Ligand Exchange On Gold Nanorods And Its Influence On Gold Nanorods Assembling Mode

As one of the most important nanomaterials, gold nanorods' self-assembly technology get more and more attention from us. The current method for micron level or local ordered structures assembly hindered the gold nanorods array structure for practical use.Gold nanorods from seed-mecidate synthesis have different capacity on combine ligand molecule at the end and the side can make ligand exchange step by step. Ligand modifications has great influence to the electrostatic forces,van der Waals force and also can adjust hydrophilic and hydrophobic interaction. As we chose two properly liangd molecules to modify the end and the side of GNRs respectively may effectively inprove the neat degree of gold nanorods array.In this paper, we will do some research on the following aspects:1. We will explore the surface ligand on gold nanorods and the stability of the gold nanorods solution system. CTAB bilayers are closely coating on gold nanorods surface and hard to replace;reducing the concentration of CTAB makes ligand exchange easy but the solution system stability become poor.So before the ligand exchang we should deeply andstand the state of the ligand molecules and the stability of the solution system.2. Exploring the precise conditions of stepwise ligand exchange.The critical point of ligand exchange step by step is how to modify the end of GNRs accurately,so we should find the node of ligand modification conditions.Since we modify the end of GNRs accurately,we can use another ligand molecules which have stronger ability to replace the CTAB on side.Then we have make the ligand exchange step by step completely.3. Assembling the modified gold nanorods. Ligand exchange makes the original gold nanorods CTAB bilayer into a single ligand molecules layer on the surface.This can adjust the distance between the rods and have effectively impact on van der Waals force. As a result,GNRs have more orientation in assembly proess.On the other hand,the distance between any two GNRs in array get more closer may enchance the near-field coupling.