There are two main concepts of nanofibers. The first is strictly defined as nanofibers. The diameter of ultrafine fibers is less than 100 nm, but the length can be more than 100 nm. Secondly, fibers that modified by filling nanoparticles are also called nanofibers and this type nanofiber is common in industry field. The nanofibers filling with nanoparticles of different properties can be used to develop various functional fibers, which have the properties of antibiosis, inflaming retarding, ultraviolet-proof, electromagnetic shielding and the others. Furthermore, nanofibers have a large specific surface area and are easy to bond with other atoms, showing strong activity. Due to the small size effect, nanofibers show unique properties in sound, light and electromagnetism that are different from macroscopic materials, which are widely used in many fields.
- Filtration materials field: Nanofibers can be used as filtration materials. Nanofibers have a large specific surface area, porosity and good permeability, which makes them easier to adsorb and separate tiny particles. In addition, the modified nanofibers have better filtration accuracy and can be used in a variety of highly demanding filtration fields, such as metal ion adsorption, air filtration, liquid filtration and the others.
- Controlled drug release field: In some treatment process, the drug release rate is needed to be controlled to achieve the best results. Nanofibers with high specific surface area are suitable to design controlled drug release system.
Figure 1. A controlled drug release system constructed by nanofiber.
- Sensor material field: Nanofiber can be applied as sensor material, and the sensitivity is high. Generally, the performance of nanofiber sensor is much better than that of the corresponding thin-film sensor. Due to the high specific surface area and excellent electrochemistry, nanofibers can be used as sensor materials for pressure, inorganic gases, organic compounds and the others. Moreover, nanofibers can be applied as biosensors to detect toxic cells in living organisms.
Figure 2. A pressure sensor designed with nanofiber.
- The others: Nanofibers also can be used in many other fields. For example, with high specific surface area and desirable chemical properties, nanofibers can be used to make a variety of nanodevices, such as nanowires, light-emitting diodes and solar cells. In addition, nanofibers have potential applications in the field of microelectronics and optoelectronic devices.
According to the composites, nanofibers can be divided into polymer nanofibers, inorganic nanofibers and organic/inorganic nanofibers.
Many methods can be used to fabricate nanofibers, including drawing method, template synthesis, self-assembly, microphase separation, electrostatic spinning and the others. Among them, with the advantages of simple operation, wide application range and relatively high production efficiency, electrostatic spinning is the mostly used method.
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