Producing naturally degradable room-temperature phosphorescent materials by covalently attaching lignin to natural polymers

Covalently embedding natural phosphors into a polymer matrix is a particularly appealing approach for producing sustainable room-temperature phosphorescent (RTP) materials. However, the fabrication of such RTP materials remains challenging. Additionally, naturally degradable RTP materials have been scarcely reported although they are crucial for sustainability. Here, we report methacrylated lignosulfonate as a phosphor, which is then covalently embedded within methacrylated gelatin by polymerization. The as-obtained Lig@Gel exhibits phosphorescence of ∼110 ms. Moreover, the Lig@Gel displays excellent biodegradability in a natural soil environment. Life cycle assessment indicates that 10 out of 14 environmental impact categories of our Lig@Gel are approximately 60%–100% lower than those of traditional luminescent materials. As a demonstration of applicability, Lig-RhB@Gel with red afterglow emission is prepared via loading Lig@Gel with rhodamine B (RhB) using an energy-transfer strategy. The as-prepared Lig@Gel and Lig-RhB@Gel could be employed as functional anti-counterfeiting coatings for fibers and paper.