1997 Fiscal Year Final Research Report Summary
Atomic Force Microscopy Study of Surface Structure of Liquids
| Project/Area Number |
08650035
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
表面界面物性
|
|---|
| Research Institution | Hiroshima City University |
|---|
Principal Investigator |
IWAMATSU Masao Hiroshima City University Department of Computer Engineering Faculty of Information Science Associate Professor, 情報科学部, 助教授 (20201345)
|
|---|
| Project Period (FY) |
1996 – 1997
|
| Keywords | Atomic force microscope / Solvation Force / Density functional theory / Wetting |
|---|
| Research Abstract |
1.The density profile and the solvation force observed by atomic force microscopy (AFM) when fluids are confined between the probe of AFM and the substrate were studied theoretically using the density functional theory combined with the Derjaguin approximation. We have examined the solvation force by varying the fluid-wall interaction which is represented by the Hamaker constants. The results are summarized as follows :
(1)The density profile of confined fluid oscillates. This oscillation is more evident, the stronger wall-fluid potential becomes. This density oscillation manifests in the oscillating solvation force.
(2)When the fluid-wall interaction is weaker than the fluid-fluid interaction, the capillary evaporation occurs when the probe-substrate distance becomes short. The solvation force shows abrupt jump at the point of capillary evaporation.
II.In order to understand the various surface phase transitions of wetting layr which are expected to be observable by AFM,we have constructed a phenomenological model of wetting which takes into account the oscillatory density profile of wetting liquid films. Using this simplified model we have determined the phase diagram of wetting using the wall-fluid interaction and the decay length of density oscillation.
III.We have attempted to measure the solvation force oscillation directly in the force curve using the commercial atomic force microscope (Seiko SPI3700) using the mica substrate and the silicon liquid (OMCTS,octamethlcyclotetrasiloxane). However, the theoretically predicted solvation force oscillation has not been observed.
|
