The role of negative high voltage power supply in electrospinning

Among the commercially available electrospinning equipment, some are equipped with only positive high voltage power supplies, some are equipped with positive and negative high voltage dual power supply systems, and some high-end models are even equipped with two positive high voltage systems. How should users choose? What is the role of the negative high voltage power supply in the equipment?

Ordinary electrostatic spinning machine, such as TL-01, the nozzle is generally connected to a positive high voltage power supply, and the receiving device is grounded, and a certain electrostatic field can be generated between the nozzle and the receiving device, usually only about 10KV of high-voltage static electricity can be prepared.出Nano fiber membrane.
Professional electrospinning machines, such as TL-Pro, are often equipped with both positive and negative high-voltage power supplies. Compared with the basic version of the equipment mentioned above, the negative high-voltage power supply can achieve the following functions:

1. Increase the thickness of the fiber membrane: The raw materials and products of electrospinning are generally high-molecular polymers. Basically these polymers are insulating materials. After spinning for a period of time, a layer will be evenly attached to the receiver. With the insulated nanofiber membrane, the electric field attraction of the receiver to the nanofiber will gradually decrease. If the receiver is not connected to negative high voltage and continues spinning, the fiber will fly to other bases in the equipment, causing pollution inside the chassis. Therefore, by loading a certain negative high voltage on the receiving end to form a certain potential difference with the environment, the fibers can be continuously oriented and deposited on the receiver to prepare a thicker fiber membrane. To
2. Keep the inside of the chassis clean: As mentioned above, because the fiber membrane is generally non-conductive, when the fiber is collected to a certain thickness, the entire wire retractor is insulated, and the ejected fiber will fly everywhere.
3. Conjugate spinning: Conjugate electrospinning is to place two nozzles with opposite high-voltage static electricity opposite to each other. During the electrospinning process, the jets with opposite charges are emitted from the two spinnerets. During the electric field stretching process The medium attracts each other, twists together, and the positive and negative charges cancel each other out and are deposited on the receiving device. This requires the equipment to be equipped with both positive and negative high-voltage power supplies.
4. Melting direct writing: Some electrospinning equipment is equipped with a melting nozzle, which can be used for melting direct writing. The melting nozzle usually uses an electric heating system, which is not suitable for loading a high-voltage power supply. At this time, the negative high voltage power supply can be connected to the receiving device, and the spray head can be grounded, and a high voltage electrostatic field can be formed between the spray head and the receiving device for melting and direct writing. TL-OMNI can add a fusion nozzle to achieve fusion direct writing.
5. Others: Sometimes, in order to study the influence of positive and negative high voltage electric fields on the formation of Taylor cones, the polarity of the power supply can be intermodulated, and the nozzle is connected to negative high voltage, the receiving device is grounded or the positive high voltage is connected. Some studies have shown that it may be Different forms of fibers. To

The above is the basic function of negative high pressure.

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