Electrospun Nanofibers Containing p-Nitrophenol Imprinted Nanoparticles for the Hydrolysis of Paraoxon

p-Nitrophenol imprinted nanoparticles with a size range of 150-300 nm in diameter were prepared through miniemulsion polymerization. The imprinted polymer exhibited higher adsorption capacity for p-nitrophenol than the nonimprinted polymer. The hydrolysis of paraoxon in aqueous phase can be accelerated in the presence of the p-nitrophenol imprinted nanoparticles. The hydrolysis rate of paraoxon incorporated with the imprinted nanoparticles was 2.83×10-7 mol/（L·min）, which was about 3.7 times higher compared to the non-imprinted nanoparticles, 12.7 times higher to the spontaneous hydrolysis. The nanoparticles have been mixed with polyacrylonitrile solution and electrospun into nanofibers, which can also be used to accelerate the hydrolysis of paraoxon and conveniently separated from liquid phase for further processing.     

AOT微乳液中通过水化电子产额调控合成BaSO_4纳米纤维

通过γ-辐照含有K2S2O8和BaCl2的二(2-乙基己基)琥珀酸酯磺酸钠(AOT)反相微乳液,将S2O82-通过辐射还原实现了SO42-的原位缓释,从而成功制备出BaSO4纳米纤维单晶,并进一步制得多层次的纳米纤维束结构.在此基础上,通过改变水与表面活性剂物质的量之比(ω值)、改变钡盐阴离子和在微乳液连续相添加芳香化合物等手段来调节水化电子(e-aq)产额,控制微乳液水池中S2O82-的还原和SO42-的缓释速率,成功实现了对BaSO4纳米粒子形貌的调控:随着ω值的增加或剂量率的增加,e-aq产额增加,从而加快了SO42-的释放,不利于BaSO4纳米纤维的生成;采用Ba(NO3)2为钡源时,NO3-能有效地降低e-aq产额和S2O82-的还原速率,因而在较高的剂量率和较高ω值下能得到BaSO4纳米纤维;在微乳液油相中加入甲苯来捕获油相中过量电子(e-oil),降低e-aq产额,从而在较高的剂量率下得到BaSO4纳米纤维.研究结果表明:通过e-aq产额调控纳米粒子形貌的机理在BaSO4纳米粒子的制备中得到很好体现.     

聚丙烯腈/氧化石墨烯复合纳米纤维的制备与性能研究

以氧化石墨烯为添加物,采用静电纺丝的方法制备不同质量分数的聚丙烯腈/氧化石墨烯(PAN/GO)复合纳米纤维。使用扫描电镜(SEM)、透射电镜(TEM)对复合纳米纤维的微观结构进行观察;采用差示扫描量热仪(DSC)和热重分析仪(TGA)研究复合纳米纤维的热学性能随着氧化石墨烯添加量增加的变化;采用微机控制电子万能试验机对复合纳米纤维的力学性能进行研究。结果表明,加入氧化石墨烯后,纺制的PAN/GO纳米复合纤维会变细,但随着GO添加量的增多出现珠节现象,降低了纤维的粗细均匀度,同时加入GO后对PAN的氧化具有一定的抑制作用,而且GO的加入也使PAN的力学性能增加,当加入量为0.1%时断裂强力增加了一倍,但添加量为1%时,断裂强力又会降低,综合实验结果显示当加入氧化石墨烯的质量分数为0.1%时最适宜。     

Selective synthesis of CdWO4 short nanorods and nanofibers and their self-assembly

Single-crystalline CdWO₄ nanorods and nanofibers are selectively prepared based on hydrothermal treatment with cetyltrimethylammonium bromide (CTAB) as capping molecule and ordinary inorganic reactant as precursors through exactly controlling the pre-treated condition. With almost uniform breadth and pointed ends, the obtained short nanorods show a relatively thick nature along [010] direction and self-assemble to an ordered structure with (001) and (010) faces, respectively, while the as-prepared nanofibers are flexible and vertically self-assemble to form woven network. The mechanism of selective preparation and self-assembly was also discussed. Both obtained nanorods and nanofibers display a very strong blue-green luminescence property at room temperature.     

Fabrication and electrochemical performance of nanofibrous micro-frameworks of α-MnO_2

A facile solid-phase conversion route is proposed to fabricate a micro-framework of α-MnO_2 with a nanofibrous structure and high porosity.The fabrication is achieved by a three-step process using a preformed manganese tartrate with a rectangular framework as the precursor followed by thermal annealing and hydrothermal oxidation to form the final nanofibrous structure.Evolution of the phase and the morphology are characterized by FESEM,XRD,TG-DTA,and TEM measurements.The electrochemically active material α-MnO_2 exhibits both attractive stability of the Coulombic efficiency after long-term cyclic charging/discharging and acceptable specific capacitance.     

Optimization and predictive modelling for the diameter of nylon-6,6 nanofibers via electrospinning for coronavirus face masks

Currently, the only widely available tool for controlling the SARS-CoV-2 pandemic is nonpharmacological interventions (NPIs). Coronavirus aerosols are around 0.3–2 µm in diameter (0.9 m in mass). The present study used artificial intelligence such as gene expression programming (GEP) and genetic algorithms (GA) were used to predict and optimize the diameter of Nylon-6,6 nanofibers via electrospinning for protection against coronavirus. It is suggested that using the controlled experimental conditions such as concentration of nylon-6,6 (16% wt/v), applied voltage (26 kV), working distance (18 cm) and injection rate (0.2 mL/h) have resulted the diameter of nylon-6,6 nanofibers about 55.8 nm. Coronavirus face masks could use the obtained diameter and electrostatic interaction between viral particles and naofibers as active layers.     

阳离子表面活性剂作用下制备一维纳米结构聚苯胺

在十六烷基三甲基溴化铵(CTAB)存在下, 以盐酸为质子酸, 过硫酸铵为氧化剂, 制备了平均直径为115 nm、具有分叉结构的聚苯胺纳米纤维和平均直径为75 nm的卷曲聚苯胺纳米线, 两者的结构产率高达90%和100%, 电导率分别为1.6×10-2和9.3×10-2 S/cm. 研究发现, 聚苯胺的一维纳米结构受盐酸浓度和苯胺与CTAB摩尔比的协同影响. 用TEM, SEM和FTIR对产物的形貌和化学结构进行了表征. 利用pH监测反应并结合SEM结果研究了聚苯胺纳米线的形成过程, 结果表明, CTAB阳离子与过硫酸根形成的絮状物的诱导作用是聚苯胺纳米纤维和纳米线形成的关键因素.     

Facile Synthesis of Mesoporous Si-containing γ-Al2O3Nanofiber with Enhanced Thermal Stability

Mesoporous γ-Al₂O₃ nanofiber was prepared via a simple reverse precipitation route using Si-containing Al(OH)₃ and HNO₃ as raw materials. The resultant Si-containing mesoporous γ-Al₂O₃ nanofiber exhibited high surface area of 320 m²/g, large pore volume of 1.17 cm³/g and large pore size of 10.5 nm. The introduction of Si element remarkably enhanced the thermal stability of mesoporous γ-Al₂O₃. The as-prepared nanofiber could maintain relative high surface area(110 m²/g) and pore volume(0.73 cm³/g) up to 1100 ℃. The effects of various experimental conditions, such as pH value, reaction temperature and aging temperature on the structural properties of the mesoporous γ-Al₂O₃ were also investigated.     

Cellulose/chitosan hybrid nanofibers from electrospinning of their ester derivatives

A facile approach has been established to generate cellulose/chitosan hybrid nanofibers with full range of compositions by electrospinning of their ester derivatives, cellulose acetate (CA) and dibutyryl chitin (DBC), followed by alkaline hydrolysis to cellulose (Cell) and chitosan (CS). DBC was synthesized by acid-catalyzed acylation of chitin (CHI) with butyric anhydride and the newly formed butyl groups on C3 and C6 were confirmed by FT-IR and ¹HNMR. DBC had robust solubility in acetone, DMAc, DMF, ethanol, and acetic acid, all except ethanol were also solvents for CA, allowing mixing of these ester derivatives. Fiber formation by electrospinning of either DBC or CA alone and together in these common solvents and their mixtures were studied. The 1/1 acetone/acetic acid was found to be the optimal solvent system to generate fibers from either DBC or CA as well as their mixtures at all CA/DBC ratios, resulting in hybrid fibers with diameters ranging from 30 to 350 nm. DBC and CA were well mixed and showed no phase separate in the hybrid fibers. Alkaline hydrolysis (NaOH) of the equal mass CA/DBC nanofibers regenerated Cell and CHI readily via O-deacylation, then proceeded to further deacetylate CHI to CS via N-deacetylation at higher alkaline concentrations and/or temperatures. Under conditions studied, hydrolysis with 5N NaOH at 100 °C for 3 h was optimal to regenerate cellulose/chitosan hybrid nanofibers.     

Simple and Effective Method to Prepare Microfiber Reinforced Nanofiber Film with Significant Improvement of Mechanical Properties

Microfiber reinforced nanofiber films were prepared with the help of two nozzles technology.We designed a new device via placing two nozzles on the opposite sides of a rolling cylinder,with a piece of thin insulation board with a certain size of hole in the middle part installed to accommodate the cylinder so as to form two entirely independent electric fields.Playing the role of support,microfiber may be favorable for enhancing the mechanic performance of the nanofiber.Compared with that of single nanofiber,the tensile strength of the composite micro/nanofiber prepared by this method has been increased by a factor of 4.5.After the further improvement of the fiber orientation,the tensile strength is 7.96 times that of non-oriented composite micro/nanofibers film,30 times that of the single nanofiber film.