Direct Observation of Covalent Adaptable Network Rearrangement Using Single-Particle Tracking

Covalent adaptable networks (CANs) have received significant attention recently because of their potential to replace conventional thermosets with recyclable materials. Current research has been limited to investigations into different chemistries and functional groups that enable structural rearrangement. This leaves a gap in understanding the nanoscale dynamics that govern this rearrangement. In this work, we synthesized CANs from poly(n-butyl acrylate-s-hydroxyethyl acrylate) (PnBA-HEA) and boric acid. With this chemistry, we will directly visualize the self-diffusion of P(nBA-HEA) chains before and after crosslinking. By tuning the molecular weight between crosslinks as well as the bond strength of the crosslinks, a wide range of diffusive behavior can be accessed. Additionally, the self-healing of adaptable networks can be visualized by dye-labeling one half of an interface and observing the evolution of the interface. Results from this study will be broadly applicable to CANs and can inform how to better design and reprocess them.