Two-photon polymerized wetting morphologies for tunable external and internal electrode micropatterning

Abstract

Numerous existing and emerging microsize technologies operate by utilizing electrical circuits on surfaces and within solid objects, i.e., external and internal electrodes, respectively. While current micropatterning techniques have achieved extensive progress on current systems via pattern resolution and discretization on simple surfaces, the introduction of new applications relies on the complexity of the parts on which these patterns are fabricated. Additionally, many state-of-the-art applications utilize novel materials for functional systems, which further complicates their fabrication. This paper introduces innovative electrode micropatterning and microchannel filling approaches that support complex 3D designs and reduce the number of fabrication steps. The approaches leverage microsize hydrophobic and hydrophilic morphologies fabricated using the two-photon polymerization (2PP) additive manufacturing (AM) process, in conjunction with the target part. Once fabricated, the part is dipped into a conductive solution or other functional liquids, forming patterns on the surfaces and filling the channels based on the pre-designed wetting morphologies. These morphologies incorporate additional structures beyond the conventional hydrophilic and reentrant hydrophobic structures to facilitate the dipping process. This paper demonstrates the efficacy of the tunable electrode micropatterning approach to fabricate various microsystems utilizing 2PP, wetting morphologies, and the developed dipping process.