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The emerging solar interfacial evaporation (SIE) technology is an effective measure to address freshwater resources. An efficient and stable solar interfacial evaporator cannot be achieved without the synergy of three key factors: water transport, solar thermal conversion, and thermal management. The performance of a solar interfacial evaporator can be improved through the rational selection of materials and the structural design of these three key factors. Due to superior nanostructures, electrospun nanofibrous materials often exhibit some unique properties that facilitate the construction of solar interface evaporators with good performance. So far, electrospinning has been used to prepare structures such as solar absorbers, water transportation, and thermal insulation in various solar interfacial evaporators. This review presents the fundamental research and technological development in the application of electrospinning techniques to solar interfacial evaporators on structures, morphology, and properties. Then, the latest advances in the use of electrospinning technology in solar interfacial evaporators are summarized and the current issues facing the application of electrospinning technology to solar interfacial evaporators are presented. These systematic discussions can provide ideas and approaches for the rational design of electrospun nanofiber materials for solar interfacial evaporators in the future. [ABSTRACT FROM AUTHOR]

Abstract: Eco-friendly tree-like porous carboxyl modified cellulose nanofiber membranes as highly efficient adsorbents for heavy metal ions were fabricated by the electrospinning of cellulose acetate (CA)/tetrabutylammonium chloride (TBAC)/manganese dioxide (MnO2) solution, and subsequent deacetylation treatment to turn CA into cellulose and citric acid modification to graft carboxyl group on the surface of cellulose nanofibers. The addition of TBAC led to the formation of tree-like structure and MnO2 particles were used as pore-forming agents. The effects of pH, initial ion concentrations and contact time on the removal capacity of heavy metal ions were investigated. During the removal process, the abundant carboxyl groups (-COOH) transferred to carboxylate ions (-COO−) which had stronger ion exchange ability to the metal ion adsorption. In addition, the tree-like porous structure supplied large specific surface area and effectively increased the removal capacity. The removal process could reach a plateau in 90 min with the maximum removal amount of 399.14 mg/g. The removal process was also depicted by Langmuir and Freundlich isotherm model. Generally, the tree-like porous structure will have extensive prospects in the fields of filtration, electrochemistry, tissue engineering and so on.Graphical abstract: [ABSTRACT FROM AUTHOR]

Herein, the composite carbon material of porous carbon nanofiber and carbon nanotube is developed via electro-blown spinning and one-step simultaneous carbonization and chemical vapor deposition without injecting every kind of reaction gas in proportion and removing catalyst in secondary processing. The carbon nanotubes are uniformly growing on carbon skeleton which dramatically improve the performances such as specific surface area (from 334.066 to 644.589 m2 g−1) and electrical conductivity (from 42.22 to 146.20 S cm−1) comparing with porous carbon nanofibers. The different spinning parameters are investigated to optimize parameters, and the porous carbon nanofiber and carbon nanotube are studied and used as electrode for supercapacitors. The results showed that it possesses excellent electrochemical properties, including high specific discharge capacity (216.5 F g−1 at 1.0 A g−1) and good cycle performance (retains ~ 98.68% after 5000 cycles). Moreover, the convenient one-step prepared method special throughout pores structure and superior performance provide a novel approach for designing new types of carbon composite materials which also possess potential application prospect in fields of catalyst, adsorption, etc. [ABSTRACT FROM AUTHOR]

Pullulan nanofiber membrane (Pull-NM) was prepared by electrospinning method and its stability in the water was improved by a chemical crosslinking with mixed solution of ethylene glycol diglycidyl ether (EGDE) and ethanol absolute as crosslinking agent. The effect of crosslinked pullulan nanofiber membrane (C-l-Pull-NM) with different process conditions was studied and the excellent crosslinking reaction condition is proved to be 1:70 (EGDE: ethanol absolute) for 24 h. The analytical methods, including SEM, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and differential scanning calorimetry, were used to study morphology, structure, and thermal performance of the nanofiber membrane. In addition, the swelling behavior and tensile were also discussed. The results showed that the water resistance of crosslinked nanofiber membrane had a significant improvement. Furthermore, the maximum water absorption and the strength were reached to about 520 and 192.7%, respectively. [ABSTRACT FROM AUTHOR]

Recently, the multi-level structure materials with some superior performances has attracted broad attentions. In this study, the elastomeric tree-like thermoplastic polyurethane (TPU) nanofiber membranes with multilevel structure were prepared by introducing tetrabutylammonium chloride (TBAC) via one-step electrospinning. The coverage rate and average diameter of the TPU tree-like nanofibers could be controlled by varying the solution concentrations and electrospun parameters. The special multilevel structure with trunk fibers (diameter 300–500 nm) and branch fibers (diameter 20–80 nm) significantly improved crystallinity, hydrophilicity and flexibility performances comparing with pristine TPU nanofibers, and the novel hierarchical elastomeric tree-like nanofiber membrane had a bright future in various potential applications, such as medical, filtration and protective field, etc. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrospinning hydrophilic/hydrophobic photothermal membranes for SDMD is proposed. • The membrane shows strong photothermal conversion properties and anti-fouling properties. • The membrane exhibits superstable and high flux in long-term desalination of SDMD. Low permeate flux and membrane fouling are major limiting factors for solar-driven membrane distillation (SDMD) industrial applications. Here, we report a Janus nanofiber membrane with electrospinning CB/PVA as hydrophilic photothermal layer and electro-blown spinning PTFE nanofiber membrane as hydrophobic layer, which exhibits excellent photothermal conversion performance, anti-fouling performance and durability. The hydrophilic photothermal layer simultaneously captures solar energy and performs photothermal conversion, repels chemical/oil-based pollutants and promotes steam flow. At the same time, the low surface of PTFE layer can guarantee the long-term durability of the composite nanofiber membrane. Under the light intensity of 1 kW·m−2, the Janus nanofiber membrane can obtain a permeate flux of 1.05 L·m−2·h−1 and a salt rejection of > 99.99 %. And the photothermal conversion efficiency reached 71.4 %. More importantly, the permeate flux of the Janus nanofiber membrane was still stable at 1.035 L·m−2·h−1 after continuous treatment of pollutant-containing feed solutions for 60 h, and the salt rejection was > 99.98 %. This indicates that the efficient photothermal conversion performance and anti-fouling properties make the CB-PVA/PTFE photothermal nanofiber membrane promising for generating fresh water from feed solutions containing various pollutants in SDMD systems. [ABSTRACT FROM AUTHOR]

As a kind of high-performance fiber, PTFE fiber has been widely used in many fields because of its unique characteristics. In this study, pure PTFE nanofiber film was prepared effectively through electro-blown spinning (EBS) under dual forces of high speed air flow and static electric method followed by a thermal treatment process. The effects of PTFE/PVA ratio, the amount of boric acid (BA), air pressure, applied voltage and sintered temperature were discussed to obtain the PTFE nanofibers with different diameters, and the film had been characterized by SEM, TG, XRD and XPS, respectively. The results showed that pure PTFE nanofiber film with good morphology could be large scale prepared through the EBS process. Moreover, this novel EBS method may realize the industrialized production of high performance polymer fibers. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is an attractive thermally-driven membrane process for desalination, brine and wastewater treatment. One of the main obstacles impeding MD application is the absence of effective MD membranes with sufficient water permeability and long-term stability. Attributed to the outstanding hydrophobicity, excellent thermal and chemical resistance, the most ideal polymer to develop MD membrane is polytetrafluoroethylene (PTFE). However, the fabrication of PTFE membranes is challenging due to its poor processability. This work describes a novel strategy to develop superhydrophobic and highly porous PTFE membranes via electrospinning. The hydrophobic nanoparticles 8 vinyl-grafted polyhedral oligosilicone (vinyl-POSS) were firstly incorporated into PTFE nanofibers to promote the crystallization of PTFE nanofiber, enhance nanofiber roughness, and improve membrane mechanical robustness and porosity. The effects of vinyl-POSS concentration, temperature and salt concentration of feed solutions on MD performance of PTFE/POSS nanofibrous membranes were investigated systemically in this study. The optimized PTFE/POSS nanofibrous membrane #POSS-2 has a three-dimensional (3D) superhydrophobic property with a water contact angle of 151 ± 4°. It exhibited a competitive water flux of 40 ± 2 Lm−2 h−1 in the direct contact membrane distillation (DCMD) process when the feed and permeate temperatures were 60 and 20 °C, respectively. Moreover, #POSS-2 possessed an excellent long-term stability in a 200-h continuous DCMD operation. Unlabelled Image • Vinyl-POSS has been incorporated into PTFE nanofibers to promote PTFE crystallization. • PTFE/POSS nanofiber shows a highly rough surface with valleys and ridges. • #POSS-2 possesses 3D superhydrophobicity, high porosity, and sufficient mechanical and chemical robustness. • #POSS-2 shows a competitive water flux and a stable rejection above 99.99% in a 200-h long-term DCMD operation. [ABSTRACT FROM AUTHOR]

In this work, the inorganic-organic nanofibrous composite separators were successfully prepared for Li-ion capacitor (LIC) via wet-laid method using electro-blown spun inorganic alumina (Al 2 O 3) nanofibers and electrospun organic polyimide (PI) nanofibers as components. Benefitting from the synergistic action of fast ions transfer performance and outstanding fire-resistance offered by Al 2 O 3 nanofibers as well as heat-resistance and entangled force derived from PI nanofibers, the novel membranes exhibited excellent film forming property, outstanding flexibility and high ionic conductivity. Moreover, it delivered superior fire-resistance with dimensional stability after burning. It was discovered that the novel membranes prepared with 50 wt% Al 2 O 3 nanofibers showed better ionic conductivity of 2.71 × 10−3 S cm−1 and broader electrochemical stability window of 5.3 V than those of commercial membranes. The LIC assembled with this novel separator reached the energy density of 12.5 Wh kg−1 even at the high power density of 15 kW kg−1. In addition, this LIC presented a high energy density of 57.3 Wh kg−1 at the current density of 0.5 A g−1 and maintained a high cycle stability even after 10,000 cycles. This study provided the design idea and experimental basis for the development of high-performance LIC separator. [ABSTRACT FROM AUTHOR]

Permeability and selectivity are the two most important parameters in membrane distillation process. The membrane with high porosity and superhydrophobicity could increase the mass transfer coefficient, decrease the heat losses and improve the resistance to wettability. To satisfy this purpose, a novel superhydrophobic polyvinylidene fluoride (PVDF)/tetrabutylammonium hexafluorophosphate (TBAHP)/polystyrene (PS) multi-scale nanofiber membrane (MNM) with high porosity and low thermal conductivity was successfully designed and developed via one-step electrospinning. The formation of multi-scale structures was caused by the addition of TBAHP. PS owns low thermal conductivity and low surface energy which can enhance the thermal efficiency and improve the hydrophobicity of MNMs. Besides, the addition of PS can amplify the classifying effect, construct the nano-micron structure and endow the membrane with superhydrophobicity. The results showed that the thermal conductivity of membranes decreased from 0.03361 W/mK to 0.02777 W/mK and the water contact angle increased from 138.2° to 151.7°. The PVDF/TBAHP/35%PS MNMs exhibited a stable MD performance with an average permeation flux of 50 ± 3 L/m2 h and a satisfactory salt rejection higher than 99.9% during 72-h continuous DCMD operation (3.5 wt% NaCl solution, the feed/permeate temperatures were 60/20 °C, respectively). Unlabelled Image • A multi-scale nanofiber membrane (MNM) was developed by electrospinning. • The MNMs exhibited high porosity and narrow pore size distribution. • The MNMs possessed low thermal conductivity and superhydrophobicity. • The MNMs showed high permeate flux (51.96 L/m2 h) and salt rejection (99.99%). [ABSTRACT FROM AUTHOR]

Highlights • A novel hybrid Octaphenyl-POSS/PMIA membrane is successfully prepared. • The separator has outstanding thermal stability and strength. • The separator shows excellent ability to absorb and store liquid electrolyte. • The separator has high ionic conductivity and stable electrochemical window. • The battery presents high safety and excellent electrochemical performance. Abstract In this study, a hybrid Poly-m-phenyleneisophthalamide/Octaphenyl-Polyhedral oligomeric silsesquioxane (PMIA/Octaphenyl-POSS) membrane (HPPS) was fabricated by electrospinning technique and its application performance as lithium-ion battery separators was discussed. The organic-inorganic feature of Octaphenyl-POSS (OPS) endowed admirable compatibility of membrane matrix for the HPPS membranes. The nanofiber membranes with OPS nanoparticles were provided with commendable thermal stability, robust mechanical strength (21.79 MPa), high porosity and electrolyte uptake, which laid a good foundation for improving the safety and cycle performance of the cells with the separator. The lithium-ion battery with the HPPS separator displayed a high ionic conductivity of 1.93 × 10−3 S·cm−1 and a stable electrochemical window of 4.98 V. More significantly, the HPPS nanofiber membrane based Li/LiCoO 2 cell exhibited excellent cycling stability with high first discharge capacity up to 157.9 mAh·g−1 and superior capacity retention of 89.04% after 100 cycles. Therefore, the HPPS separator has extraordinary potential to be used in high-performance lithium-ion battery. [ABSTRACT FROM AUTHOR]

A novel tree-like cellulose nanofiber membrane was controllably fabricated via the electrospinning method by adding certain amount of tetra butyl ammonium chloride (TBAC) into the cellulose acetate solution followed by a deacetylation treatment process. The morphological structure, material structure and air filtration performance of both the cellulose and the cellulose acetate tree-like nanofiber membranes were characterized. Water contact angles, mechanical properties, and air filtration properties were also evaluated. The air filtration efficiency of cellulose acetate tree-like nanofiber membrane can reached 99.58%, and the eventually cellulose tree-like membrane still maintain 98.37%. The eventual cellulose tree-like nanofiber membranes exhibited small pore size, excellent hydrophilicity, good solvent resistance and preferable mechanical property. The small average pore size caused by the tree-like structure and the strong resistance to organic solvent can make it a potential candidate for the membrane separation. [ABSTRACT FROM AUTHOR]

A smart tree-like nanofiber membrane with pH-responsivity was successfully fabricated by electrospinning poly(vinylidene fluoride)-graft-poly(acrylic acid) (PVDF-g-PAA). X-ray photoelectron spectroscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller surface area measurement were employed to study the molecular structure and morphology of membranes. Through realizing protonation and deprotonation in response to the pH of the aqueous media, the as-prepared membrane is able to alter its wettability and conformation, resulting in the switchable surface oil/water wettability in the aqueous media. More importantly, the as-prepared membrane realized on-demand oil/water separation using gravity alone by switching the pH of the medium. Both separations exhibited excellent efficiency and flux which were attributed to the tree-like structure of the membrane. We believed that this smart membrane with such excellent controllable permeation has potential to be used for several applications, such as water purification, oil recovery and some separation systems. [ABSTRACT FROM AUTHOR]

In this study, the F-doped poly-m-phenyleneisophthalamide (PMIA) solution was synthesized by low temperature polymerization method and spun to be three-dimensional nanofibrous membranes by electrospinning. The Energy Dispersive X-Ray Spectroscopy and Fourier Transform Infrared Spectroscopy investigations verified that F was successfully doped in PMIA membrane. The X-ray diffraction patterns showed the crystallinity degree of PMIA membrane decreased with the addition of F. The morphology, pore size and aperture distribution tests manifested that the average diameter of F-PMIA fibers became finer and their distribution was more uniform than these of PMIA fibers. The electrolyte uptake, preserving liquid electrolyte, thermal stability and shrinkage resistance of the F-dopoed membrane were also significantly enhanced than that of pure PMIA membrane. The F-PMIA membrane could be acted as matrix to prepare gel polymer electrolyte. Finally, the F-doped PMIA membrane was used in the assembled coin cells to test the properties including the electronic conductivity, battery interfacial characteristics, electrochemical stability windows and cycle performances of battery. The lower electronic conductivity and interfacial resistance, higher electrochemical stability window (5.7 V) of F-doped PMIA membranes were obtained when comparing to the pure PMIA and commercial polyethylene membrane. The cell exhibited high first-cycle discharge capacity with 145 mAh g −1 and excellent cycling stability with good capacity retention of 93.1% and coulombic efficiency of 99.3% after 100 cycles. [ABSTRACT FROM AUTHOR]