Surface treatment of glass and poly(dimethylsiloxane) using atmospheric-pressure plasma jet and analysis of discharge characteristics

An atmospheric-pressure plasma jet source based on dielectric barrier discharge (DBD) was prepared for the hydrophilic surface treatment of poly(dimethylsiloxane) (PDMS). Discharge characteristics were investigated from intensified charge coupled device (ICCD) images and by optical emission spectroscopy (OES). Different optical emission profiles were observed in plasmas with argon (Ar) and helium (He) feed gases. For Ar plasma, OH and N-2 related emission lines are dominant. On the other hand, relatively strong peaks of N-2(+) and O excited species were observed in He plasma, suggesting that a metastable He atom plays an important role in the downstream plasma region. Ar plasma was further found to be more effective than He plasma for hydrophilic surface modification. The surface reverted to being hydrophobic about 40 h after plasma irradiation. (C) 2015 The Japan Society of Applied Physics