Resolving the Pinning Force of Nanobubbles with Optical Microscopy

Many of the remarkable properties of surface nanobubbles, such as unusually small contact angles and long lifetimes, are related to the force that pins them onto their substrates. This pinning force is yet to be quantified experimentally. Here, surface-attached nanobubbles are pulled with an atomic...

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Bibliographic Details
Main Authors: Tan, Beng Hau, An, Hongjie, Ohl, Claus-Dieter
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2017
Subjects:
Online Access:https://hdl.handle.net/10356/83362
http://hdl.handle.net/10220/42573
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Institution: Nanyang Technological University
Language: English
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Summary:Many of the remarkable properties of surface nanobubbles, such as unusually small contact angles and long lifetimes, are related to the force that pins them onto their substrates. This pinning force is yet to be quantified experimentally. Here, surface-attached nanobubbles are pulled with an atomic force microscope tip while their mechanical responses are observed with total internal reflection fluorescence microscopy. We estimate that a pinning force on the order of 0.1μN is required to unpin a nanobubble from its substrate. The maximum force that the tip can exert on the nanobubble is limited by the stability of the neck pulled from the bubble and is enhanced by the hydrophobicity of the tip.