The first row of photos shows the Behavior of a Water Droplet’s Contact Angle; on superhydrophillic, normal, and superhydrophobic coated surfaces. Little or no change in the contact angles was observed following irradiation of the coatings by gamma-rays and high-energy protons. The bottom row of photos illustrates that radiation-resistant self-cleaning coatings also offer the potential to reduce terrestrial and extraterrestrial cleaning requirements on surfaces while providing biocidal and spore-repellent features.

This innovation from Goddard Space Flight Center is an antibacterial, anti-contamination, and self-cleaning coating that uses nano-sized semiconductor semimetal oxides to neutralize biological pathogens and toxic chemicals, as well as to mitigate dust accumulation.

Initial results are promising.

An experiment involving radiation-resistant hydrophobic coatings is planned for space exposure and experimental testing on the International Space Station (ISS) in 2011. The Lotus biocide coatings are designed for supporting space exploration missions. This innovation is an antibacterial, anti-contamination, and self-cleaning coating that uses nano-sized semiconductor semimetal oxides to neutralize biological pathogens and toxic chemicals, as

well as to mitigate dust accumulation (see figure).

The Lotus biocide coating is thin (approximately microns thick), lightweight, and the biocide properties will not degrade with time or exposure to biological or chemical agents. The biocide is stimulated chemically (stoichiometric reaction) through exposure to light (photocatalysis), or by an applied electric field (electrocatalysis). The hydrophobic coating samples underwent preliminary high-energy proton and alpha-ray (helium ion) irradiations at the Lawrence Berkeley National Laboratory 88" cyclotron and demonstrated excellent radiation resistance for a portion of the Galactic Cosmic Ray (GRC) and Solar Proton spectrum. The samples will undergo additional post-flight studies when returned to Earth to affirm further the radiation resistance properties of the space exposed coatings.

This work was conducted by Edward W. Taylor of International Photonics Consultants and Ronald G. Pirich of Northrop Grumman for Goddard Space Flight Center. GSC 16117-1