Scalable Fabrication of Conductive Lines by Patterned Wettability‐Assisted Bar‐Coating for Low Cost Paper‐Based Circuits

Abstract

AbstractPatterning technology on the paper based on wettability difference for paper‐based devices has attracted significant attention for its low cost, easy degradability, and high flexibility. Here, conductive lines are rapidly prepared by patterned wettability‐assisted bar‐coating for low cost paper‐based circuits. It is found that 7 s plasma treatment time for acquiring wettability difference is optimal, which resulted in not only effective splitting of the liquid film but also highly consistent line width with mask. Moreover, low retention force of hydrophobic surface is imperative for self‐confinement of the ink into hydrophilic areas, especially for ink with high solid content. The sheet resistance of patterns can reach 5 Ω ◻−1 after 980 nm laser sintering when using 50 wt% solid content ink with 110 cP viscosity. The geometries of line patterns, i.e., line width and spacing, can be readily tuned by varying the designed size of mask patterns. As‐prepared conductive patterns show good conductivity even after 500 bending cycles at 2 mm bending radius. It is believed that this study will provide deeper understanding of wettability difference‐assisted patterning process and represents a general strategy for selective wetting, especially for high viscosity ink.