Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University , Beijing 100191, China.
ACS Nano. 2016 Dec 27;10(12):10887-10893. doi: 10.1021/acsnano.6b05371. Epub 2016 Nov 22.
Microbubbles are tiny bubbles with diameters below 50 μm. Because of their minute buoyant force, the microbubbles stagnate in aqueous media for a long time, and they sometimes cause serious damage. Most traditional methods chosen for elimination of gas bubbles utilize buoyancy forces including chemical methods and physical methods, and they only have a minor effect on microbubbles. Several approaches have been developed to collect and transport microbubbles in aqueous media. However, the realization of innovative strategies to directly collect and transport microbubbles in aqueous media remains a big challenge. In nature, both spider silk and cactus spines take advantage of their conical-shaped surface to yield the gradient of Laplace pressure and surface free energy for collecting fog droplets from the environment. Inspired by this, we introduce here the gradient of Laplace pressure and surface free energy to the interface of superhydrophobic copper cones (SCCs), which can continuously collect and directionally transport CO microbubbles (from tip side to base side) in CO-supersaturated solution. A gas layer was formed when the microbubbles encounter the SCCs. This offers a channel for microbubble directional transportation. The efficiency of microbubble transport is significantly affected by the apex angle of SCCs and the carbon dioxide concentration. The former provides different gradients of Laplace pressure as the driving force. The latter represents the capacity, which offers the quantity of CO microbubbles for collection and transportation. We believe that this approach provides a simple and valid way to remove microbubbles.
微泡的直径小于 50μm，是一种微小的气泡。由于其浮力极小，微泡在水介质中长时间停滞，有时会造成严重的损害。大多数用于消除气泡的传统方法都利用浮力，包括化学方法和物理方法，但它们对微泡的影响较小。已经开发了几种方法来收集和输送水介质中的微泡。然而，实现创新策略以直接收集和输送水介质中的微泡仍然是一个巨大的挑战。在自然界中，蜘蛛丝和仙人掌刺都利用其锥形表面来产生 Laplace 压力梯度和表面自由能，从而从环境中收集雾滴。受此启发，我们在这里将 Laplace 压力梯度和表面自由能引入超疏水铜锥（SCC）的界面中，这可以连续收集和定向输送 CO 微泡（从尖端到基底）在 CO 过饱和溶液中。当微泡遇到 SCC 时，会形成一个气层。这为微泡的定向输送提供了一个通道。微泡输送的效率受 SCC 的顶点角度和二氧化碳浓度的显著影响。前者提供不同的 Laplace 压力梯度作为驱动力。后者代表了收集和输送 CO 微泡的能力。我们相信，这种方法为去除微泡提供了一种简单有效的方法。
