Spontaneous and Directional Transportation of Gas Bubbles on Superhydrophobic Cones

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, super-hydrophobic copper cones have been successfully fabricated by integrating low-surface-tension chemical coatings with conical morphology. The generated super-hydrophobic 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.