Enhancement of hydrophilicity and color strength in plasma treated PET with water vapor post-exposure using a new in-line pilot scale DBD plasma

Due to its low hydrophilicity, direct sublimation inkjet printing on woven polyester fabric surfaces is challenging. This research experimentally studies the efficacy of dielectric barrier discharge (DBD) roll-to-roll plasma treatment with or without water vapor post-exposure as a novel method to modify polyethylene terephthalate (PET) surfaces to enhance hydrophilicity, color performance, and printing quality. The Response Surface Methodology (RSM) was used to design experiments, and the optimum conditions were analyzed through statistical calculations. Their results were examined using Optical Emission Spectroscopy (OES), Atomic Force Microscopy (AFM), field emission scanning electron microscopy (FESEM), Energy Dispersive X-ray (EDX), X-ray Photoelectron Spectroscopy (XPS), and Attenuated Total Reflectance Fourier Transform Infra-Red spectroscopy (ATR-FTIR) tests. Qualitative and quantitative tests for color performance and wicking test used for hydrophilicity assessment confirms the effectiveness of this Green inline pretreatment for industries to enhance direct sublimation inkjet printing quality on PET by a decrease in absorption time from 12051 to 202 s and an increase in the color depth to 12.49%, 25.89 and 18.07% for Cyan, Magenta and Key (black) respectively. One of the stable optimum conditions in which three printed colors: Cyan, Magenta, and Black (Key), show high-quality color performance is at 15 processing rounds, 2 m/min velocity in the absence or presence of water vapor post-exposure. Water vapor post-exposure exhibits a beneficial, economic effect along with plasma treatment. The results show that the chemical modification aspect of this treatment plays a more significant role in printing quality enhancement than its morphological modification.