Optical emission characteristics of medium- to high-pressure N{sub 2} dielectric barrier discharge plasmas during surface modification of polymers

Journal Article · Tue Nov 15 00:00:00 EST 2011 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.3635372· OSTI ID:22054122

Dongping, Liu; Jinhai, Niu; Naisen, Yu ^[1]

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1. School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China) and Fujian Key Laboratory for Plasma and Magnetic Resonance, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen 361005 (China)

The authors measured the band spectra (first and second positive systems) of the nitrogen molecule by optical emission spectroscopy with an aim to understand the mechanism of surface processing by medium- to high-pressure dielectric barrier discharge (DBD) plasmas. The experimentally measured and calculated spectra were compared to determine the vibrational and rotational temperatures of the N{sub 2} (C{sup 3}{Pi}{sub u}) state in the generated plasmas. The authors generated the N{sub 2} DBD plasmas at a driving frequency of 1-7 kHz and a discharge pressure of 20-10{sup 5} Pa for the surface modification of a polyethylene terephthalate (PET) sample. It was found that the vibrational temperature was greatly affected by the N{sub 2} pressure while the rotational temperature remained constant in the N{sub 2} pressure range of 20-10{sup 5} Pa. The emission intensity of N{sub 2} first positive system (B{sup 3}{Pi}{yields}A{sup 3}{Sigma}) rapidly decreased at an increasing N{sub 2} pressure due to the collisional relaxation process of the B{sup 3}{Pi} state with N{sub 2} molecules. The N{sub 2}{sup +}(B{sup 2}{Sigma}{sub u}{sup +}{yields}X{sup 2}{Sigma}{sub g}{sup +}) radiative transition was observed in the low-pressure DBD plasmas, which was attributed to the direct electron impact ionization of N{sub 2} molecules. The surface characterizations of treated PET samples by contact angle measurement and atomic force microscopy indicate that the low-pressure N{sub 2} DBD plasma is an effective method for the surface modification of polymers. Analysis indicates the plasma characteristics such as electron temperature and ion energy are mainly dependent on the N{sub 2} pressure, which turn to determine the surface properties of treated PET samples.

• OSTI ID: 22054122
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 29, Issue 6; Other Information: (c) 2011 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC FORCE MICROSCOPY
DIELECTRIC MATERIALS
ELECTRON TEMPERATURE
ELECTRONS
EMISSION SPECTROSCOPY
ION TEMPERATURE
IONIZATION
KHZ RANGE
MODIFICATIONS
NITROGEN
PLASMA
POLYESTERS
PRESSURE RANGE MEGA PA 10-100
SURFACE PROPERTIES
SURFACE TREATMENTS
SURFACES