The Study On Surface Modification And Assembly-Disassembly Properties Of Gold Nanoparticles

In this thesis, gold nanoparticles, as the research object, were prepared by the Frens method which is a HAu Cl4-citrate Reduction Method. Using a “seed” method, gold nanorods colloids with SPR of 780 nm were prepared. And new ligands with adenine、thymine or carbon chain were synthesis independently. Then the assembly or disassembly behavior of gold nanoparticles modified new ligand was studied.Chapter 2, the result in researching the gold nanoparticles modified A-C12-SH or T-C12-SH was that concentration of ligands solution affected the aggregation of modified spherical gold nanoparticles. The acidic conditions of p H < 6 induced spherical gold nanoparticles with A-C12-SH aggregation; and spherical gold nanoparticles with T-C12-SH clusters in the strong acid solution of p H < 4. The independent assembly behavior was happened between the nanoparticles modified A-C12-SH and T-C12-SH, and controlling the assembly and disassembly behavior was by changing acid-base properties of the solution which content different spherical gold nanoparticles.Chapter 3, we require gold nanorod colloids with SPR of 780 nm by adding 150 ul Ag NO3 to the growth solution, and the gold nanorods were modified A-C12-SH and T-C12-SH. The optical absorption property and microstructure of the obtained samples were studied based on TEM and UV-Vis-NIR spectroscopic measurements. Transverse aggregation of gold nanorods modified A-C12-SH happen at p H≤6, and which of gold nanorods modified T-C12-SH happen at p H≥10, additionally. In the mixed solution of spherical gold nanoparticles with A-C12-SH and the gold nanorods modified T-C12-SH, aggregation aggravates with the increase in the proportion of gold nanospheres, which longitudinal absorption peak disappear in the ultraviolet absorption spectrum. Another, the assembling was induced at acidic and alkaline conditions.