Decontamination and protection using scanning atmospheric rf plasma

The cleaning of contaminated surfaces and production of self-cleaning coatings are of great interest in environmental protection and defense-related fields. We report scanning atmospheric rf plasma processes for decontamination of organophosphorus nerve agent films deposited on substrate surfaces and deposition of superhydrophobic coatings of various substrates. The plasma source is designed to be suitable for continuous scanning of a large surface area. In the decontamination operation, atomic oxygen, OH radicals, and excited nitrogen molecules are generated at atmospheric pressure and reacted with paraoxon and parathion deposited on metal and glass surfaces. The decomposition products of the plasma treatment are similar to ozone-induced oxidation; but the plasma-induced decomposition rate and efficiency are much higher than the UV/ozone process. The same plasma source is also capable of depositing superhydrophobic coatings on various substrate surfaces to render a self-cleaning property. If the substrate surface is already rough enough, the CH4/He plasma can be used to create optically transparent superhydrophobic coatings. On smooth surfaces, the CF4/H2/He plasma is used to produce optically transparent superhydrophobic coatings without any pre-roughening process.