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1.
PbSO4纳米片晶的微乳法制备与自组装   总被引:10,自引:0,他引:10  
采用水(溶液)/Triton X-100/环己烷/正戊醇微乳体系,制备片状PbSO4纳米晶,并利用TEM对产物进行了表征。考察并初步讨论了微乳体系中几种因素对其尺寸及形貌的影响以及PbSO4纳米晶在微也液中的生长和自组装机制。  相似文献   

2.
本文以氯化钙和氨水的混合溶液为水相,聚氧乙烯辛基苯酚醚-10(OP-10)为表面活性剂,正辛醇为助表面活性剂,环己烷为油相配制了反相微乳液。并通过向其中通入CO 2气体制备微/纳米碳酸钙,得到了铁饼状的微米碳酸钙。采用扫描电子显微镜(SEM),X射线粉末衍射(XRD)和傅里叶变换红外光谱(FTIR)表征了微米碳酸钙的形貌和晶型结构。初步探讨了铁饼状微米碳酸钙的形成机理。  相似文献   

3.
采用聚乙二醇辛基苯基醚(OP)/正戊醇/环己烷/水溶液所形成的W/O型微乳液中的水核作软模板,合成了不同形貌如球形、立方体形、纺锤形、梭形和棒形的PbS纳米粒子。运用透射电子显微镜(TEM)对产物的形貌进行了表征。考察了W/O型微乳液中水与表面活性剂的物质的量的比(ω0)、反应物浓度和陈化时间等条件对产物形貌的影响。对不同形貌PbS纳米粒子的形成机理进行了探讨。  相似文献   

4.
反相胶束法控制合成不同形貌半导体Ag_2S纳米晶   总被引:7,自引:0,他引:7  
周海成  庄京  王训  徐建  李亚栋 《化学学报》2003,61(3):372-375
采用水(溶液)/Triton X-100/环已烷/正戊醇反相胶束体系,制备出不 同形貌的Ag_2S纳米晶-100nm、长度为2.0-3.5μm、长径比为20-70的纯相幅S对合 成Ag_2S的形貌和尺寸的影响进行了研究,获得了控制合成不同形貌Ag_2S纳米晶的 反应条件.显微镜分析进行了表征.  相似文献   

5.
新型球形纳米空心SiO2的模板合成方法研究   总被引:5,自引:0,他引:5  
王洁欣  文利雄  和平  陈建峰 《化学学报》2005,63(14):1298-1302,i003
以纳米碳酸钙颗粒为新颖的无机模板剂,硅酸钠为无机硅源,通过溶胶-凝胶法形成CaCO3/SiO2的核壳结构;随后通过高温煅烧、酸溶和干燥处理,合成出了具有高比表面积的球形纳米空心二氧化硅粒子.然后,分别采用TEM,SEM,EDS,XRD,FTIR和TG等测试手段对样品进行了分析和表征,并考察了不同合成条件,如反应温度、反应pH值、煅烧温度和包覆反应时SiO2/CaCO3的配比对纳米空心二氧化硅粒子的比表面积变化.实验结果表明:较高的反应温度如60~80℃,pn值9左右、SiO2包覆量为碳酸钙质量的10%,以及煅烧温度为700℃,有利于形成空心形貌较好、比表面较大的球形纳米空心二氧化硅。  相似文献   

6.
铁络合物/八面沸石催化剂中沸石主体的纳米效应   总被引:4,自引:0,他引:4  
 采用自由配体法制备了Fephen/nano-X和Fephen/nano-Y两种\r\n不同粒度的Fephen/八面沸石纳米复合材料(简称为Fephen/FAU),\r\n并采用X射线衍射、傅里叶变换红外光谱、漫反射紫外-可见光谱、热\r\n重-差热分析和催化反应等手段对其进行了表征.研究结果发现,采用\r\n纳米沸石作主体是自由配体法制备金属络合物/分子筛复合材料中提高\r\n络合物负载量的有效方法.催化反应结果表明,与普通粒度的Fephen/\r\nY复合材料相比,两种不同粒度的Fephen/nano-X和Fephen/nano-Y\r\n纳米复合材料对环己烷氧化反应的催化活性有很大的提高.由于两种纳\r\n米沸石主体的差异,两种纳米复合材料的催化性能也明显不同,不仅对\r\n环己烷的转化能力不同,对氧化产物的选择性也不同.  相似文献   

7.
近年来,纳米材料由于具有诸多奇特效应而备受关注。将无机纳米粒子与高分子水凝胶复合,可以很大程度地改善传统水凝胶的使用性能,因而成为近年来水凝胶研究领域的热点课题之一。纳米材料的形貌多姿多彩,相同材质不同形貌的纳米材料对复合材料性能有着不同的作用。本文从不同形貌(层状、管状及球状等)的无机纳米材料对复合水凝胶性能影响出发,以无机纳米粒子的形貌分类,综述了当前无机纳米复合水凝胶的研究进展。  相似文献   

8.
采用不同质量比的柠檬酸作为晶型控制剂制备碳酸钙,研究了在气相扩散体系中柠檬酸对所制备的碳酸钙微晶的粒度、形貌的影响.结果表明,随着柠檬酸浓度的增大,碳酸钙在溶液中结晶成为纳米小单晶体的二次聚集体,其晶粒度逐步变小,其形态呈现从疏松结构的球体、密实球体、花生状颗粒、大长径比针状到密集针状球体有规律的转变,晶型从0.24%和0.72%的球霰石到更大浓度的方解石.通过对柠檬酸在溶液中的聚集状态和柠檬酸分子与碳酸钙微晶的相互作用初步解释了柠檬酸对碳酸钙微晶形貌控制作用的机理.  相似文献   

9.
反相微乳液法制备棒状羟基磷灰石纳米粒子   总被引:7,自引:0,他引:7  
在(Tritonx-100 Tween 80),环己烷,(正己醇 正丁醇),0.5mol/L Ca(NO3)2水溶液反相微乳液体系中,采用滴加0.3mol/L(NH4)2HPO4水溶液的加料方式成功制备出直径在20~25nm,长度在28~64nm的棒状羟基磷灰石纳米粒子。通过对(Triton X-100 Tween 80),环己烷,(正己醇 正丁醇)/0.5mol/L Ca(NO3)2水溶液三元相图及水溶液反应机理的分析,确定了最佳反相微乳液组成;研究了HLB值和表面活性剂用量对羟基磷灰石颗粒大小的影响。实验结果表明,最佳反相微乳液组成为:47.6(wt)%的环己烷、37.4(wt)%的表面活性剂和助表面活性剂、15(wt)%0.5mol/L的Ca(NO3)2水溶液。  相似文献   

10.
聚丙烯/PMMA/CaCO3纳米复合材料的制备、结构与力学性能   总被引:9,自引:0,他引:9  
王平华  严满清 《应用化学》2003,20(11):1066-0
分别将经不同表面处理的纳米碳酸钙粒子与聚合物PP共混,制备PP/CaCO3和PP/PMMA/CaCO3纳米复合材料。用TEM观察了表面处理后纳米粒子的粒径与分散情况,发现复合粒子分散较均匀。用DSC与WAXD研究了复合材料的结晶行为,发现原位聚合制备的PMMA/CaCO3纳米复合粒子与PP共混后,PP有异相成核作用,出现了不稳定的PPβ晶型。PP/PMMA/CaCO3纳米复合材料力学性能有大幅度的提高。  相似文献   

11.
Novel rod-shaped calcite crystals are formed by precipitation from cetyltrimethylammonium bromide (CTAB)/1-pentanol/cyclohexane microemulsions containing calcium chloride and ammonium carbonate. The calcium carbonate initially precipitates as hexagon-shaped vaterite crystals. The vaterite crystals transform to unusual rod-shaped calcite crystals over several days. The rod-shaped calcite crystals are prismatic, with the longest crystal axis displaying (110) crystal faces. A possible mechanism of crystal growth is discussed. The elongated shape of the crystals facilitates the assembly into hierarchical structures and can allow the crystals to be used as templates for fabricating advanced materials.  相似文献   

12.
The electrochemical behavior of an anthraquinone (AQ) was studied in aqueous solutions at a glassy carbon electrode, using the sodium salt of anthraquinone-2-sulfonic acid (AQS), by employing cyclic voltammetry. AQ undergoes a two-electron reduction in aqueous media. The electrochemical behavior of AQ was also investigated in micelles, reverse micelles (CTAB/1-butanol/water), and microemulsions (CTAB/1-butanol/water/cyclohexane) of cetyltrimethylammonium bromide (CTAB). The electrode reactions of AQ in reverse micelles and microemulsions are nearly reversible at low oil (cyclohexane) content. However, at higher oil content, the reversibility is gradually lost. In the case of reverse micelles, the reduction current, as well as the reduction potential, of AQ depend on the transition from a micellar solution to a stable solution of reverse micelles that occurs with added 1-butanol. In microemulsions, the change in cyclohexane content was found to cause a linear increase in the peak current for AQ reduction as well as a linear decrease in the corresponding reduction potential. As the cyclohexane content is increased, the o/w microemulsions dominated by micelles undergo a transition to a w/o microemulsion dominated by reverse micelles, which causes changes in the electrochemical behavior.  相似文献   

13.
阴离子与非离子表面活性剂复配体系反胶团的电导研究   总被引:2,自引:0,他引:2  
在SDS/Tween60/正己醇/环己烷/水形成的反胶团复配体系中,电导率(κ)与水和表面活性剂的摩尔比(W0)关系曲线上存在最大值,随着复配体系中SDS的摩尔分数(xSDS)增大,最大增溶水量(W0,max)向W0值更大的方向移动.xSDS≤0.5时,随着xSDS的增大,W0,max所对应的电导率值增大;xSDS≥0.5时,其电导率值减小.在AOT/Tween60/环己烷/水体系中,出现了与SDS/Tween60/正己醇/正己烷/水体系类似的现象,但W0,max所对应的电导率值,随着xAOT的增大而增大,不会出现极大值,两者的差异主要是由于助表面活性剂醇的影响.在SDS/TritionX-100/正己醇/环己烷/水体系中也印证了该结论.  相似文献   

14.
徐晟  彭卿 《中国化学》2005,23(9):1135-1138
CdS microspheres were prepared by a hydrothermal microemulsion method in cyclohexane/Triton X-100/pentanol/water at 180℃. The as-prepared samples were characterized by X-ray diffraction analysis, transmission electron microscopy, electron diffraction, energy diffraction X-ray analysis and photoluminescence spectra. It was found that CdS microspheres with diameter of 1.5-2.5μm were aggregated by nanocrystals. The formation mechanism was proposed.  相似文献   

15.
Size-controlled, low-dispersed calcium carbonate microparticles were synthesized in the presence of the amphiphilic block copolymer polystyrene-b-poly(acrylic acid) (PS-b-PAA) by modulating the concentration of block copolymer in the reactive system. This type of hybrid microparticles have acid-resistant properties. By investigating the aggregation behaviors of PS-b-PAA micelles by transmission electron microscopy (TEM), the mechanism of hybrid calcium carbonate formation illustrated that the block copolymer served not only as "pseudonuclei" for the growth of calcium carbonate nanocrystals, but also forms the supramicelle congeries, a spherical framework, as templates for calcium carbonate nanocrystal growth into hybrid CaCO(3) particles. Moreover, this pilot study shows that the hybrid microparticle is a novel candidate as a template for fabricating multilayer polyelectrolyte capsules, in which the block copolymer is retained within the capsule interior after core removal under soft conditions. This not only facilitates the encapsulation of special materials, but also provides "micelles-enhanced" polyelectrolyte capsules.  相似文献   

16.
The size-controllable and highly monodispersed cuboidal barium strontium titanate (BST) nanocrystals have been successfully synthesized through a glycothermal process with no mineralizers but oleic acid as growth-directing agent. The synthesized BST nanocrystals under different glycothermal conditions were structurally characterized by XRD, IR, FESEM, TEM and HRTEM and investigated with respect to the effects of key influencing factors including the amount of oleic acid, duration of glycothermal process and 1,4-butanediol/water volume ratio in the reaction media on the formation of BST nanocrystals and their size and morphological evolution. It has been found that the oleic acid incorporated into the glycothermal system plays a decisive role in promoting the formation of cuboidal nanocrystals. It allows the BST nanocrystals to form via a nucleation-growth mechanism instead of in situ reactions and the selective chemical adsorption of oleic acid molecules on the facets with lower plane indices of newly-built BST nuclei directs them to grow into uniform cuboidal BST nanocrystals. The duration of glycothermal reactions and the polarity of reaction media can remarkably affect the dynamic process of the formation of BST nanocrystals. These regularly-shaped and highly monodispersed nanocrystals show a spontaneity of self-assembling into 2D ordered architectures when they were dispersed in organic solvents like cyclohexane and droped onto a hydrophobic surface of substrates, which creates a chance for the ferroelectric oxide nanocrystals to self-assemble into nanoscale electronic devices.  相似文献   

17.
1,1-二氨基-2,2-二硝基乙烯的合成研究进展   总被引:1,自引:0,他引:1  
龙宗昆 《广州化学》2013,(4):71-78,26
1,1-二氨基-2,2-二硝基乙烯(FOX-7)是一种低感度高能量的新型含能材料.现有的1,1-二氨基-2,2-二硝基乙烯的合成包括以2-甲基咪唑、盐酸乙脒与乙二酸二乙酯、2-甲基-4,6-二羟基嘧啶为前体的三条合成路线.使用硫酸/硝酸体系硝化2-甲基-4,6-二羟基嘧啶可得到2-二硝基亚甲基-5,5-二硝基嘧啶-4,6-二酮,然后水解可得到FOX-7,正相硅胶薄层色谱可对该反应进行监测.使用曲拉通X-100/正己烷体系的反相微乳法可制备FOX-7球形纳米晶;FOX-7球形纳米晶具有良好的应用前景,对其合成工艺与路线进行探索和研究具有一定的意义.  相似文献   

18.
王农  孟庆络 《应用化学》2015,32(5):597-603
绘制了一系列辛烷基酚聚氧乙烯醚(OP-10)+正辛醇+环己烷+水(或CaCl2水溶液)拟三元体系相图,分别研究了助表面活性剂正辛醇的添加比例和CaCl2水溶液的浓度对微乳区域的影响,发现在OP-10+正辛醇+环己烷+水拟三元体系相图中,随着正辛醇/OP-10的质量比逐渐增大,微乳区的面积逐渐增大,当正辛醇/OP-10质量比为1:2.5时微乳区的面积最大,之后微乳区面积随着其质量比的增大而减小,表明适量地加入助表面活性剂正辛醇有利于微乳区的形成;但过多地增加正辛醇的量反而不利于微乳相的形成。 确定正辛醇/OP-10的质量比为1:2.5,改变CaCl2的浓度,发现OP-10+正辛醇+环己烷+CaCl2水溶液拟三元体系相图中,CaCl2浓度为0.1 mol/L时微乳区面积最大。分别配制总浓度为0.1 mol/L的5种不同摩尔比的Ca2+/Ba2+微乳液,并与等摩尔的碳酸钠水溶液反应制备共沉淀碳酸盐,使用扫描电子显微镜(SEM)对所制备样品进行表征分析,发现当微乳液为钙离子盐时,主要形成大的立方形颗粒;掺入钡离子,Ca2+和Ba2+摩尔比为3:1、1:1和1:3时,形成的沉淀分别为四棱锥形、球形和玉米棒形;当微乳液为钡离子盐时,沉淀主要为不规则多面体。  相似文献   

19.
Mitchell JW  Ganges R 《Talanta》1974,21(7):735-743
Traces of manganese have been determined quantitatively by neutron activation and substoichiometric extraction with a mixture of hexafluoroacetylacetone and tri-n-octylphosphine oxide in cyclohexane. When applied to calcium carbonate, the specific example cited here, it was necessary to make a prior separation of manganese by extraction with a mixture of pyrrolidinedithiocarbamic acid and diethylammonium dithiocarbamate in chloroform to avoid interferences from calcium. Replicate determination of sub-ppm amounts of manganese in a sample of calcium carbonate showed a relative standard deviation of 6.9% while measurements on a solution prepared by dissolving a refined-silicon standard, SRM 57, indicated a relative error of 6.0%.  相似文献   

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