Star copolymers with tunable clusteroluminescence†

Clusteroluminescence (CL) has recently drawn more attention due to its unique photophysical behaviors that differ from traditional conjugated luminogens. However, the design of red emission from such systems is still challenging due to the intrinsic drawbacks of non-conjugated luminogens and the preliminary mechanisms. In this work, we synthesized four-armed star poly(maleic anhydride-alt-vinyl acetate) (SPMV) copolymers with different chain lengths through a reversible addition–fragmentation chain transfer (RAFT) polymerization method. By adjusting the amount of the chain transfer agent added, the chain lengths of the star copolymers could be transformed from long to short, regulating their fluorescence emission from blue to red. The emission wavelengths of the star copolymers with the shortest chain lengths are significantly red-shifted and concentrated in the red-orange region. The introduction of a star structure can enhance the flexibility of copolymer chains, thus promoting strong interchain interactions and the formation of more chromophores. Concurrently, the prepared star copolymer could be employed as a coating, endowing the substrate with excellent light transmittance and fluorescence properties. This study not only offers new insights into the CL mechanism but also presents a novel method to adjust the emission of anhydride copolymers, thereby expanding the applications of CLgens to unexplored fields.