Dynamic Surface Interactions\nEnable the Self-Assembly\nof Perfect Supramolecular Crystals

Supramolecular crystals arise from noncovalent interactions\nbetween\nmacromonomers and allow for the engineering of dynamic functional\nmaterials. For two-dimensional (2D) crystals, the substrate surface\ncan induce the formation of new polymorphs not available in solution,\nadding a layer of complexity to the supramolecular self-assembly process.\nDespite extensive studies on the 2D self-assembly of supramolecular\ncrystals, unknowns remain regarding substrate–monomer interactions\nand the effects on network self-assembly and defect repair. Here,\nwe used a DNA–mica model system to modulate and understand\nthe impact of substrate–monomer interactions on the crystalline\norder. We controlled the surface interactions by tuning the Mg<sup>2+</sup> concentration, varying the divalent cation type, and adjusting\nthe relative concentration of divalent and monovalent cations. The\ncompetition between monovalent and divalent cations yielded nearly\ndefect-free crystals with minimal polygon defects. These findings\nhighlight the critical role of surface interactions in achieving high\ncrystalline order, which is essential for optimizing the efficiency\nand performance of supramolecular functional nanomaterials.