Hydrophobicity modification of large-scale PMMA by modularized DBD plasma reactor

Improving the hydrophobicity of insulation surface is an effective method to enhance the electrical insulating performance of outdoor insulation. Atmospheric pressure low temperature plasma technology has made great progress in material surface modification, but most of the existing plasma reactors range in size from a few to tens of centimeters, which cannot meet the need for efficient surface modification of large-scale insulating materials. In this paper, a novel modularized dielectric barrier discharge (MDBD) reactor with gas path optimization and discharge regulation was designed, which was applied to deposit functionalized thin film on the surface of large-scale polymethyl methacrylate (PMMA). The results show that the MDBD reactor with length of 1120 mm achieves uniform discharge, and the addition of precursor hexamethyldisiloxane (HMDSO) promotes first and then suppresses the discharge power of Ar plasma. The water contact angle (WCA) of PMMA increases after the MDBD treatment and the WCA in different positions does not exceed ±5°, indicating the uniform modification of MDBD treatment. Furthermore, the surface properties of PMMA are obviously affected by the addition amount of HMDSO under MDBD treatment. When the addition is 60 sccm, WCA increases from 67° to 140°, and the flashover voltage increases from 6 kV to 10 kV, demonstrating the improvement of surface properties by the MDBD modification.