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Creators/Authors contains: "Moon, Junho"

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  1. Abstract The intrinsic reversibility of dynamic covalent bonding, such as the furan‐maleimide Diels‐Alder (DA) cycloaddition reactions, enables reprocessable, self‐healing polymer materials that can be reconfigured via the mechanism of solid‐state plasticity. In this work, the temperature‐dependent exchange rates of stereochemically distinctendoandexoDA bonds are leveraged to achieve tunable, temperature‐ and stress‐activated shape morphing in Diels‐Alder polymer (DAP) networks. Through thermal annealing, ≈35% ofendoDA isomers are converted in neat DAP networks to the thermodynamically favoredexoform, achieving ≈97%exoafter complete annealing at 60 °C. This conversion results in a ≈1.7 fold increase in elastic modulus, from 1.7 to 3.0 MPa, and significantly alters the stress relaxation and shape recovery behavior. Spatially resolved annealing, is further showcased enabling the precise control of spatial distributions ofendoandexoDA bonds across planar geometries. The locally distinct concentrations ofendo/exoisomers, achieved by temperature‐induced conversion ofendoDA isomers to the thermodynamically stableexoDA isomers, gave rise to the spatial distributions of stress relaxation rates and elastic strain recovery mismatch to enable controlled stereochemical shape morphing. This approach provides a simplified, thermally driven method for shape morphing, with potential applications in soft robotics and flexible electronics. 
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