Enhancing Dynamic Modulation in Covalent Adaptable\nNetworks via Accurate Manipulation of Functional Moieties in Vinylogous\nEster Monomers

An\neffective and accurate strategy for tailoring the dynamic properties\nof covalent adaptable networks (CANs), which relies on the capability\nto trigger bond rearrangements within the polymer network, involves\nthe precise control of the material’s microstructure through\nmolecular-scale structural design. Herein, we propose a novel approach\nto modulate the dynamics of vinylogous bonds by changing the adjacent\nchemical moieties of the functional monomers, thereby enabling reversible\nexchange reactions with alcoholic hydroxyl groups. Vinylogous bonds-modified\ncarbonyl group (vinylogous ester bond) revealed dynamic behavior at\na lower temperature than vinylogous bonds attaching to ester motif\n(vinylogous carbonate bond). It was attributed to the extended conjugated\nregion in vinylogous ester moieties. Meanwhile, the dynamic vinylogous\nester bonds exhibited a dissociative mechanism, and an association\nmechanism was offered by vinylogous carbonate motifs. Additionally,\nCANs composed of a vinylogous ester bond (BPAP–OH) displayed\na rapid dynamic feature and a lower activated energy, compared with\nthat of CANs consisting of vinylogous carbonate motifs. Similarly,\nthe shape fixation ratio also indicates comparable dynamic properties.\nIt is noteworthy that BPAP–OH enables degradation in DMSO and\nrecyclability by hot press. This approach offers a versatile tool\nfor tuning the dynamic characteristics of CANs and exploring their\npotential in various applications.