| 研究課題/領域番号 |
21F20769
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| 研究機関 | 北海道大学 |
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研究代表者 |
グン 剣萍 北海道大学, 先端生命科学研究院, 教授 (20250417)
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| 研究分担者 |
LAMA MILENA 北海道大学, 先端生命科学研究科(研究院), 外国人特別研究員
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| 研究期間 (年度) |
2021-04-28 – 2023-03-31
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| キーワード | Photonic hydrogel / lamellar bilayers / self-assembly / mechanical properties / surfactant |
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| 研究実績の概要 |
As a first approach, the phase diagram of DGI was qualitatively determined by polarized light microscopy. The reverse hexagonal phase has been identified. Other characterizations are required to confirm the phase diagram of DGI.
By modifying the type and amount of co-surfactants in the precursor solution, we observed a reinforcement of the mechanical properties of the hydrogels. A macroscopically aligned lamellar phase could be induced for all the co-surfactants. Specifically, the hydrogels with neutral or cationic co-surfactants exhibited a pronounced strain-hardening at large deformation, not present with anionic co-surfactants.
Aside, we were hoping to observe both the hexagonal phases at solution state evidenced by polarized light microscopy and the structure of the lamellar bilayers at gel state by transmission cryo-electron microscopy thanks to a collaboration. At solution state, we have been able to observe vesicles but no hexagonal packing formation. Some samples were difficult to observe due to their high or low concentration in amphiphilic monomer. It is possible that such characterization method was not suitable for observing hexagonal geometries or that hexagonal phases require a certain degree of confinement and/or specific surface chemistry for anchorage.
At gel state, several technical problems were encountered during sample preparation, and the contrast between (vitrified) water and the polymer was too low to enable proper observation. We are hoping that this ongoing work will help for future observations in hydrogel systems.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
The initial plan of the project based on the first hypothesis started well (hypothesis confirmed) but progress was slowed down at some point due to technical difficulties for producing the hydrogels. Other ways were explored to circumvent these difficulties, which actually led to unexpected results. It was then decided to pursue in the direction of those results (second study). Since we wanted to clarify the deformation mechanisms together with the structure of the different hydrogels, we waited for an opportunity to perform USAXS analysis at a synchrotron facility which delayed the project. In the meantime, writing the paper based on this second study delayed the progress of the first study. Thanks to the summer school abroad during the second year, a collaborator was found in Japan in order to perform cryo-electron microscopy observations that were necessary to clarify some hypotheses of the first study. Unfortunately, due to the novelty of the technique on such materials, observations were difficult and could not confirm the hypotheses. The part of the plan regarding the use of customized rheometer was technically being set-up, but a lack of time prevented the start of this part of the study.
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| 今後の研究の推進方策 |
The reasons behind the modification of mechanical behavior of the hydrogels due to such small amount of co-surfactant added in the system remain unclear. Therefore, a more systematic approach will be adopted in order to compare all the selected systems more thoroughly. USAXS analysis is expected to provide crucial information, both at undeformed state and stretched state, and at different temperatures if the beamtime is sufficient. In parallel, the article on this topic will be continued. The results and first conclusions will be presented at upcoming national conferences.
Since some observations by transmission cryo-electron microscopy remained difficult, some samples at solution state will try to be analyzed by USAXS in order to detect if there are differences in the formation of self-assembled structures.
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