Deciphering Structure–Functionality Relationship of Polycarbonate-Based Polyelectrolytes by AIE Technology

Conjugated polyelectrolytes prepared from carbon–carbon coupling polymerization have difficulties in controlling the precision molecular weight (Mn), so that the effect of Mn on their performance remains vague. Herein, we develop a strategy to prepare well-defined polyelectrolytes with adjustable Mn through a combination of controllable polymerization and aggregation-induced emission (AIE) technique. The resultant tetraphenylethylene-labeled polycarbonates show tunable Mn in the range of 2300–9500 g mol–1, which is further quantitatively converted to polyelectrolytes via thiol–ene click chemistry. The AIE-active polyelectrolytes are used for Zn2+ detection to decipher structure–functionality relationships. Fluorescence variation indicates that Zn2+ detection is tightly associated with Mn. For Mn < 5600 g mol–1, the shrinkage of the nanoparticle is caused by the diffusion of Zn2+ into the loose space between the COO– groups in a single nanoparticle. For Mn > 7600 g mol–1, the possible entanglement and wrapping of long chains hinder the diffusion of Zn2+, triggering the coordination of Zn2+ between different nanoparticles. This work may provide insights into comparing the self-assembly behavior of materials with different architectures.