Fabrication Of Surface Micro / Nanometer Based On New Photochemical Method

Material surface modification and functionalization is of prime importance in micro/nanofabrication. In practical applications, in order to fabricate such an assembly and surface patterning, interfacial chemical modification has been proved to be a powerful tool to tailor surface properties and induce functional material assembly. This study selects two substrates, one is ITO, another is a precious metal Au. As the important integrated circuits materials, more refined surface modification and micro/nanofabrication on these two kinds of materials become more and more important. Therefore, the surface design and control on chemical and physical structure of surface is essential for functional material assembly.The research work is as follows:(I) the modification of indium tin oxide by a kind of confined photocatalytic oxidation reaction method and micro-structure fabrication of the functionalized materials:(1) the grafting of sulfate anion groups on the exposed ITO surfacePersulfate-based confined photocatalytic oxidation reaction (CPO) is utilized to directly modify the inorganic PET-ITO surfaces at small molecules level, which can be controlled on the micron scale through a photomask site-selective exposure, thus producing highly hydrophilic and ionizable pattered surfaces.(2) interface-mediated multicomponent assemblingA patterned modified surface can serves as a molecular template to mediate hybrid material assembly, including zinc oxide, barium titanate, lipid membrane, cadmium sulfide, colloids, liquid crystals and conductive polymer micro patterns. The fabrication of zinc oxide and barium titanate film use liquid phase deposition (LPD), through the solution system, with low power consumption and environmentally friendly way to achieve thin films, and to improve material performance. Specially the low temperature deposition process is beneficial to the growth of zinc oxide and barium titanate film, and patterning on flexible and thermo-sensitive PET-ITO substrate. The micropatterned deposition of other functional materials including cadmium sulfide, colloids, liquid crystals and conductive polymer can be implemented via the simple utilization of spin-coating. Especially liquid crystals, a large-area site-elective alignment can be achieved through a simple one-step spin-coating process without the requirements of a rubbing and alignment layer. By using polymer/glass-supported ITO material, the basic unit for a flat and flexible device could be conveniently fabricated in a fast, high-efficient, inexpensive, and low-temperature way. It is expected that these results could stimuli the development of flexible organic optoelectronic devices.(Ⅱ) micro/nanofabrication on precious metal film by pyridine-containing molecular derivatives:(1) the effect of various factors on the etching rateOur research work mainly focuses on the effect of various conditions to mediate the etching rate on the gold film in an aqueous etching solution of N-bromosuccinimide/pyridine. These factors include temperature, concentration of reactant, time, pH, chemical and physical structure of pyridine and its derivatives, and self-assembly SAMs on the gold.(2) self-assembled monolayer-assisted negative/positive lithographyThis method features a unique photoirradiation-imprinted patterning process that simply consists of two steps:① UV irradiation on an OH-terminated SAM-modified gold surface through a photomask,② the subsequent immersion of the exposed substrate in an aqueous etching solution of N-bromosuccinimide/pyridine to develop a wet lithographic pattern. The entire experimental process reveals a finding from previous work that the etching rate on the UV-exposed regions with disordered molecular packing could be modulated to be slower than that in the unexposed well-defined SAM regions. Longer irradiation times would also revert the patterns from negative to positive. Thus, by merely using one kind of SAM-modified surface to provide both positive and negative micropatterns on gold layers, one could obtain flexible opportunities for high-resolution micro/nanofabrication resembling photolithography.