Method and device for restoring and maintaining superhydrophobicity under liquid
AssigneeThe Regents of the University of California
InventorsChang-Jin Kim, Choongyeop Lee
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Abstract
A superhydrophobic surface includes a plurality of microfeatures disposed on a substrate and a gas generator disposed within the microfeatures, the gas generator configured to generate a gas within the microfeatures. Gas is generated within the microfeatures when at least a portion of the microfeatures is in a wetted state to restore the microfeatures to a dewetted state. Gas generation is self-regulating in that gas generation automatically starts when a wetted condition exists and stops when sufficient gas has been generated to recover a dewetted state that restores superhydrophobicity.
Claims16
A superhydrophobic surface substantially immersed in water comprising:
- a substrate substantially immersed in the water;
- a plurality of microfeatures in the shape of posts or grates extending away from the substrate and substantially separated from one another by a distance and oriented substantially orthogonal to a surface of the substrate, wherein adjacent microfeatures define spaces there between;
- a plurality of gas generators disposed on or embedded in the substrate or microfeatures;
- wherein each gas generator is configured to automatically generate one of hydrogen gas (H2) or oxygen gas (O2) within the respective space when water invades the space and contacts the gas generator and wherein gas generation automatically stops when water is expelled from the space by the generated hydrogen gas (H2) or oxygen gas (O2);
- and
- wherein the gas fraction, contact angles, and height (H) to pitch (L) ratio of the microfeatures are within a range that directs the generated hydrogen gas (H2) or oxygen gas (O2) to grow into a substantially continuous layer of gas filling the spaces between the microfeatures rather than allowing the generated hydrogen gas (H2) or oxygen gas (O2) to form individual bubbles of gas leaving the superhydrophobic surface during filling of the spaces.
A superhydrophobic surface substantially immersed in water comprising:
- a substrate substantially immersed in the water;
- a plurality of microfeatures in the shape of posts or grates extending away from the substrate and substantially separated from one another by a distance and oriented substantially orthogonal to a surface of the substrate, wherein adjacent microfeatures define spaces there between;
- a plurality of gas generating electrodes disposed on or embedded in the surface of the substrate or microfeatures;
- a power source coupled to the gas generating electrodes, wherein the gas generating electrodes are configured to automatically generate one of hydrogen gas (H2) or oxygen gas (O2) within the respective space when the water invades the space and contacts the gas generating electrode and wherein hydrogen gas (H2) or oxygen gas (O2) generation automatically stops when water is expelled from the space by the generated hydrogen gas (H2) or oxygen gas (O2);
- and
- wherein the gas fraction, contact angles, and height (H) to pitch (L) ratio of the microfeatures are within a range that directs the generated hydrogen gas (H2) or oxygen gas (O2) to grow into a substantially continuous layer of gas filling the spaces between the microfeatures rather than allowing the generated hydrogen gas (H2) or oxygen gas (O2) to form individual bubbles of gas leaving the superhydrophobic surface during filling of the spaces.
Dependencies are inferred from the claim text.