Acid-Triggered Crystallization Constructs Efficient Nontraditional Room-Temperature Phosphorescence Polymers

Traditional room-temperature phosphorescence (RTP) materials rely on complex aromatic structures. However, achieving efficient and long-lived emission from simple polymers remains an appealing but difficult challenge. Herein, we propose an acid-triggered crystallization strategy for acrylamide (AM) and hydroxyethyl methacrylate (HEMA) copolymers. The introduction of HCl drives the conversion of AM into 3-chloropropionamide (3-CPA) crystals and generates protonated nitrogen species, with the hydroxyl and ester groups from HEMA working synergistically to reinforce the hydrogen-bonding network. This structural evolution significantly boosts the overall crystallinity of the polymer network, reinforcing conformational rigidification and effectively restricting molecular motion. The strategy extends the emission lifetime from an initial 4.3 ns to 366 ms, accompanied by all overall photoluminescence quantum yield (PLQY) of 15.4%. The resulting poly(acrylamide-hydroxyethyl methacrylate) (PAMHE) derivative exhibits a green afterglow. This work offers a straightforward, metal-free paradigm for the design of high performance nontraditional RTP materials, holding immense promise for advanced anticounterfeiting applications.