Efficient ultralong and color-tunable room-temperature phosphorescence from polyacrylamide platform by introducing sulfanilic acid

Pure organic room-temperature phosphorescent (RTP) materials have evoked increasing attention due to their potential application in many fields. However, the preparation of ultralong and color-tunable RTP materials were still facing challenges. Herein, two facile strategies were applied to construct ultralong RTP materials based on non-covalent and covalent linking of sulfanilic acid (SA) on amorphous polyacrylamide (PAM) framework. The hydrogen bonding in PAM/SA and poly(acrylamide-co-4-acrylamidobenzenesulfonic acid) (PAMABS) can effectively help to suppress non-radiative transition, and induce ultralong RTP emission at ambient condition. The RTP emission intensity and lifetime of PAM/SA can be controlled by the molar ratio of acrylamide to SA. Remarkably, PAMABS shows excitation-dependent color-tunable phosphorescence emission. Due to the destructive effect of water on the system rigidity, PAM/SA and PAMABS both exhibit RTP responsiveness to water and heat stimuli. Furthermore, the convenient preparation and excellent properties enable these new organic RTP materials extremely suitable for anti-counterfeiting and information encryption.