A large surface area, scalable porosity, and versatility have made nanofibres one of the most widely investigated morphologies among the nanomaterials. The characteristic properties of nanofibres have made them useful in a broad range of applications, such as filters, membranes, tissue engineering, wound dressings, protective clothing, reinforcement in composite materials, and sensors. So far, various top-down and bottom-up approaches were proposed to produce nanofibres. In this paper, a comprehensive review is presented on non-electro fiber spinning techniques, along with their mechanisms. The parameters of these techniques are also discussed in detail, while process-specific gains were emphasized according to the end uses. This review paper also provides a literature insight into the biomedical, filtration, optical, and energy applications of nanofibres produced via the most typical and widely used methods.

This study reports on the effects of BaTiO₃—a high dielectric constant additive—addition on charging and filtration properties of meltblown polypropylene (PP) electret filters. Since electrostatic capture efficiency of electret filters is mainly dependent on electrical forces, surface potential and aerosol filtration properties were analyzed and compared. Due to quasi-permanent nature of electret property, stability of charging and filtration performance was also investigated via following an isothermal charge decay procedure. Addition of BaTiO₃ did not alter fiber morphology significantly. Particularly, the stability of electrostatic filtration performance was found to be promising with the addition of BaTiO₃. Possible microstructural changes after addition of BaTiO₃ were investigated via wide angle X-ray diffraction. Changes in crystal structure of PP upon addition of BaTiO₃ did not deteriorate electrostatic properties. Copyright 2015 American Association for Aerosol Research

In this study, silica based nanofibers were produced via centrifugal spinning (C-spin) and subsequent calcination. The produced heat resistant media was challenged with NaCl nanoparticles to investigate their filtration performance. To obtain inorganic SiO₂ nanofibers, C-spun organic PVP – TEOS nanofibers were calcinated at 300-600 °C. Effects of solution concentration and calcination temperature on crystallinity, morphology and air filtration performance of nanofibers were investigated. Scanning electron microscopy (SEM) analysis was performed to analyze fiber diameter and morphology of nanofibrous webs. Differential thermal analysis (DTA) was realized for the thermal behavior of samples. Moreover, X-ray Diffraction (XRD) and Fourier Transform Infrared Spectra (FTIR) analysis were realized for further characterization. In addition to the chemical and morphological analysis, the ductility of the samples was investigated via tensile tests. Finally, calcinated webs were challenged with 0.4μm salt particles to analyze their filtration performance. The calcinated 5wt% TEOS/PVP silica nanofiber webs were more brittle due to three times lower precursor content. Therefore, flexibility (percent elongation) of 15wt%TEOS/PVP sample was nearly five times higher than 5wt%TEOS/PVP sample. The calcinated 15wt%TEOS/PVP sample showed the highest filtration performance among all the silica nanofibers. The average fiber diameter of the optimized web was found to be the lowest, which is around 521 ± 308 nm, which resulted in enhanced filtration efficiency around 75.89%. Copyright © 2019 American Association for Aerosol Research