Sustainable lignin-derived elastomers with exceptional UV shielding, photothermal conversion, and power generation properties

As the most abundant aromatic biomass resource in nature, lignin exhibits excellent ultraviolet (UV) absorption, photothermal conversion, and antioxidant properties. However, its complex structure and poor processability limit its application in flexible functional materials. In this work, a series of lignin- graft -poly(acrylamide- co - n -butyl acrylate) (Lignin- g -P(AM- co -BA)) copolymers was designed and synthesized by homogeneous reversible addition-fragmentation chain transfer (RAFT) polymerization. These Lignin- g -P(AM- co -BA) copolymers show tunable glass transition temperatures ranging from −21.9 to 51.2 °C and adjustable tensile strength values from 0.24 to 20.2 MPa by manipulating the PAM and lignin contents. Benefiting from the efficient light absorption and non-radiative relaxation processes of the aromatic conjugated structure of lignin, the lignin-based elastomers possess outstanding UV-shielding performance and extraordinary photothermal conversion ability. Furthermore, these Lignin- g -P(AM- co -BA) copolymer films can be integrated as a photothermal layer into thermoelectric power generation (TEG) devices to construct a flexible photothermal power generation system. Overall, this study provides a new strategy for the high-value utilization of lignin, and the developed lignin graft copolymers show great application potential in smart devices.