2020 Fiscal Year Research-status Report
Effect of liquid flow on the forces and physical properties of surfaces in liquids
| Project/Area Number |
19K05264
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| Research Institution | Shinshu University |
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Principal Investigator |
マクナミー キャシー 信州大学, 学術研究院繊維学系, 准教授 (40504551)
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| Co-Investigator(Kenkyū-buntansha) |
小川 智之 東北大学, 工学研究科, 准教授 (50372305)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | Experiment planning / Force experiments / data analysis / discussion |
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| Outline of Annual Research Achievements |
We prepared silicon surfaces with chemically tethered polymers. These surfaces were used to determine (1) how the orientation of the polymer chains change in the presence of a liquid flow and (2) how the forces between a charged surface and the polymer surface change with a liquid flow. The effect of the concentration of salt in the solutions was also studied. Atomic Force Microscopy imaging was used to determine the orientation of the polymer chains in aqueous solutions, when a flow was induced in the aqueous solution. Force-distance curves (force curves) were measured using the Atomic Force Microscope between a silica particle and the silicon surfaces with chemically tethered polymers. The images and force curves are being analyzed, in order to prepare a manuscript for publication. The results from Year 2019 were used for this analysis.
In preparation for our studies in Year 2021, we also established a method to prepare surfaces with a controlled roughness from silica nano-particles. A manuscript discussing this preparation method has been submitted to Langmuir. This method will be used in Year 2021, in order to determine how surface roughness affects the change in the forces and physical properties between two charged surfaces in the presence of a liquid flow.
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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
In year 2020, we planned to study the effect of flow on surfaces stabilized by polymers adsorbed via chemical forces. We had intended to determine the effect of the molecular weight of the polymers that were chemically attachedto silicon wafers on the force-distance curves between a silica probe and those silicon substrates. However, we could only successfully chemically attach a single type of polymer to the silicon wafers, meaning that the effect of the molecular weights of the polymers on the force curves could not be determined. Instead, we measured the effect of the concentration of salt in the aqueous solution on the change in the forces measured between a charged silica particle and the silicon substrates to which have polymers were chemically attached.We measured the effect of flow on the morphology of the attached polymer chains via Atomic Force Microscopy imaging. The results are currently being analyzed and the results summarized, in order to prepare a manuscript for publication.
In preparation for the experiments in Year 2021, we also determined a method to prepare surfaces with a controlled roughness by using silica nano-particles, in order to determine how surface roughness affects the change in the forces and physical properties between two charged surfaces in the presence of a liquid flow. One manuscript concerning the preparation of rough surfaces from nano-particles has been submitted to Langmuir.
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| Strategy for Future Research Activity |
In year 2021, we plan to determine how surface roughness affects the change in the forces and physical properties between two charged surfaces in the presence of a liquid flow.The forces between two charged surfaces have been shown to change with the surface roughness in the absence of a liquid flow, due to a decrease in the contact area between the two surfaces with a surface roughness increase. The forces measured between a smooth surface and a rough surface is expected to change with a liquid flow, as a liquid flow is predicted to rupture the adhesions resulting from van der Waals or other attractive forces between the two surfaces. We will use the method determined in Year 2020 to prepare the rough surfaces from silica nano-particles. The effect of the surface hydrophobicity will also be studied by using silane coupling agents to modify the rough surfaces, which were prepared from silica nano-particles.
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| Causes of Carryover |
The remaining money from year 2020 will be used to help fund the consumable items (cantilevers, substrates, particles, chemicals, etc) used inthe research in Year 2021, publication costs (open access fees,etc) and travel. The costs of the consumable items and publication costs are expected to cost more than the previous year.Additionally, new cantilevers and other consumables will be required to perform the planned research of Year 2021. The costs of these materialsare more expensive than originally planned. The results from the research in Year 2020 could not all be presented at conferences, due to many conferences being cancelled or postponed due to COVID-19. Thus, money from Year 2020 that was intended to be used to attend conferences will go towards participation in conferences in YEAR 2021 instead.
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