A small size radiofrequency plasma jet source able to produce cold plasma jets at atmospheric pressure is presented. The surface modi. cation of polyethylene terephtalate, polyethylene and polytetrafluorethylene foils is performed by using a scanning procedure. The contact angle measurements reveal that the treatment leads to hydrophilicity increase. The roughening of surface, specific to each material is noticed. A significant improvement of adhesion is obtained as result of atmospheric plasma treatments. (C) 2008 Elsevier B. V. All rights reserved.