Langmuir layers of fullerene C60 and its mixtures with amphiphilic polymers
| Autor: | Alexey G. Bykov, Boris A. Noskov, Kirill A. Timoshen |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
Langmuir Fullerene Materials science Nanoparticle 02 engineering and technology Polymer Surface rheology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Surface pressure 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Electronic Optical and Magnetic Materials chemistry Chemical engineering Ellipsometry Monolayer Physics::Atomic and Molecular Clusters Materials Chemistry Physical and Theoretical Chemistry 0210 nano-technology Spectroscopy |
| Zdroj: | Journal of Molecular Liquids. 320:114440 |
| ISSN: | 0167-7322 |
| Popis: | The application of dilational surface rheology and optical microscopy combined with the more conventional methods of surface tensiometry, ellipsometry and atomic force microscopy shows that the properties of mixed spread layers of fullerene C60 with poly(vinylpyrrolidone) (PVP) and poly(N-isopropylacrylamide) (PNIPAM) are determined by the polymer at low surface pressures (less than the maximum value for a pure polymer monolayer) and by the fullerene at higher surface pressures. In particular, the dependences of the dynamic surface elasticity on the surface pressure for the mixed layers have two local maxima corresponding to the polymer and fullerene. These results indicate that the layer consists of two separate phases at low surface pressures below the characteristic value of the polymer displacement from the interface. Although the collapse of the fullerene layers starts at surface pressures of far less than 70 mN/m, some patches of the layers sustain surface pressures up to this value. The high stability of the fullerene spread layer and its strong adhesion to water can be explained by the hydroxylation of the fullerene molecules where they contact the water. A similar explanation of the high stability of fullerene aggregates in bulk water has been proposed recently. The fullerene layer is heterogeneous and consists mainly of surface aggregates with dimensions of approximately 40–60 nm in the X-Y plane. The local folding of the layer of these aggregates at high surface pressures (>30 mN/m) leads to the striation patterns, which are typical for the collapse of nanoparticle monolayers. |
| Databáze: | OpenAIRE |
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