Effect of rf cold plasmas on polysaccharides

Abstract

Low temperature-low pressure argon, nitrogen, and air plasmas generated with rf radiation have been used to treat cotton cellulose and other saccharides. The physical and chemical nature of each substrate was altered by the cold plasma. Although no gross topographical changes of the cotton surface were visible even under the electron microscope, plasma-treated cotton wetted more rapidly and more uniformly than its control, and other saccharides were more soluble in water and other chemical reagents (such as ammonium hydroxide) after plasma treatment. Free radicals were created within the cellulose matrix and structures of all other saccharides. ESR signals, which indicate presence of carbon radicals, degenerated asymmetrically, implying that other types of radicals also existed. ESCA spectra of cotton cellulose showed that some carbon atoms had been oxidized and some oxygen atoms reduced during plasma activation. Activated cottons displayed chemiluminescence and had redox powers that varied with their environments. When cotton and organic monomers were simultaneously present in cold plasma, reactive centers initiated polymerization ofthin films upon the cotton surface. Plasmaactivated cottons exhibited the same chemical reactions as a-hydroxyperoxides or their precursors from living organisms.