烷硫醇包覆金纳米棒的超瑞利散射研究

发布时间：2018-01-11 12:42

本文关键词：烷硫醇包覆金纳米棒的超瑞利散射研究　出处：《武汉大学》2017年硕士论文　论文类型：学位论文

【摘要】：金纳米棒具有独特的光学性质以及很好的生物相容性,其在光学传感、生物分子成像、医学诊断和肿瘤治疗等领域都有很广阔的应用前景。但是金纳米棒的高比表面能又使其不够稳定,易于发生集聚。为了有效利用金纳米棒,须对其表面进行修饰与包覆。好的包覆层既可以增强其稳定性,又能增加新功能,其中的硫醇衍生物包覆层可以与金纳米微粒形成稳定的金-硫配位键,在生物检测中具有很高的灵敏度,因而被广泛研究。超瑞利散射(HRS)技术是研究材料二阶非线性性质的常用方法之一,它广泛地应用于液体中纳米微粒和分子的检测。该论文根据HRS理论,站在非线性光学的视角对烷硫醇包覆的金纳米棒展开研究。该工作基于银离子辅助种子生长法分别合成了具有十六烷基三甲基溴化铵(CTAB)、十二烷基硫醇和十八烷基硫醇包覆层的金纳米棒,并采用HRS测试技术以及透射电镜、紫外-可见吸收光谱对它们的特性进行了研究;该工作还模拟了棒状分子中心对称型集聚的超瑞利散射响应,对实验结果进行了对比分析。结果表明CTAB包覆层增强了一阶超极化率,而烷硫醇包覆层削弱了一阶超极化率;相对于短链烷基的烷硫醇包覆层,具有长链烷基的烷硫醇包覆层能更有效的地阻止棒粒的聚集,但是具有不同长度烷基链的烷硫醇包覆层对一阶超级化率的削弱程度却是相同的。通过分析偏振超瑞利散射的强度响应可以计算出"去极化率"和"权重参数",实验和模拟结果都表明对于尺寸较小(远小于入射光波长的十分之一)且表面存在缺陷的球形纳米微粒或者是长链分子,电偶极子作用占主导,去极化率的值约为0.2,权重参数的值约为0;当纳米微粒的表面缺陷得到补偿或者微粒尺寸增加,电四(多)极子作用的比重增加,去极化率和权重参数的值都将增大。超瑞利散射方法在探查纳米颗粒的表面缺陷和分子的聚集行为方面有很高的灵敏度。
[Abstract]:Gold nanorods have unique optical properties and good biocompatibility, in optical sensing, molecular imaging, medical diagnosis and treatment of cancer and other fields have a very broad application prospect. But the high surface area of gold nanorods can make it is not stable enough, prone to agglomeration. In order to make effective use of gold nanorods, must be carried out modification and coating on its surface. The coating layer can enhance its stability, but also can increase the new function, the thiol derivative coating layer can form stable gold sulfur coordination bonds with gold nanoparticles, has very high sensitivity in biological detection, so it has been widely studied. The hyper Rayleigh scattering (HRS) technology is one of the commonly used methods of materials of two order nonlinear properties, it is widely used in the detection of liquid nano particles and molecules. On the basis of HRS theory, nonlinear optical standing in the angle of view to the alkythio Study on alcohol coated gold nanorods. Silver ion assisted seed growth method based on the work were synthesized with sixteen alkyl three methyl bromide (CTAB), twelve and eighteen alkyl thiol alkyl thiol coated gold nanorods, and using HRS test and transmission electron microscopy, UV Vis absorption spectra of their properties studied the work; simulated the hyper Rayleigh scattering response center symmetric compact molecules, the experimental results were analyzed. The results show that the CTAB coating enhanced hyperpolarability, while the alkanethiolate coated layer weakens hyperpolarability; compared with short chain alkyl alkanethiolate coated layer, with long alkyl chain alkanethiolate coated layer can effectively prevent particle rod aggregation, but with different length of alkyl chain alkanethiolate coated layer on the first hyperpolarizability of the weakening degree is the same By the analysis of polarization hyper Rayleigh scattering intensity response can be calculated "depolarization ratio" and "weight parameters, experimental and simulation results show that for small size (much less than the wavelength of the incident light 1/10) spherical nanoparticles and surface defects or long chain molecules, the electric dipole effect dominates, to the polarization rate is about 0.2, the value of parameters is about 0; when the surface defects of nanometer particle are compensated or particle size increases, four (multiple) pole effect proportion increase, the depolarization ratio and weight parameter value will increase. The hyper Rayleigh scattering method has very high sensitivity in the aggregation behavior of surface defects and molecular probe nano particles.

【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O614.123;TB383.1

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