also increases with the drive speed. What is also noticeable on the retraction

Further support for the notion that nanobubbles pre-existed on the hydrophobic surfaces and that their bridging was responsible for the measured attractions subsequently came from de-aeration experiments, which showed that the force tended to be more short-ranged when measured in de-aerated water [115, 126]. Wood and Sharma [126] showed that the force was also of shorter range when measured between surfaces that had never been exposed to the atmosphere, which

suggests that the bubbles attached to defects on the surfaces when they were taken through the air-water interface.