Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity Contact
Most inorganic material surfaces exposed to ambient air can adsorb water, and hydrogen bonding interactions among adsorbed water molecules vary depending on, not only intrinsic properties of material surfaces, but also extrinsic working conditions. When dimensions of solid objects shrink to micro- a...
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doaj-9311608a724442f3a810f9e3c27d71db2020-11-25T02:30:05ZengMDPI AGColloids and Interfaces2504-53772019-08-01335510.3390/colloids3030055colloids3030055Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity ContactChen Xiao0Pengfei Shi1Wenmeng Yan2Lei Chen3Linmao Qian4Seong H. Kim5Tribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, ChinaTribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, ChinaTribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, ChinaTribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, ChinaTribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, ChinaTribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, ChinaMost inorganic material surfaces exposed to ambient air can adsorb water, and hydrogen bonding interactions among adsorbed water molecules vary depending on, not only intrinsic properties of material surfaces, but also extrinsic working conditions. When dimensions of solid objects shrink to micro- and nano-scales, the ratio of surface area to volume increases greatly and the contribution of water condensation on interfacial forces, such as adhesion (<i>F</i><sub>a</sub>) and friction (<i>F</i><sub>t</sub>), becomes significant. This paper reviews the structural evolution of the adsorbed water layer on solid surfaces and its effect on <i>F</i><sub>a</sub> and <i>F</i><sub>t</sub> at nanoasperity contact for sphere-on-flat geometry. The details of the underlying mechanisms governing water adsorption behaviors vary depending on the atomic structure of the substrate, surface hydrophilicity and atmospheric conditions. The solid surfaces reviewed in this paper include metal/metallic oxides, silicon/silicon oxides, fluorides, and two-dimensional materials. The mechanism by which water condensation influences <i>F</i><sub>a</sub> is discussed based on the competition among capillary force, van der Waals force and the rupture force of solid-like water bridge. The condensed meniscus and the molecular configuration of the water bridge are influenced by surface roughness, surface hydrophilicity, temperature, sliding velocity, which in turn affect the kinetics of water condensation and interfacial <i>F</i><sub>t</sub>. Taking the effects of the thickness and structure of adsorbed water into account is important to obtain a full understanding of the interfacial forces at nanoasperity contact under ambient conditions.https://www.mdpi.com/2504-5377/3/3/55water adsorptionwater condensationmolecular configurationadhesion forcefriction force |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Chen Xiao Pengfei Shi Wenmeng Yan Lei Chen Linmao Qian Seong H. Kim |
spellingShingle |
Chen Xiao Pengfei Shi Wenmeng Yan Lei Chen Linmao Qian Seong H. Kim Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity Contact Colloids and Interfaces water adsorption water condensation molecular configuration adhesion force friction force |
author_facet |
Chen Xiao Pengfei Shi Wenmeng Yan Lei Chen Linmao Qian Seong H. Kim |
author_sort |
Chen Xiao |
title |
Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity Contact |
title_short |
Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity Contact |
title_full |
Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity Contact |
title_fullStr |
Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity Contact |
title_full_unstemmed |
Thickness and Structure of Adsorbed Water Layer and Effects on Adhesion and Friction at Nanoasperity Contact |
title_sort |
thickness and structure of adsorbed water layer and effects on adhesion and friction at nanoasperity contact |
publisher |
MDPI AG |
series |
Colloids and Interfaces |
issn |
2504-5377 |
publishDate |
2019-08-01 |
description |
Most inorganic material surfaces exposed to ambient air can adsorb water, and hydrogen bonding interactions among adsorbed water molecules vary depending on, not only intrinsic properties of material surfaces, but also extrinsic working conditions. When dimensions of solid objects shrink to micro- and nano-scales, the ratio of surface area to volume increases greatly and the contribution of water condensation on interfacial forces, such as adhesion (<i>F</i><sub>a</sub>) and friction (<i>F</i><sub>t</sub>), becomes significant. This paper reviews the structural evolution of the adsorbed water layer on solid surfaces and its effect on <i>F</i><sub>a</sub> and <i>F</i><sub>t</sub> at nanoasperity contact for sphere-on-flat geometry. The details of the underlying mechanisms governing water adsorption behaviors vary depending on the atomic structure of the substrate, surface hydrophilicity and atmospheric conditions. The solid surfaces reviewed in this paper include metal/metallic oxides, silicon/silicon oxides, fluorides, and two-dimensional materials. The mechanism by which water condensation influences <i>F</i><sub>a</sub> is discussed based on the competition among capillary force, van der Waals force and the rupture force of solid-like water bridge. The condensed meniscus and the molecular configuration of the water bridge are influenced by surface roughness, surface hydrophilicity, temperature, sliding velocity, which in turn affect the kinetics of water condensation and interfacial <i>F</i><sub>t</sub>. Taking the effects of the thickness and structure of adsorbed water into account is important to obtain a full understanding of the interfacial forces at nanoasperity contact under ambient conditions. |
topic |
water adsorption water condensation molecular configuration adhesion force friction force |
url |
https://www.mdpi.com/2504-5377/3/3/55 |
work_keys_str_mv |
AT chenxiao thicknessandstructureofadsorbedwaterlayerandeffectsonadhesionandfrictionatnanoasperitycontact AT pengfeishi thicknessandstructureofadsorbedwaterlayerandeffectsonadhesionandfrictionatnanoasperitycontact AT wenmengyan thicknessandstructureofadsorbedwaterlayerandeffectsonadhesionandfrictionatnanoasperitycontact AT leichen thicknessandstructureofadsorbedwaterlayerandeffectsonadhesionandfrictionatnanoasperitycontact AT linmaoqian thicknessandstructureofadsorbedwaterlayerandeffectsonadhesionandfrictionatnanoasperitycontact AT seonghkim thicknessandstructureofadsorbedwaterlayerandeffectsonadhesionandfrictionatnanoasperitycontact |
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