Uniform Area Treatment for Surface Modification by Simple Atmospheric Pressure Plasma Treatment Technique

Dong Ha Kim,Jeong Hyun Seo,Bhum Jae Shin,Choon-Sang Park,Heung-Sik Tae

doi:10.1109/access.2019.2930534

Abstract

The atmospheric pressure plasma jet (APPJ) has a merit to treat curved or 3D surface without using a ground electrode but nonetheless limits applications for expanding treatment area due to the localized ionization energy induced by the propagation along the direction of guided ionization waves. This paper proposes a uniform area treatment for surface modification based on the experimental case studies relative to variations of the APPJ structures, such as the number of array jets and guide-tube, including bluff-body (GB) system plus gas compositions. In these case studies, the current, infrared (IR), and optical emission spectrum (OES) are analyzed to investigate the factors affecting intensive glow-like plasma generation for uniform area treatment. Plasma-treated polyethylene terephtalate (PET) films are additionally examined to check the possibility of uniform area treatment for surface modification by using atomic force microscope (AFM), Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA). Only in case of three-array jets with GB system using Ar with O2 gas, the intense glow-like plasma is observed to be produced widely in discharge space, thereby enabling the entire surface of PET films to be treated uniformly. In particular, the proposed APPJs are observed to generate more abundantly the reactive nitrogen species (RNS) ranging from 330 and 380 nm and the reactive oxygen species (ROS) at 777.4 and 844.6 nm. Furthermore, the plasma-treated PET film shows that the abundant RNS and ROS play a significant role in smoothening and changing its surface into hydrophilic surface. As a result, it is confirmed that the intense glow-like plasma generated broadly by the proposed APPJs can uniformly treat the entire surface of PET films.

Highlights

Atmospheric pressure plasma (APP) device has attracted attention as advantages of non-thermal, dry process, and replacing of conventional expensive low-pressure plasma
We confirmed that the secondary flow and static pressure were increased via optimized glass-tube and bluff-body (GB) system [18], meaning that the flow direction of the plasma produced by the atmospheric pressure plasma jet (APPJ) was randomly changed against the flow direction of gas in which it normally appeared in the conventional APPJs
In order to improve the capability of the uniform area-treatment for the conventional APPJs, we experimentally performed case studies depending on the variations of APPJ structures, such as the number of array jets and GB system including gas compositions

Summary

Introduction

Atmospheric pressure plasma (APP) device has attracted attention as advantages of non-thermal (low temperature), dry process, and replacing of conventional expensive low-pressure plasma. The surface modification and polymer synthesis using atmospheric pressure plasma jets (APPJs) and dielectric barrier discharge (DBD) have been extensively studied due to the advantage for localized three-dimensional (3D) treatments [9]–[12], and large area-treatments, respectively [13], [14]. To overcome this weakness of the conventional APPJs in view of a surface treatment, the required discharge characteristics would be a glow-like plasma instead of a streamer even though the jets are used as an APP source In this sense, the new types of APPJs that can produce the intensified broad glow-like plasma in a discharge space needs to be studied. The guided ionization waves were weakened and converted into an intense glow-like plasma due to the randomness of gas flow direction with the help of GB system in the APPJs [18]

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Conclusion