Methods of Restoring and Maintaining Gas Film on Superhydrophobic Surfaces while Underwater

Tech ID: 22142 / UC Case 2011-040-0


UCLA researchers in the Department of Mechanical and Aerospace Engineering have developed a method of maintaining and restoring a gas film on a superhydrophobic surface while underwater.


A liquid interfaced directly with a solid creates frictional forces. For example, these frictional forces slow down a boat traveling through the water and require it to use more power and fuel. A gas film layer between the solid and liquid interfaces would act to reduce frictional forces because the frictional drag of a liquid flowing over a gas film is lower than that of a liquid flowing directly over a solid.

Despite its usefulness, such a gas film layer is thermodynamically unstable. The gas film destabilizes from many different factors, including high liquid pressure, gas diffusion into the liquid, or physical defects on the surface - all of which are inevitable in most real life applications. Past research in the field focused on how to make the superhydrophobic surfaces more robust to prevent the gas film from destabilizing. None were directed at restoring and maintaining the gas film once it is disturbed.


Researchers at UCLA have identified methods to re-establish a gas film on a structured hydrophobic surface underwater when the gas film is disrupted or depleted. The new methods immediately restore the gas film when a breakdown begins, thereby ensuring that a gas film is sustained for a sufficiently long time under various harsh conditions.


  • Water craft manufacturing
  • Water sports including surfing, wind sailing, water skis, etc.
  • Any physical device that functions in water


  • Reduction of frictional drag under laminar and turbulent flow conditions
  • Lower fuel costs
  • Increase speed
  • Prevent solid surface damage

State Of Development

The current methods have been demonstrated and experimentally verified using superhydrophobic surfaces.

Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 10,125,271 11/13/2018 2011-040
Republic Of Korea (South Korea) Issued Patent 10-1906613 10/02/2018 2011-040
Japan Issued Patent 6320754 04/13/2018 2011-040
United States Of America Issued Patent 9,314,818 04/19/2016 2011-040
China Issued Patent ZL 2011800466557 03/23/2016 2011-040
European Patent Office Published Application EP2598433 06/05/2013 2011-040


Learn About UC TechAlerts - Save Searches and receive new technology matches


  • Kim, Chang-Jin

Other Information


gas film, superhydrophobic surface, thermodynamics, frictional drag

Categorized As