静电纺丝技术制备Y_2O_3∶Yb~(3+),Er~(3+)上转换纳米纤维及其表征

采用静电纺丝技术制备了PVA/[Y(NO3)3+Yb(NO3)3+Er(NO3)3]复合纳米纤维,将其在适当的温度下进行热处理,得到Y2O3∶Yb3+,Er3+上转换纳米纤维.XRD分析表明,复合纳米纤维为无定形,Y2O3∶Yb3+,Er3+上转换纳米纤维属于体心立方晶系,空间群为Ia3.SEM分析表明,复合纳米纤维的平均直径约为150nm;随着焙烧温度的升高,纤维直径逐渐减小.经过600℃焙烧后,获得了直径约60nm的Y2O3∶Yb3+,Er3+上转换纳米纤维.TG-DTA分析表明,当焙烧温度高于600℃时,复合纳米纤维中水分、有机物和硝酸盐分解挥发完毕,样品不再失重,总失重率为83%.FTIR分析表明,复合纳米纤维与纯PVA的红外光谱一致,当焙烧温度高于600℃时,生成了Y2O3∶Yb3+,Er3+上转换纳米纤维.该纤维在980nm的半导体激光器激发下发射出中心波长为521,562nm的绿色和656nm的红色上转换荧光,分别对应于Er3+离子的2H11/2/4S3/2→4Il5/2跃迁和4F9/2→4Il5/2跃迁.对Y2O3∶Yb3+,Er3+上转换纳米纤维的形成机理进行了讨论.     

静电纺丝制备荧光导电双功能复合纳米纤维及其表征

采用静电纺丝技术将导电聚苯胺(PANI)和铕/铽稀土配合物掺杂到高分子基质聚乙烯吡咯烷酮(PVP)中,制备出荧光导电复合纳米纤维。用扫描电镜(SEM)、荧光光谱仪(FL)、宽频介电松驰谱仪对荧光导电复合纳米纤维的性能进行分析,结果显示,在270nm紫外光激发下,铕系列与铽系列复合纳米纤维分别发出红光和绿光。同时,复合纳米纤维的电导率可以达到1.18×10~(-6) S/cm,两种复合纳米纤维同时具有优异的荧光性能及良好的导电功能。     

YF3:Eu3+纳米纤维/高分子复合纳米纤维的制备与表征

采用静电纺丝技术制备了Y2O3:Eu3+纳米纤维,使用NH4HF2为氟化剂,经双坩埚法氟化和脱氨后得到YF3:Eu3+纳米纤维,再采用静电纺丝技术制备了YF3:Eu3+纳米纤维/PVP复合纳米纤维. XRD分析表明,立方相的Y2O3:Eu3+氟化后,得到了正交相的YF3:Eu3+纳米纤维,空间群为Pnma;YF3:Eu3+纳米纤维/PVP复合纳米纤维具有明显的YF3:Eu3+的衍射峰. SEM分析表明,YF3:Eu3+纳米纤维与YF3:Eu3+纳米纤维/PVP复合纳米纤维的直径分别为91±11 nm、319±43 nm,表面光滑. 用Shapiro-Wilk方法检验,纤维直径属于正态分布. 荧光光谱分析表明,YF3:Eu3+纳米纤维和YF3:Eu3+纳米纤维/PVP复合纳米纤维的最强发射峰均位于588 nm和595 nm,属于Eu3+的5D0→7F1跃迁,表明Eu3+占据YF3基质中Y3+晶格点的C2对称格位. PVP对YF3:Eu3+发光峰位没有影响,但发光强度降低;YF3:Eu3+的含量与YF3:Eu3+纳米纤维/PVP复合纳米纤维的发光强度成线性关系.     

Surface Functionalization of PEO Nanofibers Using a TiO2 Suspension as Sheath Fluid in a Modified Coaxial Electrospinning Process

Convenient and integration fabrication process is a key issue for the application of functional nanofibers. A surface functionalization method was developed based on coaxial electrospinning to produce ultraviolet(UV) protection nanofibers. The titanium dioxide(TiO₂) nanoparticles suspension was delivered through the shell channel of the coaxial spinneret, by which the aggregation of TiO₂ nanoparticles was overcome and the distribution uniformity on the surface of polyethylene oxide(PEO) nanofiber was obtained. With the content of TiO₂ increasing from 0 to 3%(mass fraction), the average diameter of nanofibers increased from (380±30) nm to (480±100) nm. The surface functionalization can be realized during the electrospinning process to gain PEO/TiO₂ composite nanofibers directly. The uniform distribution of TiO₂ nanoparticles on the surface of nanofibers enhanced the UV absorption and resistance performance. The maximum UV protection factor(UPF) value of composite nanofibers reaches 2751. This work presented a novel surface-functionalized way for the preparation of composite nanofiber, which has great application potential in the field of micro/nano system integration fabrication.     

Nanofibers of barium strontium titanate (BST) by sol-gel processing and electrospinning

This paper describes the fabrication of barium strontium titanate (Ba0.6Sr0.4TiO3 or BST) nanofibers by electrospinning method using a solution that contained poly(vinylpyrrolidone) and a sol-gel solution of BST. The as-spun and calcined BST/PVP composite nanofibers were characterized by TG-DTA, X-ray diffraction, FT-IR, SEM and TEM, respectively. After calcination of the as-spun BST/PVP composite nanofibers at above 700 degrees C in air for 2 h, BST nanofibers of 188+/-25 nm in diameter having well-developed cubic-perovskite structure were successfully obtained. The crystal structure and morphology of the nanofibers were influenced by the calcination temperature. Calcination at below 700 degrees C resulted in amorphous phase whereas BST with second phase such as barium titanate were formed at above 700 degrees C. Diameters of the nanofibers decreased from 208+/-35 to 161+/-18 nm with increasing calcination temperature between 600 and 800 degrees C.     

Synthesis of TiO2/Bi2WO6 nanofibers with electrospinning technique for photocatalytic methyl blue degradation

TiO₂/Bi₂WO₆ composite nanofibers have been successfully synthesized by a simple electrospinning process. XRD, SEM, HR-TEM, nitrogen adsorption–desorption isotherms and UV–visible diffuse reflectance spectra were used to characterize the composite nanofibers. The composite fibers with diameters about 100 nm was composed of nanoparticles and possessed of high specific surface area (49.6 m² g^?1) and porous structure. Besides, the TiO₂/Bi₂WO₆ composite nanofibers exhibited excellent visible photocatalytic property in the photodegradation of methylene blue (MB), and over 97.2 % of MB was degraded within 5.5 h.     

γ-Fe2O3纳米纤维的丙酮敏感特性

采用静电纺丝法制备了PVP/FeC₆H₅O₇复合纳米纤维, 并将复合纤维在500 ℃高温烧结3 h, X射线衍射分析(XRD)表明, 烧结后的产物为正尖晶石结构的γ-Fe₂O₃晶体. 扫描电子显微镜(SEM)观测结果表明, 制得了直径均匀、 连续的复合纳米纤维, 其平均直径约为1000 nm; 烧结后的γ-Fe₂O₃纳米纤维保持了其连续性, 但纤维发生了收缩, 直径较烧结前小, 平均约为600 nm. 比表面积分析表明, γ-Fe₂O₃纳米纤维比表面积为57.18 m²/g. 气敏性能测试结果表明, 230 ℃为γ-Fe₂O₃纳米纤维检测丙酮气体的最佳工作温度. 在此温度下, γ-Fe₂O₃纳米纤维对丙酮气体表现出高响应度[S=6.9, c(Acetone)=7.88×10⁴ mg/m³]和线性度(7.88×10²~1.58×10⁵ mg/m³浓度范围内). 同时, γ-Fe₂O₃纳米纤维气体传感器件还表现出良好的长期稳定性.     

静电纺丝法制备ZrO2纳米纤维

纳米级ZrO：因具有高氧离子传导和高折射率而被广泛应用于催化剂、氧传感器、燃料电池以及对Cr(Ⅵ)污染的处理等方面．目前已成功地制备了ZrO2的纳米颗粒、纳米管及纳米薄膜等．但是，对于具有准一维结构的ZrO2纳米纤维的制备及性能研究尚未见报道．     

基于CeO2-Co3O4纳米纤维的催化发光式甲醛传感器研究

采用双喷嘴静电纺丝法制备了CeO2-Co3 O4纳米纤维,将制备的CeO2-Co3 O4纳米纤维均匀涂覆于 ω型加热线圈表面形成催化发光薄膜,设计了一种新型催化发光甲醛传感器.采用X射线衍射仪、 扫描电子显微镜、 全自动程序化学吸附仪和X-射线光电子能谱仪,表征了Co3 O4-CeO2纳米纤维的相组成和微观形貌,讨论了甲醛在CeO2-Co3 O4催化剂表面的电化学特性和催化发光机理.在优化条件下,即波长500 nm、 温度550℃ 、 载气流速0.2 L/min,甲醛传感器件(Ce30)催化发光强度与甲醛浓度在1.2~50μg/m3范围内有良好的线性关系,灵敏度为40.04 a.u./(μg/m3),检出限为1.2μg/m3,动态响应和恢复时间分别为2.4和3.5 s.此传感器可用于汽车尾气中甲醛浓度检测,相对误差范围为0.4%~1.1%,相对标准偏差RSD<3%(n=6).     

添加Al2O3对Ni0.5Zn0.5Fe2O4纳米纤维结构和磁性能的影响

采用静电纺丝技术制备了添加0～20wt%Al2O3的Ni0.5Zn0.5Fe2O4纳米纤维。通过XRD、FESEM、TEM和VSM对样品的物相结构、形貌和磁性能进行了表征。结果表明,所合成的复合纳米纤维的直径都分布在40～150 nm之间,添加到纤维中的Al2O3主要以非晶态形式分布于铁氧体晶粒边界;随着Al2O3添加量的增加,可观察到γ-Fe2O3相逐渐析出,Ni-Zn铁氧体的晶格常数单调减小,说明有一些Al2O3进入到尖晶石晶格中取代了B位的Fe3+离子,Ni-Zn铁氧体的平均晶粒尺寸先增大后减小,在Al2O3添加量为8wt%时达到最大值39.2 nm;比饱和磁化强度和矫顽力随Al2O3添加量的增加呈现出相同的变化规律,先减小后增大,当Al2O3添加量超过5wt%时又开始变小。     

静电纺丝法制备聚丙烯腈/聚苯胺复合纳米纤维及其表征

利用静电纺丝技术,以聚丙烯腈(PAN)和苯胺(ANI)为前驱物,用过硫酸胺(APS)溶液在低温下缓慢氧化聚合,制备了PAN/PANI复合纳米纤维,直径约500 nm.通过扫描电子显微镜(SEM)、红外光谱(FTIR)、X射线衍射(XRD)和激光拉曼(RAMAN)光谱仪等测试手段对材料的形貌和结构进行了表征.探讨了材料制备过程中影响纤维形貌、尺寸、均匀度的因素和PANI含量对复合纤维导电性能的影响,结果表明,PAN浓度、ANI的加入量和电压是影响纤维特性的主要因素;PANI在PAN基体中呈纳米尺寸分布,复合纳米纤维具有良好的导电性能,导电率可达10-2S/cm.     

静电纺丝技术制备Tb（BA）3phen/PANI/PVP光电双功能复合纳米纤维

采用静电纺丝技术将聚苯胺(PANI)和稀土配合物[Tb(BA)3phen]掺杂到高分子材料(PVP)中,制备出一类新型的具有光电双功能的Tb(BA)3phen/PANI/PVP复合纳米纤维.用扫描电子显微镜(SEM)、X射线能量色散谱仪(EDS)、荧光光谱仪及宽频介电松弛谱仪对样品进行了表征.结果表明,复合纳米纤维直径为(331±43)nm.在276 nm紫外光激发下,Tb(BA)3phen/PANI/PVP复合纳米纤维发射出主峰位于491,547和585 nm的绿光,对应Tb3+的5D4→7F6,5D4→7F5和5D4→7F4跃迁.当Tb(BA)3phen∶PANI∶PVP的质量比为15∶10∶100时,复合纳米纤维的荧光发射最强,其电导率随PANI含量的增大而升高,在PANI∶PVP为50%(wt%)时,其电导率在高频(106Hz)下达1.531×10-6S/cm.     

静电纺丝制备Eu(BA)3phen/PANI/PVP光电双功能复合纳米纤维及其性能

采用静电纺丝技术将聚苯胺(PANI)和稀土配合物Eu(BA)3phen掺杂到高分子材料聚乙烯吡咯烷酮(PVP)中, 制备出新型的具有光电双功能的Eu(BA)3phen/PANI/PVP复合纳米纤维. 采用扫描电子显微镜、 X射线能量色散谱仪、 荧光光谱仪及宽频介电松弛谱仪对样品进行了表征. 实验结果表明, 复合纳米纤维直径为(270±31) nm. 在275 nm紫外光激发下, Eu(BA)3phen/PANI/PVP复合纳米纤维发射出主峰位于580, 594和617 nm的红光, 对应于Eu3+的 5D0→7F0, 5D0→7F1和5D0→7F2跃迁. 当m[Eu(BA)3phen]:m(PANI):m(PVP)=15:10:100 时, 复合纳米纤维的荧光发射最强. 复合纤维的电导率随PANI含量的增大而升高. 在m(PANI):m(PVP)=50:100时, 其电导率在高频(106 Hz)下达到1.5×10-6 S/cm.     

Preparation of Mn2O3 and Mn3O4 nanofibers via an electrospinning technique

Thin PVA/manganese acetate composite fibers were prepared by using sol-gel processing and electrospinning technique. After calcinations of the above precursor fibers, Mn₂O₃ and Mn₃O₄ nanofibers with a diameter of 50-200 nm could be successfully obtained. The fibers were characterized by TG-DTA, Scanning electron microscopy, FT-IR, WAXD, respectively. The results showed that the crystalline phase and morphology of nanofibers were largely influenced by the calcination temperature.     

Nanofibers of LiMn2O4 by electrospinning

Through sol-gel processing and electrospinning technique, extrathin fibers of poly(vinyl alcohol) (PVA)/lithium chloride/manganese acetate composite fibers were prepared. After calcination of the above precursor fibers at 600 degrees C, the spinel lithium manganese oxide (LiMn2O4) nanofibers, with a diameter of 100-200 nm, were successfully obtained. The fibers were investigated by TG-DTA, XRD, FT-IR, and SEM, respectively. The results showed that the crystalline phase and morphology of the fibers were largely influenced by the calcination temperature.     

Encapsulation and selective recognition of molecularly imprinted theophylline and 17beta-estradiol nanoparticles within electrospun polymer nanofibers

Molecularly imprinted nanoparticles are cross-linked polymer colloids containing tailor-made molecular recognition sites. In this study, molecularly imprinted nanoparticles were easily encapsulated within polymer nanofibers using an electrospinning technique to produce a new type of molecular recognition material. Poly(ethylene terephthalate) (PET) was used as the supporting nanofibers matrix to encapsulate theophylline and 17beta-estradiol imprinted nanoparticles. The composite nanofibers had an average diameter of 150-300 nm, depending on the content of molecularly imprinted nanoparticles. For the theophylline and 17beta-estradiol imprinted polymers, an optimal loading of molecularly imprinted nanoparticles was 25-37.5 wt % based on PET. The composite nanofibers prepared under these conditions had a well-defined morphology and displayed the best selective target recognition. Our approach of electrospinning-for-molecularly imprinted nanoparticles-encapsulation has unique advantages and opens new application opportunities for molecularly imprinted nanoparticles and electrospun nanofibers.     

A phosphorescent copper(I) complex: synthesis, characterization, photophysical property, and oxygen-sensing behavior

In this paper, we report the synthesis, crystal structure, photophysical properties, and electronic nature of a phosphorescent Cu(I) complex of [Cu(Phen-Np)(POP)]BF4, where Phen-Np and POP stand for 2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline and bis(2-(diphenylphosphanyl)phenyl) ether, respectively. [Cu(Phen-Np)(POP)]BF4 renders a yellow phosphorescence peaking at 545 nm, with a long excited state lifetime of 4.69 μs. Density functional calculation reveals that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. We electrospun composite nanofibers of [Cu(Phen-Np)(POP)]BF4 and polystyrene (PS), hoping to explore the possibility of using the composite nanofibers as an oxygen sensing material. The finally obtained samples with average diameter of ～300 nm exhibit a maximum sensitivity of 7.2 towards molecular oxygen with short response time of 7s due to the large surface-area-to-volume ratio of nanofibrous membranes. No photobleaching is detected in these samples.     

SnO2/TiO2复合纳米纤维的制备及光催化性能

采用静电纺丝技术,以聚乙烯吡咯烷酮和钛酸正丁酯为前驱体,制得锐钛矿相TiO2纳米纤维。以TiO2纳米纤维为模板,通过水热合成法,制备了具有异质结构的SnO2/TiO2复合纳米纤维。利用扫描电镜(SEM)、X射线能量色散光谱（EDS）、透射电镜(TEM)和X射线衍射(XRD)等分析测试手段对其形貌和结构进行了表征,结果表明,SnO2纳米粒子均匀地生长在TiO2纳米纤维表面,形成了异质结构的SnO2/TiO2复合纳米纤维材料。通过改变反应物浓度,能有效地实现SnO2/TiO2复合纳米纤维的可控合成。以罗丹明B为模拟污染物,考察了SnO2/TiO2复合纳米纤维的光催化性能,与纯TiO2纳米纤维相比光催化活性明显提高,初步探讨了光催化反应机理。     

Enhancement in the photocatalytic activity of TiO2 nanofibers hybridized with g-C3N4 via electrospinning

TiO₂/g-C₃N₄ nanofibers with diameter of 100–200 nm were prepared by electrospinning method after calcination at high temperature, using polyvinylpyrrolidone (PVP), Melamine (C₃H₆N₆), Ti(OC₄H₉)₄ as raw materials. The composite nanofibers were characterized by XRD, FT-IR, SEM, UV–vis and PL respectively. The effects of different g-C₃N₄ contents on structure and photocatalytic degradation of the composite nanofibers were investigated. The results indicated that with increasing g-C₃N₄ content, the diameter of the composite fibers increased and the morphology changed from uniform structure to a nonuniform one, containing beads. The composite nanofibers displayed the best photocatalytic degradation on RhB, when the g-C₃N₄ content was 0.8 wt%. The degree of degradation was up to 99% at the optimal conditions of 40 min. The degradation activity of the composite nanofibers on RhB, MB and MO was found to be higher than that of the TiO₂ nanofibers.     

From monomeric nanofibers to PbS nanoparticles/polymer composite nanofibers through the combined use of gamma-irradiation and gas/solid reaction

Organic metal-salt (lead dimethacrylate (Pb(MA)2)) nanofibers are prepared, and these Pb(MA)2 monomeric nanofibers are successfully converted into PbS nanoparticles/polymer composite nanofibers through the combined use of gamma-irradiated polymerization and gas/solid reaction. The resulting composite nanofibers have excellent thermal and chemical stability, and the PbS nanoparticles (with diameters of about 4 nm) are well dispersed in the polymer-fiber matrices. This approach could also be extended to methacrylates containing other metal ions. We anticipate that this method would provide a platform for the fabrication of diverse and multifunctional polymer nanocomposite fibers, which would have potential applications in fabricating devices with optical, electric, and magnetic properties.