金属纳米颗粒电磁/热极性驱动分析与吸收特性实验研究

【作者】 时光；

【导师】 王皓；

【作者基本信息】 电子科技大学 ， 机械电子工程， 2011， 硕士

【摘要】 近年来,金属纳米壳球体的制备和应用研究已经成为材料科学中十分活跃的领域,这类材料因为具有很高的可调控性和独特的光学性质而受到研究者的青睐。金属纳米壳球体在药物缓释、免疫分析、癌症治疗、成像以及生物传感等很多领域有着广阔的应用前景。随着纳米材料制备技术的发展,许多研究组已经依据不同方法制备出了各种尺寸的球状、椭球状、棒状、三角状、棱柱体等形状的金或银纳米颗粒。本文介绍了金纳米壳球体消光性的产生机理,金的Drude模型、Mie散射理论,并对文中要用到软件的算法进行了介绍。本文提出了一种具有非对称球壳的金纳米壳球体,介绍了该粒子的材料和结构。利用有限积分法针对单个非对称粒子明确了其入射电磁波入射方向、极化方向、粒子椭球形金冠厚度等参数对其电磁极性分布的影响,为选定实际需要的粒子与入射波组合提供依据。而且针对电磁极性的最优组合,分析了单个粒子的热极性,结果表明热极性分布与电磁极性分布有很大关系,电场能量大的位置也就是热量大的位置,增强粒子的电磁极性,热极性也会随之增大。并对多个非对称金壳纳米粒子组合模式进行了分析,结果表明组合模式可以对电场强度的峰值大小和位置进行调节。本文针对具有热极性的粒子,讨论了流体初速度、粒子热源朝向、流道热源位置等对流道内流体运动情况的影响。结果表明粒子热源朝向对运动情况基本没有影响;流道添加热源会改变流体速度的分布;流道和流体同时添加热源后,流体大小速度的分布以粒子为界线,在流经粒子前较无大速度出现。压力差比单纯的流道加热源情况要大,对粒子的引导作用也就更强。本文使用胶体还原法和分子自组装法制备了以二氧化硅为核金为壳的核壳结构的纳米粒子,并使用扫描电子显微镜和紫外可见光分光光度计对其进行了表征,实验得到的金纳米壳球体形状均匀、粒径均一,粒径大约为160nm,也就是壳厚30nm,吸收峰值在540nm左右。并通过改变实验中试剂的浓度和用量,改变了粒子的核壳比。更多还原

【Abstract】 In recent years, the research on the fabrication and application of metal nanoshell has become very active in the field of material science. Its high tenability and unique optical properties have attracted much attention of scientists. Metal nanoshells display a wide range of application prospect in the field of drug delivery, immunoassay, cancer treatment, imaging, biological sensor and etc. With the developing of fabrication technique, a variety size of spherical, ellipsoidal, rod-like, triangular-shaped, prism-shaped gold and silver nanoparticles have been fabricated based on different methods.In this paper, the mechanism of extinction property is discussed, and the drude model of gold, Mie scattering theory and algorithms used in this paper are introduced.A kind of nanoparticle consisting of asymmetrical metal nanoshell and polystyrene core are put forward. With the use of finitude integration technique, the influence of incident direction, polarization direction, the thickness of ellipsoidal shape gold coronal on electromagnetic polarity of single asymmetrical nanoshell are analyzed, which underlie the selection of incident wave and particles properties. For the combination which has the best electromagnetic polarity, its thermal polarity is also calculated. The result shows that the distributions of thermal polarity are closely related to that of electromagnetic polarity, the position where a lot of electric field energy exists also has more heat. So the thermal polarity can be enhanced by strengthening electromagnetic polarity. Some preliminary investigations on combining cluster mode are also carried out for observing the changes of the polarity in multi particles condition. And it indicates that the position of peak of electric field could be adjusted with combining mode, providing a new possibility to control the behavior of particles.What would fluidic initial velocity, particle heat source orientation and location of flow channel heat source effect on the fluid motion is discussed. It turns out that particle heat source orientation has nothing to do with fluid motion. When flow channel heat source is added, the distribution of fluid velocity changes. If particle heat source and flow channel heat source are added at the same time, there would be a clearly boundary of fast and slow velocity at the position of nanoparticle. The fast velocities show up at the half channel near the exit, and slow velocities the other half one. The pressure difference is bigger than that of only particle heat source and flow channel heat source, so is the driving power.A kind of nanoshell consisting of gold shell and silica core are fabricated using colloid reduction method and molecular self-assembly method. And use SEM, ultraviolet visible spectrophotometer to analyses the characterization. It proves that the shape of nanoshells fabricated here is uniform, and the size is uniformity. The diameter of nanoshell is about 160nm, which means the thickness of gold shell is 30nm. The absorption peak is around 540nm. And at the end of experiment, the core-shell ratio is altered by changing the concentration and amount of reagent.更多还原