The surface oxidation of metal is investigated through plasma treatments with an atmospheric-pressure dielectric barrier discharge (DBD) for comparison with a conventional thermal oxidation process. After the plasma treatment of a copper plate, the Cu surface was noted to have abundant CuO and Cu(OH)(2) which act the part of hydrophilic functional elements. Highly improved wettability was also noted. When a greater amount of atomic oxygen is generated in the plasma by the DBD at a high applied voltage and a high O(2) additive concentration, the hydrophilic functional elements become more abundant and therefore enhance the wettability of the oxidized surface. (C) 2010 Elsevier B.V. All rights reserved.