含有金纳米粒子的复合纳米纤维的制备和表征

以氯金酸(HAu Cl4)为原料,柠檬酸钠(C6H5Na3O7·4H2O)为还原剂,聚乙烯吡咯烷酮(PVP)为保护剂,乙醇为溶剂制备出含有金纳米粒子的溶胶溶液;采用高压静电纺丝技术制备了含有金纳米粒子的聚乙烯吡咯烷酮复合纳米纤维。通过紫外光谱研究了不同含量的金纳米粒子对纤维吸光度的影响;通过扫描电子显微镜和透射电子显微镜考察了含有金纳米粒子的聚乙烯吡咯烷酮复合纳米纤维的形貌。研究表明,随着金纳米粒子在纺丝溶液含量的增大,金纳米颗粒的特征吸收峰越来越明显,且有红移趋势;随着金纳米颗粒的增多,纤维逐渐变细,浓度过高时则不能生成纤维。     

小尺寸纳米铁颗粒的液相还原控制制备

在液相还原法基础上,以醇水混溶为溶剂,聚乙烯吡咯烷酮(PVP)为稳定剂,通过控制醇和PVP用量合成出粒径在9~20nm的粒径均一、分散性好的纳米铁粒子.通过动态光散射(DLS)、透射电子显微镜(TEM)以及紫外-可见分光光度计等表征手段对醇和PVP在液相合成中的作用以及小尺寸纳米铁的活性进行考察.研究表明,醇的作用主要为抑制纳米铁生长以及使Fe2+均匀分散到PVP中,而PVP则通过其空间位阻作用和静电排斥作用阻止纳米粒子的团聚;随醇中羟基数增加、碳链长度增长,纳米铁粒径逐渐减小;随醇浓度增加,纳米铁粒径减小;同时,随纳米铁尺寸减小,其活性显著增强.     

磁场退火诱导下组装的FePt纳米粒子体系(英文)

为解决FePt纳米粒子在磁记录应用中面临的三个问题:高的转变温度、强的磁耦合和垂直取向,提出一个统一的解决方案.包覆聚乙烯吡咯烷酮(PVP)分子的FePt纳米颗粒体系在磁场诱导下被组装.磁退火后,得到具有较低转变温度和垂直取向的FePt纳米颗粒组装体系.碳化的壳层不仅抑制了粒子的生长,还降低了相邻粒子之间的交换耦合.     

利用聚乙烯吡咯烷酮制备银纳米粒子

利用聚乙烯吡咯烷酮(PVP)的还原性,通过水热法还原Ag2O制备了Ag纳米粒子,并初步探讨了PVP作为还原剂的还原机理.利用X-ray粉末衍射(XRD)、透射电子显微镜(TEM)和选区电子衍射(SAED)对Ag纳米粒子进行了表征分析.实验结果发现,PVP在制备Ag纳米粒子的过程中可同时起到还原剂和表面活性剂的双重作用.     

HEPES溶液中钯纳米颗粒的制备及对Suzuki反应的催化

以氯化钯为反应原料,在HEPES溶液中采用回流法合成钯纳米颗粒,该法具有环境友好、简便的特点.运用能量分析光谱仪(EDX)、透射电镜(TEM)、高分辨透射电镜(HRTEM)和选区电子衍射(SAED)对所合成样品进行表征.考察了表面活性剂、反应时间对纳米颗粒分散性和尺寸的影响.测定了钯纳米颗粒对Suzuki反应的催化活性及重复使用效果.结果表明,所合成的钯粒径在10～13nm之间,PVP的存在可提高纳米钯的分散性、减小颗粒尺寸,过长的反应时间不利于小颗粒及分散性好的钯颗粒的形成.所合成的纳米钯在乙醇/水体系中对Suzuki反应有很好的催化活性和循环使用稳定性,催化活性显著高于商业化的钯碳催化剂,重复使用3次产率均可达90%以上.     

印制电子技术中纳米铜导电墨水的研制

以次磷酸钠(NaH_2 PO_2·H_2O)为还原剂,硫酸铜(CuSO_4·5H_2O)为前驱体,十六烷基三甲基溴化铵(CTAB)为表面活性剂,聚乙烯吡咯烷酮(PVP)为保护剂,在一缩二乙二醇(DEG)有机液相溶液中采用化学还原法成功地制备了铜纳米颗粒.采用XRD、TEM、SEM、纳米粒度仪及IR对所制备的铜纳米颗粒的结构、形貌、粒径大小及表面物质进行表征.结果表明制备的纳米铜粒子为球型颗粒,分散较好,尺寸较为均匀,平均粒径约为27 nm,并且具有立方晶型结构,其表面被有机物包覆.涂布纳米铜导电墨水的样品,其在高于250℃的温度下烧结60min后得到导电铜薄膜.温度在300℃烧结后,导电铜薄膜更加致密,可以推测铜薄膜的导电性能会增加.     

水热法制备BaF2纳米颗粒

采用水热合成法,以BaCl2和KF为反应物,在聚乙烯吡咯烷酮(PVP)作表面活性剂的水-醇体系中制备了结晶良好的BaF2纳米颗粒.考察了PVP用量对纳米颗粒生成的影响.利用X射线衍射(XRD)、透射电镜(TEM)和红外光谱(IR)等测试手段对样品进行了表征.结果表明,以PVP为表面活性剂可以完善BaF2的结晶质量,以形成立方结构的BaF2纳米颗粒.     

纳米MnO_2在碳棒上的固载

用电解法制备了纳米MnO2颗粒.以聚乙烯吡咯烷酮(PVP)与纳米MnO2颗粒作为前驱体,以无水乙醇为溶剂,在超声波震荡下制得纳米MnO2均匀分散的黄绿色PVP溶胶.以电纺丝技术制得PVP/MnO2纤维和PVP/MnO2纤维充分缠绕的碳电极.氮气保护下,于550℃马弗炉中处理,得到固载良好的纳米MnO2电极.用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、红外吸收光谱(FT-IR)等测试手段对超细纤维进行了表征.     

氢氧化镁纳米丝和纳米棒的合成及表征

探索新型无卤、无毒添加型无机阻燃材料.利用PVP高分子在溶液中的一维聚集特点,在PVP/乙二醇溶液相体系中形成一维纳米胶束结构,并利用该胶束结构(PVP)作为纳米功能材料的软模板,用低温回流法合成了多晶、长径比较高的一维(或准一维)氢氧化镁纳米丝和纳米棒.并以XRD,TEM,HRTEM和TG等测试手段进行了表征.测试结果表明,该样品比以往同类产品具有更好的热稳定性和更高的热加工安全性.     

高分子稳定的水溶性铂氧化物纳米颗粒的制备

利用铂氯化物的水解反应,制备出聚乙烯吡咯烷酮(PVP)稳定的水溶性二氧化铂纳米颗粒.此法所得的产物颗粒小,粒径分布窄,稳定,室温下放置几个月无沉淀.用紫外-可见光谱检测纳米颗粒的形成过程,用X-射线光电子能谱(XPS)和透射电子显微镜(TEM)对样品的成分、形貌、尺寸进行了表征,并考察了PVP的浓度以及体系的酸碱度对形成二氧化铂颗粒粒径的影响.     

Shape controllable preparations of PbS nanocrystals using cysteine as the precursor of S^2- ions

Flowerlike, spherical and cubic PbS nanoparticles have been successfully synthesized by refluxing cysteine and lead nitrate in an alkaline solu- tion. The influences of the cysteine to Pb2 molar ratio, the pH value of the reaction mixture as well as the refluxing time on the shape of PbS nanoparticles were investigated. Detailed experimental results demonstrated that a higher molar ratio of cysteine to Pb2 (5.2:1) and shorter refluxing time favor the for- mation of flowerlike PbS nanoparticles at pH 9.0. While lower pH value (8.0) favors the formation of spherical PbS nanoparticles, and higher pH value (10.0), however, favors the formation of cubic PbS nanoparticles. The mechanism for the shape control of PbS nanoparticles is discussed.     

ZnSe纳米颗粒的制备及光学性能研究

以硝酸锌和硒粉为源物质,以乙二醇和氢氧化钠的水溶液为反应介质,采用水热法制备了ZnSe纳米颗粒,利用差热分析仪(TG-DTA)、X射线衍射仪(XRD),扫描电子显微镜(SEM)和光致发光谱(PL)对产物进行热稳定性、结构、形貌和光学性能表征.差热结果表明ZnSe在常温下具有一定稳定性,直到450℃以上时在空气中可转化为ZnO纳米材料.XRD和SEM研究结果表明,纳米颗粒具有闪锌矿结构并且随着反应时间的增加颗粒尺寸有所增大.PL测试显示近带边发射峰较强,这说明产物的结晶状况良好,并且具有较好的光致发光性能.     

油溶性纳米Ni微粒的表面修饰

本文在水溶液中，使用硬脂酸为改性剂，采用一步还原法制备了油溶性Ni纳米颗粒．并使用透射电镜观察了制备颗粒的形貌及大小，并利用光学显微镜考察了颗粒的分散性，同时也对颗粒与甲苯闻的浸润性及抗沉降能力进行了研究．结果表明：Ni纳米颗粒经过表面改性后，颗粒大小约为30nm，在油性介质中分散能力：浸润性、抗沉降能力方面均得到明显提高．     

固相反应法合成纳米氧化锌及其光学性能研究

采用ZnSO4.7H2O和N a2CO3为原料,通过固相反应简便合成了氧化锌纳米晶,X-射线衍射(XRD)图谱证明产物为纤锌矿型晶体结构,粒度在16~25 nm范围之间.紫外吸收光谱(UV)表明产物在波长360 nm处显示很好的激子吸收,与体材料的激子吸收峰(373 nm)相比产生了蓝移,具有明显的量子尺寸效应.光致发光光谱(PL)检测结果发现,产物的紫外发光峰位随着粒径的减小向短波方向移动(蓝移),也表现出强烈的尺寸效应.     

Structural,morphological, and optical properties of tin(Ⅳ) oxide nanoparticles synthesized using Camellia sinensis extract: a green approach

Tin oxide (SnO2) nanoparticles were cost-effectively synthesized using nontoxic chemicals and green tea (Camellia sinensis) extract via a green synthesis method.The structural properties of the obtained nanoparticles were studied using X-ray diffraction,which indicated that the crystallite size was less than 20 nm.The particle size and morphology of the nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy.The morphological analysis revealed agglomerated spherical nanoparticles with sizes varying from 5 to 30 nm.The optical properties of the nanoparticles' band gap were characterized using diffuse reflectance spectroscopy.The band gap was found to decrease with increasing annealing temperature.The O vacancy defects were analyzed using photoluminescence spectroscopy.The increase in the crystallite size,decreasing band gap,and the increasing intensities of the UV and visible emission peaks indicated that the green-synthesized SnO2 may play future important roles in catalysis and optoelectronic devices.     

Structural,morphological,and optical properties of tin(Ⅳ) oxide nanoparticles synthesized using Camellia sinensis extract: a green approach

Tin oxide(SnO_2) nanoparticles were cost-effectively synthesized using nontoxic chemicals and green tea(Camellia sinensis) extract via a green synthesis method. The structural properties of the obtained nanoparticles were studied using X-ray diffraction, which indicated that the crystallite size was less than 20 nm. The particle size and morphology of the nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy. The morphological analysis revealed agglomerated spherical nanoparticles with sizes varying from 5 to 30 nm. The optical properties of the nanoparticles' band gap were characterized using diffuse reflectance spectroscopy. The band gap was found to decrease with increasing annealing temperature. The O vacancy defects were analyzed using photoluminescence spectroscopy. The increase in the crystallite size, decreasing band gap, and the increasing intensities of the UV and visible emission peaks indicated that the green-synthesized SnO_2 may play future important roles in catalysis and optoelectronic devices.     

Fabrication of well-disper sive yttrium-stabilized cubic zirconia nanoparticles via vapor phase hydrolys is

The well-dispersive yttrium-stabilized cubic zirconia nanoparticles were fabricated via vapor phase hydrolysis process,and the as-synthesized cubic zirconia nanoparticles were characterized by X-ray di...     

金属纳米颗粒的极化率与异常光学性质

基于金属纳米材料的异常光学现象,考虑了束缚电荷作用的情况,从理论上推导出在光波照射下金属纳米颗粒的极化率与颗粒尺度关系的结果,进而得到金属颗粒对光波的吸收率,并讨论颗粒尺度对极化率和吸收率的影响,即当金属粒子尺寸达到纳米级时,将金属粒子看作纳米小球,小球极化率出现半径的立方因子,且小球半径小于电子平均自由程,电子的衰减因子受小球半径的制约.由推导结果可以得出,光吸收峰增强,并产生红移.这些结果为深入理解金属纳米颗粒的异常光学性质,揭示和开发应用金属纳米材料的性质提供理论基础.     

CdSe量子点修饰物DSPE-PAA对其荧光增强效应的研究

采用有机热溶剂法制备出荧光量子效率高、单分散性良好的油溶性CdSe半导体量子点,将其用水溶性低分子量两性聚合物DSPE-PAA[poly（acylicacid）-1,2-distearoyl-sn-glycero-3-phosphoethanolamine,聚丙烯酸-1,2-二硬脂酰-sn-丙三醇-3-磷脂酰乙醇胺]进行修饰,得到水溶性和生物相容性良好的量子点。用透射电子显微镜（TEM）和荧光光谱等方法对CdSe纳米微粒的结构、形貌和光学特性分别进行了表征。并探讨和研究了在修饰过程中发生的DSPE-PAA对量子点由于荧光共振能量转移（FRET）作用产生的量子点荧光增强的现象。     

Simultaneous acquisition of Fe_3O_4 monocrystals:Tunable magnetic properties with various morphologies

Fe_3O_4 nanoparticles(NPs) with a face-centered cubic(fcc) structure and two different morphologies(nanospheres and nanoprisms) were synthesized by a facile one-step method.The synthesized Fe_3O_4 nanospheres and nanoprisms were monocrystalline and separable in a magnetic field.In different volume ratios of oleylamine(OAm) to dibenzyl ether,the sizes of the prepared Fe_3O_4 NPs ranged from 5 to 21 nm.The OAm amount in the synthesis can significantly control the morphology of Fe_3O_4 NPs.As the OAm content increased from 10 ml to 30 ml,the faceted nanoprisms shrank while the nanospheres enlarged.At an OAm content of 25 ml,the nanoprisms diminished while more hexagonal and sphere-like particles appeared,implying a critical point of morphology transition from triangle to hexagon.The magnetic properties also depended on the NP morphology and size.The prepared Fe_3O_4 NPs are promising candidates in medical applications such as magnetic resonance imaging,targeted drug delivery,blood purification,and tumor hyperthermia.