Ultrawide Property Range Thiol‐Ene Photopolymers for 3D Printing

Abstract Multimaterial 3D printing enables the integration of materials with vastly different mechanical properties. Yet, in practice, existing multimaterial 3D printing methods are often constrained in the range of achievable properties within a single print, necessitating continued reliance on manual assembly for several applications such as soft robotics. Various material systems are developed to address this limitation by incorporating novel chemistries and/or modifying process parameters. Complementing these advancements, a thiol‐ene‐based photopolymer resin is introduced for multimaterial 3D printing that broadens the achievable range of elastic modulus and hardness, spanning five orders of magnitude and two full Shore hardness scales, respectively. It is defined by two extreme materials with disparate cross‐linking densities, but compatible photopolymerization mechanisms, providing access to intermediate properties upon blending. Moreover, continuous gradients are demonstrated through in situ material mixing and controlled diffusion, even at sub‐filament scales. The versatile resin is compatible with direct ink writing, vat photopolymerization, and potentially other processes like material jetting, opening opportunities in soft electronics, personal protective equipment, and biomedical implants.