. Needleless electrospinning cannot accurately feed the liquid, the required voltage is high, the spinning position is uncontrollable, and the fiber diameter distribution is wide. In order to prepare high-quality nanofibers on a large scale, we proposed to build a new type of array disc-type nozzle needless equipment. The jet is emitted from the spinneret hole, which can accurately control the spinning site and precise feeding. The angle between the adjacent spinneret holes is 30°, and the angle between the spinneret hole and the vertical line is 15°, which can avoid the interaction between the spinneret holes and weaken the edge effect. Firstly, the structure model of the spinneret was optimized. Based on the principle of single variable, three-dimensional models of different structures were established by changing the structural parameters of the spinneret (central axis diameter, disc number, disc spacing, disc outer diameter, and auxiliary electrode). The simulation software was imported to simulate the electric field strength of the spinneret, and the optimal structural parameters of the spinneret were obtained. Secondly, the spinning process parameters (applied voltage, and receiving distance) were changed to determine the spinning parameters. It is found that the field strength and CV value of the spinneret decrease with the increase of the number of discs. The disk spacing has a significant effect on the field strength distribution. As the disk spacing increases, the field strength increases and the CV value decreases significantly. The increase of the outer diameter of the disc and the diameter of the central axis will lead to the decrease of the field strength value and have little effect on the CV value. The increase of the auxiliary electrode significantly reduces the CV value and uniforms the field strength. With the increase of voltage, the field strength increases significantly, but it has no effect on the uniformity of field strength. With the increase of voltage, the field strength increases significantly, but it has no effect on the uniformity of field strength. As the receiving distance increases, the field strength decreases, and the effect on the field strength CV value is not obvious. 
The results show that when the number of discs of the new spinneret is 10, the disc spacing is 40 mm, the outer diameter of the disc is 40 mm, the receiving distance is 100 mm, and the voltage is 25 kV, the average electric field intensity is 1.48×106 V/m, and the CV value is 1.60%. It shows that the spinneret structure effectively overcomes the edge effect and reduces the voltage required for spinning, so that the electric field intensity of the spinning device model at the spinning mouth is high and the distribution is extremely uniform, and high-quality nanofibers can be prepared in batches.

Key words: electrospinning, array disc-type spinneret, electric field intensity, finite element analysis