Photothermally Triggered Self‐Healing Polyurethane Elastomers for Multifunctional Thermochromic Fluorescence Devices

ABSTRACT Self‐healing polymeric materials have attracted significant attention for use in protective coatings and biomedical systems. However, most existing self‐healing systems depend on thermal activation, which limits their applicability under ambient or localized conditions. Herein, we report a photothermally triggered self‐healing polyurethane elastomer (PUM) incorporating molybdenum dioxide (MoO 2 ) nanomaterials into a dynamic polymer network containing disulfide linkages and hydrogen bonding. It demonstrates broad‐spectrum spectral absorption under sunlight or near‐infrared (NIR) irradiation, during which MoO 2 efficiently converts light into localized heat, activating reversible bond exchange and enabling rapid, autonomous damage repair. The optimized PUM exhibits exceptional mechanical performance, including a tensile strength of 40.8 MPa, an elongation at break of 1225.5%, and a toughness of 189.6 MJ m − 3 , alongside an ultrafast self‐healing process in which surface cracks completely disappear within 2 min. To further extend functionality, thermochromic fluorescent components were incorporated to obtain a fluorescent PUM (FPUM) exhibiting reversible color‐tunable luminescence under 980 nm irradiation. The FPUM can be readily processed into printable luminescent inks for use in anti‐counterfeiting and optical display applications. This work introduces a versatile photothermal activation strategy for self‐healing polymers and demonstrates the potential of multifunctional MoO 2 ‐photothermal systems in advanced optical devices.