An electrospinning device for preparing uniform film thickness

Abstract

The invention relates to an electrospinning device for preparing uniform film thickness. The device consists of a constant temperature water bath, a catheter, a peristaltic constant current pump and a high-voltage generator as a spinning system, and a radius-adjustable spherical skeleton, an upper hydraulic system and a lower hydraulic system. The hydraulic system is used as a spinning collection system, in which the radius-adjustable spherical frame is composed of multiple hinged connecting rods. Through a special combination method, the inner radius of the spherical frame can be continuously adjusted, and the spinning needle can always be positioned at the center of the spherical frame. At the center of the sphere, the inner side of the spherical skeleton is kept perpendicular to the electric field line during the spinning process, ensuring that the electric potential energy of each point on the inner side is equal, and the probability of nanofibers attaching to any point is equal, ensuring that the thickness of the prepared nano-film is completely uniform. The radius of the collector provided by the invention is continuously adjustable, which can satisfy the preparation of different types of fibers.

Description

technical field [0001] The invention relates to the technical field of nanofiber manufacturing, in particular to an electrostatic spinning device for preparing uniform film thickness. Background technique [0002] Fiber is a substance that exists widely in nature, and man-made fibers have long been used in various industries. Among them, fiber toughening technology is an effective means to improve the strength of materials. According to the Griffith fracture theory, the mechanical strength of materials has obvious size effects. The smaller the point, the higher the breaking strength. At the same time, Gao Huajian further hypothesized that when a material is manufactured thin enough to reach a critical thickness in the nanometer range, the material may even show a strength value close to the theoretical strength, at which point the failure is no longer controlled by the Griffith criterion, Instead, determined by the strength of the atomic bonds under this regime, the materi...

AI Technical Summary

Problems solved by technology

As the name implies, the flat plate collecting device uses the flat conductor as the high voltage negative pole (or positive pole) and the spinning needle as the positive pole (or negative pole). The electric field lines between the point electrode and the plate are radially distributed, so the Coulomb force is the strongest at the position closest to the needle, and the weakest at the farthest position from the needle. It can be seen that the electric field force distributed on the plate is not uniform. After the fibers are formed, the probabilities of flying to each position of the flat plate are also different, and it is easy to reunite at the position closest to the needle on the flat plate, resulting in the phenomenon that the middle is thick and the surrounding is thin

The drum collector makes the collecting device into a conductive drum and keeps rotating during the spinning process, but there is also the phenomenon of uneven distribution of electric field force, the most fibers are collected at the position closest to the needle, and less fibers are collected at the position far away from the needle

[0005] In response to this phenomenon, there have been many reports on the improvement of spinning equipment. For example, this phenomenon can be improved by moving the spinning needle back and forth at present, so that the spinning needle can reciprocate above the collector, which can improve the spinning process to a certain extent. The thickness of the obtained fiber film is uneven, but due to the uneven distribution of the electric field force itself, the obtained fiber film still cannot be completely uniform

CN203904515U discloses a kind of arc-shaped collection device, which makes the electric field force equal in size on the plane where the needle head is located, and can make the fibers evenly distributed on this plane, but the arc-shaped plane can only ensure that the electric field force is completely equal on the plane where the needle head is located. The electric field force below will still decrease due to the increase of the absolute distance from the needle, so the fiber obtained by this method is thinner at the upper and lower ends and thicker in the middle

There are also technologies that disclose the use of spherical collectors to improve the uneven distribution of electric field force, but the radius of the current spherical collectors cannot be continuously adjusted, and when preparing different types of nanofibers, the spinning distance needs to be adjusted according to the conductivity and viscosity of the solution. Adjustment, if the spinning needle cannot be guaranteed to be located at the center of the spherical collector in order to meet the spinning distance requirements, the electric field force distribution is still uneven, and the thickness of the nanofiber film obtained at this time is also uneven

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