Using Catalytic Control of Dynamic Bond Exchange to Understand Flow and Self-Assembly in Model Networks

The introduction of dynamic covalent bonds (DCBs) into polymer networks facilitates plastic flow upon activation of molecular-level scale reactions in response to stimuli. Thus, by tailoring the onset and extent of bond exchange, these materials present opportunities to access both thermoset and thermoplastic-like properties depending on the conditions of use. While this presents significant opportunities to access recyclable thermosets or to facilitate advanced manufacturing, there remains a lack of fundamental understanding of connecting the chemical details of molecular-scale exchange reactions to bulk thermomechanical properties. In this work, we will discuss recent efforts in our lab to link the rheological behavior at varying amplitudes and frequencies to underlying chemical mechanisms of exchange using model systems where the loading or species of catalyst can be used to tune bond exchange in chemically-identical networks. Additionally, we extend this understanding to control self-assembly in well-defined networks. Finally, we will present best practices for characterizing these materials to understand dynamics at various lengthscales.