2004 Fiscal Year Final Research Report Summary
Molecular recognition process in the ultrathin-film surface observed by surface plasmon spectroscopy (SPR)
| Project/Area Number |
14550854
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子構造・物性(含繊維)
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| Research Institution | NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY |
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Principal Investigator |
TAWA Keiko National Institute of Advanced Industrial Science and Technology, Research Institute for Cell Engineering, senior researcher, セルエンジニアリング研究部門, 主任研究員 (80344109)
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| Project Period (FY) |
2002 – 2004
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| Keywords | Rotaxane ultrathin-film / Poly(ethylene glycol) / Optical control / Azobenzene / Cyclodextrin / Surface Plasmon Spectroscopy / Self-assembled monolayer |
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| Research Abstract |
It has been known that poly (ethylene glycol)(PEG) can form a polyrotaxane with α-cyclodextrin(α-CD) due to the molecular recognition. In this study, a self-assembled-monolayer(SAM) composed of mixture thiols, MeAzoPEGn (n=6,10,16) and diluent thiol (11-undecanol thiol : HSC11OH or dodecane thiol : HSC12), was prepared, and the formation process of polyrotaxane-ultrathin film with α-CD and its photo-controllability were investigated by the surface plasmon resonance spectroscopy(SPR).
The novel compounds, MeAzoPEGn, synthesized by ourselves consist of 4-methyl azobenzene moiety, PEG (unit number:6,10,16), and mercapt group. The increase in the film thickness of 2.0±0.2 nm was observed at the SAM of MeAzoPEG6 after addition of α-CD solution. α-CD rings were found to form polyrotaxane-film selectively with MeAzoPEG6 chain regardless of the kind of the diluent thiols. 4-methyl azobenzene moiety substituted at the end of MeAzoPEG6 is considered to be a trigger molecule to capture α-CD rings and then, CD rings can penetrate through a PEG chain. As the result, a PEG chain was extended and a new rotaxane layer was observed. In the case of the SAM of MeAzoPEG10 and MeAzoPEG16,the increase in the film thickness by adding α-CD was larger. It is considered to be due to that more CD molecules are possible to form a thicker polyrotaxane-film for the longer PEG chain.
Furthermore, the formation of polyrotaxane-film was investigated under UV irradiation. UV irradiation induces the isomerization of azobenzene moiety and the increase in the film thickness after adding α-CD was suppressed by 1.4 nm. The complete control was impossible but the partial control was possible for the formation of the polyrotaxane-film by UV light irradiation.
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