Elucidating the effect of boundary curvature on the wrinkling of thin suspended films by theory and experiment
| Project/Area Number |
21K03782
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 18010:Mechanics of materials and materials-related
|
|---|
| Research Institution | Okinawa Institute of Science and Technology Graduate University |
|---|
Principal Investigator |
JANSSENS Stoffel 沖縄科学技術大学院大学, 力学と材料科学ユニット, スタッフサイエンティスト (00817629)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
フリード エリオット 沖縄科学技術大学院大学, 力学と材料科学ユニット, 教授 (70735761)
|
|---|
| Project Period (FY) |
2021-04-01 – 2024-03-31
|
| Project Status |
Granted (Fiscal Year 2022)
|
| Budget Amount *help |
¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2023: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2022: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2021: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
|
|---|
| Keywords | wrinkling / diamond / nanochannel / nanofluidics / laser / glass / etching / thin films |
|---|
| Outline of Research at the Start |
The effect of boundary curvature on the wrinkling of a thin suspended film, such as eardrums and plant leaves, is poorly understood. To captures the main physical ingredients that explain this effect, methods for the microfabrication of suspended diamond films that in a controlled way mimic such systems will be developed together with a theoretical model. The final goal is to advance our fundamental understanding of wrinkling phenomena but also provide a foundation for advancing various applications, such as the design of devices with functional wrinkles, and to understand natural phenomena.
|
| Outline of Annual Research Achievements |
We synthesized ultra-thin nanocrystalline diamond (NCD) films on Corning Lotus NXT glass substrates with microwave plasma-enhanced chemical vapor deposition. We patterned these films through direct femtosecond laser writing. We accidentally found that nanochannels could be made between the glass substrate and the nanocrystalline diamond film at relatively low laser pulse energies. At relatively high laser pulse energies, portions of the film could be removed, which was our initial goal. Techniques such as focused ion beam milling and electron-beam lithography are currently used to fabricate open nanochannels that are sealed by intricate processes. Manufacturing nanochannel-based devices by such traditional methods is therefore complex, expensive, and time-consuming, hindering progress in the field. Our method for nanochannel manufacturing overcomes such issues and consequently has a high-impact potential. We further investigated the mechanism behind our method and demonstrated that the nanochannels conduct water by fabricating a nanofluidic device. A patent will be filed in April 2023. Immediately after that, we will submit a manuscript to an international journal.
In parallel, we also found new phenomena in the wrinkling of NCD films that are compressively strained after deposition and partly released from the glass substrate through substrate etching. Boundary curvature is observed to play a role in the wrinkling of these films, which follows our hypothesis. However, we found that the amount of substrate etched also plays a crucial role.
|
| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
In the project's first stage, we made the required structures with femtosecond writing. Because of this work, we accidentally found a simple and cost-effective method for fabricating nanochannels for nanofluidic devices. Consequently, we will file a patent and submit a manuscript to a well-respected scientific journal.
In the project's second stage, we planned to systematically investigate the effect of boundary curvature on the wrinkling of suspended nanocrystalline diamond (NCD) films. We found that not only boundary curvature affects wrinkling but also the amount of substrate that is etched. The latter determines the portion of the film that is suspended. We found that wrinkling does not occur after a relatively small amount of etching. At a relatively intermediate amount of etching, the suspended portion of the film strongly wrinkles but does not buckle. After a relatively large amount of etching, buckling occurs. A decrease in the mean wrinkle length marks this event. Our collaborator is also performing finite element simulations in parallel with the experiments. These are in line with our findings. We are still working on a simple theoretical model that can capture our observations.
|
| Strategy for Future Research Activity |
We plan to make structures with photolithography and reactive ion etching instead of with direct femtosecond laser writing. The reason is that the former technique provides a higher feature resolution. This is necessary to investigate the regimes of relatively small and relatively intermediate amounts of etching. We also plan to increase the number of etching steps and reduce the etching time to more clearly define the not wrinkling to wrinkling transition, and the non buckling to buckling transition. We will do this for strongly negative, zero, and strongly positive signed boundary curvature structures. Results from finite element simulations will accompany the experiments. We will also try developing a simple theoretical model to explain our results. We plan to disseminate our work in a well-respected scientific journal.
|
Report
(2 results)
Research Products
(3 results)
