Nanofiber

Nanofiber refers to a fiber with diameter in the nanometer range, typically tens to a few thousand nanometers, yielding a high aspect ratio and a large surface area relative to volume. Nanofibers are usually collected as nonwoven mats, though aligned arrays can be produced.

The most common production method is electrospinning, which uses an electric field to draw a polymer solution or melt into continuous fibers. Other approaches include melt spinning, solution blow spinning, phase separation, self-assembly, and template-assisted synthesis. Fiber diameter and orientation depend on solution properties, processing parameters, and collector design.

Materials span polymers (polycaprolactone, poly(vinyl alcohol)), ceramics (silica, alumina), carbon, and composites. Fibers can be solid, hollow (core–shell), or porous, and may be randomly oriented or aligned. The high surface-area and tunable mechanical properties make them suitable for engineering textiles and membranes.

Applications include filtration (air and liquid), tissue engineering scaffolds, wound dressings, drug delivery, sensors, catalysis, and energy storage components such as batteries and supercapacitors. Nanofiber mats can enhance mechanical strength when used as reinforcement in composites.

Challenges include scalable production with uniform diameters, mechanical fragility of mats, sterilization and biocompatibility for biomedical uses, and cost. Ongoing research focuses on more controllable fabrication methods, multi-material fibers, and functionalization.