Browsing by Author "Chiang, Ming-Hung"

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An Optimized Two-Step Nitrogen-Based Plasma Treatment Procedure under Atmospheric-Pressure Condition and its Surface Amination Mechanism
(2015-07-01)
Yang, Yi-Wei
;
Wu, Jane-Yii
;
Liu, Chih-Tung
;
Liao, Guo-Chun
;
Cheng, Kuang-Yao
Atmospheric pressure nitrogen-based dielectric barrier discharge (DBD) jet with two-step plasma treatment procedure has been verified to be very effective in facilitating nitrogen-containing group incorporation on Polylactide (PLA) surface. It includes: 1) pretreatment plasma treatment by a nitrogen discharge with a trace amount of oxygen, and 2) ammonia plasma treatment by a nitrogen discharge with a small amount of ammonia. In this study, the optimized operation condition of two-step plasma procedure is investigated under different concentrations of added gases (0-1% oxygen; 0-10% ammonia). XPS analysis shows that approximate to 0.19 of N/C ratio can be achieved by means of the optimized two-step plasma procedures. Furthermore, a surface amination mechanism is proposed based on the observations of Optical Emission Spectra (OES), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectra (XPS) analyses.
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.
Fast incorporation of primary amine group into polylactide surface for improving C2C12 cell proliferation using nitrogen-based atmospheric-pressure plasma jets
(2014-01-01)
Yang, Yi-Wei
;
Wu, Jane-Yii
;
Liu, Chih-Tung
;
Liao, Guo-Chun
;
Huang, Hsuan-Yu
In this article, we report the development of the fast incorporation of primary amine functional groups into a polylactide (PLA) surface using the post-discharge jet region of an atmospheric-pressure nitrogen-based dielectric barrier discharge (DBD). Plasma treatments were carried out in two sequential steps: (1) nitrogen with 0.1% oxygen addition, and (2) nitrogen with 5% ammonia addition. The analyses show that the concentration of N/C ratio, surface energy, contact angle, and surface roughness of the treated PLA surface can reach 19.1%, 70.5 mJ/m(2), 38 degrees and 73.22 nm, respectively. In addition, the proposed two-step plasma treatment procedure can produce a PLA surface exhibiting almost the same C2C12 cell attachment and proliferation performance as that of the conventional gelatin coating method. Most importantly, the processing/preparation time is reduced from 13-15 h (gelatin coating method) to 5-15 min (two-step plasma treatment), which is very useful in practical applications. (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 160-169, 2014.
Highly Effective Large-Area Inactivation of B. subtilis Spore Using a Planar Dielectric Barrier Discharge Jet With CF4/Air Mixture
(2012-11-01)
Yang, Yi-Wei
;
Wu, Jane-Yii
;
Chiang, Ming-Hung
;
Wu, Jong-Shinn
;
機械工程學系
In this paper, we demonstrate that, by adding a small amount of CF4 (2%) into a compressed-air planar dielectric barrier discharge (DBD), one can effectively inactivate a B. subtilis spore up to 50 mm in width in the postdischarge jet region after ten passes of exposure of plasma plume (equivalent plasma exposure time of 1 s) for treatment distance of up to 14 mm for the spore concentration in the range of 10(5)-10(7) CFU/mL. A possible mechanism is proposed, i.e., the chemically active F atoms and CFn (n = 1-3) are generated through the help of abundant excited nitrogen molecules in the postdischarge region.
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.