Electric field-coupled two-photon polymerization system for on-demand modulation of 3D-printed structural color.

Advanced manufacturing has been extensively studied using various resin monomers and customized apparatus. Multimaterial microfabrication tools remain limited due to the size constraints inherent in extrusion-based fabrication methods. In addition, prior research predominantly employs monomers as "inert" resins, with minimal emphasis on altering their properties during fabrication. In this study, we propose a novel approach to field-coupled advanced manufacturing, wherein external stimulative fields are integrated to dynamically modulate the properties of "dynamic" resins during 3D printing. As a demonstration, we utilize an electric field-coupled two-photon polymerization (EF-TPP) technique to fabricate structurally colorful microstructures. To address the challenges of limited fabrication approach and resins in the field of structural color, we present an EF-TPP system that enables the production of 3D structural colorful microstructures. By coupling the electric field with the two-photon polymerization (TPP) process, this method enhances 3D printing capabilities, allowing for the bottom-up fabrication of structural colorful microstructures. Furthermore, it integrates existing electrically tunable heliconical cholesteric liquid crystals, enabling the modulation of structural color during printing while also accelerating the printing speed. This approach facilitates the production of microstructures with multiple structural colors without requiring changes to the resin ink. By eliminating the lithography step, the EF-TPP system promotes green manufacturing practices and introduces an unconventional paradigm for fabricating dynamic, microscale structural colorful devices. Additionally, the electric field-integrated two-photon lithography system provides a foundational strategy for advancing field-coupled manufacturing methodologies.