Phase-Locked Dynamics: Decoupling Mechanical Stability and Reprocessability in Vitrimer Elastomers

Vitrimers have emerged as a powerful class of dynamic polymer networks, yet their design has been largely governed by chemical exchange kinetics. This chemistrycentric view, however, falls short of rationalizing the persistent trade-off between mechanical stability and reprocessability in vitrimer elastomers. Here, we introduce Phase-Locked Dynamics (PLD) as a physics-based framework in which dynamic covalent bond exchange is hierarchically confined by multiphase architectures, including crystalline domains, supramolecular clusters, entanglement networks, and filler-induced physical locks. In PLD systems, relaxation processes are deliberately separated across length and time scales, enabling dynamic bonds to remain chemically active while mechanically latent under service conditions. We further discuss how nonequilibrium processing fields selectively activate exchange pathways by coupling multiscale relaxation modes, offering a route to program vitrimer topology and anisotropy without altering intrinsic bond chemistry. By integrating polymer physics, simulation-guided insights, and emerging experimental evidence, this Perspective establishes Phase-Locked Dynamics as a general design principle for vitrimer elastomers with decoupled mechanical stability and processability.