Enhancing Dynamic Modulation in Covalent Adaptable Networks via Accurate Manipulation of Functional Moieties in Vinylogous Ester Monomers

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