复合纳米纤维静电纺丝法的制备及其磁性

以聚乙烯吡咯烷酮（PVP）和金属盐为原料,利用静电纺丝法成功制备出了摩尔比为1：1的SrTiO3-SrFe12O19磁电复合纳米纤维。并通过FT-IR,XRD,SEM和VSM等技术对纤维前驱体及其产物的结构、热处理产物的物相、形貌及磁性能进行了表征。结果表明,样品经900℃焙烧2h后,即可得到纯的SrTiO3和SrFe...     

静电纺丝法制备聚丙烯腈/聚醋酸乙烯酯复合纳米纤维膜

采用静电纺丝法制备了聚丙烯腈(PAN)/聚醋酸乙烯酯(PVAc)复合纳米纤维膜。利用原子力显微镜(AFM)、电子显微镜(SEM)分析了纤维的直径分布、整体形貌及单根纳米纤维的表面形貌;利用傅里叶变换红外光谱(FT-IR)分析了PAN、PAN/PVAc、PVAc纳米纤维膜的化学组成;同时借助热重(TG)分析了PVAc的加入对复合纤维膜热性能的影响。结果表明,当m(PAN)∶m(PVAc)=5∶5、质量分数为10%时,所得纤维膜最有利于制备聚合物电解质膜;PAN与PVAc之间产生配位键,从而提高了纤维膜的热性能。     

Li+‐Containing,Continuous Silica Nanofibers for High Li+ Conductivity in Composite Polymer Electrolyte

Solid‐state electrolytes have recently attracted significant attention toward safe and high‐energy lithium chemistries. In particular, polyethylene oxide (PEO)‐based composite polymer electrolytes (CPEs) have shown outstanding mechanical flexibility and manufacturing feasibility. However, their limited ionic conductivity, poor electrochemical stability, and insufficient mechanical strength are yet to be addressed. In this work, a novel CPE supported by Li⁺‐containing SiO₂ nanofibers is developed. The nanofibers are obtained via sol–gel electrospinning, during which lithium sulfate is in situ introduced into the nanofibers. The uniform doping of Li₂SO₄ in SiO₂ nanofibers increases the Li⁺ conductivity of SiO₂, generates mesopores on the surface of SiO₂ nanofibers, and improves the wettability between SiO₂ and PEO. As a result, the obtained SiO₂/Li₂SO₄/PEO CPE yields high Li⁺ conductivity (1.3 × 10^?4 S cm^?1 at 60 °C, ≈4.9 times the Li₂SO₄‐free CPE) and electrochemical stability. Furthermore, the all‐solid‐state LiFePO₄‐Li full cell demonstrates stable cycling with high capacities (over 80 mAh g^?1, 50 cycles at C/2 at 60 °C). The Li⁺‐containing mesoporous SiO₂ nanofibers show great potential as the filler for CPEs. Similar methods can be used to incorporate Li salts into other filler materials for CPEs.     

1D Coordination Polymer Nanofibers for Low‐Temperature Photothermal Therapy

Near‐infrared (NIR)‐light‐triggered photothermal therapy (PTT) usually requires hyperthermia to >50 °C for effective tumor ablation, which can potentially induce inflammatory disease and heating damage of normal organs nearby, while tumor lesions without sufficient heating (e.g., the internal part) may survive after treatment. Achieving effective tumor killing under relatively low temperatures is thus critical toward successful clinical use of PTT. Herein, we design a simple strategy to fabricate poly(ethylene glycol) (PEG)‐modified one‐dimensional nanoscale coordination polymers (1D‐NCPs) with intrinsic biodegradability, large surface area, pH‐responsive behaviors, and versatile theranostic functions. With NCPs consisting of Mn2+/indocyanine green (ICG) as the example, Mn‐ICG@pHis‐PEG display efficient pH‐responsive tumor retention after systemic administration and then load Gambogic acid (GA), a natural inhibitor of heat‐shock protein 90 (Hsp90) that plays an essential role for cells to resist heating‐induced damage. Such Mn‐ICG@pHis‐PEG/GA under a mild NIR‐triggered heating is able to induce effective apoptosis of tumor cells, realizing low‐temperature PTT (~43 °C) with excellent tumor destruction efficacy. This work not only develops a facile approach to fabricate PEGylated 1D‐NCPs with tumor‐specific pH responsiveness and theranostic functionalities, but also presents a unique low‐temperature PTT strategy to kill cancer in a highly effective and minimally invasive manner.     

仿生壳聚糖基纳米纤维的自组装构建

通过天然阳离子型高分子壳聚糖与三聚磷酸钠的静电自组装,制备模仿细胞外基质纳米结构的仿生壳聚糖基纳米纤维。研究了介质、壳聚糖浓度、反应物比例、添加胶原等因素对自组装复合产物的影响;并采用透射电镜、X射线衍射和红外光谱等技术表征了纳米纤维的结构。结果表明,介质对壳聚糖基纳米复合物的结构和形态的影响很大;以己二酸溶液为介质,在温和条件下,可获得结构可控的壳聚糖基纳米纤维,有望用于构建模仿天然细胞外基质的组织工程支架。     

In Situ Fabrication of Branched TiO2/C Nanofibers as Binder‐Free and Free‐Standing Anodes for High‐Performance Sodium‐Ion Batteries

Herein, 1D free‐standing and binder‐free hierarchically branched TiO₂/C nanofibers (denoted as BT/C NFs) based on an in situ fabrication method as an anode for sodium‐ion batteries are reported. The in situ fabrication endows this material with large surface area and strong structural stability, providing this material with abundant active sites and smooth channels for fast ion transportation. As a result, BT/C NFs with the character of free‐standing membranes are directly used as binder‐free anode for sodium‐ion batteries, delivering a capacity of 284 mA h g^?1 at a current density of 200 mA g^?1 after 1000 cycles. Even at a high current density of 2000 mA g^?1, the reversible capacity can still achieve as high as 204 mA h g^?1. By means of kinetic analysis, it is demonstrated that the remarkable surface pseudocapacitive behavior is also a major factor to achieve excellent performance. The rationally designed structure coupled with the inherent pseudocapacitive behavior gives this material potential for sodium‐ion batteries.     

Fabrication of Graphene Sheets Intercalated with Manganese Oxide/Carbon Nanofibers: Toward High‐Capacity Energy Storage

Herein, 3D nanohybrid architectures consisting of MnO_x nanocrystals, carbon nanofibers (CNFs), and graphene sheets are fabricated. MnO_x‐decorated CNFs (MCNFs) with diameters of about 50 nm are readily obtained via single‐nozzle co‐electrospinning, followed by heat treatment. The MCNFs are then intercalated between graphene sheets, yielding the ternary nanohybrid MCNF/reduced graphene oxide (RGO). This straightforward synthesis process readily affords product on a scale of tens of grams. The ultrathin CNFs, which might be a promising alternative to carbon nanotubes (CNTs), overcome the low electrical conductivity of the excellent pseudocapacitive component, MnO_x. Furthermore, the graphene sheets separated by the MCNFs boost the electrochemical performance of the nanohybrid electrodes. These nanohybrid electrodes exhibit enhanced specific capacitances compared with a sheet electrode fabricated of MCNF‐only or RGO‐only. Evidently, the RGO sheet acts as a conductive channel inside the nanohybrid, while the intercalated MCNFs increase the efficiency of the ion and charge transfer in the nanohybrid. The proposed nanohybrid architectures are expected to lay the foundation for the design and fabrication of high‐performance electrodes.     

One‐Pot Process to Control the Elaboration of Non‐Wetting Nanofibers

The surface wettability, such as superhydrophobic properties, of nanofibrous structures is highly depending on their size, length, spacing or orientation to the surface. Finding a way to control all these characteristics is extremely important in a theoretical point of view and for various applications. Here, we report the possible tuning of all these characteristics by adjusting the length (n) of the alkyl chains of electrodeposited poly(3,3‐dialkyl‐3,4‐propylenedioxythiophene), which allows the formation of horizontally or vertically oriented nanofibers of various dimensions and spacings. Here, we play especially on the hydrophilic/hydrophobic characteristics of the polymer to change the growth of a polymer on a substrate and the distance between the polymer backbones. For example, a change in the fiber orientation from horizontal to vertical is observed for n = 2. For n < 2, the polymer fibers are mainly horizontally aligned while for n > 2, the polymer fibers are vertically aligned.     

Shape‐Enhanced Photocatalytic Activities of Thoroughly Mesoporous ZnO Nanofibers

1D mesoporous materials have attracted extensive interest recently, owning to their fascinating properties and versatile applications. However, it remains as a grand challenge to develop a simple and efficient technique to produce oxide nanofibers with mesoporous architectures, controlled morphologies, large surface areas, and optimal performances. In this work, a facile foaming‐assisted electrospinning strategy with foaming agent of tea saponin is used to produce thoroughly mesoporous ZnO nanofibers with high purity and controlled morphology. Interestingly, mesoporous fibers with elliptical cross‐section exhibit the significantly enhanced photocatalytic activity for hydrogen production, as compared to the counterparts with circular and rectangular cross‐sections, and they also perform better than the commercial ZnO nanopowders. The unexpected shape dependence of photocatalytic activities is attributed to the different stacking modes of the mesoporous fibers, and a geometrical model is developed to account for the shape dependence. This work represents an important step toward producing thoroughly mesoporous ZnO nanofibers with tailored morphologies, and the discovery that fibers with elliptical cross‐section render the best performance provides a valuable guideline for improving the photocatalytic performance of such mesoporous nanomaterials.     

基于电纺技术构筑多孔SnO2纳米纤维膜的研究

以聚乙烯吡咯烷酮(PVP)作为纺丝助剂,五水合四氯化锡(SnCl4·5H2O)作为前驱体,采用静电纺丝技术结合高温煅烧法成功制备了直径为(363±28)nm的多孔氧化锡纳米纤维膜.使用SEM表征了纤维膜的微观形貌和尺寸,利用X射线衍射仪(XRD)研究了焙烧温度对晶粒尺寸的影响,利用傅里叶变换红外光谱仪(FTIR)、热重和差热同步仪(TGA-DTA)及拉曼光谱仪(Raman)等研究了纤维膜的分子结构变化、热稳定性和物相结构.研究结果表明,固定两喷丝头间距15.0 cm、流速0.5 mL/h、电场强度1.1～1.4 kV/cm时,可以电纺出表面光滑、直径均一的纳米纤维膜;经900℃焙烧制备得到晶粒尺寸约12.27 nm的四方相金红石型晶体结构的氧化锡纤维膜.     

M型锶铁氧体纳米纤维静电纺丝和磁性能

以聚乙烯吡咯烷酮(Polyvinylpylrrolidone,PVP)和金属盐为原料,采用静电纺丝法制备了SrFe12O19/PVP复合纤维前驱体,前驱体经焙烧后得到M型锶铁氧体纳米纤维.通过FTIR、TG/DSC、XRD、SEM和VSM技术对复合纤维前驱体及所制备的M型锶铁氧体纳米纤维进行了表征.结果表明,复合纤维前驱体的直径与溶液中金属盐浓度有关,随盐浓度的升高纤维直径增大;经800℃焙烧2h后,得到纯相M型锶铁氧体纳米纤维,直径在100～150nm,组成纤维的平均晶粒大小约为49nm,且随焙烧温度的升高,晶粒长大;经1000℃焙烧2h后得到的锶铁氧体纤维的磁性能最佳,此时纤维平均直径约为100nm,晶粒尺寸约为61nm,室温下测得的饱和磁化强度为68.5A.m2/kg,矫顽力为503kA/m.