2006 Fiscal Year Final Research Report Summary
Migration of Nanometer-thick aggregates formed at liquid/liquid interfaces by external fields and its application to separation.
| Project/Area Number |
16350046
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Analytical chemistry
|
|---|
| Research Institution | Hiroshima University |
|---|
Principal Investigator |
TSUKAHARA Satoshi Hiroshima University, Graduate School of Science, Associate Professor, 大学院理学研究科, 助教授 (50207338)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Terufumi Graduate School of Science, Professor, 大学院理学研究科, 教授 (80127703)
OKAMOTO Yasuaki Graduate School of Science, Research Associate, 大学院理学研究科, 助手 (40213988)
|
|---|
| Project Period (FY) |
2004 – 2006
|
| Keywords | Liquid / liquid interface / Nanometer-thick aggregates / Optical microscope / Thin-layer two-phase microcell / Light absorption anisotropy / Localized direct current electric field / Tetraphenylporphyrin / In situ microscopic spectroscopy |
|---|
| Research Abstract |
A thin-layer two-phase microcell, which was previously invented by us, was used for in situ microscopic observations and measurements of substances formed or existing at liquid/liquid interfaces.
5,10,15,20-Tetraphenylporphine (tpp) was diprotonated and adsorbed at dodecane/acidulated water interfaces. Then, the interfacial H_2tpp^<2+> was changed to its aggregate there. In situ microscopic measurements showed that rhombic microdomains of H_2tpp^<2+> aggregate were formed at a dodecane/aqueous H_2SO_4 interface prepared in the microcell. Their size was about 10-200 um. In situ absorption spectra of the individual microdomains showed that they had a large absorption at 473 nm. The absorbance at the wavelength and their absorption coefficient indicated that their thickness were a monolayer level. Furthermore, the microscopic absorption anisotropy of individual microdomains revealed that they had a transition dipole moment almost parallel to the major axis of the rhombus. This fact indicated that the microdomains had an ordered structure, like single crystals.
The microdomains of H^2tpp^<2+> aggregates at the dodecane/aqueous H_2SO_4 interface were successfully moved in a localized direct current (dc) electric field, which was applied to the interface with two electrodes possessing a small end. The electrodes were immersed in the dodecane phase, and the ends were located at 100-170 um above the interface. The distance between the ends of the two electrodes was 100-300 um. A positive dc voltage (0 to +100 V) or a negative voltage (-100 to 0 V) against the ground was applied to the electrode with high-voltage supplies. The microdomains migrated toward the interfacial position just under the negative electrode, whereas they leaved from the positive electrode. This indicated that the microdomains had some negative charge and that they were moved by the Coulomb force.
|
