The research on electrospinning technology first started with the development of organic polymer nanofibers. With the deepening of research, there have been more than one hundred polymers and biomolecules that can be constructed by electrospinning technology with different structures, morphologies and properties. Functional micro-nanofibers. Recently, besides the development of organic polymer nanofibers, electrospinning technology has also been widely used to prepare ceramic fibers. In fact, electrospinning technology cannot be used to directly obtain ceramic fibers, and an additional heat treatment process is required to remove organic polymers. The increased heat treatment process favors the creation of porous or hollow-structured ceramic fibers (Figure 1). These novel and controllable morphologies and structures enable electrospun nanofibers to be widely used as carriers for electronic devices, sensing materials, filter materials, reinforcement materials, superhydrophobic materials, catalysts and enzymes , energy, environmental science and life science and many other fields.
1. Biomedical field
Many types of polymers can be fabricated into nanofibers by electrospinning, and these nanofibers have been widely used in biomedical fields such as tissue engineering, artificial organ applications, drug delivery, and wound repair. For example, in 2001, Smith et al. first reported the use of electrospinning fibers to repair skin wounds, and the types of polymer fibers and drugs could be changed to meet the needs of different wounds. This achievement shows that simple spinning equipment has been developed to The material stage for application in wound repair can be prepared directly. Moreover, electrospinning technology can also deposit biocompatible electrospun microfibers on the surface of medical devices to form ultra-thin porous films. The hardness mismatch at the tissue/medical device interface prevents and reduces the possible damage to the tissue caused by the medical device, and is conducive to the growth of tissue on its surface.
2. The fields of light, electricity and magnetism
Nanofibers prepared by electrospinning technology can also be widely used in the fields of optics, electricity and magnetism. For example, in 2005, Sabine Schlecht took the lead in adding ZnSe quantum dots to polylactic acid to prepare spinning fibers by electrospinning technology, and investigated its optical properties. We also successfully introduced the complexes of rare earth pins into polyacrylonitrile to prepare fluorescent fibers with red light emission, and by studying their optical properties, it was confirmed that the coating of electrospun fibers is beneficial to improve their fluorescence quantum yield and fluorescence lifetime. Not only that, we further prepared nanofibers with dual functions of fluorescence and magnetism, which do not affect each other even if the dual functions exist due to the effective isolation of the nanofiber structure (Figure 2).
3. areas of catalysis
Nanofibers prepared by electrospinning technology can also be widely used in the field of catalysis. For example, Bai et al. used β-cyclodextrin as raw material, mixed with polymethyl methacrylate, polystyrene, polyacrylonitrile, and then used electrospinning technology to prepare β-cyclodextrin/polymerization composite nanofibers. The composite fiber membrane made by supporting precious metal particles on its surface can be used for the research of nitro compound catalytic hydrogenation reaction and the Heek reaction of iodobenzene and acrylic compound. In addition, various metal oxide one-dimensional nanofibers can be obtained by combining electrospinning technology and subsequent heat treatment process, and these materials can be widely used in photocatalytic degradation of organic dyes in water. Shao’s research group at Northeast Normal University has done a lot of outstanding work in this area. For example, they can prepare TiO2 nanofibers using electrospinning technology and subsequent heat treatment process, and controllably grow various inorganic compounds on the surface of TiO2 nanofibers through combined hydrothermal reaction, thereby obtaining Bi4Ti3O12/TiO2 [Figure 3(a)] , SnO2/TiO2 [Figure 3(b)], SrTiO3/TiO2 [Figure 3(c)] and other composite secondary materials, and these composites have excellent performance for degrading organic dyes in water. We have used the same method to prepare Fe3O4/TiO2 secondary composites with controllable morphology [Figure 3(d)], which not only can effectively degrade organic dyes in water, but also can easily degrade organic dyes in water due to their magnetic properties. The composites were simply separated from the water after catalytic degradation.
4. Sensing Fields
Nanofibers prepared by electrospinning technology can also be widely used in the field of sensing. Electrospun fibers that can be used in the sensing field mainly include the following two aspects.
(1) Electrospinning of polymer fiber films containing fluorescent molecules
In order to make the use of fluorescent probes simpler and easier to use, fluorescent thin film sensing materials have become a research hotspot. The researchers grafted fluorescent small molecules with specific functions onto polymers, and then prepared thin-film sensing materials that were easy to reuse by electrospinning. For example, Wang et al. modified rhodamine molecules on the surface of electrospun fibers to prepare a fluorescent thin film sensor that can be used for colorimetric sensing of Cu2+. When the prepared thin film sensor is placed in a solution containing Cu2+, the thin film sensor can be used as a test paper to test the content of Cu2+ in the aqueous solution. Moreover, the tested films can be used to remove the adsorbed Cu2+ by adding EDTA, so as to achieve the effect of repeated use.
(2) Combined electrospinning technology and subsequent heat treatment process to prepare inorganic oxide sensing materials
The interest in rare-earth-decorated one-dimensional nanomaterials is not only limited to the field of luminescence, but also extends to the field of sensing. For example, Xu et al. used electrospinning to prepare In2O3-CeO2 nanotube series samples with sub-porous structure for the first time, and by adjusting the molar ratio of the two oxides, the morphology and gas sensing performance of the nanotubes were effectively regulated . When the optimized nanotube material was subjected to gas-sensing tests at different temperatures, the material exhibited excellent gas-sensing properties to hydrogen sulfide and acetone gases.
5. Industries
Nanofibers prepared by electrospinning technology can also be widely used in industrial fields. The non-woven nanofiber membrane prepared by electrospinning technology has the characteristics of large specific surface area and small pore size, so it has strong adsorption capacity and good filtration performance. For example, based on polypropylene non-woven fabric, nylon 66 nanofiber mesh is a new type of filter material with excellent performance. Allabashi et al. first used electrospinning technology to prepare electrospun ceramic fibers such as Al2O3, SiC and TiO2, and then mixed them with various polymers to form chemical bonds between them and undergo polymerization to prepare organic-inorganic fibers. Composite filter. This composite membrane can effectively remove a variety of organic pollutants such as monocyclic and polycyclic aromatic hydrocarbons, pesticides, and methyl tert-butyl ether.
