在SDS-PVP团簇软模板中自组装多脚状金纳米粒子

利用十二烷基硫酸钠(SDS)与聚乙烯吡咯烷酮(PVP)组成的团簇为软模板, 在微波辅助下以柠檬酸钠为还原剂快速还原氯金酸生成金晶并自组装成多脚状金纳米粒子. TEM结果显示, 得到回转直径约为50 nm的多脚状纳米结构, 电子衍射(ED)证实其为多晶结构. XRD结果表明, 该多脚状金纳米结构主要沿(111)晶面生长, 构成该纳米结构的晶粒尺寸约为12.7 nm. SDS与PVP组成的团簇结构对金纳米粒子的形貌有显著影响, 固定PVP浓度时, 随着SDS浓度增大, 金纳米粒子的形貌由球形向多脚状转变, 同时还原产物水溶液的UV-Vis光谱在800 nm附近的吸收逐渐增强.     

调控金纳米花表面凸起的策略及其表面增强拉曼散射活性

以聚乙烯吡咯烷酮(PVP)与十二烷基硫酸钠(SDS)通过阳离子架桥形成的拟聚阴离子为软模板,通过改变PVP、SDS和纳米材料前驱体氯金酸(HAu Cl₄)浓度以及反应时间等因素,调控还原产物金纳米花形貌及粒径。表面张力、电导率、毛细管电泳及Zeta电位等实验结果表明PVP-SDS-HAu Cl₄形成新的拟聚阴离子,透射电子显微镜和X射线衍射结果表明SDS、PVP和HAu Cl₄的较低浓度组合更易获得表面凸起丰富的金纳米花。PVP-SDS拟聚阴离子发挥了二级软模板作用,在PVP (50 g·L^-1)-SDS (2 mmol·L^-1)-HAu Cl₄ (0.25 mmol·L^-1)溶液中调控合成的金纳米花为{111}晶面为主的面心立方结构,其平均等效粒径为108 nm,且表面上密集分布约16.5 nm的凸起。该金纳米花有较强的表面增强拉曼散射(SERS)活性,探针分子罗丹明6G的SERS信号强度依赖于金纳米花的表面凸起形貌。该研究中金纳米...     

溶剂热法制备银纳米晶

以聚乙烯吡咯烷酮(PVP)作为表面活性剂,利用乙二醇溶剂热法成功制备了银纳米颗粒;利用场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)分析了样品的形貌和晶体结构,并考察了溶剂组成等因素对银纳米颗粒形貌的影响.研究结果表明所得银纳米晶粒径均一,直径约为90nm;增大PVP的加入量会降低产物的粒径,溶剂中水的引入会影响银纳米晶的形貌.     

纳米镍包覆超细铝复合粉末的氧化性能

通过置换还原法, 快速、简洁、定量地制备出了纳米镍包覆的超细铝粉复合粉末. 利用扫描电子显微镜(SEM)、热重分析(TGA)、差示扫描量热(DSC)和X射线衍射(XRD)等分析手段对原料Al粉和复合粉末的形貌及其氧化性能进行研究. 结果表明, 原料Al粉在1050 ℃时增重率为122%, 当包覆的纳米镍粉质量分数为0.75%时, 可以使铝粉在1050 ℃时的增重率达到135%, 并且随着镍粉含量的增加, 铝粉的增重率进一步提高. 当镍的质量分数达到8.93%时, 复合粉末在约1000 ℃时出现点火燃烧现象. 纳米镍粉的氧传递对促进超细铝粉的氧化起到了至关重要的作用.     

以SDS-PVP项链状软团簇为模板简易一锅法合成Cu2O中空亚微球

在SDS-PVP水溶液中采用N2H4•H2O还原CuSO4, 在pH (10±0.5), (40±1.0) ℃条件下反应55 min得到橙色Cu2O溶胶, 离心分离产物经XRD鉴定为Cu2O立方晶系晶体; SEM和TEM表明该法获得的晶体为形状规整、粒径分布窄的Cu2O中空亚微球, 并证实系由大量10 nm量级的原级Cu2O纳米晶粒组装而成. 根据实验事实推断, SDS-PVP项链状软团簇提供了“双重软模板”功能, 借助独特的“模板诱导两级组装”作用一锅法合成了Cu2O中空亚微球. Cu2O中空亚微球生长的可能途径为: 首先, 项链状软团簇中的SDS束缚胶束作为第一重软模板, 诱导一级组装10 nm量级的原级Cu2O纳米晶粒; 然后, 软团簇中立体桥联SDS束缚胶束的PVP链节作为第二重软模板, 诱导一定空间范围内的原级Cu2O纳米晶粒长大并进一步聚集/二级组装, 经一锅法合成得到次级Cu2O中空亚微球. 实验结果证明该一锅法温和、简便、快捷, Cu2O中空亚微球的粒径分布窄.     

自催化还原制备微米和纳米级空心镍球的研究

提出了一种新型的制备超细空心金属镍粉的方法.通过FESEM,TEM和XRD衍射对该制备方法进行了研究,并考察了有关工艺参数对产物粒径和粒度分布的影响.研究认为,通过在胶核表面发生自催化还原反应,形成金属镍壳,同时胶核发生自分解,最后可得到空心金属镍球.控制反应物浓度和NaOH的配比可得到粒径均匀的镍球;通过调整这两个参数可得到粒度在微米或纳米尺度的空心镍球.     

二苯胺磺酸钠还原法制备粒径可控的金纳米粒子

采用二苯胺磺酸钠还原四氯合金酸的方法,在室温条件下,用SDS(十二烷基硫酸钠)、SDBS(十二烷基苯磺酸钠)作表面活性剂,成功地合成了金纳米粒子.分别讨论了还原剂二苯胺磺酸钠、表面活性剂(SDS、SDBS)及四氯台金酸的浓度等对金纳米粒子的粒径和形貌的影响.通过控制反应条件,可以合成出平均粒径大约为10、14、30、36nm的金纳米粒子.利用透射电镜(TEN)、紫外-可见(UV-Vis)吸收光谱对金纳米粒子进行了表征.研究结果表明不同的SDS或SDBS/HAuCl4的摩尔比,对金纳米粒子的尺寸大小有影响.     

以SDS-PVP项链状软团簇为模板简易一锅法合成Cu2O中空亚微球

在SDS-PVP水溶液中采用N2H4•H2O还原CuSO4, 在pH (10±0.5), (40±1.0) ℃条件下反应55 min得到橙色Cu2O溶胶, 离心分离产物经XRD鉴定为Cu2O立方晶系晶体; SEM和TEM表明该法获得的晶体为形状规整、粒径分布窄的Cu2O中空亚微球, 并证实系由大量10 nm量级的原级Cu2O纳米晶粒组装而成. 根据实验事实推断, SDS-PVP项链状软团簇提供了“双重软模板”功能, 借助独特的“模板诱导两级组装”作用一锅法合成了Cu2O中空亚微球. Cu2O中空亚微球生长的可能途径为: 首先, 项链状软团簇中的SDS束缚胶束作为第一重软模板, 诱导一级组装10 nm量级的原级Cu2O纳米晶粒; 然后, 软团簇中立体桥联SDS束缚胶束的PVP链节作为第二重软模板, 诱导一定空间范围内的原级Cu2O纳米晶粒长大并进一步聚集/二级组装, 经一锅法合成得到次级Cu2O中空亚微球. 实验结果证明该一锅法温和、简便、快捷, Cu2O中空亚微球的粒径分布窄.     

超细纳米Pd粒子与聚乙烯吡咯烷酮的相互作用

在微量聚乙烯吡咯烷酮(PVP)存在下, 利用超声还原氯化钯水溶液, 制备出超细纳米Pd颗粒, 用高分辨透射电镜、红外光谱、紫外-可见光谱和X射线光电子能谱等技术对其表面形貌及结构进行了表征. 结果表明, 纳米Pd粒子的粒径均一, 大约为3 nm. 纳米Pd/PVP复合粉末的羰基红外吸收峰比PVP的羰基吸收峰红移9 cm^-1; 且当超声反应50 min时, PVP紫外吸收波峰蓝移16 nm, 表明了纳米Pd与PVP之间存在一定的相互作用力. XPS结果证明, 纳米Pd与PVP的羰基基团通过配位作用使超细纳米Pd粒子得以稳定分散存在.     

十六烷基膦酸表面修饰纳米镍粉及其复合材料的制备和性能

以十六烷基膦酸作为修饰剂, 对纳米镍粉进行表面改性处理, 通过溶液共混的方法制备改性镍粉与聚丙烯的聚合物基复合材料. 利用X射线光电子能谱(XPS)、 X射线衍射(XRD)及透射电子显微镜(TEM)等测试手段研究改性镍粉的表面形态; 利用扫描电子显微镜(SEM)研究复合材料断面形貌; 利用介电频谱分析系统对复合材料的介电常数和介电损耗等进行了测试. 结果表明, 纳米镍粉表面形成厚度为2~4 nm的十六烷基膦酸包覆层, 使纳米镍粉由亲水性变为亲油性; 聚丙烯基复合材料中, 改性镍粉均匀分散; 复合材料的介电常数在镍填充量为40%时, 可以达到纯聚丙烯的近10倍.     

纳米金属粉对高氯酸铵热分解动力学的影响

The thermal decomposition characteristics of general ammonium perchlorate (g-AP) influenced by the addition of aluminum, nickel with different particle sizes (general and nano) are studied by TG and DSC. The results show that aluminum powders (both general and nano size) are nearly uninfluenced. Nano nickel powders have the greatest influence on the decomposition properties of g-AP among metal powders. Such accelerating effects of nanonickel powders are more apparent on the stage of high temperature decomposition than low temperature decomposition of g-AP and will be weakened with the decrease of the content of nanonickel. Nanonickel powders are also more effective than super fine nickel powders on accelerating the thermal decomposition of superfine AP (s-AP). The kinetic parameters of the thermal decomposition of s-AP and mixture of s-AP and nano nickel powders are obtained from the TG-DTG curves bythe integral method based on the Coats-Red fern equation. Nanonickel powders reduce the apparent activation energy of the thermal decomposition of s-AP from 157.9 kJ/mol to 134.9 kJ/mol. The most probable mechanism functions of the thermal decomposition reaction for s-AP and mixture of s-AP and nano nickel powders both belong to systems of Avrami-Erofeev equations. The mechanism of such accelerating effects has been discussed.     

溶液还原法制备球形超细镍粉

超细镍粉由于表面活性高、导电性和导热性好而被广泛应用于化学催化剂、烧结活化剂、导电浆料门等方面．目前，制备超细镍粉的方法主要有问：真空蒸馏冷凝法、机械粉碎法、电解法、羰基镍热分解法、浆化氢还原法和溶液还原法等．在这些方法中，溶液还原法的工艺简单，所得粉末纯度高，颗粒尺寸小且分布均匀[3]．法国的Figlarz等[4]用弱有机还原剂乙二醇还原粒径小干0．1μm的Ni（OH）2。超细粉末，引入AgNO3。作为成核剂后，制得了粒径＜1μm的超细镍粉，但这种方法需长时间高温回流反应，对原料要求苛刻，且采用有机分散介质成本较高，…     

Nanoparticle formation of poorly water-soluble drugs from ternary ground mixtures with PVP and SDS

Poorly water-soluble drugs N-5159, griseofulvin (GFV), glibenclamide (GBM) and nifedipine (NFP) were ground in a dry process with polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS). Different crystallinity behavior of each drug during grinding was shown in the ternary Drug/PVP/SDS system. However, when each ternary Drug/PVP/SDS ground mixture was added to distilled water, crystalline nanoparticles which were 200 nm or less in size were formed and had excellent stability. Zeta potential measurement suggested that the nanoparticles had a structure where SDS was adsorbed onto the particles that were formed by the adsorption of PVP on the surface of drug crystals. Stable existence of crystalline nanoparticles was attributable to the inhibition of aggregation caused by the adsorption of PVP and SDS on the surface of drug crystals. Furthermore, the electrostatic repulsion due to the negative charge of SDS on a shell of nanoparticles could be assumed to contribute to the stable dispersion.     

Surfactant-assisted polyol preparation of nickel powders with different morphologies

Sub-micrometer nickel powders of controlled size and morphology were produced by a surfactant-assisted polyol method, using ethylene glycol (EG) as solvent and reductant in the presence of sodium dodecyl sulfate (SDS) surfactant and NaOH. The resultant Ni powders were characterized by XRD, SEM, EDS, and FTIR. Spherical, hexagonal, and triangular fcc Ni powders from 0.30 to 0.60 μm were obtained in the presence of SDS; irregular spherical fcc Ni powders were obtained in its absence. The concentrations of SDS, NaOH and Ni(CH₃COO)₂·4H₂O greatly influence the product morphology and size.      

制备参数对ZrO2气凝胶超细粉织构和结构性质的影响 Ⅰ.水凝胶pH值

用超临界流体干燥（ＳＣＦＤ）法制备出大孔高比表面ＺｒＯ２气凝胶超细粉，详细考察了初始水凝胶ｐＨ值对ＺｒＯ２超细粉形貌、晶相组成、颗粒大小与分布、比表面积及孔结构等织构和结构性质的影响。在实验范围内，当水凝胶ｐＨ值为１０．３０时，所制得的ＺｒＯ２超细粉具有最大的比表面积和孔体积，最小的表观堆密度和平均粒径，颗粒分布均匀狭窄，颗粒间连接成三维网络构状态，较好地保持了凝胶原始织构。     

Effect of Polyvinylpyrrolidone on Separation Performance of Cellulose Acetate-Polysulfone Blend Membranes

Blend membranes comprising cellulose acetate and polysulfone (CA/PSf) were prepared through a solution casting method using a different concentration of polyvinylpyrrolidone (PVP) as the pore former. Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate structural properties of membranes. Membranes morphology and its thermal properties were characterized by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The strength of membranes was studied by mechanical stability. The effect of PVP concentration on separation performance of the prepared membranes was studied. The separation performance of prepared membranes was tested by using an aqueous solution of cadmium metal complexed with humic acid. The results showed that an increase in the PVP concentration in the cast film from 0 to 3 wt% increased the thermal stability, water content (%), pure water flux, and solute rejection. SEM results showed that the pore size decreased but the number of pores increased on an increase in the PVP concentration.     

Cu nanoparticles of low polydispersity synthesized by a double-template method and their stability

Cu nanoparticles of well-defined size and stability were synthesized with the aid of a double-template method. The templates consisted of sodium dodecyl sulfate (SDS) aggregates combined with and wrapped by poly(vinylpyrrolidone) (PVP) chains. Copper sulfate was reduced within the templates resulting in multicrystalline Cu nanoparticles. The size of the particles was uniform. They were capped by PVP–SDS complexes and the shape turned out to be non-spherical. PVP used in the experiments has an average molecular weight of 40,000. In this case, the particle dimensions were essentially determined by the chosen concentration of SDS in the reaction solution. No oxidation of the as-grown copper particles was detected even in the absence of inert gas protection during the synthesis process. When exposed to air at room temperature, Cu nanoparticles capped by PVP–SDS complexes showed much better resistance to oxidation than those without the capping agents. Furthermore, the steric and screening effect of the capping agents permitted the preparation of uniform colloidal dispersions stable over months. The material obtained by this double-template method was found to be very sensitive to the synthesis temperature. At synthesis temperatures above 40 °C, CuO instead of Cu was obtained.     

Ni-P-C复合材料的制备及其电催化产氢性能研究

通过化学镀技术制备了亚微米级的Ni-P镀层石墨粉复合粉体新材料(即Ni-PC).采用扫描电子显微镜、X-射线能谱仪、X-射线粉末衍射仪对Ni-P-C复合粉体分别进行表面形貌分析、表面成分分析和物相分析.通过对Ni-P-C材料电极进行电解水析氢、循环伏安和Tafel极化等电化学测试,研究对比了Ni-P-C(石墨)材料与试剂石墨粉体以及纯Ni电极的电化学催化产氢性能.结果表明:利用化学镀技术成功地在石墨粉体表面镀上了一层亚微米级且均匀、致密的非晶态Ni-P合金.Ni-P-C(石墨)复合电极材料析氢能力强,具有良好的电化学活性.