Creation of two-dimensional hollow platelets by reducing the polymer crystal interfacial strength

The accurate manipulation of monodisperse nanomaterials, featuring distinct spatial functionalities and characteristics, is of significant interest in materials science. The living crystallization-driven self-assembly (CDSA) technique of crystallizable block copolymers (BCPs) is a highly effective strategy for fabricating two-dimensional (2D) polymer nanostructures, offering precise control over their dimensions and properties. Revealing the in-depth mechanistic principle of seeded heteroepitaxial growth enables the formation of segmented platelets where the core components are spatially defined. In present work, we reveal that the crystalline core compatibility is an alternative important factor that would determine the seeded heteroepitaxial growth. Experimental results have shown that poor core compatibility and less ordered copolymer cores would lead to less effective epitaxial growth, yielding poorly developed deposited crystals, while better core compatibility and ordered block cores results in well-defined 2D crystalline domains that will surround the preformed platelet seeds. More importantly, decreasing the crystallization temperature enables the creation of well-defined concentric platelets, but the interfacial strength between two crystals is reduced when the core compatibility is poor. Consequently, the inner crystalline platelet seeds would slide out from the segmented platelets during aging process, yielding 2D hollow platelets. The fracture of crystal interfaces could also be obtained when co-crystallization occurs for different crystallizable cores at low crystallization temperatures, which provides an alternative facile approach to create 2D hollow platelets. • 2D segmented platelets with different core compositions are prepared. • Crystal interfacial strength is regulated by crystallization temperature, core compatibility and chain regularity. • By reducing the interfacial strength, the inner crystal domain would slide out from the segmented platelet. • Providing a facile method to prepare 2D hollow polymeric platelets.