Curvature-induced hydrophobicity at imogolite–water interfaces
| Autor: | Mark R. Johnson, Alejandro Fernandez-Martinez, Ian C. Bourg, James J. De Yoreo, Adam F. Wallace, Laurent Charlet, Garrison Sposito, Jinhui Tao, Gabriel J. Cuello |
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| Rok vydání: | 2020 |
| Předmět: |
Nanotube
Materials science Materials Science (miscellaneous) Force spectroscopy Imogolite 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Molecular dynamics Adsorption Chemical engineering Aluminosilicate Wetting 0210 nano-technology Gibbsite General Environmental Science |
| Zdroj: | Environmental Science: Nano. 7:2759-2772 |
| ISSN: | 2051-8161 2051-8153 |
| DOI: | 10.1039/d0en00304b |
| Popis: | Imogolite, a nanotubular aluminosilicate mineral, is commonly found in volcanic soils, where it exerts a control on carbon dynamics. Synthetic imogolites are used for the removal of contaminants from industrial effluents and are considered for a range of other applications including gas adsorption and functionalised heterogeneous catalysts. In spite of their environmental and industrial relevance, the properties of imogolite–water interfaces remain poorly understood. Here, an experimental and computational study is presented in which the structure and energetics of water are characterized on the curved external surface of imogolite and the hydrophilicity of this surface is contrasted with that of gibbsite, its planar counterpart. Atomic force spectroscopy experiments show that in spite of their identical surface structure, imogolite has a lower hygroscopicity than gibbsite. Molecular dynamics simulations provide an explanation for this observation: the curvature of imogolite prevents the formation of in-plane H-bonds along the directions of the nanotube circumference, lowering the enthalpy of adsorption of water molecules. The different arrangement of surface H-bonds and the resulting differences in hydration properties also affects the acidity constants of surface hydroxyl groups. This ‘nanotube effect’ may be relevant to other nanotubular systems with high curvatures, potentially impacting their wetting properties, their colloidal stability and their affinity towards hydrophobic organic moieties. |
| Databáze: | OpenAIRE |
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