Heterogeneous Growth of 3D Printed Polymer Network for Multi‐Material Integration

Abstract 3D printing has been highly pursued owing to its effortless fabrication of custom‐defined geometries, yet the integration of multi‐material with diverse properties in one printed object remains challenging. In this work, a digital light 3D‐printed polymer network that is capable of heterogeneous growth to seamlessly integrate multi‐material is designed. This is accomplished through orthogonal photochemistry design, where visible light is utilized to initiate radical polymerization of acrylates for 3D printing. Inspired by plants’ phototropism due to uneven auxin distribution, UV light is employed to induce spatiotemporal catalyst generation for promoting network heterogeneous growth. In this process, it is found that the UV‐generated catalyst effectively facilitates the hydrolysis of ketals to produce hydroxyls, which can further serve as “growing sites” to initiate the ring‐opening polymerization of polycaprolactone. This enables precise manipulation of both shape and mechanical properties in 3D‐printed objects. The distinctive heterogeneous growth mechanism of 3D printing enables the production of multi‐material components using a single resin.