Tunable Broadband Clusteroluminescence in Hydroxylated Maleic Anhydride Copolymers via Hydrogen-Bond Network Regulation

Abstract

Nonconjugated clusteroluminescent polymers provide a promising route to photofunctional materials without relying on extended π-conjugated structures. However, achieving efficient, long-wavelength emission remains a challenge. Herein, hydroxyethyl methacrylate (HEMA) was introduced into a maleic anhydride/vinyl acetate copolymer backbone to design hydroxylated maleic anhydride copolymers, enabling the regulation of hydrogen bonding, segmental motion, and through-space electronic coupling. The poly(maleic anhydride-co-vinyl acetate-co-hydroxyethyl methacrylate) (PMVH) obtained by solution polymerization exhibits excitation-dependent broadband clusteroluminescence, indicating the presence of multiple oxygen-rich emissive clusters with different local packing environments. Upon complexation with sodium carboxymethyl cellulose (CMCNa), the resulting transparent composite films exhibit enhanced red-region clusteroluminescence, with an absolute photoluminescence quantum yield (QY) of 15%. The enhanced red-region emission in the composite system benefits from the synergistic interactions among the hydroxyl groups in HEMA, the carboxylate groups of CMCNa, and Na+ ions. Na+ coordination can construct locally rigid domains, restrict segmental motion, and promote compact packing of oxygen-rich groups and through-space electronic coupling, thereby facilitating long-wavelength clusteroluminescence. Moreover, the composites can be processed into fluorescent fibers via wet spinning, retaining characteristic clusteroluminescence with maximum emission at 440 nm and a QY of 9.66%. This work provides a strategy for modulating broadband clusteroluminescence in nonconjugated polymers through side-chain functionalization and coordination engineering.