Visible Light Driven Diselenide Chemistry for Simultaneous 3D Patterning and Mechanical Reinforcement.

Three-dimensional (3D) patterning on polymer surfaces is typically achieved by photolithography or related techniques, which often involve complex procedures, high-energy ultraviolet light, and risk of material damage. Here, we report a visible light-driven strategy that exploits the dual functionality of stress relaxation via dynamic bond exchange and radical-initiated polymerization to create raised 3D patterns on diselenide-containing polyurethane films. Under mild visible light irradiation through a photomask, the diselenide bonds undergo homolytic cleavage, enabling local stress relaxation and simultaneously generating selenium radicals that polymerize a methacrylate monomer swollen in the matrix. The resulting patterns exhibit high fidelity to the mask. The method is compatible with complex templates (letters, Braille, QR codes, and photographs) and even with a commercial projector as a maskless light source. Moreover, the large modulus contrast between the patterned phase and the pristine matrix enables strain isolation, allowing conductive coatings on illuminated regions to maintain electrical continuity under stretching. This rapid, low-damage, and versatile approach provides a new route to functional 3D surface architectures for applications in tactile displays, flexible electronics, and strain-isolated devices.