2020 Fiscal Year Annual Research Report
Fabrication of highly optically transparent functional wood utiIizing its natural nano structure
| Project/Area Number |
20F20095
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| Research Institution | Kyoto University |
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Principal Investigator |
矢野 浩之 京都大学, 生存圏研究所, 教授 (80192392)
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| Co-Investigator(Kenkyū-buntansha) |
BISWAS SUBIR 京都大学, 生存圏研究所, 外国人特別研究員
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| Project Period (FY) |
2020-04-24 – 2022-03-31
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| Keywords | Wood / Transparent / Polarizing behavior / Cellulose nanofibers / Wood structure / Nano structure |
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| Outline of Annual Research Achievements |
Wood is a plant tissue composed of hollow cells called fibers. The cellulose occurs as thin (4 nm dimeter) and long (several micrometers) nanofibers and their bundles (10-30 nm diameter) in the fibers, which does not scatte light. Therefore, wood becomes transparent when the opaque brownish lignin is replaced with a transparent resin (Transparent wood: TW). It was found that TW exhibits anisotropic light transmission in which a laser point becomes elongated perpendicular to fiber direction. Based on this finding, we hypothesized that TW might show light polarizing behavior. Therefore, the light polarization performance of TW (WA) was measured using a custom-built equipment. It was demonstrated that the wood definitely polarizes light to a certain degree, which is about 33% at 600 nm.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
透明化した木材が偏光性を示すことが定量的に明らかになり、木材の光学材料としての新たな特性および用途が見いだされつつある。
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| Strategy for Future Research Activity |
1.Lignin-removed wood will be impregnated with TEMPO-oxidized cellulose nanocrystals before transparent resin impregnation. The hypothesis is that the cellulose nanocrystals will be self-aligned in the cell lumen under vacuum due to the capillary action. This would enhance the polarizing performance of TW in the visible wavelength range.
2.The effect of compression to reduce the gap in the cell-wall-grid structure will be investigated in terms of light polarization performance of TW.
3.Effect of refractive indices of resins on the optical behavior of TW will be explored.
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