Hydrophilicity Improvement of Quartz Glass Surface by a Large-Area Atmospheric Pressure Plasma Generator

In this article, experimental study of a device combining the advantages of dielectric barrier discharge (DBD) and atmospheric pressure plasma jet (APPJ) has been presented. This device with a total length of 500 mm was capable of generating stable uniform atmospheric pressure plasma (APP) with a length of 400 mm, which was operated using a 12-kV HV supply and the air flow rate of 20-30 L/min. The plasma spectra were obtained by optical emission spectroscopy (OES), in which N2(C-B) and N2
⁺
can be observed, and the rotational temperature was calculated to be 360 K. The macroscopic temperature was measured by an infrared camera. The result showed that the central temperature was room temperature. In addition, quartz glass substrates were treated by this device. The surface properties of quartz glass were investigated by water contact angle (WCA), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The results revealed that hydrophilicity and surface roughness of the quartz substrates were gradually increased with increasing treatment time. However, the results of XPS indicated that the content of hydrophilic groups at the surface had a slight change. Therefore, hydrophilicity of quartz glass improved effectively after APP treatment, which was due to the change in surface morphology and the increase in roughness.