Nanoscale condensation of water on self-assembled monolayers
We demonstrate that water is almost universally present on apparently dry self-assembled monolayers, even on those considered almost hydrophobic by conventional methods such as water contact goniometry. The structure and kinetics of nanoscale water adsorption onto these surfaces were investigated us...
| Main Authors: | , , , , , , , |
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| Format: | Journal Article |
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RSC Publishing
2011
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| Online Access: | http://hdl.handle.net/20.500.11937/21113 |
| _version_ | 1848750499539451904 |
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| author | James, M. Darwish, T. Ciampi, Simone Sylvester, S. Zhang, Z. Ng, A. Gooding, J. Hanley, T. |
| author_facet | James, M. Darwish, T. Ciampi, Simone Sylvester, S. Zhang, Z. Ng, A. Gooding, J. Hanley, T. |
| author_sort | James, M. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We demonstrate that water is almost universally present on apparently dry self-assembled monolayers, even on those considered almost hydrophobic by conventional methods such as water contact goniometry. The structure and kinetics of nanoscale water adsorption onto these surfaces were investigated using X-ray and neutron reflectometry, as well as atomic force microscopy. Condensation of water on hydrophilic surfaces under ambient conditions formed a dense sub-nanometre surface layer; the thickness of which increased with exponentially limiting kinetics. Tapping mode AFM measurements show the presence of nanosized droplets that covered a small percentage (~2%) of the total surface area, and which became fewer in number and larger in size with time. While low vacuum pressures (~10-8 bar) at room temperature did nothing to remove the adsorbed water from these monolayers, heating to temperatures above 65 °C under atmospheric conditions did lead to evaporation from the surface. We demonstrate that water contact angle measurements are not necessarily sensitive to the presence of nanoscale adsorbed water and do not vary with time. For the most part they are a poor indicator of the kinetics and the amount of water condensation onto these surfaces at the molecular level. In summary, this study reveals the need to exclude air containing even trace amounts of water vapor from such surfaces when characterizing using techniques such as X-ray reflectometry. © 2011 The Royal Society of Chemistry. |
| first_indexed | 2025-11-14T07:37:48Z |
| format | Journal Article |
| id | curtin-20.500.11937-21113 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:37:48Z |
| publishDate | 2011 |
| publisher | RSC Publishing |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-211132018-03-29T09:06:22Z Nanoscale condensation of water on self-assembled monolayers James, M. Darwish, T. Ciampi, Simone Sylvester, S. Zhang, Z. Ng, A. Gooding, J. Hanley, T. We demonstrate that water is almost universally present on apparently dry self-assembled monolayers, even on those considered almost hydrophobic by conventional methods such as water contact goniometry. The structure and kinetics of nanoscale water adsorption onto these surfaces were investigated using X-ray and neutron reflectometry, as well as atomic force microscopy. Condensation of water on hydrophilic surfaces under ambient conditions formed a dense sub-nanometre surface layer; the thickness of which increased with exponentially limiting kinetics. Tapping mode AFM measurements show the presence of nanosized droplets that covered a small percentage (~2%) of the total surface area, and which became fewer in number and larger in size with time. While low vacuum pressures (~10-8 bar) at room temperature did nothing to remove the adsorbed water from these monolayers, heating to temperatures above 65 °C under atmospheric conditions did lead to evaporation from the surface. We demonstrate that water contact angle measurements are not necessarily sensitive to the presence of nanoscale adsorbed water and do not vary with time. For the most part they are a poor indicator of the kinetics and the amount of water condensation onto these surfaces at the molecular level. In summary, this study reveals the need to exclude air containing even trace amounts of water vapor from such surfaces when characterizing using techniques such as X-ray reflectometry. © 2011 The Royal Society of Chemistry. 2011 Journal Article http://hdl.handle.net/20.500.11937/21113 10.1039/c1sm05096f RSC Publishing restricted |
| spellingShingle | James, M. Darwish, T. Ciampi, Simone Sylvester, S. Zhang, Z. Ng, A. Gooding, J. Hanley, T. Nanoscale condensation of water on self-assembled monolayers |
| title | Nanoscale condensation of water on self-assembled monolayers |
| title_full | Nanoscale condensation of water on self-assembled monolayers |
| title_fullStr | Nanoscale condensation of water on self-assembled monolayers |
| title_full_unstemmed | Nanoscale condensation of water on self-assembled monolayers |
| title_short | Nanoscale condensation of water on self-assembled monolayers |
| title_sort | nanoscale condensation of water on self-assembled monolayers |
| url | http://hdl.handle.net/20.500.11937/21113 |