title: Coalescence, Growth, and Stability of Surface-Attached Nanobubbles.
abstract: Surface-attached nanobubbles once formed and kept under constant conditions show remarkable stability against dissolution. When observing a large population of nanobubbles using total internal reflection fluorescence (TIRF) microscopy, we find rare events of coalescence, i.e., the merging of two neighboring bubbles. The new bubble covers the convex hull of their "footprint", with most of the three-phase contact line remaining pinned. Interestingly, the newly formed bubble is not shape-stable but grows in height within several 100 ms. This growth dynamic can be described with the classical diffusion theory using contact line pinning and Henry's law. This theory also shows that surface nanobubbles can attain a stable shape with a contact angle larger than 90° in supersaturated liquid.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Chon U
authors.initials: CU
authors.lastname: Chan
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Manish
authors.initials: M
authors.lastname: Arora
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
authors.forename: Claus-Dieter
authors.initials: CD
authors.lastname: Ohl