Non-covalent interactions in conjugated polymer blends: insights into the stability of PVC/PM6 and CPE/PM6 systems

Abstract

This study investigates the role of non-covalent interactions (NCIs) in stabilizing blends of the conjugated polymer PM6 with additives polyvinyl chloride (PVC) and chlorinated polyethylene (CPE). Using the NCI index, reduced density gradient analysis, and energy decomposition analysis (EDA), we quantify the contributions of van der Waals forces, hydrogen bonding, and steric repulsions in these systems. Our results reveal that PVC/PM6 blends exhibit stronger NCI, particularly C–H⋯π and C–Cl⋯π interactions, compared to CPE/PM6 blends. EDA further shows that dispersion forces and electrostatic interactions are the primary stabilizing factors in the PVC blend, with hydrogen bonding also playing a critical role. These findings highlight the importance of chlorine content in enhancing NCI and promoting the stability of polymer blends. The insights from this work provide valuable guidance for designing more stable polymer-additive systems in organic electronics and other material applications.