Soft Matter & Interfaces Group, School of Engineering, RMIT University , Melbourne, VIC 3001, Australia.
Revalesio Corporation, 1200 East D Street, Tacoma, Washington 98421, United States.
Langmuir. 2016 Nov 1;32(43):11265-11272. doi: 10.1021/acs.langmuir.6b02066. Epub 2016 Aug 1.
Regulating the formation and growth of microscopic bubbles at solid-liquid interfaces is essential in many physical, chemical, and catalytic processes, such as the electrolysis of water or a dry-wet transition of a superhydrophobic surface. The growth of bubbles in a group is influenced by the neighboring bubbles as well as the overall gas concentration in the system. In this work, we have investigated the growth of multiple microbubbles on highly ordered hydrophobic microcavity arrays, seeded by pre-existing gas pockets trapped inside the cavities. A pulse of gas oversaturation at an extremely low level was supplied in a process we call solvent exchange. Our results show that the distance between the seeding air pockets has significant effects on the location, number density, and size of bubbles on the array. With closely spaced microcavities, growing microbubbles self-organized into symmetric patterns. Their growth rate was enhanced at the corners and edges of the array, and interior bubbles dissolved because of the competitive growth. By contrast, no symmetric patterns were observed when the space between the microcavities was large. The findings reported in this work provide important insights into solvent exchange and collective interactions in the formation of surface nanobubbles.
调控固液界面处微小气泡的形成和生长在许多物理、化学和催化过程中至关重要，例如水的电解或超疏水表面的干湿转变。在一组气泡中，气泡的生长受相邻气泡以及系统中整体气体浓度的影响。在这项工作中，我们研究了在高度有序的疏水性微腔阵列上多个微气泡的生长，这些微气泡是由预先存在的被困在腔体内的气体口袋作为种子形成的。我们采用一种称为溶剂交换的方法，在极低的过饱和度气体脉冲下进行实验。研究结果表明，种子气穴之间的距离对微腔阵列上气穴的位置、数密度和尺寸有显著影响。在微腔紧密排列的情况下，生长中的微气泡会自组织成对称图案。在阵列的角和边缘处，气泡的生长速度加快，内部气泡由于竞争生长而溶解。相比之下，当微腔之间的空间较大时，没有观察到对称图案。本工作的研究结果为溶剂交换和表面纳米气泡形成中的集体相互作用提供了重要的见解。
