Supramolecular Maleimide–Styrene Copolymers with Fluorophenyl Side Chains for High-Performance Guest–Host Electro-Optic Materials

This study reports the precise molecular design of maleimide-styrene alternating copolymers, poly(MI-alt-S), as host polymers for supramolecular guest–host electro-optic (EO) materials, combining a benchmark push–pull tetraene chromophore to achieve performance optimization. Leveraging the inherent sequence control, high glass transition temperature, and synthetic versatility of poly(MI-alt-S), four fluorophenyl-substituted copolymers were synthesized to incorporate three to five fluorine atoms onto the phenyl side chains, tuning the weak hydrogen bonding interactions. Guided by theoretical calculations, this work encompasses monomer synthesis, copolymerization, and spectroscopic characterization of fluorobenzyl ether-functionalized poly(MI-alt-S) polymers to reveal how subtle variations in fluorine substitution govern nanoscale morphology, critical cracking thickness, electric field poling, and EO performance of guest–host polymers. EO activity, polar order, and thermal stability of poled films were evaluated using high-accuracy attenuated total reflection (ATR) measurement. Notably, two of the polymers demonstrated large and thermally stable EO coefficients of ∼170 pm/V at 1306 nm and ∼100 pm/V at 1541 nm, among the best ATR-validated performances for guest–host polymers. These findings highlight that tailored nonclassical hydrogen bonds from fluorophenyl side chains effectively balance intermolecular interactions, mechanical properties, orientational polarization, and thermal stability, illustrating how molecular-level precision in the design of guest–host EO polymers translates into optimized photonic functionality.