Wavelength selective fragmentation of metastable photoresponsive platelets via light irradiation

Polymer lamellar crystals commonly consisting of folded chains are frequently formed since they are kinetically favorable. Hence, the metastability of polymer crystals can be regulated by crystallization pathways, and the thinner lamellar crystals display a tendency to transform into thicker crystals via lamellar thickening process. Herein, we report that photoresponsive two-dimensional (2D) platelets with low metastability undergo controllable fragmentation upon light irradiation. Mechanistic studies indicate that the metastability within a single platelet particle is heterogeneous across different domains. Light irradiation triggers lamellar thickening preferentially within less stable domains decorated with photoresponsive molecules, leading to site-specific fragmentation. To illustrate the utility of light-stimulated fragmentation, wavelength selective fragmentation of 2D segmented platelets with spatially defined photoresponsive molecules is achieved upon light irradiation, yielding 2D hollow platelet structure. This important feature holds significant promise for advanced applications such as spatially resolved therapeutic delivery systems, thereby broadening the functional scope of 2D nanomaterials. Two-dimensional platelets are typically formed from polymer lamellar crystals, with metastability regulated by crystallization pathways. Here, the authors report photoresponsive platelets with low metastability, which undergo controllable fragmentation on light irradiation.