Bio‐Based Thermoplastic Room Temperature Phosphorescent Materials with Closed‐Loop Recyclability

Abstract Producing thermoplastic room temperature phosphorescent (RTP) materials with closed‐loop recyclability from natural sources is an attractive approach but hard to achieve. Here, the study develops such RTP materials, Poly(TA)/Cell, by thermally polymerizing thioctic acid in the presence of cellulose. Specifically, polymerized thioctic acid poly(TA) forms strong hydrogen bonding interactions with CNF, promoting formation of molecular clusters between the oxygen‐containing units. The as‐formed clusters generate humidity‐ and excitation‐sensitive green RTP emission. Red afterglow emission is also obtained by integrating Poly(TA)/Cell together with Rhodamine B (RhB) via an energy transfer process. Attributed to the thermoplastic properties, the as‐obtained Poly(TA)/Cell can be thermally molded into flexible shapes with uncompromised RTP performance. Moreover, owing to the alkali‐cleavable properties of the disulfide bond in Poly(TA)/Cell, thioctic acid and cellulose can be successfully recycled from Poly(TA)/Cell with a yield of 92.3% and 81.5%, respectively. As a demonstrator for potential utility, Poly(TA)/Cell is used to fabricate materials for information encryption.