Direct-Ink Writing of Designer Materials

3D printing is an emerging additive manufacturing technique, one which has been successfully commercialized for both prototyping and distributed manufacturing with industrial applications in architectures, automobile, aerospace, engineering, food, and biomedical areas. Direct-ink writing is a rapid and low-cost 3D printing route that enables design and patterning of planar and three-dimensional (3D) structures with functional ink materials. In this filamentary printing approach, a concentrated ink with tailored rheological properties is extruded through a micronozzle(s) that is translated using a three-axis positioning stage. The ink rapidly solidifies to maintain its shape so that spanning or free-standing structures can be deposited both in- and out-of-plane. With this approach, we aim to demonstrate multi-scale (e.g., from the nano- to macro- length scales) assembly of arbitrarily complex, hierarchical 3D structures composed of multiple materials (e.g., polymers, metals, and ceramics). Here, we present an overview of our recent work on developing functional inks for printing 3D microstructures with designs that have been optimized for structural and functional properties.