| Autor: |
Akira Nishihara, Yukiya Yamashita, Kenichi Nakashima, Satoshi Yasuda |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Colloids and Surfaces A: Physicochemical and Engineering Aspects. 139:251-257 |
| ISSN: |
0927-7757 |
| DOI: |
10.1016/s0927-7757(98)00320-3 |
| Popis: |
Adsorption and excimer formation of 4-(1-pyrenyl)-butyltrimethylammonium bromide (PyB) on non-porous silica nanoparticles (Aerosil) have been studied in aqueous dispersions. The efficiency of excimer formation is remarkably enhanced on going from the homogeneous aqueous solution to the silica dispersion. This is ascribed to the effective adsorption of PyB onto the silica surfaces. Adsorption isotherm data are not fitted to a simple Langmuir binding model, suggesting cluster formation of PyB molecules on the silica surfaces. From the dependence of PyB excimer fluorescence intensity on the surface density of the probe on the silica surface, it is elucidated that PyB molecules are inhomogeneously distributed on the surfaces. Excitation spectra and fluorescence decay curves reveal that the excimers of PyB on Aerosil surfaces are mainly originated from ground-state dimers, i.e. dynamic processes through lateral diffusion of the probe on the surface are less important in the present case. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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