Spontaneous and Directional Transportation of Gas Bubbles on Superhydrophobic Cones

Abstract

Understanding the behavior of gas bubbles in aqueous media and realizing their spontaneous and directional manipulation are of vital importance in both scientific research and industrial applications, owing to their significant influences on many processes, such as waste water treatment, gas evolution reactions, and the recovery of valuable minerals. However, the behaviors of gas bubbles in aqueous media are mainly dominated by the buoyant force, which greatly impedes gas bubble transportation to any other direction except upward. Consequently, the spontaneous and directional transportation of gas bubbles in aqueous media is still identified as a big issue. Here, superhydrophobic copper cones have been successfully fabricated by integrating low‐surface‐tension chemical coatings with conical morphology. The generated superhydrophobic copper cones are capable of transporting gas bubbles from their tip to the base spontaneously and directionally underwater, even when they are vertically fixed with tips pointing up. The present study will inspire people to develop novel strategies to achieve efficient manipulation of gas bubbles in practical applications.

Superwettability of Gas Bubbles and Its Application: From Bioinspiration to Advanced Materials

“…[63] This illustrates that the superaerophobic and aerophobic cones fail to trap or transport gas bubbles (Figure 6a,b). When the gas bubble impacts with the superaerophobic or aerophobic cone, it bounces off.…”

Recent Progress in Fabricating Superaerophobic and Superaerophilic Surfaces

“…In addition, a novel strategy for realizing spontaneous and directional transportation of gas bubbles was put forward by using superhydrophobic Cu with conical morphology. Irrespective of the orientation of the cones, bubbles showed a tendency to move toward the base of the superhydrophobic cone, attributed to the differential Laplace pressure and apex angle of the cone . Later, the same group explored the possibility of a “transporting strategy” of the hydrogen bubbles generated at the conical shaped Cu electrodes, instead of the previously adopted “releasing strategy”; by incorporating a superaerophilic sponge to the base of the electrode.…”

“…A blockage caused by air bubble in liquid perfused microtubes, artificial transplants could affect the health of a patient adversely . Most importantly, the rapid depletion of fossil fuels, adverse climatic changes, and energy scarcity continuously demand for renewable and green fuels . Fuel cell is considered as a plausible alternative for energy generation in an efficient and eco‐friendly way.…”

New conceptual microfluidics technology: light manipulation of liquid slugs in liquid crystal polymer microactuators

“…1b, a wetting liquid droplet confined in a conical capillary could self-propel toward the narrower end, owing to the axial force arising from different curvature pressures across its end caps. Inspired by these special surfaces, various methods have been developed to prepare surfaces with similar directional liquid transport abilities and designed for practical applications, such as liquid transportation, liquid mixture, water harvest, liquid-liquid separation, and bubble collection [6,7].…”

“…1b, a wetting liquid droplet confined in a conical capillary could self-propel toward the narrower end, owing to the axial force arising from different curvature pressures across its end caps. Inspired by these special surfaces, various methods have been developed to prepare surfaces with similar directional liquid transport abilities and designed for practical applications, such as liquid transportation, liquid mixture, water harvest, liquid-liquid separation, and bubble collection [6,7].However, because of the length limit of these cone or beak structures, liquid cannot transport for a long distance. Injecting energy, such as light [8], vibrations [5] or heat, into the system is thus an alternative method for liquid motion.…”