Electrospun nanofibers are extensively studied and their potential applications are largely demonstrated. Today, electrospinning equipment and technological solutions, and electrospun materials are rapidly moving to commercialization. Dedicated companies supply laboratory and industrial-scale components and apparatus for electrospinning, and others commercialize electrospun products. This paper focuses on relevant technological approaches developed by research, which show perspectives for scaling-up and for fulfilling requirements of industrial production in terms of throughput, accuracy, and functionality of the realized nanofibers. A critical analysis is provided about technological weakness and strength points in combination with expected challenges from the market.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mame.201200290

Industrial Upscaling of Electrospinning and Applications of Polymer Nanofibers: A Review

Oil/water separation, especially emulsified oil/water mixture separation, has become a widespread concern because of the severe fouling problem caused by the easy adsorption of oil droplets onto the surfaces of filtration membranes. Many strategies have been employed to eliminate the fouling problem, but it remains a challenge and impedes the development of membrane technology. In this short review, we discuss the recent development of membrane technology for emulsified oil/water separation. As shown in the image, in addition to polymer- and ceramic-dominated traditional membranes, nanomaterial-based membranes have recently demonstrated their superiority and have achieved high performance.

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Recent progress in developing advanced membranes for emulsified oil/water separation

Advances in three-dimensional nanofibrous macrostructures via electrospinning

https://dr.ntu.edu.sg/bitstream/10356/104282/1/Progress%20in%20electrospun%20polymeric%20nanofibrous%20membranes%20for%20water%20treatmen.pdf

Progress in electrospun polymeric nanofibrous membranes for water treatment : fabrication, modification and applications

Developing a feasible and efficient separation membrane for the purification of highly emulsified oily wastewater is of significance but challenging due to the critical limitations of low flux and serious membrane fouling. Herein, a biomimetic and superwettable nanofibrous skin on an electrospun fibrous membrane via a facile strategy of synchronous electrospraying and electrospinning is created. The obtained nanofibrous skin possesses a lotus-leaf-like micro/nanostructured surface with intriguing superhydrophilicity and underwater superoleophobicity, which are due to the synergistic effect of the hierarchical roughness and hydrophilic polymeric matrix. The ultrathin, high porosity, sub-micrometer porous skin layer results in the composite nanofibrous membranes exhibiting superior performances for separating both highly emulsified surfactant-free and surfactant-stabilized oil-in-water emulsions. An ultrahigh permeation flux of up to 5152 L m−2 h−1 with a separation efficiency of >99.93% is obtained solely under the driving of gravity (≈1 kPa), which was one order of magnitude higher than that of conventional filtration membranes with similar separation properties, showing significant applicability for energy-saving filtration. Moreover, with the advantage of an excellent antioil fouling property, the membrane exhibits robust reusability for long-term separation, which is promising for large-scale oily wastewater remediation.

Biomimetic and Superwettable Nanofibrous Skins for Highly Efficient Separation of Oil-in-Water Emulsions

Continuous polymer nanofiber yarns prepared by self-bundling electrospinning method

Development of hydrophilic barrier layer on nanofibrous substrate as composite membrane via a facile route

A new route to high-performance electrospun polymer fibers was developed using a self-bundling electrospinning technique combined with post-treatments such as stretching and annealing under conditions similar to those used for conventional fibers. Self-bundled electrospun PAN fiber yarns were characterized by SEM, mechanical tests, polarized FT-IR spectroscopy and WAXD. The obtained results revealed that the PAN nanofiber yarns possessed enhanced alignment, a higher degree of crystallinity and higher molecular orientation after treatments, resulting in a remarkable improvement in mechanical performance, approaching the strength value of the corresponding conventional fibers.

Enhanced Mechanical Performance of Self‐Bundled Electrospun Fiber Yarns via Post‐Treatments

Low pressure high flux thin film nanofibrous composite membranes prepared by electrospraying technique combined with solution treatment

Poly(L-lactic acid) (PLLA) tissue engineering scaffolds with porous inner structures of individual fibers and controllable architectures were successfully fabricated from the homogeneous polymer–solvent–nonsolvent system (PLLA, CH2Cl2 and DMF) by a single capillary electrospinning with certain conductive patterned templates as fiber collectors. PLLA was dissolved in dimethylformamide (DMF) and methylene chloride (CH2Cl2) mixed solvent with different ratios. Semi-hollow fiber with porous inner structure and compact shell wall was formed by controlling the content of DMF in the mixed solvents. It is believed that the phase separation should be the key origin for the formation of this microstructure. In order to mimic the natural extracellular matrix (ECM) with a specific structure, conductive patterned collectors were designed and employed to manufacture PLLA ultrafine fibrous scaffolds with three-dimensional architectures. We believe these kinds of multi-scale biodegradable fibrous scaffolds with specific microstructure and macro-architectures could make the electrospun fibrous scaffold better mimic the natural extracellular matrix to satisfy tissue engineering.

Kai Zhang

Papers

Continuous polymer nanofiber yarns prepared by self-bundling electrospinning method

Development of hydrophilic barrier layer on nanofibrous substrate as composite membrane via a facile route

Enhanced Mechanical Performance of Self‐Bundled Electrospun Fiber Yarns via Post‐Treatments

Low pressure high flux thin film nanofibrous composite membranes prepared by electrospraying technique combined with solution treatment

Bionic electrospun ultrafine fibrous poly(L-lactic acid) scaffolds with a multi-scale structure.