Room temperature phosphorescent wood hydrogel.

Room temperature phosphorescent (RTP) hydrogels exhibit great potential but show poor mechanical performance (Tensile strengthen <1 MPa) and non-tunable RTP performance, hindering their practical applications. Here, we develop wood hydrogel (W-hydrogel) by the in situ polymerization of acrylamide in the presence of delignified wood. As a result of the molecular interactions between the components of delignified wood and polyacrylamide, the W-hydrogel exhibit a tensile strengthen of 38.4 MPa and green RTP emission with a lifetime of 32.5 ms. Moreover, the tensile strength and RTP lifetime are increased to 153.8 MPa and 69.7 ms, upon treating W-hydrogel with ethanol. Significantly, the mechanical and RTP performance of W-hydrogel is switched by alternating "ethanol and water" treatments. Additionally, W-hydrogel is used as energy donor in order to produce red afterglow emission using RhB via an energy transfer process. Taking advantage of these properties, W-hydrogel is processed into multiple hydrogel-based luminescent materials.