(560h) Tunable, Phase-Separated Dynamic Networks through Thia-Michael Chemistry

Dynamic covalent networks (DCNs) are a broad class of polymeric materials containing covalent crosslinks that undergo exchange reactions (ideally in a reversible fashion). By changing the molecular exchange dynamics, the network relaxation properties can be directly manipulated. In this talk, recent advancements in DCNs comprised of strongly tunable, catalyst-free, ambient temperature dynamic thia-Michael (tM) bonds are detailed. While the ambient dynamic exchange would typically result in weak materials, tM DCNs undergo an emergent dynamic reaction-induced phase separation process (DRIPS) that leads to robust mechanical properties. The underlying morphology of phase-separated domains, as well as user-defined modulation of the (thermo)mechanical properties and stress relaxation behavior through electronic substituents, are highlighted through a diverse suite of characterization techniques (NMR kinetics, AFM, Raman-coupled rheology, and stress relaxation experiments).