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Title: Bio-inspired functional ceramic materials
Authors: Shoo, Favier Wen Long.
Keywords: DRNTU::Engineering
Issue Date: 2011
Abstract: The micro/nano-structures of the Morpho butterfly wing scale were examined, and the entire architecture was completely replicated by Titanium Dioxide (TiO2) through Sputtering deposition, Solution Gelation and annealing method. In order to understand the effects of replicas thickness and annealing temperature on the morphological, optical and crystalline properties of TiO2 replicas, different sputtering time and annealing temperature were varied. The morphological, optical and crystalline properties of the replicas were primarily characterized using Optical Microscope, Scanning Electron Microscopy, Field Emission Scanning Electron Microscopy, X-ray diffraction, Transmission Electron Microscopy and UV-Visible spectrophotometer. Taping technique was introduced to optimize the replicas structures. Replicas that were sputtered for 20 min and 60 min displayed a significant improvement in the orderliness of the ridge-lamellae micro/nano-structures. These results were most likely due to adequate step coverage of Ti being sputtered onto bio-template that resulted in less cracks and splits during thermal expansion in annealing. All the annealed replicas above 450 °C were polycrystalline to an extent with common strongest peak at (101), Anatase phase. At higher temperature, replica structures gain enough energy to eliminate the pores and grain boundaries in Ti and increase its density, which resulted in higher crystallinity. The 20 min replica was found to demonstrate gas sensing potential. Finally, the effect of different replicas thickness was examined for photocatalytic activity. Optical property and photocatalytic reaction tests were conducted. It was found that replica sputtered for 20 min had a unique extension of absorbance peak into 450 nm visible region and exhibited the highest degradation ratio. The 20 min replica had the potential function as an enhanced photocatalyst by having wider absorption ability into visible region. This was largely due to the optimal dimension that provided most desirable surface area for photocatalytic reactions.
Rights: Nanyang Technological University
Fulltext Permission: restricted
Fulltext Availability: With Fulltext
Appears in Collections:MSE Student Reports (FYP/IA/PA/PI)

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