Stimuli-responsive helical polymeric particles with amplified circularly polarized luminescence

Abstract

The stimuli-responsive circularly polarized luminescence (CPL) property is highly desirable for the development of advanced multifunctional optical materials. However, the fabrication of CPL solid materials showing stimuli-responsive behavior in terms of tuning and amplifying the luminescence dissymmetry factor (g_lum) remains a great challenge owing to the disorder and aggregation-caused quenching of solid aggregates. Herein, novel solid-state stimuli-responsive CPL helical polymeric particles (SRCHPs) with a fully conjugated skeleton have been successfully fabricated via the precipitation copolymerization of chiral and fluorescent propargylamide monomers. The SRCHPs exhibit stimuli-responsive intense circular dichroism, fluorescence emission, and amplified CPL effects under temperature, pH, and polarized light stimulation conditions. This is attributed to the coordination of the intramolecular hydrogen bonding and conjugated π–π stacking interactions at a large scale based on the cis-transoidal dynamic helical structure, resulting in the amplification of chirality and circularly polarized energy. The present study reports a promising CPL stimuli-responsive and amplification process in the solid state based on a special main-chain conformation to achieve a simultaneous improvement in chirality and fluorescence.