IDEALPLUSING | What is electrospinning?

Electrospinning is the process of spinning polymer solution under high voltage static electricity. Electrospinning can produce fibers with diameters ranging from tens to hundreds of nanometers. The products have high porosity and large specific surface area, diversified composition, and uniform diameter distribution. They have high application value in biomedicine, environmental engineering, and textile fields.

Principle

The polymer solution or melt is charged with high voltage static electricity of several thousand to tens of thousands of volts. The charged polymer droplets are accelerated at the Taylor cone vertex of the capillary tube under the action of the electric field force. When the electric field force is large enough, the polymer droplets overcome the surface tension to form a jet stream. During the jetting process of the stream, the solvent evaporates or solidifies, and the liquid falls on the receiving device to form a fiber felt similar to a non-woven fabric.

Device

The electrospinning device is mainly composed of a propulsion pump, an injector, a high-voltage power supply, and a receiving device. Among them, the positive and negative electrodes of the high-voltage power supply are connected to the needle of the injector and the receiving device respectively, and the receiving device is also in a variety of forms, which can be a stationary plane, a high-speed rolling drum, or a disc. The parameters and environmental conditions of spinning are crucial to the spinning process.

Propellant pump Injector

30kV 1mA 30W high voltage DC power supply

50kV 1mA 50W high voltage DC power supply

Reciprocator

Collector roll

Polymer

At present, electrospinning technology can be used for dozens of different polymers, including electrospinning of flexible polymers such as polyester, polyamide, polyvinyl alcohol, polyacrylonitrile, as well as electrospinning of polyurethane elastomers and liquid crystal rigid polymers such as poly(p-phenylene terephthalamide).

Influencing factors

There are many influencing factors for the preparation of nanofibers by electrospinning, which can be divided into solution properties, such as viscosity, elasticity, conductivity and surface tension: controlled variables, such as electrostatic voltage in the capillary, potential at the capillary mouth and the distance between the capillary mouth and the collector; environmental parameters, such as solution temperature, air humidity and temperature in the spinning environment, air flow velocity, etc.

Coaxial electrospinning

Coaxial electrospinning is a modification of electrospinning. Its basic principle is to inject core and shell solutions into two coaxial capillaries with different inner diameters. The two are combined at the end of the nozzle and solidified into composite nanofibers under the action of electric field force. Coaxial electrospinning solves the defect that the spinning solution must be a uniform system during spinning. The prepared coaxial fibers are superior to fibers obtained by other methods in terms of averageness and continuity. Hollow fibers and nanocomposite fibers can be prepared by coaxial electrospinning.

Application

Nanofibers prepared by electrospinning technology have the characteristics of large specific surface area, high porosity, easy size control, and easy surface functionalization (such as surface coating and surface modification). They have important application value in many fields. Electrospun nanofibers can be used for water treatment, protective clothing, masks, etc. in filtration and personal protection; they can be used as resistance sensors, optical sensors, etc. in the field of sensors; they can be used as catalysts in the chemical industry; they can be used in wound dressings, tissue engineering scaffolds, drug carriers, etc. in the biomedical field.