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The interplay between apparent viscosity and wettability in nanoconfined water
Deborah Ortiz-Young1, Hsiang-Chih Chiu, Suenne Kim
11] School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332-0430, USA [2] School of Chemistry, Georgia Institute of Technology, 901 Atlantic Avenue, Atlanta, Georgia 30332-0430, USA [3].
Nature Communications
|September 21, 2013
Summary
Viscous forces in nanoconfined water are amplified by hydrophilic surfaces and reduced by hydrophobic ones. This phenomenon, explained by interfacial slip, offers new ways to control nanoscale fluid flow.
Area of Science:
- Fluid dynamics
- Nanotechnology
- Surface science
Background:
- Understanding fluid behavior at the nanoscale is crucial for technological advancements.
- Nanoconfined fluids exhibit unique properties compared to bulk fluids.
- Interfacial properties significantly influence nanoscale fluid dynamics.
Purpose of the Study:
- To investigate the impact of surface hydrophobicity on viscous shear forces in nanoconfined water.
- To develop a model explaining the observed changes in viscous forces.
- To explore the implications for energy dissipation and nanoscale flow control.
Main Methods:
- Experimental measurement of viscous shear forces in nanoconfined water with varying surface properties.
- Development of a theoretical model incorporating interfacial slip velocity.
- Analysis of energy dissipation using a vibrating tip perpendicular to a surface.
Main Results:
- Viscous shear forces in nanoconfined water are orders of magnitude larger on hydrophilic surfaces than in bulk water.
- Forces significantly decrease on increasingly hydrophobic surfaces.
- A model including slip velocity quantitatively explains this decrease.
- Interfacial viscous forces and dissipation can decrease up to two orders of magnitude due to slippage.
Conclusions:
- Surface properties dramatically alter viscous forces and energy dissipation in nanoconfined water.
- Interfacial slip is a key factor in understanding these nanoscale fluid behaviors.
- Findings provide insights for controlling fluid flow at the nanoscale.
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