Precise Construction of Helical Unimolecular Micelles from Poly(phenylacetylene)s for Tunable Circularly Polarized Luminescence and Sensing

Chiral nanocomposites have attracted much attention due to their fascinating size-dependent characteristics. Such nanomaterials could be precisely synthesized by templates from randomly coiled unimolecular micelles with poor chiroptical activities. Helical polymers possessing secondary chirality usually display stronger chiral induction than random-coiled polymers do. However, the controllable preparation of helical unimolecular micelles still remains challenging, which hinders the investigation into the effect of morphology and size on chiroptical properties. In this study, multiarmed star-shaped poly-(phenylacetylene)-s (PPAs) with target composition, molecular weight, and size were precisely prepared from the multisited initiator via living polymerization. Based on acid-base interactions, chiral transfer from PPAs to various dyes was accomplished in composite membranes and suspension. Notably, the chiral nanocomposites consisting of star-shaped PPAs displayed enhanced helical stability, Cotton effect, and circularly polarized luminescence (CPL) compared with linear analogues. Furthermore, this system displayed the triple-mode (photoluminescence, circular dichroism, and CPL) detection toward the volatile organic compound for environmental monitoring.