![]() This situation makes selection and optimization steps critical.Ĭentrifugal ES is known by force spinning or rotary spinning as well. The melting temperature of the polymer can affect the structure and function of these additives (e.g., proteins, drugs, etc.). Requirement of high temperatures to melt the polymer can also be a disadvantage at this point. To reduce the fiber diameter or to obtain fibers with uniform diameters, some research groups used polymer blends or additives. Because of the high viscosity of the polymer, greater charge is required to initiate the jets. But in most of the cases, one of the major problems of melt ES is broad fiber diameter range due to the high viscosity of the melt polymer. This method can be used with the polymers that do not have a suitable solvent at room temperature. Main advantages of this method can be described as the absence of a solvent system and the high throughput rate of the polymer. and c was reproduced with the permission from Blachowicz and Ehrmann ). b was reproduced with the permission from Taghavi et al. (a was reproduced with the permission from Brown et al. (a) Melt electrospinning setup, (b) centrifugal electrospinning setup, and (c) magnetic-field-assisted electrospinning setup. This chapter mainly focuses on the different production methods of nanofibers, their characterization techniques, recent developments in tissue engineering applications. When all the advantages considered (high aspect ratio, tunable properties, ability to form 3D networks, etc.), nanofibers are perfect nominee for different biomedical applications, such as tissue engineering (TE), regenerative medicine, drug delivery, nanoparticle delivery, etc. It is also possible to blend fiber materials to acquire a composition that can be organic, inorganic, carbon-based, or a composite. According to its nature, one can produce natural or engineered nanofibers while one can produce nonporous, porous, hollow, core-shell nanofibers due to its structure. Types of nanofibers can vary due to their nature, structure, and composition. The vital point of nanofiber technology is the availability of a wide range of materials such as natural and synthetic polymers, composites, metals, metal oxides, carbon-based materials, etc., which can be used for fiber production process. And because almost all their properties are tunable, one can select and use nanofibers in numerous applications. ![]() Nanofibers have many advantages because of their scales, which gave them high aspect ratio (length/diameter value) above 200 and high surface area. After almost 60–70 years later, Formhals’ work was appreciated, understood, and widened. Forming fibers in nanoscale was a major drawback at that time, and not much attention was paid to the topic until the breakthrough of nanotechnology in the late 1990s. The use of viscoelasticity in the solutions led the formation of nanofibers because the applied electric field caused a considerable reduction of the fiber diameter due to the bending instability, which is later mentioned by Reneker. Although electrospinning process was used before Formhals, no one was able to form long filaments due to the use of inelastic Newtonian fluids. Going back to its origins, nanofibers are produced for the first time by Formhals (1934) by electrospinning of cellulose acetate solution. Nanofibers have two alike dimensions (diameter) in the nanoscale and a third dimension, which is significantly larger (length). Specific definition of nanofibers can vary from one discipline to another, but according to one of the most common descriptions, fibers with a diameter below 100 nm are referred as nanofibers. ![]()
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