Polymer Platelets via Crystallization-Driven Self-Assembly of Block Copolymers: Precision Growth, Structural Complexity and Emerging Functions.

Crystallization-driven self-assembly (CDSA) provides a versatile route to low-curvature polymer nanostructures with controlled dimensions and hierarchical organization. 2D platelets represent a particularly important class of CDSA assemblies, combining ordered crystalline cores, accessible surfaces, and chemically programmable coronas. These features make them well-suited for precision structural engineering and functional integration. In this Review, recent advances in the preparation and application of 2D platelets are discussed. We summarize strategies for preparing uniform 2D platelets with controlled dimensions, discuss the key factors governing heteroepitaxial crystallization, and highlight flat-on epitaxial growth as a route to structurally complex 2D platelet architectures. This review also examines emerging strategies for constructing 2D hollow platelets through selective disassembly. Finally, it highlights the applications of 2D platelets in catalysis, biomedicine, optical encoding and energy transport, and provides an outlook on remaining challenges in mechanistic understanding, scalable synthesis and functional transformation. These advances establish 2D platelets as programmable crystalline soft-matter platforms for next-generation functional nanomaterials.