Microfluidic Architecting of Patchy MXene Core‐Shell Particles for Ultralow‐Loading Photothermal Shape‐Memory Actuation

ABSTRACT

Shape memory polymers capable of remote actuation are promising for soft robotics, adaptive structures, and biomedical devices, yet efficient photothermal actuation remains limited by particle aggregation, localized thermal hotspots, and poor energy utilization. Here, we introduce a microfluidic architecture‐engineering strategy that transforms MXene nanosheets into spatially distributed patchy core–shell particles for efficient near‐infrared (NIR)‐triggered actuation at ultralow loadings. Flow‐focusing microfluidics assembles Ti ₃ C ₂ T _x MXene nanosheets into 7–10 nm patchy shells around polymeric cores, suppressing restacking while maximizing accessible photothermal interfaces. Incorporated into poly(L‐lactic acid), these particles enable the composite to reach its glass‐transition temperature within 10 s under NIR irradiation (850 nm, 1.8 W cm ⁻² ) at MXene loading of only 0.0024 wt%, resulting in ≈95% shape recovery within 25 s. In contrast, composites containing directly dispersed MXene exhibit localized heating and achieve only ≈63% recovery after 150 s. Combining Monte Carlo photon transport and finite‐element thermal simulations, we show that the patchy‐shell architecture enhances photon harvesting and volumetric heat generation by spatially distributing photothermal interfaces throughout the material. This work establishes architecture‐controlled photothermal transport as a design principle for next‐generation smart composites and demonstrates microfluidic engineering of functional particle architectures as a scalable route toward high‐performance remotely actuated materials.