Cosolvent-Mediated Carbon Dots Aggregation in Microgel Microenvironments for Multicolor Dynamic Fluorescence Modulation.

Dynamic fluorescent materials are attractive for tunable emission colors, but most multicolor systems are limited by a few switching states and complex modulation. To address these challenges, a composite system (MG-CDs) was designed by embedding aggregation-induced color-tuning carbon dots (CDs) into microgels. When respectively swollen in water (H2O), ethanol (EtOH), or ethylene glycol (EG), MG-CDs formed distinct internal hydrogen-bonding networks, yielding varied CDs aggregation states and fluorescence emissions. In an H2O-EtOH-EG cosolvent, MG-CDs established more complex hydrogen-bonding networks and heating-induced solvent volatilization driven hydrogen-bonds reorganization, which simultaneously tuned the CDs aggregation and polymer conformations, endowing diverse thermo-responsive fluorescence transitions and multiple programmable emission states within a unitary system. This mechanism highlighted that coupling solvent-responsive hydrogen-bond regulation in polymer microenvironments with emitter aggregation enables tunable dynamic fluorescence.Furthermore, MG-CDs were used as inks in which a cosolvent treatment and heating-driven printed patterns were used from monochromatic to polychromatic, achieving programmable color evolution for information storage.