| Research Abstract |
During a scheduled period, we have developed a preparation technique enables casting film on quartz or HOPG substrate using high density nanocolloids and observed their structure by STM/AFM which is incorporated in our laboratory. In the last year, we have focused our effort on the formation of gold nanoparticle film together with the confirmation of the size of isolated particles.
In addition to the previous preparation method using physical process, a new colloid chemical method was also attempted. It was found that a particle with the smallest size of 1um was prepared when using thiolate as a size controller. A particle whose size is larger than 10nm was formed by the organic reduction method and was fount that the size distribution width is narrow as 15%. The precise surface state of this thiolate-modified particles was determined using various physico-chemical method. In order to aim the particle crystal formation, we have developed a large scale amount synthesis in the order of g using thiol surface modified method. This amount is far from that by the physical dry process in the order of mg. In the final stage of the experiment, particle crystal formation was tested using Au-MSA modified nanoparticles. The regulation parameters tested were content of water/organic solvent, a kind of solvent (methanol, ethanol, 2-propanol),salt concentration, a kind of salt (ammonium sulfate, ammonium chloride), and crystallization temperature. More than several hundreds different conditions were tested using a micro-plating method, well-known in the field of protein chemistry. Unfortunately, a large size crystal formation was not perceived appropriate for the X-ray analysis.
The size separation technique such as chromatography or the size-selected precipitation method was remained in a future study to form a three dimensional large size crystal.
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