Imine-based semiconducting polymers are promising candidates for transient, degradable organic electronics due to their charge transport properties and acid-labile imine bonds. In addition to their degradability, these materials exhibit tunable optical properties in response to acid exposure, driven by protonation of the imine nitrogen atoms. Despite recent progress, the role of dynamic covalent bonds on the structural and electronic properties of imine-based conjugated polymers is not fully understood. Here, we report enhanced crystallinity and electrical conductivity in imine-based conjugated polymers compared to commercially available permanent polymers (PQT-12). Imine-based dynamic polymers were synthesized via step-growth polymerization without acid catalysts. Polymer samples were processed using high temperature and pressure via hot pressing, as elevated temperatures are required to activate imine bond exchange (specifically imine metathesis in solid-state materials). Applied pressures could facilitate dynamic bond exchange by promoting backbone planarity and closer π - π stacking. Our results show that elevated temperature in hot pressing resulted in high degrees of crystallinity and electrical conductivity (~10-5 S/cm at room temperature) after iodine vapor doping. To further promote dynamic bond exchange, p-toluene sulfonic acid (PTSA) was added before hot pressing. The addition of PTSA led to more pronounced morphological changes and higher electrical conductivity (~10-4 S/cm at room temperature), which is attributed to a combination of imine bond protonation and catalyzed bond exchange by acids. Overall, these results suggest that dynamic covalent bond exchange provides a promising strategy for tuning and enhancing the structural and electronic properties of semiconducting polymers.
