The manipulation of supramolecular assembly enables single-component architectures to possess diverse structures and functions. Here, we report directed phase transitions of dipeptide supramolecular gel to crystals with excellent selectivity and tunable mechanical properties. To be specific, lamellar-to-orthorhombic rearrangement of dipeptide molecules in the supramolecular assembly was guided by application of ammonia gas, while lamellar-to-hexagonal realignment was generated upon water vapor exposure of the assembly. Importantly, this crystal phase control originated from distinct gas-mediated reconstitution of hydrogen-bonding interactions, which endowed the dipeptide materials with remarkably modulated stiffness. The selective phase transformation offers a simple and effective platform for self-assembling peptide crystals with diverse long-range-ordered structures from a single gel-state aggregation. This work opens up new perspectives on peptide-based biomaterials via gas-directed hydrogen-bonding chemistry.

超分子组装的操纵使单组分体系结构能够具有多种结构和功能。在这里，我们报告了具有优异的选择性和可调的机械性能的二肽超分子凝胶的定向相变。具体而言，通过施加氨气引导超分子组装体中二肽分子的层状至正交排列重排，而在暴露于水蒸气中时产生层状至六方排列。重要的是，这种晶体相的控制源自氢键相互作用的独特的气体介导的重构，这赋予了二肽材料明显的调节刚度。选择性相变为从单个凝胶态聚集体自组装具有多种不同长程结构的肽晶体提供了一个简单有效的平台。这项工作为通过气体导向氢键化学的基于肽的生物材料开辟了新的视角。