Hydration lubrication of polyzwitterionic brushes leads to nearly friction- and adhesion-free droplet motion

Hydration lubrication of polyzwitterionic brushes leads to nearly friction- and adhesion-free droplet motion
Title:
Hydration lubrication of polyzwitterionic brushes leads to nearly friction- and adhesion-free droplet motion
Other Titles:
Communications Physics
Keywords:
Publication Date:
04 September 2019
Citation:
Daniel, D., Chia, A.Y.T., Moh, L.C.H. et al. Hydration lubrication of polyzwitterionic brushes leads to nearly friction- and adhesion-free droplet motion. Commun Phys 2, 105 (2019). https://doi.org/10.1038/s42005-019-0205-x
Abstract:
Recently, there has been much progress in the design and application of oil-repellent superoleophobic surfaces. Polyzwitterionic brush surfaces are of particular interest, because of their ability to repel oil under water, even in the absence of micro-/nanostructures. The origin of this underwater superoleophobicity is attributed to the presence of a stable water film beneath the oil droplet, but this had not been demonstrated experimentally. Here, using optical interferometric techniques, we show that an oil droplet effectively hydroplanes over a water film, whose thickness is between one hundred and hundreds of nanometres. In addition, using a custom-built droplet force apparatus, we find the friction and adhesion forces to be in the nN range for millimetric-sized droplets. These forces are much lower than for other classes of well-known liquid-repellent surfaces, including the lotus-leaf effect and lubricant-infused surfaces, where the typical force is on the order of μN.
License type:
http://creativecommons.org/licenses/by/4.0/
Funding Info:
We are grateful to the Agency for Science, Technology and Research (A*STAR) for providing financial support under the PHAROS Advanced Surfaces Programme (grant number 1523700101, project number IMRE/16-2P1203).
Description:
ISSN:
2399-3650
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