Nanofibers

These are ultrafine fibers with diameters in the nanometer range. They have high strength, large surface area, and unique mechanical properties. Nanofibers find applications in filtration, tissue engineering, and protective clothing.

Nanofibers are promising candidates for acting as carriers for applications such as water treatment, fuel cell, targeted drug delivery, tissue engineering, cosmetics, biosensors, energy production, wound dressing, and more.

Nanofibers have a high surface area-to-volume ratio and scalable porosity because of which they find a wide range of applications. For drug delivery, they are usually produced keeping into consideration the specificity of drug, target location, and the time required for the drug to achieve therapeutic effects.

Applications:
About two-thirds of the patents filed on Electrospinning applications are in the biomedical field, due to the high surface area to volume ratio.

– Tissue engineering
In tissue engineering this technique is used to produce scaffolds with interconnected pore structure of nanometer scale. Supports are produced for growth, adhesion, migration, proliferation and reproduction of biological tissue to be replaced.

Substrates and electrospun membranes are produced for wound dressing such as burns and abrasions, controlled release of medicines (in fact, nanofibers are used as a vehicle for the transport and release of the medicine) where the active ingredient is introduced into the polymer solution and then the nanofibers are produced with the electrospinning technique.

Supports for biocatalysis and barriers for the prevention of adhesion can be realized, in fact, the size of nanofibers is not compatible with the size of bacteria, if properly electrospun through proper regulation and management of process parameters, but allows the exchange of gases such as oxygen, carbon dioxide, and water vapor, thus allowing the transpiration of tissues.

Tissue engineering does not remain limited to the biomedical field but finds outlets for use in other sectors as well.

– Fluid filtration
In the field of fluid filtration it is possible to use electrospun membranes thanks to the unordered structure, always obtained through a correct management of the process parameters, and to the porosity of the same. Due to the high surface/volume ratio and the high surface cohesion, fine particles can be “trapped”. By electrically charging the nanofibers, it is possible to increase the attraction of the particles to be filtered in the case of electrically charged particles.

– Energy field
In the energy field, this technique, with appropriate polymers, allows the conduction of electrons and/or ions, making the obtained nanofibers interesting in the production and storage of energy. In this field, nanofibers can be applied for photovoltaic panels, rechargeable batteries and supercapacitors, through the use of electroactive polymers, membranes for sensors and actuators can be obtained.

Also in the energy field, nanofibers can be used for rechargeable batteries by exploiting the properties of silicon. This application is interesting in order to improve the efficiency of lithium batteries present in plug-in electric vehicles.

Still in the automotive field, nanofibers are used for the production of more efficient car filters.

– Military field
In the military, nanofibers are used to improve the ability to detect chemical and biological agents with maggioreselectivity. Protective structures, composed of nanofibers, have improved the protection of military personnel due to their ability to filter and decompose toxins.

This particular field of application has given rise to self-cleaning/self-detoxifying personnel protection devices. These devices mainly consist of masks composed of two “layers”: the first serving to filter the air and the second, a bed of activated carbon, which absorbs harmful gases and contaminants. 

Suitable nanofibers can then be created to replace the activated carbon layer. These are also known to provide better breathability and comfort for the end user. In addition, nanofibers are able to trap small particles such as viruses.

– Sensor field
The remarkable characteristics of electrospun nanofibers (including high surface area, porosity, flexibility, and relatively low cost) make them an excellent choice for sensor applications. They find use in sensors monitoring biological parameters such as glucose values, through to gas monitoring systems.

– Textile field
In this area, nanofibers have found applications in protective clothing. In fact, electrospun microporous membranes have the potential to provide thermal comfort to the wearer while also providing protection from a wide variety of hazards