Dynamic Covalent–Enabled Highly Entangled Silicone Elastomers with a Wide Service Temperature Range for Vat Photopolymerization

Silicone elastomers are attractive candidates for vat photopolymerization due to their intrinsic thermal stability and biocompatibility. However, the mechanical properties of photocurable silicone elastomers are fundamentally limited by the insufficient chain entanglement degree and weak intermolecular interactions, which restrict stress transfer and energy dissipation after curing. In this work, this intrinsic structure–property limitation is addressed by constructing a silicone polyurethane acrylate elastomer featuring a highly entangled yet cross-linked network. In brief, dynamic covalent urea bonds and diamine are introduced together to construct a highly entangled polymer chain and dense physical constraints between flexible silicone segments. This structure significantly enhances topological confinement and dissipative interactions while preserving segmental mobility, thereby decoupling mechanical robustness from excessive chemical cross-linking. As a result, chain rearrangement and crystallization are effectively suppressed, particularly under cryogenic conditions. The resulting high-viscosity silicone resin is printed by the linear scanning vat photopolymerization (LSVP) system, enabling stable printing and subsequent network reconstruction through a photothermal dual-curing process. Owing to the synergistic effects of entanglement-dominated stress transfer and reversible physical interactions, the elastomer exhibits a tensile strength of 8.76 MPa and an elongation at break of 405% at room temperature, representing increases of 525.7% and 492.1%, respectively, after heat treatment. Remarkably, it retains an elongation of 108% under tensile testing at −80 °C. This work demonstrates that enhanced chain entanglement and improved intermolecular interactions together provide an effective strategy for overcoming the long-standing mechanical and both high- and low-temperature limitations of reduction photopolymerization-based silicone elastomers, providing a rational design methodology for high-performance 3D printable elastomeric materials.