Studies on selective surface modification method and integration method for nanoparticles

对纳米颗粒进行适当的功能化处理，使其单层覆盖，可以极大地改变纳米颗粒的物理和化学性质，是这些材料应用的关键因素。如果我们能够很容易地将定量的有机化合物从纳米颗粒表面的期望区域移除，然后在这些空白区域包裹其他化合物而不使纳米颗粒变形，我们就可以利用修饰后的颗粒来构建特殊应用的靶向结构。在本工作中，利用类朗缪尔技术获得了DODAC包覆的Au纳米粒子的二维组装，然后在Au粒子的另一半表面覆盖HFOTAI。将改性后的低聚物制成不同的溶剂。低聚物形成的重要因素是纳米粒子与溶剂之间的亲和力以及氢化氢碳链和/或氟碳链之间的相互作用。进一步，用紫外光/臭氧对DODAC包覆的金纳米粒子进行处理，制得半包覆DODAC的金纳米粒子。经处理后的纳米粒子的总频谱图表明，Au纳米粒子表面失去了中心对称结构，即受保护的表面活性物质分子分布不对称。这一结果表明有机化合物的分解是从纳米颗粒的上部开始的。进一步，将得到的半表面活性剂包覆的金纳米粒子用作低聚物结构的构建块。当底物上的金纳米粒子在甲苯中超声处理时，以60%的高产率得到了齐聚物。由此发现，在纳米颗粒表面引入两种被覆盖的有机化合物有助于制备纳米颗粒的低聚物结构。

Monolayer coverage of nanoparticles for appropriate functionalization, which can drastically change the physical and chemical properties of the nanoparticles, is a key factor in the application of these materials. If we are able to easily remove quantitative organic compounds from desired regions on a nanoparticles surface and then coat other compounds at these vacant regions without deformation of nanoparticles, we could construct target structures for special applications by the use of the modified particles. In the present work, 2D assembly of half DODAC-covered Au nanoparticles was obtained by the Langmuir-like technique, and then the other half-surface of Au particles was covered with HFOTAI. Oligomers were made into various solvents by using the modified particles. The important factor for oligomer formation was found to be the affinity between nanoparticles and solvents and the interaction between hydrocaobon chains and/or fluocarbon chains. Further, DODAC-covered Au nanoparticles were treated by UV/ozone to make half DODAC-covered particles. The sum frequency generation spectra of the treated nanoparticles indicated the loss of the centrosymmetric structure at the surface of Au nanoparticle, i.e., asymmetric distribution of protected surfactant molecule. This result shows that the decomposition of the organic compound starts from the upper part of the nanoparticles. Further, the half surfactant-covered Au nanoparticles obtained were employed as building blocks of oligomer structure. When the Au nanoparticles on a substrate were sonicated in toluene, oligomers were obtained in a high yield of 60%. Thus, it was found that the introduction of two covered-organic compounds to the nanoparticle surface is useful for fabricating the oligomer structures of nanoparticles.