Nanofibres pore structure

Electrospinning of natural fibres offers unique capabilities for producing novel natural nanofibres and fabrics with controllable pore structure. Current research efforts have been focused on improving the understanding of the influence of different governing parameters on the electrospinning of natural fibres. 

Abstract Liquids are essential for most of the lives and activities on earth, where liquid filtration is an important tool to remove undesired suspended solids, emulsified particles, dissolved molecules, and ions from liquids by separating the permeate from the unwanted impurities through filters. Electrospun nanofibrous membranes (ENMs) have been developed as filtration media having unique advantages over traditional membranes, due to high porosity, interconnected pore structures, large surface-to-volume ratio with capability for chemical/physical functionalization, and cost-effectiveness. The new fibrous membrane format has been used in many applications, including filtration, (membrane) distillation, and pervaporation. 

In 2012, Yeh and co-workers first applied ENMs in water/ethanol pervaporation [112]. As shown in Fig. 13.16, the separation membrane system consists of a cross-linked PVA hydrophilic top layer, a cellulose nanofibrous buffer layer, an ENM layer with high porosity and fully interconnected pore structure, and a PET support layer. In water/ethanol pervaporation test, the separation factor of the new membrane could reach 80.8, and flux was 765 kg/m h, which were significantly higher than conventional membranes (e.g., Sulzer 1210). Using ENMs promised the novel pervaporation membrane a higher permeate flux than conventional ones, and using the cellulose nanofibrous layer prevented the penetration of the barrier layer. 

Electrospun nanohbrous structure possess several attractive features, such as high porosity and interconnected open pore structure, submicron pore sizes, and a large surface area-to-volume ratio. These characteristics make them an ideal material candidate for removing sohd substances from air or hquid [6]. To demonstrate the filtration performance of electrospun nanohbre membrane, a thin coat of electrospun PAN nanohbres over a metal mesh has been shown to collect more than 95 % of PM2.5 (i.e. particulate matter in size of 2.5 pm) in a polluted city environment with 90 % transparency [323]. Filtration efficiency, which is closely associated with fibre fineness, is one of the most important concerns for the filter performance [6]. Molaeipour et al. [324] used ultrafine cellulose acetate nanofibres with different diameters to evaluate their filtration efficiencies for tar removal. It was found that... 

Nevertheless, formation of lithium dendrites and deteriorated battery performance still exist owing to uneven current distribution derived from the relatively large pore size of electrospun membranes. To construct nanofibrous separators with controllable pore structure, Zhai et al. prepared hierarchically structured Si02 nanoparticles coated polyetherimidepolyurethane (PEI-PU) composite nanofibrous membranes by combining the advantages of electrospun nanofibers with surface... 

Bhattarai et al. developed a novel biodegradable electrospun membrane as a scaffold for tissue engineering. A nanofibrous matrix of poly(p-dioxanone-co-L-lactide)-block-poly(ethylene glycol) (PPDO/PLLA-b-PEG) copolymer was evaluated for cell proliferation and its morphology of cell-matrix interaction. The electrospun structure composed of fibers with an average diameter of 380 nm, medium pore size 8 mm, porosity greater than 80% and mechanical strength of 1.4 MPa is favorable for cell-matrix interaction [39]. 

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