We report new dirhamnolipid ester forming reverse wormlike micelles in nonpolar solvents without the addition of any primer. Therefore, these compounds represent a rare case of a binary system showing this gel-like behavior. In this study, the influence of the concentration of the rhamnolipid ester and the ester alkyl chain length on the rheological properties of the reverse wormlike micelles in toluene was investigated in detail. Highly viscoelastic solutions were obtained even at a relatively low concentration of less than 1 wt %. The phase transition temperatures indicate that the formation of reverse wormlike micelles is favored for dirhamnolipid esters with shorter alkyl chain lengths. Oscillatory shear measurements for the viscoelastic samples reveal that the storage modulus (G') and the loss modulus (G'') cross each other and fit the Maxwell model very well in the low-ω region. As is typical for wormlike micelle systems, the normalized Cole–Cole plot of G''/G''_max against G'/G''_max was obtained as a semicircle centered at G'/G''_max = 1. The formation of network structures was also verified by polarized light microscopy. The sample was birefringent at ambient temperature and anisotropic at an elevated temperature. Differential scanning calorimetry analysis yielded a transition enthalpy of about ΔH_SG/GS = ±7.2 kJ/mol. This value corresponds to a strong dispersion energy and explains the formation of the highly viscous gels by the entanglement of wormlike micelles through the interaction of the alkyl chains.

中文翻译：

---

地拉尼脂酯–在二元（无底漆）系统中形成反向蠕虫状胶束

我们报道了在不添加任何引物的情况下，在非极性溶剂中形成新的蠕虫脂质体的反迪拉姆脂酯。因此，这些化合物代表了显示这种凝胶状行为的二元系统的罕见情况。在这项研究中，鼠李糖脂酯的浓度和酯烷基链长度对反向蠕虫状胶束在甲苯中流变性质的影响进行了详细研究。即使以低于1重量％的相对低的浓度也获得了高粘弹性溶液。相变温度表明，对于具有较短烷基链长度的去甲脂肪酯而言，有利于形成反向蠕虫状胶束。粘弹性样品的振荡剪切测量表明，储能模量（G'）和损耗模量（G'）G''）彼此交叉，并在低ω区域很好地拟合麦克斯韦模型。由于是典型的蠕虫状胶束体系，的归一科尔-科尔图G“” / G“”_最大值对G“ / G‘’_最大值，为半圆为中心的在G” / G‘’_最大值= 1的形成偏振光显微镜也证实了网络结构的变化。样品在环境温度下是双折射的，而在高温下是各向异性的。差示扫描量热法分析得出的过渡焓约为ΔH _{SG / GS}＝±7.2kJ / mol。该值对应于强的分散能，并解释了通过烷基链的相互作用使蠕虫状胶束缠结而形成的高粘性凝胶。