Tuning the physicochemical properties of conjugated polymers via intramolecular noncovalent interactions
Intramolecular noncovalent conformational locks (NoCLs) have emerged as a potent strategy for engineering high-performance organic/polymeric semiconductors (OPSs) by suppressing non-radiative decay. While the impact of NoCLs on small molecules is well-documented, their influence on the physicochemical properties of conjugated polymers (CPs) remains poorly understood due to the structural complexity, low crystallinity, and poor solubility of CPs. This study addresses that gap by integrating theoretical calculations with advanced experimental techniques—temperature-dependent absorption spectroscopy, cryogenic electron microscopy (cryo-EM), dynamic light scattering (DLS), small-angle neutron scattering (SANS), and freeze-drying transmission electron microscopy (TEM). The results demonstrate that incorporating NoCLs into CP backbones increases chain rigidity, enhances intermolecular interactions, promotes the formation of pre-aggregates with optimal length, and improves charge transport. These findings provide a mechanistic framework for designing high-performance CPs, overcoming the limitations of conventional characterization methods that are restricted to small molecules. The work establishes a correlative link between NoCL-induced conformational locking and macroscopic transport properties, offering a rational design pathway for next-generation organic optoelectronic devices.