Understanding morphological transformations upon temperature-induced mesophase transitions offers mechanistic insights into the self-assembly process. We have recently reported the unexpected formation of a microfibrillar lamellar gel in SDS-glycerol mixtures above a critical gelation concentration (CGC) as low as ~2 wt%. The gel phase comprised a fibrillar structure on the microscale and a lamellar structure on the nanoscale. Here, the nanoscopic structure of the gel as a function of temperature was probed with small-angle neutron scattering (SANS). The gel underwent a gel-to-fluid transition at a critical gelation temperature, T_GC = 45 °C, forming cylindrical micelles at elevated temperatures. Upon cooling, a hexagonal phase formed at ~T_GC, evident from the SANS Bragg peaks. This hexagonal phase upon the fluid-to-gel transition sheds light on the gelation mechanism, in which self-assembled SDS micelles undergo a cylindrical-to-lamellar morphological transition via a hexagonal phase. This unprecedented observation also highlights the complexity of self-assembly in nonaqueous hydrogen-bonding rich media.

了解在温度诱导的中间相转变后的形态转变为自组装过程提供了机械的见解。最近，我们报道了在SDS-甘油混合物中，当临界胶凝浓度（CGC）低于〜2 wt％时，会意外地形成微纤维状层状凝胶。凝胶相在微米尺度上包括原纤维结构，在纳米尺度上包括层状结构。在此，通过小角度中子散射（SANS）探测了凝胶的纳米结构随温度的变化。凝胶在临界胶凝温度T _GC  = 45°C下经历了从凝胶到流体的转变，在升高的温度下形成了圆柱形胶束。冷却后，六方相形成在〜Ť _GC从SANS布拉格峰很明显。流体-凝胶转变过程中的此六方相阐明了凝胶化机理，在该机理中，自组装的SDS胶束通过六方相经历了圆柱到薄片的形态转变。这种空前的观察还突出了在非水氢键富介质中自组装的复杂性。