Long-Lived Room-Temperature Phosphorescent Cellulose Materials with Dynamic Cross-Linking

In this work, a multicomponent boric acid cross-linking strategy was developed to prepare cellulose-based RTP materials, using sodium carboxymethyl cellulose as the rigid matrix, poly(vinyl alcohol) (PVA) as the auxiliary network regulator, boric acid as the dynamic covalent cross-linker, and 9-phenanthreneboronic acid (PA) as the phosphorescent guest. Boric acid forms a dynamic covalent cross-linked network with hydroxyl groups of CMC and PVA, while PA is tightly immobilized in the matrix through hydrogen bonding and boron-associated coordination interactions, constructing a dense and rigid confined microenvironment. The cellulose-based film exhibits excellent RTP performance, with a phosphorescence lifetime of 2.61 s, an absolute quantum yield of 13.85%, and a visually distinguishable afterglow lasting up to 20 s. Meanwhile, the cross-linked structure endows the material with outstanding mechanical properties (tensile strength of 140 MPa). Additionally, the material displays multiple functional characteristics, including time-resolved information encryption, water-rewritable capability, and reversible responsiveness to humidity and pH.