共查询到19条相似文献,搜索用时 78 毫秒
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以乳液聚合法制备的平均粒径1.2~1.5 μm单分散聚苯乙烯(PS)微球为核,经过超声敏化、化学镀、还原等过程制备了PS/Ag核壳结构复合微球。采用透射电镜、X射线衍射、红外光谱、紫外可见光谱对其形貌、物相、结构与光学性质进行了表征与分析。结果表明:PS/Ag复合微球粒径相对均一;通过多次敏化、控制二次银氨溶液浓度(0.002~0.006 mol/L),可实现对纳米银壳层厚度的调控;纳米银壳层沉积生长过程中,随着PS微球表面银粒子的增多、增大,复合微球的光学等离子体共振吸收峰产生显著的展宽与红移。 相似文献
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采用超声化学沉积法制备了ZnS:Mn2+/聚苯乙烯核壳结构和ZnS:Mn2+空心球.产物分别用透射电镜、X射线衍射仪和光致发光谱进行了表征.透射电镜结果表明,在聚苯乙烯胶体微球表面覆盖了平均尺寸为9nm的ZnS:Mn2+纳米颗粒,X射线衍射结果进一步验证了这个结论.将核壳粒子在500℃灼烧除去PS核后,可以得到空心的ZnS:Mn2+微球,Mn2+的发射谱的峰位在540nm,与体相材料相比,蓝移了45nm,这可能是由于壳层结构引起Mn-O八面体畸变,进而导致能带结构变化引起的. 相似文献
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纳米 Au 球壳材料的制备及其近红外光热转换性质 总被引:2,自引:0,他引:2
报道了一种采用湿化学法,以Ag纳米球为模板合成纳米Au球壳水溶胶的新方法,并对这种材料的光热转换性质进行了研究。TEM分析表明,Au纳米颗粒呈球壳结构,粒径约为20nm,粒径分布比较均匀,无明显硬团聚体存在。随着氯金酸加入量的增加,Au球壳的吸收峰位置从可见区(-400nm)逐渐红移至近红外区(-800nm)。测量了不同浓度的Au球壳水溶胶经近红外激光照射后的温度变化。结果表明,经1.9W/mm^2的808nm近红外光照射10min,温度最高升高了5.5℃。由于800—1200nm是人体组织的透射窗口,肿瘤细胞在42℃左右即可被杀死,这种纳米Au球壳材料有望在利用光热转换的红外热疗中得到应用,并有可能利用光动力实现药物释放。 相似文献
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采用同步辐射能量色散X射线衍射(EDEX)技术和金刚石对顶砧高压装置,对纳米硫化锌球壳进行了原位高压X射线衍射实验。最高压力达33.3 GPa。常压下纳米硫化锌球壳为纤锌矿结构和闪锌矿结构共存的混相结构。压力达到11.2 GPa时,纳米硫化锌空心球中的纤锌矿结构全部转变为闪锌矿结构。压力达到16.0 GPa时,发生了由闪锌矿结构向岩盐矿结构的相变,在17.5 GPa和21.0 GPa时分别出现未知峰,33.3 GPa时基本完全转变为岩盐矿结构。两个相变均为可逆相变。 相似文献
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Co-P-coated nickel hollow spheres (NHSs) were prepared by electroless plating technology. The morphology and component content of Co-P coating varies with the change of sodium citrate concentration in elctroless plating solution. And as phosphorus content increases in coatings, resulting in smaller grain, coercivity of microspheres decreases. The microwave absorption properties of spheres-wax composite were investigated in the range of 2-18 GHz. Both permittivity and permeability increase with an increase of cobalt content in coatings. For composite layer, a minimal reflection loss (RL, −36.9 dB) of was predicted at 8.1 GHz with a thickness of 3 mm. 相似文献
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Silver porous hollow spheres (SPHS) were fabricated via ultrasonic spray pyrolysis of aqueous solutions containing AgNO3 and glucose. In the hot spherical liquid droplets, glucose, as reducing agent, reacted with Ag+ to form Ag nanoparticles, which subsequently moved to the periphery of the hot liquid droplets to form Ag nanoparticles-glucose hybrid shell. With the temperature further increased, aforementioned Ag nanoparticles melted to form Ag skeleton decorated with unreacted glucose, which converted to SPHS via dissolving unreacted glucose in water. Due to their porous hollow structures, SPHS exhibited a wide Vis-NIR adsorption in the range of 400-1100 nm. 相似文献
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The hollow structural submicrometer-sized nickel spheres were successfully fabricated by the autocatalytic reduction method. Because of the metallic and ferromagnetic behaviour of the nickel spheres, the low-density microspheres could obtain high dielectric constant and magnetic loss in microwave frequencies. The abrupt variation of the real part and the sharp peaks of the imaginary part of permittivity and permeability were observed for the micrometer-sized and nanometer-sized nickel hollow spheres. Reflection loss less than −25 dB were predicted over 11 GHz with a thickness of 1.5–2.0 mm. 相似文献
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《Current Applied Physics》2020,20(1):178-185
Hollow Fe-doped TiO2 spheres with various Fe dopant concentrations, 0.25, 0.50 and 1.0 wt%, were synthesized via a hydrothermal method using carbon spheres as templates. The prepared samples were calcined in air at temperatures of 500 and 550 °C for 3 h and characterized using XRD, SEM, TEM, SAED, EDX, XPS and UV–vis spectroscopy. The analytical results showed that the presence of a very low concentration of Fe3+ incorporated into hollow nanoporous TiO2 spheres inhibited the growth of nanocrystals as well as the anatase to rutile phase transformation inside the anatase TiO2 lattice. Doping with 1.0 wt% Fe3+ resulted in a reduction of the TiO2 sphere diameter from 205.71 ± 25.29 nm to 68.70 ± 7.07 nm. The optical energy gap of the samples was determined from UV–Vis absorption spectra. The results showed that the absorption edge of TiO2@Fe was shifted toward the visible light region with increased Fe content. 相似文献
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采用红外显微图像技术对单层掺硫空心微球上出现的不均匀结构进行了表征分析,证明了不均匀结构的产生来源于掺硫剂PSS(聚苯乙烯磺酸钠)。同时对PSS的成膜性能进行了研究,并使用红外显微图像技术和偏光显微镜对PSS平面薄膜进行表征,结果表明,掺硫剂PSS成膜性能较差,薄膜表面存在分子有序化聚集体和结晶现象。热处理结果显示PSS薄膜与聚苯乙烯薄膜热性能相差较大,易产生脆性开裂并从聚苯乙烯表面剥离,说明PSS不适合于高掺硫量微球制备。 相似文献
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采用微流体注射成型技术,以邻苯二甲酸二丁酯为内外油相,间苯二酚/甲醛(RF)溶液为水相,经过溶胶-凝胶、溶剂交换、超临界干燥等过程制备出了RF气凝胶空心微球。分别采用红外光谱、光学显微镜、X光显微分析、透射电镜(TEM)、N2吸附-脱附,对RF空心微球成分、形貌、孔径、直径分布等进行表征。结果表明:RF为单层空心微球,具有典型的气凝胶多孔结构,由粒径为10 nm左右、且粒度分布较为均匀的纳米粒子构成,平均孔径为20 nm左右,球形度和同心度大于95%,微球直径分布在550~750 mm,最大可达到800 mm,达到了快点火靶的基本要求。 相似文献
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Preparation of titania hollow spheres by catalyst-free hydrothermal method and their high thermal stabilities 总被引:1,自引:0,他引:1
Xuan Feng 《Applied Surface Science》2010,257(3):756-2691
TiO2 hollow spheres have been prepared by hydrothermal method using carbon spheres as hard templates based on template-directed deposition and calcination in order to remove templates. The morphology and structure of samples were systematically characterized by using various techniques, including XRD, zeta analyzer, SEM, TEM, DRS and FTIR. In this approach, the anatase phase was retained for temperatures up to 900 °C. Moreover, negative charged titania is deposited onto the negative charged surface of carbon spheres, which is proved by nanoparticle size analyzer. Therefore, a possible formation mechanism of TiO2 hollow spheres was proposed. TiO2 hollow spheres calcined at 550 °C exhibited the superior photocatalytic activity for the degradation of Rhodamine B, 2.9 times greater than that of Degussa P25. Furthermore, thermal stability of TiO2 hollow spheres was examined. Fortunately, we found that hollow structures could still be visible distinctly after calcining at 900 °C. 相似文献
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以十六烷基三甲基溴化胺(CTAB)为软模板剂,采用种子法制备出三角形银纳米粒子,应用透射电镜、能量散射X射线谱仪、紫外 可见分光光度计研究了粒子的性能。结果表明:所得三角形银纳米粒子是面心立方单晶,边长随着种子加入量的减少而递增,可在20~100 nm范围内调节;CTAB以薄膜形式包覆于粒子表面阻止其氧化,粒子胶体的吸收光谱呈现典型的三角形粒子吸收峰。用扫描电镜观测到粒子在硅片上自组装成一定的2维阵列结构。 相似文献