The Study Of Layer-By-Layer Self-Assembly Under High Gravity Field

The layer-by-layer self-assembly (LbL) technique is a significant method to fabricate the laminar multilayer film. It has many characteristics, such as simple operation, environmental protection, suitable for the preparation of multilayer films on substrates with various shapes. In the past two to three decades, the LbL technique was given more and more attention. The research and discovery of various building blocks and driving forces made the LbL technique become an important technology of fabricating films. However, the conventional LbL technique employs the way of immersing substrates in solution, and it is time-consuming. In order to promote extensive application of the LbL technique, the shortcoming of long time assembly process must be solved immediately.In this study, we first introduced high gravity technology into conventional LbL process, and we proposed a method to prepare the multilayer film rapidly. The new rapid method is called layer-by-layer self-assembly technique under high gravity field (HG-LbL). In this study, we designed the high gravity equipment and assembly process. We chose nanoparticles and polyelectrolytes as the building blocks, and coordinate bond as the driving forces. Under these experimental conditions, we researched the assembly process under high gravity environment. By studying the adsorption kinetic curves, sequential adsorption of multilayer films, surface morphologies of monolayer and multilayer film and other data, we confirmed that the HG-LbL technique accelerated the speed of preparation of nanoparticles and polyelectrolytes multilayer films on the substrate surface. We summed up the mechanism of HG-LbL process. The HG-LbL technique accelerated diffusion process of building blocks. Therefore it accelerated speed of assembly.In addition, we chose nanoparticles, small inorganic molecules, and polyelectrolytes as the building blocks, and electrostatic interaction, coordinate bond and hydrogen bond as the driving forces. Under these experimental conditions, we researched the assembly process under high gravity environment. From experimental results, we conclude that the HG-LbL technique can be applied in those assembly processes above. It is a universal rapid way to prepare laminated multilayer film. To the building blocks of polyelectrolyte and inorganic small molecules, the HG-LbL technique can prepare multilayer films with lower surface roughness. The proposing of HG-LbL technique not only solves the time-consuming of the conventional layer-by-layer self-assembly technique, but also provides a new approach to combine traditional chemistry with commercial industrial production.