Digital Light Processing 3D Printing of PDMS-Based Soft and Elastic Materials with Tunable Mechanical Properties

Herein, a family of thiourea containing silicone-based photoresins suitable for creating silicone objects with excellent elasticity was developed for use in conventional digital light processing 3D printers. Rapid manufacturing of silicone products is highly desirable for small-volume manufacturing, especially for the application of customer-specific medical devices. However, because of their intrinsic high viscosity and lack of intermolecular interactions, 3D printing with silicone remains an ongoing challenge as suitable resins are not commercially available. To improve the elasticity of 3D-printed silicones, dynamic noncovalent intermolecular interactions between polymer chains were increased through the introduction of thiourea groups. Furthermore, a molecular design strategy was implemented based on utilizing “oligomeric” and “polymeric” PDMS units to adjust the ratio of thiourea segments. The cured silicone elastomer developed here displayed a maximum elongation of up to 1000% under tensile load and excellent cyclic compression durability. Moreover, this approach allowed for the 3D printing of PDMS-based objects with complex microarchitectures, high resolution, excellent surface finishing, and low cytotoxicity. The silicone thiourea resins have potential application in medical devices, wearable devices, and soft robotics.