Layer‐By‐Layer Shear‐Printing of Bulk Mechanoresponsive Photonic Crystals

Abstract Mechanoresponsive photonic crystals (MPCs) exhibit tunable optical properties and hold great promise for a wide range of applications. However, fabricating them in bulk form remains a significant challenge. In this study, a novel approach is presented for producing bulk MPCs with enhanced optical properties. By incorporating shear‐ordering into the 3D molding process, this study successfully fabricates bulk MPCs that display bright, saturated structural colors with 80% reflectance. The bulk MPCs are constructed layer‐by‐layer via successive shear‐printing using colloidal particles embedded in photocurable resins. Each layer is subjected to oscillatory shear facilitated by a modified 3D printing setup. This process creates a highly ordered face‐centered cubic lattice structure throughout the bulk material. The final product exhibits distinct colors on its various faces, depending on the lattice planes exposed at different orientations. The material is highly strain‐resilient, with pronounced color shifting in response to applied stress. A detailed experimental study of the shear‐ordering mechanism and the resulting structures is provided. This method offers an efficient way to fabricate bulk MPCs with optical performance comparable to the best thin films and can be extended to more complex shapes.