Two-Photon Polymerization 3D Printed Hydrophobic and Hydrophilic Surface Morphologies for Electrode Micropatterning via Dip Coating Techniques and Enhanced Microchannel Filling

Abstract

Numerous existing and emerging microsize technologies operate by utilizing electrical circuits on surfaces and within solid objects, such as electrode micropatterns and filled microchannels. While current micropatterning techniques have achieved extensive performance of current systems through pattern resolution and discretization on surfaces with simple geometry, the introduction of many new applications relies on the complexity of 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 three-dimensional 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 another functional liquid, 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 design of microstructures for a micropatterning approach that allows coating of electrodes using an electrode dipping process for the creation of a microsize strain gauge.