Tunable Multicolor Luminescence Polyglycidol-Acrylates: One-Pot Preparation and Properties

Unconventional fluorescent polymers have attracted increasing attention due to their simple preparation, good biocompatibility, and stable photophysical properties. Polyglycidol-acrylates (PGL-acrylates) with tunable multicolor emission were prepared by one-pot in this study. First, PGL was synthesized by the ring-opening polymerization of glycidol, and then the terminal hydroxyl groups in polyglycidol were modified using propiolic acid ester via the oxa-Michael reaction in situ, forming PGL-acrylates with terminal acrylate units. The fluorescence emission of PGL-acrylate follows the clustering-triggered emission (CTE) mechanism, where the through-space interaction (TSI) between the acrylate units forms the clusters. All of the prepared PGL-acrylates show typical concentration-enhanced emission and excitation-dependent emission, and significant emission at 640 nm was observed. Particularly, PGL-acrylate demonstrated an unusual concentration-excitation-dependent emission (EDE) behavior, in which the maximum excitation and emission wavelengths of the solution showed considerable red-shift with the increased PGL-acrylate concentration. This could come from the increased π-π* interactions with increased double-bond concentration, which stack and drive a more compact structure of the luminescent clusters. The compact cluster structure enhances the TSI effect and expands the delocalized electrons, leading to increased emission and red-shift. As the steric hindrance of the terminal methyl acrylate unit increases, it is difficult to form a more compact cluster structure, and the fluorescence emission is blue-shifted. PGL-acrylate also has low cytotoxicity and good cell imaging ability and is expected to be used in biomedical applications.