The Preparation Of Micro And Nano Noble Metal Superstructure Using Polymer As Substrate And The Mechanism Of Formation

As one of the most popular direction in scientific research, the achievements in the investigation about noble metal micro and nano structures indicate their bright prospect in many scientific fields of synthetic chemistry, materials science, physics, biology, and medicine and the high potential for a variety of application. Assembling small molecules or particles into a specific structure is an important process to form a new material. The exciton-exciton interaction, magnetic dipole interaction and surface plasmon resonance between nanoparticles offer the assembled structures new electromagnetic, optical and catalytic properties. There have been many methods to achieve the assembly of noble metal nanoparticles into micro and nano superstructures. Among these, organic materials-assisted assembly of metal nanoparticles to generate organic-inorganic composite superstructures with specific structure has been the most dynamic areas of research and an important way to realize application of nanomaterials. Therefore, combination of organic materials and inorganic materials for future technological, economic and social development has a significant impact. Among organic materials, polymers exhibit unique properties that small molecules do not do, and have become the preferred matrix or substrate for preparation of metal micro and nano structures. In this thesis, polymer brushes, polymer films and polymer colloid particles were chosen as the substrates to prepare noble metal/polymer micro and nano composite structures, and the structure, composition and application were studied. The main achievements are as follows:The preparation of micro and nano silver structure on polymer brush substrate and its application in SERS. Initially, homogeneous polymer brushes were prepared on flat silicate substrate by using ultraviolet light to initiate the polymerization. Then, the-SO3 H groups were introduced on the benzene ring by sulfonation of polystyrene(PS) brush. The as-prepared poly(styrene sulfonic acid) brushes were used as substrate to adsorb the silver precursor and the substrate was treated with reducing agent to fabricate silver superstructures. By varying the adsorption time of Ag precursors, an array of well-defined Ag superstructures with different morphologies are harvested. The polymer brush/ silver micro nano structure substrate for surfaceenhanced Raman spectroscopy is established. It is exhibits high sensitivity in trace detection of molecules. When the concentration of R6 G is even as low as 10-12 M, obviously enhanced Raman peaks can be observed.The preparation of micro and nano noble metal structure on polymer film substrate and bimetal structure. Firstly, the –NH2 terminated APTES films with different thickness were prepared on flat silicate substrate via alkylation reaction. PAA and PEI film also produced using layer-by-layer method. Due to different polymer film with different properties, we can prepare micro and nano structure with various morphologies. We also studied the application of the prepared structure in producing nanoporous bimetal structures.Using nonspherical copolymer as substrate to prepare latex particles/silver structure. Nonspherical poly(styrene-co-methacrylic acid) latex particles with well-defined shapes and high yields by emulsifier-free polymerization. Varying the molar ratio of styrene(St) to methacrylic acid(MAA), latex particles show different morphology. Because of the presence of carboxyl, we can generate silver particle on the latex particles to form composite through electrostatic adsorption and reduction without any surface modification of the latex particles.