Air-Retaining-Grids - Grids for stable Gas Retention under Fluids


Ref.-No. 4541

The present invention „Air-Retaining-Grids-Technology“ describes a new way of architecture and construction of surfaces, which are capable of keeping a layer of gas stable, even under changing pressure conditions if immersed in liquid. Structured, nonwettable surfaces are used for various applications. The surfaces of the lattice structures are liquid-repellent and in particular hydrophobic as well as oleophobic. Grids or grid-like structures which are mounted over a surface and supported by a spacer, enclose a stable gas layer as soon as it is submerged under liquid. By means of the lattice structures it is possible to absorb mechanical stresses more elastically and in the case of a mechanical impact it is possible to maintain the gas layer. Various structures of the gratings or grid-like structures, which are supported, allow the surface to be subdivided into sealed gas volumes. As a result, there is a long-term stable gas hold under liquid.

Keywords: Salvina Effekt, unbenetzbare Oberflächen, Salvina Paradox, hydrophob, Luftschicht, Gashaltung, Gasschicht, Netz, Schiffsbau, Reibungsreduktion, Salvina effect, unwettable surfaces, Salvina paradox, hydrophobic, air layer, gas retention, gas layer, net, drag reduction, ship hulls

Competitive Advantages 

  • Use on large surface (e.g., ship´s hull)
  • Large-area gratings can be produced easily, homogeneously, placed on a substructure and fixed
  • Aligned for loads under dynamic conditions
  • Remain stable against mechanical influences (e.g., fast flowing waters)
  • Cost-effective simple production
  • Can also be used in the field of sensorics

Commercial Opportunities 

The Air-Retaining-Grids-Technology is ideal for large-scale implementation of bionic air-retaining surfaces. Great potential lies in the production of friction reducing ship coatings, where structures are permanently immersed in liquids or water. Through the grids a stable air conditioning can be achieved. Because the gas layers remain stable under liquids, the surfaces can be used for friction reduction or as an antifouling coating on ship hulls or other liquid-overflowed surfaces. It is also conceivable use in the sensor as a sensor for currents or pressure.

Current Status 

The invention has been applied for a patent. We are happy to inform you about the status of the proceedings. The functionality has been proven experimentally. On behalf of the Rheinische Friedrich-Wilhelms University Bonn, PROvendis offers licenses to interested companies for the invention and the patent application. 
Relevant Publication

The Salvinia Paradox: Superhydrophobic Surfaces with Hydrophilic Pins for Air Retention Under Water. Advanced Materials 22 (21), 2325-2328. W. Barthlott, T. Schimmel, S. Wiersch, K. Koch, M. Brede, M. Barczewski, S. Walheim, A. Weis, A. Kaltenmeier, A. Leder and H. F. Bohn (2010).
An invention of the Rheinische Friedrich-Wilhelms University Bonn. 


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