Hydrophilic surface morphology for intricate conductive coatings

Abstract

Conductive surfaces and patterns are at the forefront of electronics research with a need to go smaller and create more intricate electronic designs and devices while still maintaining easy manufacturability. This paper investigates an approach of patterning conductive traces for microsize electrically driven devices with the focus on enabling and patterning complicated geometries. The approach includes the design and fabrication of hydrophilic microstructures along the channels with hydrophobic borders on devices' surfaces. The channels are connected to larger electrodes outside the device. When a conductive solution is applied to the outside electrode area, hydrophilic morphologies stimulate the solution to feed along the channels and fill the predesigned patterns. Therefore, the major objective of this study is to explore different designs of microstructures to increase surface hydrophilicity for liquid electrode patterning for variously oriented surfaces. Due to numerous physical forces, material domains, and interactions involved, experimental approach is selected to study the method of surface electrode micropatterning through wetting. Microstructured surfaces are fabricated using the two-photon polymerization 3D printing technique due to its superior resolution. Analysis of various morphologies is completed, a microsize electromechanical device with selected hydrophilic morphologies is fabricated, patterned with liquid electrode, and tested. The findings in this paper further the development of electrode patterning and help determine which hydrophilic microstructures show superior patterning ability along horizontal and vertical vectors.