Browsing by Author "Lu, Chi-Chang"

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CHARACTERIZATION OF A NITROGEN-BASED PLANAR DBD APPJ AND ITS APPLICATION IN ITO GLASS CLEANING
(2009)
Chiang, Ming-Hung
;
Lin, I-Min
;
Lu, Chi-Chang
;
Huang, Hao-Yuan
;
Wu, Jong-Shinn
A parallel-plate dielectric barrier discharge (DBD) driven by a quasi-pulsed power supply (60 kHz) under atmospheric-pressure condition was developed and characterized. Various types of working gases, including pure nitrogen, various ratios of volume flow rates of nitrogen to oxygen and compressed air, were tested and compared. A colorful planar jet plume up to 50 mm wide, 25 mm long and gas temperature of 330K was formed at the exit of the parallel-plate channel for both pure and oxygen-traced nitrogen jets. OES measurements in the post-discharged nitrogen jet region showed that UV intensities increase dramatically with trace addition of oxygen (e.g., 1/1000) as compared to the pure nitrogen case. The post-discharge jet region was applied to improve the hydrophilicity of a moving ITO glass surface. Results showed that the measured contact angle of ITO glass surface can reduce from 84 to 26 degrees with a relative moving speed of 9 cm/s.
Modification of Hydrophilic Property of Polypropylene Films by a Parallel-Plate Nitrogen-Based Dielectric Barrier Discharge Jet
(2010-06-01)
Chiang, Ming-Hung
;
Liao, Kuo-Chi
;
Lin, I-Min
;
Lu, Chi-Chang
;
Huang, Hao-Yuan
Modification of the hydrophilic properties of polypropylene (PP) films has been investigated using the postdischarge region of a pulsed nitrogen-based dielectric barrier discharge under atmospheric-pressure conditions. Results show that, for the stationary PP films, the contact angle (CA) decreases dramatically from 103 degrees(untreated) to less than 30 degrees (treated) with a wide range of O(2)/N(2) ratios (<1%) and treating distances (<10 mm). In addition, the CA can still be maintained at similar to 40 degrees after 24 h of the aging test. For the nonstationary PP films, a highly hydrophilic surface can only be obtained when the PP film is placed near the jet exit with O(2)/N(2) ratios of 0.06%-0.2%. Additionally, the CA can only be maintained at similar to 80 degrees-90 degrees when the moving speed is similar to 1 cm/s after 24 h of the aging test. These observations are explained through measured optical emission spectra and ozone concentration data, in which the metastable nitrogen plays a key role in breaking the surface chemical bounds and the UV emission (200-300) participates in the process of converting the ozone into oxygen radical. Furthermore, X-ray photoelectron spectroscopy analysis showed that the O/C ratio increases dramatically for improved hydrophilic surface and the incorporation of functional groups containing oxygen (e. g., C-O and C = O) is critical in increasing the aging time after plasma treatment.