Frank–Kasper σ 相中超分子微胞變形能力的調控

Abstract

可變形性（deformability）被視為自組裝系統通往結構複雜化的重要途徑。基於此，本研究以樹枝狀兩親性分子為模型，透過引入疏水外殼鏈長不對稱性，賦予 Frank–Kasper（FK）σ 相中超分子微胞可調控之各向異性變形能力；此一形變自由度可緩解局部空間填充挫折，因而在實驗上實現並穩定 FK σ 相。結果顯示，過度不對稱之 AD1 僅形成典型球狀相 bcc；相對地，適度不對稱之 AD2 可形成具各向異性的 FK σ 相，其繞射強度呈現區域與取向依賴性。各向異性 Debye–Waller 因子模擬進一步支持該強度差異源自微胞層級的形變與取向選擇。進一步引入疏水客體十二烷可補償外殼空缺並關閉變形能力，使σ相轉為各向同性 bcc。綜上，可變形性可作為可調控之結構參數以主導晶格對稱性與相變行為，並提供設計具適應性與階層化複雜組裝體之策略基礎。

Deformability has been regarded as a key pathway by which self-assembling systems access higher structural complexity. Here, dendritic amphiphiles were used as a model platform, where chain-length asymmetry in the hydrophobic corona was introduced to endow supramolecular micelles in the Frank–Kasper (FK) σ phase with a tunable anisotropic deformation capability. This additional shape freedom alleviates local packing frustration, enabling the experimental realization and stabilization of the FK σ phase. The results show that excessively asymmetric AD1 forms only the conventional spherical bcc phase, whereas moderately asymmetric AD2 yields an anisotropic FK σ phase with pronounced spatial- and orientation-dependent diffraction intensities. Simulations using an anisotropic Debye–Waller factor further support that these intensity variations originate from micelle-level deformation and orientation selection. Moreover, incorporation of a hydrophobic guest (dodecane) compensates the corona voids and switches off deformability, converting the σ phase into an isotropic bcc phase. Collectively, these findings establish deformability as a tunable structural parameter that governs lattice symmetry and phase transitions, and provide a design basis for adaptive, hierarchically complex supramolecular assemblies.