Electrospinning (Electrospinning) refers to the polymer fluid under the action of a high-voltage electrostatic field of thousands of volts to tens of thousands of volts, so that the polymer droplets overcome the surface tension to produce jetting trickles, which stretch and solidify during the jetting process. On the receiving screen, the technology of finally forming a non-woven, continuous mesh fiber mat is currently the only method that can directly and continuously prepare polymer nanofibers. Electrospinning has the advantages of stable performance, superior quality, wide variety of spinnable materials and controllable technology. It has a wide range of application prospects in the development of engineering materials for physical interception of pollution. It is a safe, environmentally friendly and efficient air filter material.
The main ways to control electrospinning nanofibers: 1. Adjust the properties of the spinning solution (viscosity, surface tension, conductivity, etc.); 2. Adjust the spinning process parameters (voltage, flow rate, receiving distance, temperature and humidity, etc.) ; 3. Improvement of electrospinning device (such as double shoulder jet, coaxial jet, thin disc collection, etc.). In addition, the morphology, diameter, and orientation of the nanofibers can be further controlled by subsequent chemical modification or heating treatment.
The use of electrospun nanofiber membranes for air filtration has great advantages. On the one hand, electrospun nanofibers can not only trap large particles through mechanical screening, but also have more direct interception and inertial impact effects on particle filtration. It is notable to improve the filtration efficiency of the fiber membrane; on the other hand, the nanofiber has a large specific surface area and good surface adsorption, which can increase the probability that the suspended particles in the air diffuse to the surface and deposit, and some of them will enter the membrane. Particles are trapped by adsorption, thereby improving the filtration efficiency of small particles; at the same time, the porosity is high, the pore size distribution is relatively uniform, and the interpenetrating porous structure between the fibers ensures that the nanofiber membrane has a relatively low pressure drop.
