静电纺丝法制备柔性SERS基底及性能研究

利用静电纺丝技术制备了聚乙烯醇(PVA)/银纳米粒子高活性SERS柔性基底.将硝酸银、聚乙烯醇按照一定比例混合配置纺丝溶液,纺丝成膜后采用紫外光照射还原法得到纳米纤维基底.采用扫描电子显微镜(SEM),透射电子显微镜(TEM),傅立叶红外光谱(FT-IR),拉曼光谱(Raman),紫外可见光谱(UV-Vis)等技术,对合成的纳米纤维基底进行表征.研究表明,银纳米颗粒呈球形分布在复合纤维中,粒径小于10 nm.以罗丹明为探针分子,硝酸银含量16 wt;,紫外光照射3 h制备的基底具备最优的SERS性能.同时将此基底应用于烟酸药品检测,拉曼检测极限可达10-5 mol·L-1.     

Dynamically Resettable Electrode-Electrolyte Interface through Supramolecular Sol-Gel Transition Electrolyte for Flexible Zinc Batteries

Flexible batteries based on gel electrolytes with high safety are promising power solutions for wearable electronics but suffer from vulnerable electrode-electrolyte interfaces especially upon complex deformations, leading to irreversible capacity loss or even battery collapse. Here, a supramolecular sol-gel transition electrolyte (SGTE) that can dynamically accommodate deformations and repair electrode-electrolyte interfaces through its controllable rewetting at low temperatures is designed. Mediated by the micellization of polypropylene oxide blocks in Pluronic and host-guest interactions between α-cyclodextrin (α-CD) and polyethylene oxide blocks, the high ionic conductivity and compatibility with various salts of SGTE afford resettable electrode-electrolyte interfaces and thus constructions of a series of highly durable, flexible aqueous zinc batteries. The design of this novel gel electrolyte provides new insights for the development of flexible batteries.     

Braided Fiber Current Collectors for High-Energy-Density Fiber Lithium-Ion Batteries

Fiber lithium-ion batteries represent a promising power strategy for the rising wearable electronics. However, most fiber current collectors are solid with vastly increased weights of inactive materials and sluggish charge transport, thus resulting in low energy densities which have hindered the development of fiber lithium-ion batteries in the past decade. Here, a braided fiber current collector with multiple channels was prepared by multi-axial winding method to not only increase the mass fraction of active materials, but also to promote ion transport along fiber electrodes. In comparison to typical solid copper wires, the braided fiber current collector hosted 139 % graphite with only 1/3 mass. The fiber graphite anode with braided current collector delivered high specific capacity of 170 mAh g⁻¹ based on the overall electrode weight, which was 2 times higher than that of its counterpart solid copper wire. The resulting fiber battery showed high energy density of 62 Wh kg⁻¹.     

Fe2BiTaO7纳米催化剂的组织结构及光催化性能

用固相反应合成法合成了光催化剂Fe2BiTaO7,通过XRD、SEM、TEM、紫外-可见漫反射等表征方法对其组织结构及光催化性能进行了研究。结果表明Fe2BiTaO7为立方晶系烧绿石结构,空间群为Fd3m,禁带宽度为1.72 e V。通过比较Fe2BiTaO7、P25TiO2、掺氮Ti O2和Bi2In Ta O7的可见光光催化降解罗丹明B,发现Fe2BiTaO7降解效果及催化活性均高于其它催化剂,并且Fe2BiTaO7降解罗丹明B效率是掺氮二氧化钛的1.5倍。Fe2BiTaO7降解罗丹明B的曲线符合一级动力学,一级动力学常数为0.022 93 min-1。研究了罗丹明B可能的降解路径和Fe2BiTaO7在可见光下降解苯酚的效果。Fe2BiTaO7(可见光)光催化剂系统适用于纺织工业废水处理。     

Mechanochromic Photonic‐Crystal Fibers Based on Continuous Sheets of Aligned Carbon Nanotubes

A new family of mechanochromic photonic‐crystal fibers exhibits tunable structural colors under stretching. This novel mechanochromic fiber is prepared by depositing polymer microspheres onto a continuous aligned‐carbon‐nanotube sheet that has been wound on an elastic poly(dimethylsiloxane) fiber, followed by further embedding in poly(dimethylsiloxane). The color of the fiber can be tuned by varying the size and the center‐to‐center distance of the polymer spheres. It further experiences reversible and rapid multicolor changes during the stretch and release processes, for example, between red, green, and blue. Both the high sensitivity and stability were maintained after 1000 deformation cycles. These elastic photonic‐crystal fibers were woven into patterns and smart fabrics for various display and sensing applications.     

Flexible,Stretchable, and Rechargeable Fiber‐Shaped Zinc–Air Battery Based on Cross‐Stacked Carbon Nanotube Sheets

The fabrication of flexible, stretchable and rechargeable devices with a high energy density is critical for next‐generation electronics. Herein, fiber‐shaped Zn–air batteries, are realized for the first time by designing aligned, cross‐stacked and porous carbon nanotube sheets simultaneously that behave as a gas diffusion layer, a catalyst layer, and a current collector. The combined remarkable electronic and mechanical properties of the aligned carbon nanotube sheets endow good electrochemical properties. They display excellent discharge and charge performances at a high current density of 2 A g^?1. They are also flexible and stretchable, which is particularly promising to power portable and wearable electronic devices.     

Realizing both High Energy and High Power Densities by Twisting Three Carbon‐Nanotube‐Based Hybrid Fibers

Energy storage devices, such as lithium‐ion batteries and supercapacitors, are required for the modern electronics. However, the intrinsic characteristics of low power densities in batteries and low energy densities in supercapacitors have limited their applications. How to simultaneously realize high energy and power densities in one device remains a challenge. Herein a fiber‐shaped hybrid energy‐storage device (FESD) formed by twisting three carbon nanotube hybrid fibers demonstrates both high energy and power densities. For the FESD, the energy density (50 mWh cm^?3 or 90 Wh kg^?1) many times higher than for other forms of supercapacitors and approximately 3 times that of thin‐film batteries; the power density (1 W cm^?3 or 5970 W kg^?1) is approximately 140 times of thin‐film lithium‐ion battery. The FESD is flexible, weaveable and wearable, which offers promising advantages in the modern electronics.     

Preparation and characterization of natural zeolite supported nano TiO2 photocatalysts by a modified electrostatic self‐assembly method

Natural zeolite supported nano TiO₂ photocatalysts were prepared by a modified electrostatic self‐assembly (ESA) method. First, γ‐mercaptopropyltrimethoxysilane with sulfhydryl (―SH) functional groups was modified on the zeolite powders by using a ‘dry process’. Second, silane with ―SH functional groups was oxidized to sulfonate (―SO₃H) groups by using a hydrogen peroxide/glacial acetic acid mixed solution, and the surface of ―SO₃H silane–zeolite was electronegative charged due to the ionization of ―SO₃H. Third, the hydrolytic titanium polycation from TiCl₄ solution assembled onto the electronegative charged zeolite under electrostatic attraction in the reaction solutions. Finally, zeolite supported nano TiO₂ photocatalysts can be obtained after the above compounds calcined at certain temperature. The samples were characterized by X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface areas, Fourier transform infrared spectroscopy (FT‐IR), X‐ray photoelectron spectroscopy (XPS) and X‐ray fluorescence (XRF). The photocatalytic activities of the samples were evaluated by the degradation of methyl orange in aqueous solution. The results showed that ESA method effectively improved the composite efficiency of zeolite with TiO₂. The photocatalysts prepared by ESA method exhibited higher photocatalytic and recycling activities than that of traditional method. Copyright © 2014 John Wiley & Sons, Ltd.     

Mechanochromic Fibers with Structural Color

Responsive photonic crystals have been widely developed to realize tunable structural colors by manipulating the flow of light. Among them, mechanochromic photonic crystals attract increasing attention due to the easy operation, high safety and broad applications. Recently, mechanochromic photonic crystal fibers were proposed to satisfy the booming wearable smart textile market. In this Concept, the fundamental mechanism, fabrication, and recent progress on mechanochromic photonic crystals, especially in fiber shape, are summarized to represent a new direction in sensing and displaying.     

水凝胶流变学研究概况

水凝胶具有良好的生物相容性和生物可降解性,其结构呈三维网状结构,与细胞外基质相似,在药物释放和组织工程等领域具有广阔的应用前景,被广泛地用于生物制药、生物材料和医学等领域。流变学可以描述材料的流动特性和力学性能,水凝胶的粘弹响应对材料内部结构的变化也非常敏感,因此流变行为被视为研究水凝胶的一种重要方法。本文综述了流变学方法在水凝胶研究中的应用,介绍了水凝胶流变学的研究方法,讨论了影响水凝胶流变学特征的因素,并展望了水凝胶流变学的发展前景。