Kinetic Programming of Dynamic Covalent Networks via Isomer-Pure Diels-Alder Kinetics.

Abstract

The precise control of material properties through molecular-level architecture remains an enormous challenge in materials science. Here, we present a platform for the kinetic programming of covalently cross-linked networks by translating selective cycloreversion kinetics of isomer-pure endo- and exo-Diels-Alder (DA) diastereomers into controlled material responses. By combining experimental kinetic studies with density functional theory (DFT) calculations, we identify a selectivity window at 70 °C that enables sequential, temperature-selective cycloreversion. We demonstrate that these thermolabile motifs retain their molecular-level kinetic selectivity when incorporated into bulk macromolecular networks, as confirmed by differential scanning calorimetry (DSC) and high-resolution magic-angle spinning (HR-MAS) NMR spectroscopy. To demonstrate such precise kinetic control, we fabricate mono- and multimaterial microstructures via multiphoton printing that can be degraded in a stepwise and temperature-selective manner. We herein establish a robust design strategy for responsive materials for multimaterial 3D microfabrication, whose distinct macroscopic changes are programmed at the stereochemical level of a single molecular motif.