Thermoplasmonic-Induced Phase Separation of Polymer Blends for Multicomponent Patterning

Precise spatial control of multicomponent polymer systems is critical for advanced soft materials manufacturing. We present a method for localized phase separation in thermoresponsive polymer blends using Photoinduced Electron/Energy Transfer Reversible Addition-Fragmentation Chain Transfer (PET-RAFT)-synthesized polymers and gold nanorods for photothermal heating under near-infrared light. Optical excitation induces temperature-driven phase separation, enabling microscale patterning without bulk heating. Characterization reveals tunable cloud points, mechanical properties, and rapid heating profiles sufficient to exceed lower critical solution temperature (LCST) thresholds. This thermoplasmonic approach enables scalable, light-directed structuring of polymer domains, offering applications in responsive coatings, additive manufacturing, and functional biomaterials.