Durable Thin-Film DLC on Wafer Surfaces of Gravure Cylinders for Roll-to-Roll Printing of 1-Bit Electrodes and Microtext in Flexible Electronics and Graphic Security

Abstract

Diamond-Like Carbon (DLC), a thin-film material, is emerging as a promising alternative for durable surfaces due to its eco-friendly application process. This study evaluated the use of thin-film DLC on the wafer surface of gravure cylinders for roll-to-roll printing of fine-line electrodes and microtext patterns, specifically for applications in flexible electronics and graphics security. Results suggested that using thin film DLC on the wafer surface allows reliable reproduction of isometric grids and line structures with widths of 15, 20, and 30 µm, as well as solid electrodes. The uniform conformity of thin-film DLC on the wafer surface, featuring an engraved micron-size cell structure, demonstrates superior ink transfer onto flexible PET (polyethylene terephthalate) substrates. This results in increased electrode line width and reduced electrical resistance compared to chrome. Statistical analysis confirmed the reliability and repeatability of the findings. Visual analysis of lines and microtext also demonstrated the reliable print-reproducing capabilities of DLC-coated surfaces. Overall, these results suggest that thin-film DLC is a promising alternative for use as a protective layer on gravure wafer surfaces. It has the potential to produce high-quality, high-volume electronics, such as sensors, antennas, and batteries, for applications in the Internet of Things (IoT) and other sustainable technologies.

Keywords: chrome (Cr); conductive ink; diamond‐like carbon (DLC); electrode lines; flexible electronics; gravure; guilloche; microtext; printing.