科创中国

Bubble elecrospinning is an excellent and novelty method to fabricate nanofibres with high throughout. This paper investigates experimentally the effects of solution concentration and its viscosity on diameter and morphology of bubble electrospun polyvinyl alcohol (PVA) nanofibres, where pure water is used as a solvent for environmental consideration. The experiment shows that the as spun fibres change their morphology from few beads, smooth surfaces and finally to larger diameter fibres when PVA solution concentration increases gradually. An allometric relation between the fibre diameter and the solution concentration is obtained. The minimal diameter is as small as 38•3 nm.

R. R. Yang;J. H. He;岚 徐;建勇 俞

Materials Science and Technology

2010-11-1

Superhydrophobic and superoleophilic nanofibrous membranes exhibiting robust oil-water separation performance were prepared by a facile combination of electrospun cellulose acetate (CA) nanofibers and a novel in situ polymerized fluorinated polybenzoxazine (F-PBZ) functional layer that incorporated silica nanoparticles (SiO₂ NPs). By employing the F-PBZ/SiO₂ NPs modification, the pristine hydrophilic CA nanofibrous membranes were endowed with a superhydrophobicity with the water contact angle of 161°and a superoleophilicity with the oil contact angle of 3°. Surface morphological studies have indicated that the wettability of resultant membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. The quantitative hierarchical roughness analysis using the N ₂ adsorption method has confirmed the major contribution of SiO ₂ NPs on enhancing the porous structure, and a detailed correlation between roughness and solid-liquid interface pinning is proposed. Furthermore, the as-prepared membranes exhibited fast and efficient separation for oil-water mixtures and excellent stability over a wide range of pH conditions, which would make them a good candidate in industrial oil-polluted water treatments and oil spill cleanup, and also provided a new insight into the design and development of functional nanofibrous membranes through F-PBZ modification.

Yanwei Shang;Yang Si;Aikifa Raza;Liping Yang;Xue Mao;彬 丁;建勇 俞

Nanoscale

2012

The exploration of non-noble metal catalysts toward the electrochemical nitrogen reduction reaction (NRR) is crucial for industrial-scale ammonia synthesis. Although metal sulfides have long been predicted to be electrocatalytically more efficient than other compounds, there has been no substantial progress made on them due to the difficulties in the controllable synthesis of elaborate nanostructures with optimized NRR performance. Besides, their inferior electrical conductivity is not favorable for electrocatalysis. Herein, we propose an interesting conceptual design to integrate novel metal sulfide catalysts with a fascinating conductive matrix. Through self-organized growth under solvothermal conditions, flower-like SnS₂ and forest-like ZnS nanoarrays are directly formed on Ni foam with intimate adhesion. Both SnS₂ and ZnS exhibit remarkable abilities in nitrogen activation, which are further enhanced by forming well-aligned nanoarrays on 3D porous Ni foam, offering a large surface area and enabling easy electrolyte permeation. Moreover, Ni foam significantly outperforms carbonaceous materials as a conductive matrix because of its far better electrical conductivity and mechanical robustness. The resulting SnS₂@Ni and ZnS@Ni foams show synergistic superiority as advanced hybrid catalysts, delivering high ammonia yields and faradaic efficiencies comparable to or even better than those of noble-metal-based catalysts.

Xingxing Chen;Yi Tao Liu;Chunlan Ma;建勇 俞;彬 丁

Journal of Materials Chemistry A

2019

Electrospun nanofibrous membranes with thin fiber diameter, small pore size, and high porosity have attracted a great deal of attention in the waterproof and breathable field. However, great challenges still remain in simultaneously reinforcing the mechanical and waterproof-breathable performance of such materials. In this study, a new type of fluorinated polyurethane/polyacrylonitrile/polyvinyl butyral nanofibrous membranes (FPU/PAN/PVB NFM) with a blocked isocyanate prepolymer (BIP) as chemical cross-linking agent were fabricated. The composite NFM, with robust mechanical, waterproof and breathable performance, has been prepared using an innovation strategy combining electrospinning with thermally induced physical bonding and chemical cross-linking. By systematically tuning the cross-linked temperature and time as well as the concentration of PVB and BIP, large breaking elongation (81.5%), good hydrostatic pressure (110 kPa) and modest WVTR (9.6 kg m² d¹) of the membranes were achieved. Meanwhile, the physically bonded structure and chemically cross-linked networks between PVB and BIP endowed the composite NFM with the robust tensile strength of 32.8 MPa, which was three times higher than that of pristine FPU/PAN membranes. Considering the excellent performance of the as-prepared membranes, this simple and intriguing approach may provide a versatile platform for exploring the applications of the bonded and cross-linked membranes in separation processes, membrane distillation, self-cleaning materials, and protective clothing.

Junlu Sheng;Min Zhang;Wenjing Luo;建勇 俞;彬 丁

RSC Advances

2016

Hierarchical porous, magnetic Fe ₃O ₄@carbon nanofibers (Fe ₃O ₄@CNFs) based on polybenzoxazine precursors have been synthesized by a combination of electrospinning and in situ polymerization. The benzoxazine monomers could easily form thermosetting nanofibers by in situ ring-opening polymerization and subsequently be converted into CNFs by carbonization. The resultant fibers with an average diameter of 130 nm are comprised of carbon fibers with embedded Fe ₃O ₄ nanocrystals, and could have a high surface area of 1885 m ² g ^-1 and a porosity of 2.3 cm ³ g ^-1. Quantitative pore size distribution and fractal analysis were used to investigate the hierarchical porous structure using N ₂ adsorption and synchrotron radiation small-angle X-ray scattering measurements. The role of precursor composition and activation process for the effects of the porous structure is discussed, and a plausible correlation between surface fractal dimension and porous parameter is proposed. The Fe ₃O ₄@CNFs exhibit efficient adsorption for organic dyes in water and excellent magnetic separation performance, suggesting their use as a promising adsorbent for water treatment, and also provided new insight into the design and development of a carbon nanomaterial based on a polybenzoxazine precursor.

Yang Si;Tao Ren;Yan Li;彬 丁;建勇 俞

Carbon

2012-11

TiO₂-based heterojunction fibrous membranes with stable hierarchical nanostructures, excellent visible-light-driven photocatalytic activity, and easy-recycling ability would hold great promise in environmental remediation; however, it still remains a great challenge to construct such fantastic fibrous membranes. Herein, soft and hierarchical heterostructured BiOBr-anchored TiO₂ nanofibrous membranes (BiOBr@TiO₂ NFM) were fabricated by the sol-gel electrospinning technique combined with a facile successive ionic layer adsorption and reaction (SILAR) process. The well-crystallized BiOBr nanoplates with lamellar structure were uniformly grown onto TiO₂ nanofibers, and the size and amount of BiOBr nanostructures could be finely regulated through rationally adjusting the growth cycles of SILAR. Benefiting from the large surface area, enhanced visible-light response, and intimately connected interfacial heterojunctions, the resultant membranes exhibited superior photocatalytic performance for rhodamine B (RhB) degradation under visible light irradiation, including a high degradation efficiency of 95.5% within 120 min and excellent reusability in 5 cycles. More importantly, the membranes still maintained good mechanical flexibility and structural integrity after utilization and could be directly extracted from solution. This study may provide a new strategy for the design and fabrication of soft hierarchical nanostructured TiO₂-based fibrous membranes for environmental remediation and other potential applications.

Yuting Cai;Jun Song;Xiaoyan Liu;Xia Yin;Xiaoran Li;建勇 俞;彬 丁

Environmental Science: Nano

2018

Two-dimensional (2D) polyacrylic acid (PAA) nano-nets that comprise interlinked ultrathin nanowires with diameters of 10-30 nm are successfully prepared by a facile electro-netting process. Nano-nets feature a clear geometric characteristic with ideal and weighted Steiner networks due to the rapid phase separation process and its obeyed minimal energy principle. The versatile nano-nets create enhanced interconnectivity and additional surface area and facilitate the diffusion of analytes into the membranes, which significantly boost the gas diffusion coefficient and sensing properties. As one example, PAA membranes containing fibers and nano-nets used as sensing materials are deposited by electrospinning/electro-netting on an electrode of a quartz crystal microbalance (QCM) for trimethylamine (TMA) detection, which exhibits a quick response (∼180 s), low detection limit (1 ppm) and ideal selectivity at room temperature.

X. Wang;彬 丁;建勇 俞;Yang Si;Shangbin Yang;Gang Sun

Nanoscale

2011-3

(Figure Presented). Airborne particle filtration proposed for fibers requires their assembly into porous structures with small pore size and low packing density. The ability to maintain structural stability upon deformation stress in service is essential to ensure a highly porous packing material that functions reliably; however, it has proven extremely challenging. Here, we report a strategy to create anti-deformed poly(ethylene oxide)@polyacrylonitrile/polysulfone (PEO@PAN/PSU) composite membranes with binary structures for effective air filtration by combining multijet electrospinning and physical bonding process. Our approach allows the ambigenous fiber framework including thin PAN nanofibers and fluffy PSU microfibers, through which run interpenetrating PEO bonding structures, to assemble into stable filtration medium with tunable pore size and packing density by facilely optimizing the bimodal fiber construction and benefiting from the PEO inspiration. With the integrated features of small pore size, high porosity, and robust mechanical properties (8.2 MPa), the resultant composite membrane exhibits high filtration efficiency of 99.992%, low pressure drop of 95 Pa, and desirable quality factor of 0.1 Pa^-1; more significantly, it successfully gets rid of the potential safety hazards caused by unexpected structural collapsing under service stress. The synthesis of PEO@PAN/PSU medium would not only make it a promising candidate for PM_2.5 governance but also provide a versatile strategy to design and develop stable porous membranes for various applications.

Shichao Zhang;Hui Liu;Xia Yin;建勇 俞;彬 丁

ACS applied materials & interfaces

2016-3-30

A novel, sensitive, selective, and reproductive formaldehyde sensor has been developed by coating polyvinylamine (PVAm) modified electrospun polyacrylonitrile (PAN) nanofibrous membranes on quartz crystal microbalance (QCM) for the first time. Benefiting from the abundant primary amine groups in PVAm, large specific surface area, high porosity and hierarchal structure of PAN nanofibers, and the strong interaction between PVAm molecule and formaldehyde, the as-prepared QCM sensors achieved an extremely low detection limit of 500 ppb in a remarkably short period of time (120 s). Moreover, the sensitivity of the fibrous membranes based sensors are 2.5 times higher than that of flat film-based ones when upon exposure to 500 ppb formaldehyde. Furthermore, the as-prepared QCM sensors possess excellent reproducibility, reversibility, and good selectivity by virtue of the reversible nucleophilic addition reaction between formaldehyde molecule and primary amine group in PVAm. Hence, such promising QCM sensors could not only potentially allow for monitoring gaseous formaldehyde, but also pave a way for designing and development of novel QCM sensing systems based on functionalized nanofibrous membranes.

Wei Huang;Xueqin Wang;永堂 贾;Xiaoqi Li;Zhigao Zhu;Yan Li;Yang Si;彬 丁;Xueli Wang;建勇 俞

RSC Advances

2013-12-7

A ready-to-use L-ascorbic acid (L-AA) colorimetric strip based on polyaniline (PANI)/polyamide 66 (PA 66) nanofiber/net (NFN) membrane with spider-web-like structure was fabricated through a facile bend electrospinning/netting process. Introduction of PANI component into the membrane turns the strip undergoes a brilliant brown-to-green color transition within 30 min upon incubation with L-AA. Moreover, ascribing to the three-dimensional microscopic structural, continuous pore channels, and distinctive nano-nets structure, the color change that is caused by 50 ppb L-AA can be easily perceived by naked eyes. Furthermore, RGB (red-green-blue) digital parameters that obtained from photographs of the strips were automatically read out via an iPhone. Subsequently, the parameters were converted into a color-difference map and processed statistically through principal component analysis, then used to elaborate standard curve. Combining the map and curve, we realized a method for assaying and quantifying L-AA concentration in real food samples, which avoids the time-consuming sample preparation, expensive laboratory techniques, and specialized personnel needed to carry out conventional analytical methods.

Yanan Wen;Yan Li;Yang Si;Xueqin Wang;Faxue Li;建勇 俞;彬 丁

Talanta

2015-8-12