负载银纳米立方体的醋酸纤维素纳米纤维及其SERS活性（英文）

报道了一种采用同轴静电纺丝法制备的表面增强Raman散射(SERS)活性衬底,用于微量环境污染物的快速检测。采用醋酸纤维素(CA)/丙酮-二甲基乙酰胺溶液作为前驱液分散银纳米立方体,利用丙酮促进银颗粒适度团聚,采用同轴静电纺丝法制备了大面积银立方体/CA纳米纤维。由于团聚态银纳米立方体之间的等离子体耦合作用,复合薄膜具有优异的SERS活性,是单分散态的银立方体/CA纳米纤维SERS灵敏度的4倍,实现了0.1nmol/L的对巯基苯胺以及10nmol/L的甲基对硫磷农药的SERS检测,SERS信号强度偏差小于12%。     

醋酸纤维素纳米纤维复合气凝胶的制备及性能研究

以醋酸纤维素(CA)为原料,通过静电纺丝制备CA纳米纤维;将CA纳米纤维在去离子水中形成均匀的分散体,然后在分散液中引入N-羟甲基丙烯酰胺(HAM),通过冷冻、热处理制备CA纳米纤维/HAM复合气凝胶(CNFA);探讨了HAM添加量对CNFA力学性能和隔热性能的影响.结果表明:当纺丝液CA质量分数为15％时,静电纺CA...     

静电纺丝纳米纤维的制备工艺及其应用

简述了静电纺丝制备纳米纤维的原理;探讨了静电纺丝电压、流速、接收距离、溶剂浓度等工艺条件;介绍了同轴静电纺丝制备皮芯结构的超细纤维及中空纤维技术以及静电纺丝纳米纤维毡在生物医药方面的应用。指出静电纺丝纳米纤维材料在生物医用方面具有广阔的应用前景,进一步实现低压纺丝、开发无毒溶剂,控制同轴静电纺丝纳米纤维的释放性能是今后静电纺丝的研发方向。     

静电纺丝工艺对二醋酸纤维素纳米纤维形貌及直径的影响

以质量比为2∶1的丙酮/N,N-二甲基乙酰胺混合溶液为溶剂配制二醋酸纤维素(CA)溶液,采用静电纺丝制备CA纳米纤维,探讨了CA浓度、纺丝电压、接收距离和溶液推进速度等工艺条件对CA纳米纤维形貌、直径及其分布的影响。结果表明:CA纳米纤维的直径随CA浓度增加而增大,随纺丝电压增大而减小;适当的接收距离和溶液推进速度可以获得直径较小且分布均匀的纤维;当CA质量分数为11%、纺丝电压为30 k V、接收距离为15 cm、溶液推进速度为0.010 m L/min时,纺丝效果好,纤维平均直径约130 nm,且直径分布较均匀。     

用静电纺丝法制备橡胶/黏土纳米复合材料微米纤维(英文)

采用静电纺丝工艺制备了表面形态良好的溴化丁基橡胶/黏土纳米复合材料微米纤维,研究了其微观结构。结果表明,静电纺丝工艺制备的纤维内部黏土空间分散状态明显优于常规溶液法制备的橡胶/黏土纳米复合材料。     

聚丙烯腈/氧化铁纳米粒子复合纳米纤维的制备及表征

利用静电纺丝技术制备了一种聚丙烯腈(PAN)/氧化铁(Fe_2O_3)纳米粒子复合纳米纤维。不同分子量的PAN得到不同直径的纤维薄;将PAN的N,N-二甲基甲酰胺溶液(DMF)与纳米Fe_2O_3混合得到PAN/Fe_2O_3溶液,然后利用静电纺丝技术制备PAN/Fe_2O_3纳米粒子复合纳米纤维;将静电纺丝制备的PAN纳米纤维膜与氯化铁(FeCl_3)溶液在不同p H条件下水热合成PAN/Fe_2O_3纳米粒子复合纳米纤维。采用扫描电子显微镜(SEM)、热重分析仪(TGA)对纳米纤维膜进行表征。结果表明:静电纺丝制备的PAN纳米纤维在水热条件下可以一定程度上克服Fe_2O_3纳米粒子易团聚问题。     

静电纺醋酸纳米纤维滤膜的制备及性能分析

为了制备高效低阻的纳米纤维空气过滤膜,采用静电纺丝技术,制备了醋酸(CA)不同质量分数、不同纺丝时间的CA纳米纤维膜,研究了CA质量分数和纺丝时间对CA纳米纤维膜的微观形貌、透气性、过滤性能等性能的影响。结果发现:随着CA质量分数和纺丝时间的增加,CA纳米纤维膜的透气率先减小后增加,过滤效率和阻力压降均先升高后降低,当CA的质量分数为12%,纺丝时间为60 min时,透气率达到247.67 mm/s,水接触角104°,过滤效率为99.94%,阻力压降为238.14 Pa,此时品质因子达到最大数值为0.030 95 Pa~(-1)。     

含纳米铝粉的纳米NC纤维的制备

为了克服纳米铝粉在推进剂使用过程中分散不均匀的问题,采用静电纺丝技术制备了材料表面光滑、直径均匀、且纳米铝粉分散均匀的纳米NC纤维.用扫描电镜研究了含水率、溶液浓度、电压和挤出速率对纤维形态和直径的影响,得到静电纺丝最佳工艺条件:含水率为10%～15%,NC纺丝液质量分数5%～10%,电压25～30kV,挤出速率0.5...     

原位热溶剂法制备ZnO纳米晶/PU复合纳米纤维及其吸附性能研究

通过静电纺丝法制备了直径为(320±51)nm的前驱体醋酸锌/聚氨酯(Zn(OAc)2/PU)复合纳米纤维。将前驱体先后经过0.1 mol/L NaOH乙醇溶液和甘油浴热处理,得到ZnO纳米晶/PU复合纳米纤维。讨论了甘油浴温度和时间对纳米纤维结构和形貌的影响,研究了其吸附性能。实验结果表明,经过0.1 mol/L NaOH乙醇溶液处理后,前驱体纤维Zn(OAc)2/PU转变为ZnO/PU纤维且ZnO主要以低结晶和无定型态存在;再经过甘油浴处理后,低结晶和无定型态的ZnO转变为晶型完整的六方晶系纤锌矿结构,得到了ZnO纳米晶/PU复合纳米纤维,该纤维对有机染料分子罗丹明B有良好的吸附性能。     

钒掺杂TiO2纳米纤维的制备及其光催化性能

以体积比为1∶2的N,N-二甲基甲酰胺和丙酮为溶剂、钛酸四丁酯[Ti(OiPr)4]和氯化钒[VC13]为前驱体、醋酸纤维素(CA)为模板,采用静电纺丝法制备了V-TiO2/醋酸纤维素纳米纤维.将V-TiO2/醋酸纤维素纳米纤维用0.1 mol/L NaOH/乙醇溶液水解得到V-TiO2/纤维素纳米纤维.在500℃煅烧V-TiO2/纤维素纳米纤维5h,得到直径为(200±53)nm的V-TiO2纳米纤维.利用扫描电子显微镜、X射线粉末衍射仪和紫外-可见漫反射光谱对纤维形貌、物相和结构进行了表征.以染料罗丹明B为目标降解物考察了纤维的光催化活性.结果表明:掺杂少量V后,TiO2对紫外光的最大吸收峰和吸收带边发生了红移,说明V-TiO2对光响应更宽、光利用率更高.TiO2和V-TiO2纳米纤维在20min内对罗丹明B的降解率分别为67％和77％.     

Co-assembly of Au nanorods with Ag nanowires within polymer nanofiber matrix for enhanced SERS property by electrospinning

Gold nanorods (AuNRs) can be successfully co-assembled with Ag nanowires (AgNWs) to form a kind of AuNR-AgNW nanocomposite by electrostatic attraction, in which the AuNRs are arranged along the long axial direction of the AgNWs with a preferential string-like alignment. The assembled AuNR-AgNW nanocomposites are then further embedded within polyvinyl alcohol (PVA) nanofibers by electrospinning, by which both AuNRs and AgNWs can be stabilized and arranged along the axis of polymer nanofibers. When the polymer nanofibers are aligned by collecting on a copper mesh with a woven structure, the AuNR-AgNW nanocomposites assembled within the electrospun nanofibers are also arranged. The influences of the AuNR-AgNW assemblies with different amounts of AuNRs attached on AgNWs on the optical properties and surface enhanced Raman scattering (SERS) enhancement have been investigated. The resulting AuNR-AgNW/PVA electrospun mats show red-shifted and broader absorption bands and higher SERS performances compared with the normal casting films with randomly dispersed AuNRs and AgNWs, or electrospun mats with monometallic components, due to the order alignment of AuNR-AgNW nanocomposites on a large scale.     

Cocontinuous cellulose acetate/polyurethane composite nanofiber fabricated through electrospinning

Cocontinuous cellulose acetate (CA)/polyurethane (PU) composite nanofibers were obtained through electrospinning of partially miscible CA and PU in 2:1 N,N‐dimethylacetamide (DMAc)/acetone mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were affected by component ratio in the binary mixtures. PU component not only facilitated the electrospinning of CA at CA concentration down to 12 wt%, but reinforced the tensile strength of CA/PU nanofibrous mats, while semirigid component CA in the composite nanofibers could greatly improve the rigidity and dimensional stability of CA/PU nanofibrous mats. In a series of nanofibrous mats with varied CA/PU composition ratios, CA/PU 20/80 showed excellent tensile strength and Young's modulus. The residual product after selective removal of any one of the components in CA/PU composite nanofibers by washing with proper solvent maintained the fiber structure but greatly reduced the fiber size, suggesting CA/PU composite fibers showed a cocontinuous nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

ZnO nanocrystallites/cellulose hybrid nanofibers fabricated by electrospinning and solvothermal techniques and their photocatalytic activity

ZnO nanocrystallites have been in situ embedded in cellulose nanofibers by a novel method that combines electrospinning and solvothermal techniques. Zn(OAc)₂/cellulose acetate (CA) precursor hybrid nanofibers with diameter in the range of 160–330 nm were first fabricated via the electrospinning technique using zinc acetate as precursor, CA as the carrier, and dimethylformamide (DMF)/acetone(2 : 1) mixture as cosolvent. The precursor nanofibers were transformed into ZnO/cellulose hybrid fibers by hydrolysis in 0.1 mol/L NaOH aqueous solution. Subsequently, these hybrid fibers were further solvothermally treated in 180°C glycerol oil bath to improve the crystallite structure of the ZnO nanoparticles containing in the nanofibers. The structure and morphology of nanofibers were characterized by scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction. It was found that hexagonal structured ZnO nanocrystallites with the size of ～ 30 nm were dispersed on the nanofiber surfaces and within the nanofibers with diameter of about 80 nm. The photocatalytic property of the ZnO/cellulose hybrid nanofibers toward Rhodamine (RhB) was tested under the irradiation of visible light. As a catalyst, it inherits not only the photocatalytic ability of nano‐ZnO, but also the thermal stability, good mechanical property, and solvent‐resistibility of cellulose nanofibers. The key advantages of this hybrid nanofiber over neat ZnO nanoparticles are its elasticity, dimensional stability, durability, and easy recyclability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Behavior of toluene adsorption on activated carbon nanofibers prepared by electrospinning of a polyacrylonitrile-cellulose acetate blending solution

Activated carbon nanofibers were prepared with polymer blends that consisted of polyacrylonitrile (PAN) and cellulose acetate (CA), by electrospinning and subsequent thermal treatment. The average fiber diameter of samples was about 200 nm, ranging from 150 to 400 nm. The specific surface area, total pore volume, and micropore volume increased with increasing CA content. As the CA content was increased up to 20%, the pore characteristics for the adsorption performance were enhanced. However, excess CA content (over 30%) was harmful to volatile organic compounds (VOCs) adsorption ability due to changing morphology of the activated carbon nanofibers. The O/C ratio was increased with increasing CA content. However, the O/C ratios of all activated carbon nanofibers prepared with blends represent small values revealing non-polarity of the surface. The adsorption capacities of PC10, PC09, PC08 and PC07 were 65 g/100 g, 66 g/100 g, 72 g/100 g and 67 g/100 g. The blends of the PAN with CA showed better characteristics than those of PAN alone, but apparently there is an appropriate blending ratio (20%) for high-performance of activated carbonaceous materials.     

Environmentally friendly biological nanofibers based on waste feather keratin by electrospinning with citric acid vapor modification

Waste feather keratin (FK)-based nanofibers by electrospinning and citric acid (CA) vapor modification has been successfully prepared and investigated. FK, poly(vinyl alcohol), and poly(ethylene oxide) have been used as raw materials and CA vapor as cross-linker. The structural, thermal, hydrophobicity, and mechanical properties of FK-based nanofibers by CA vapor modification with various cross-linking time have been completely explored. In order to investigate the effect of H₂O vapor on CA vapor modification, H₂O vapor modification was performed on the FK-based nanofibers at the same conditions. The results show that the average diameter of nanofibers increased from 250.83 ± 29.65 nm to 338.79 ± 31.43 nm by CA vapor modification with 15 h. Similarly, the thermal stability and water resistance of FK-based nanofibers by CA vapor modification have been significantly improved. The tensile strength (σ_b) and elongation at breakage point (ε_b) of FK-based nanofibers after CA vapor modified for 15 h were about 1.5 and 2 times higher than that of nonmodified nanofibers, respectively. By comparison, scanning electron microscopy results suggest that the FK-based nanofibers modified by H₂O vapor cannot maintain the morphology of the nanofibers, resulting in large-scale adhesion. The thermal properties of FK-based nanofibers with H₂O vapor modification have no obvious change. The hydrophobicity and mechanical properties of FK-based nanofibers by H₂O vapor modification are not as good as that of CA vapor modification. In summary, these results exhibit that nontoxic and natural CA can be used as cross-linking agent to enhance the comprehensive performance of FK-based nanofibers. This study provides a new method to modify FK-based nanofibers and refined the waste feathers, which not only protected the environment, but also gained benefits, which has a broad application prospect.     

基于银纳米簇的纳米传感平台用于丙酮酸的检测

现存丙酮酸(Pyruvate, Py)检测方法大都需要特殊仪器,并且受某些适用范围的影响而存在缺乏选择性等问题。提出一种基于荧光银纳米簇(Ag nanoclusters, AgNCs)构建纳米传感平台定量精确检测Py的方法,建立了AgNCs的荧光发射强度与Py浓度线性定量关系,标准曲线方程为y=116.714+0.306x,R²=0.991,Py浓度线性检测范围为200~1 400μmol/L。同时实验结果表明人体血液、尿液中的常见成分如葡萄糖(Glucose, GO)、尿酸(Uric acid, UA)、肌氨酸(Sarcosine, SO)、乳酸(Lactic acid, LA)等不会干扰该平台对于Py的测定。该方法具有很强的特异针对性,可实现对Py含量的高灵敏度和高选择性检测。     

Facile preparation and characterization of poly(vinyl alcohol)/chitosan/graphene oxide biocomposite nanofibers

Poly(vinyl alcohol) (PVA)/chitosan (CS)/graphene oxide (GO) biocomposite nanofibers have been successfully prepared using aqueous solution by electrospinning. CS colloidal gel in 1% acetic acid can be changed to homogeneous solution by using electron beam irradiation (EBI). The uniform distributions of GO sheets in the nanofibers were investigated by field emission scanning electron microscopy (FESEM) and Raman spectroscopy. FESEM images illustrated that the spread single GO sheet embedding into nanofibers was formed via self-assembly of GO sheet and PVA/CS chains. And the average diameters of the biocomposite nanofibers decreased (200, 173, 160 and 123 nm) with increasing the contents of GO (0.05, 0.2, 0.4 and 0.6 wt%). Raman spectra verified the presence of GO in the biocomposite nanofibrous mats. The mechanical properties of as-prepared materials related with GO contents. It revealed that the highest tensile strength was 2.78 MPa, which was 25% higher than that of neat PVA/CS nanofibers. Antibacterial test demonstrated that the addition of GO to PVA/CS nanofiber had great ability to increase inhibition zone till 8.6 mm. Overall, these features of PVA/CS/GO nanofibers which were prepared by eco-friendly solvent can be a promising candidate material in tissue engineering, wound healing and drug delivery system.     

Nanostructured membranes based on cellulose acetate obtained by electrospinning. Part II. Controlled release profile and microbiological behavior

Nanofiber membranes of cellulose acetate (CA) were produced with four mixtures of solvents, that is, acetic acid/water, acetone/water, dimethylacetamide (DMAc)/acetone, and DMAc/acetone/water, with the incorporation of the drug gentamicin sulfate at two concentrations. We evaluated the influence of the drug concentration in the electrospinning process. The best membrane produced in this stage was the membrane electrospun with the DMAc/acetone/water solvent mixture, whose process was shown to be viable and did not alter the membrane diameter or aspect with the variation of the drug concentration. Membranes prepared in this way and loaded with 50% of the drug were used for the studies of the release kinetics. Comparisons between the release profiles of the same membranes coated with hydroxypropyl methylcellulose, Eudragit L100, and electrospun CA nanofibers were carried out. The best results on the drug‐release profile were obtained with the membrane coated with nanofibers of CA, which caused a decrease of 9 h in the burst effect. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2772–2779, 2013     

Preparation and surface-enhanced Raman performance of electrospun poly(vinyl alcohol)/ high-concentration-gold nanofibers

A facile approach to prepare electrospun poly(vinly alcohol) (PVA) nanofibers with high concentration of gold nanoparticles (Au NPs) on the fibers, had been developed. These PVA/Au nanofibers could be used as flexible surface-enhanced Raman scattering (SERS) substrates. Relatively high concentration of PVA aqueous solution (10 wt %) was used as the stabilizing agent for gold salt precursor, as well as the starting solution for electrospinning. This method was demonstrated to be effective to prepare high-concentration-gold nanoparticles without aggregation and precipitation by reducing high concentration of gold salt in the presence of PVA aqueous solution. SEM and TEM images showed that both the amount and the size of Au NPs which embedded in PVA nanofibers, increased with increasing the gold salt content, while the gap between the adjacent NPs decreased. Raman spectra showed an apparent enhancement in the signal of 4-mercaptobenzoic acid (4-MBA) molecules pre-absorbed from its ethanol solution onto the PVA/Au nanofibers. The high SERS activity to 4-MBA in solution with a relatively low concentration (10⁻⁶ M), could be mainly attributed to the reduced gap of Au NPs.     

Electrospun progesterone-loaded cellulose acetate nanofibers and their drug sustained-release profiles

Novel cellulose acetate (CA) nanofibers incorporated with hormone progesterone (P₄) were prepared by electrospinning and its potential as a controlled release system for medicine and veterinary was evaluated by controlled release essay. The morphology, thermal behavior, and structure of P₄-loaded CA nanofibers were characterized by scanning electron microscopy, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The analyses revealed that the incorporation of P₄ increased nanofibers' diameter from around 340 to 892 nm to 8% w/w P₄-loaded CA nanofibers. Furthermore, P₄ has demonstrated high interaction with CA affecting its crystalline structure, since pure CA nanofibers presented 67.23% of crystallinity while P₄-loaded CA nanofibers where amorphous. Ultimately, the drug release essay demonstrated a two-stage profile, and regarding release kinetics, the samples evidenced a diffusion mechanism depending on P₄ concentration in the nanofiber.