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81.
We report on the synthesis and characterization of electrospun polyvinyl alcohol (PVA)/graphene nanofibers. The samples produced were characterized by Raman spectroscopy for structural and defect density analysis, scanning electron microscopy (SEM) for morphological analysis, and thermogravimetric (TGA) for thermal analysis. SEM measurements show uniform hollow PVA fibers formation and excellent graphene dispersion within the fibers, while TGA measurements show the improved thermal stability of PVA in the presence of graphene. The synthesized polymer reinforced nanofibers have potential to serve in many different applications such as thermal management, supercapacitor electrodes and biomedical materials for drug delivery. 相似文献
82.
This review summarizes recent progress of the robust and smart hydrogels prepared from natural polymers including polysaccharides,proteins,etc.These hydrogels exhibit outstanding mechanical properties due to their nanofibrous aggregated microstructures and special crosslinking networks.Furthermore,these hydrogels show some smart stimuliresponsive behaviors triggered by pH,temperature,light,electricity and magnetism.Hopefully,these hydrogels derived from natural polymers with inherent biodegradation and biocompatibility have great application potential in the fields of biomedicine,tissue engineering,soft robots and bio-machine. 相似文献
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84.
Self-assembled natural biomaterials offer a variety of ready-made nanostructures available for basic science research and technological applications. Most natural structural materials are made of self-assembled nanofibers with diameters in the nanometer range. Among these materials, chitin is the second most abundant polysaccharide after cellulose and is part of the exoskeleton or arthropods and mollusk shells. Chitin has several desirable properties as a biomaterial including mechanical strength, chemical and thermal stability, and biocompatibility. However, chitin insolubility in most organic solvents has somewhat limited its use. In this research highlight, we describe recent developments in producing biogenic chitin nanofibers using self-assembly from a solution of squid pen β-chitin in hexafluoroisopropanol. With this solution based assembly, we have demonstrated chitin-silk composite self-assembly, chitin nanofiber fabrication across length-scales, and manufacturing of chitin nanofiber substrates for tissue engineering. 相似文献
85.
Nilhan Kayaman Apohan Sevim Karataş Buket Bilen Atilla Güngör 《Journal of Sol-Gel Science and Technology》2008,46(1):87-97
A series of UV-curable nanocomposite coating materials were prepared by sol–gel technique from tetraethoxysilane (TEOS), methacryloxypropyltrimethoxysilane
(MAPTMS) in the presence of urethane acrylate resin based on polyethylene glycol 400 (PEG400). The sol–gel precursor content
in the hybrid coatings was varied from 0 to 30 wt.%. In addition, acrylated phenylphosphine oxide oligomer (APPO) is replaced
with urethane acrylate resin in order to investigate its effect on the nanocomposite property. The physical and mechanical
properties such as; gel content, hardness, adhesion, gloss, impact strength as well as tensile strength were examined. Results
from these measurements showed that all the properties of the hybrid coatings improved effectively by gradual increase in
sol–gel precursor and APPO resin content. The real time infrared technique was used to follow the degree of acrylic double
bond conversion. The thermal stabilities of the UV-cured nanocomposites were investigated by thermogravimetric analysis. The
results revealed that the addition of sol–gel precursor and APPO oligomer into the organic network leads to an improvement
in the thermal and flame resistance properties of the hybrid materials. It was also determined that the APPO containing hybrid
coating with 20 wt.% silica content gave higher char yield than the coating without APPO. It is a desirable achievement to
improve simultaneously both the flame retardancy and mechanical properties of a protective coating. SEM studies indicated
that inorganic particles were dispersed homogenously through the organic matrix. The hybrids were nanocomposite. It was also
found that, incorporation of APPO resin might govern the silica organization and this leading to formation of nanofibrillar
structure. 相似文献
86.
Dissipative Particle Dynamics (DPD) method was carried out to investigate the self‐assembly phase behavior of peptide amphiphile (PA) molecules. The simulations showed that these molecules were self‐assembled into three‐dimensional fiber‐like cylindrical aggregates by the assistance of water solvent. The results of DPD simulation are sensitive to various factors including the size of solvent bead, temperature, and the bead ratio of PA to solvent. We found that using 5 to 9 water cluster and solvent bead gives a result of the aggregation of PA molecules into cylindrical fibers. The criteria of forming nanofibers are bead ratios of PA to water larger than 1:6 and temperature above 340 K. The estimated diameter of the cylindrical aggregate agrees well with the experimentally measured value. 相似文献
87.
同轴静电纺丝法在纳米中空TiO2纤维中填充Ag的应用 总被引:1,自引:0,他引:1
以聚乙烯吡咯烷酮(PVP)溶胶/钛酸四正丁酯和PVP溶胶/银颗粒为前驱体, 以共轴静电纺丝法制备了银填充的TiO2中空纳米纤维. 将双组分纤维在200 ℃下热处理去除乙醇与表面吸附水后, 继而在空气气氛中焙烧至600 ℃, 可以得到在内表面上沉积银颗粒的TiO2纳米管, 银颗粒的直径为5-40 nm, TiO2纳米管的外径150-300 nm, 管臂厚10-20 nm. 用红外吸收光谱(IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等测试手段对超细纤维进行了表征. 中空纤维的直径和管壁可以通过改变电纺参数来调节. 与Ag-TiO2纳米纤维、TiO2纳米中空纤维、TiO2纳米纤维及TiO2纳米粉体相比较, Ag颗粒填充的TiO2纳米中空纤维在光分解亚甲基蓝上表现出了更好的光催化性能. 相似文献
88.
通过对传统短肽表面活性剂氨基酸序列的改良, 设计了具有楔形几何结构的新型短肽表面活性剂A3V3D. 圆二色谱(CD)分析表明, 该短肽的二级结构为无规则卷曲, 透射电子显微镜(TEM)和原子力显微镜(AFM)表征发现, 该短肽在水溶液中能够发生有序的自组装, 形成稳定的光滑平直的纳米纤维. 芘探针荧光光谱分析显示, 该短肽形成了疏水区并将芘分子包裹其中. 由此推测A3V3D在其楔形几何结构的影响下, 以柱状胶束的形式发生自组装, 是一种新型的自组装短肽材料, 说明了几何形状效应在控制短肽的自组装行为中起着关键作用. 相似文献
89.
Fangyuan Zhao Xin Zhao Bo Peng Feng Gan Mengyao Yao Wenjun Tan Jie Dong Qinghua Zhang 《中国化学快报》2018,29(11):1692-1697
Heteroatoms-doped carbon nanofiber membranes with flexible features were prepared by electrospinning with heterocyclic polyimide (PI) structures containing biphenyl and pyrimidine rings. The products with optimized treatment could achieve 695 mAh/g at 0.1 A/g and retain 245 mAh/g at 1.5 A/g after 300 cycles when used as anode for Li-ion batteries. 相似文献
90.
Electrospinning is a nanofiber-forming process by which either polymer solution or melt is charged to high voltages. With high specific surface area and porous structure, electrospun fibrous membranes are excellent candidates for immobilization of enzymes. In this paper, immobilization of cellulase in nanofibrous poly(vinyl alcohol) (PVA) membranes was studied by electrospinning. PVA and cellulase were dissolved together in an acetic acid buffer (pH 4.6) and electrospun into nanofibers with diameter of around 200 nm. The nanofibrous membranes were crosslinked by glutaraldehyde vapor and examined catalytic efficiency for biotransformations. The activity of immobilized cellulase in PVA nanofibers was over 65% of that of the free enzyme. Nanofibers were superior to casting films from the same solution for immobilization of cellulase. The activity of immobilized cellulase descended with ascending in enzyme loading efficiency and crosslinking time, which retained 36% its initial activity after six cycles of reuse. 相似文献