Supramolecular 3D Printing Enabling One‐Step Generation of Healable and Recyclable Structurally Colored Objects

Abstract Structurally colored objects with 3D geometries are intriguing in optical devices and visual sensors, but their preparation is bottlenecked by complicated procedures and limited material choices. Herein, a facile supramolecular 3D printing strategy is proposed via direct ink writing (DIW) supramolecular colloidal inks (SCIs) consisting of polymers and colloids based on supramolecular interactions to construct healable and recyclable structurally colored objects. Optimized supramolecular interactions balance the rheological requirements for DIW and the high particle volume fraction for the one‐step and immediate generation of structural color. The shear‐thinning and thixotropy features of the SCIs, characterized by a two‐order‐of‐magnitude decrease in viscosity during the printing process and 50% storage modulus recovery thereafter, ensure the reversible solid–liquid transition during the extrusion and deposition process. The short‐range ordered arrangements of colloids within the matrix give rise to angle‐independent structural color. Moreover, 3D structurally colored objects from the SCIs are healable and, more importantly, can be closed‐looped recycled thanks to the reversibility of supramolecular interactions. Leveraging optimized supramolecular interactions, various SCIs with a wide range of material choices meeting the DIW process are extended to construct 3D structurally colored objects directly. This study paves the way for constructing advanced 3D materials with a supramolecular strategy.