Recent measurements of the elastic constants in lyotropic chromonic liquid crystals (LCLCs) have revealed an anomalously small twist elastic constant compared to the splay and bend constants. Interestingly, measurements of the elastic constants in the micellar lyotropic liquid crystals (LLCs) that are formed by surfactants, by far the most ubiquitous and studied class of LLCs, are extremely rare and report only the ratios of elastic constants and do not include the twist elastic constant. By means of light scattering, this study presents absolute values of the elastic constants and their corresponding viscosities for the nematic phase of a standard LLC composed of disk-shaped micelles. Very different elastic moduli are found. While the splay elastic constant is in the typical range of 1.5 pN as is true in general for thermotropic nematics, the twist elastic constant is found to be one order of magnitude smaller (0.30 pN) and almost two orders of magnitude smaller than the bend elastic constant (21 pN). These results demonstrate that a small twist elastic constant is not restricted to the special case of LCLCs, but is true for LLCs in general. The reason for this extremely small twist elastic constant very likely originates with the flexibility of the assemblies that are the building blocks of both micellar and chromonic lyotropic liquid crystals.

最近对溶致发色液晶（LCLC）的弹性常数的测量表明，与张开和弯曲常数相比，扭曲弹性常数异常小。有趣的是，由表面活性剂形成的胶束溶致液晶（LLC）中的弹性常数的测量是迄今为止最普遍使用和研究的LLC类，它非常少见，仅报告弹性常数的比率且不包括扭曲弹性常数。通过光散射，该研究给出了由圆盘状胶束组成的标准LLC向列相的弹性常数的绝对值及其对应的粘度。发现非常不同的弹性模量。展开弹性常数通常在1.5 pN的范围内，这在一般向热向列相中是正确的，扭转弹性常数比弯曲弹性常数（21 pN）小一个数量级（0.30 pN），几乎小两个数量级。这些结果表明，较小的扭转弹性常数不仅限于LCLC的特殊情况，而且通常适用于LLC。这种极小的扭转弹性常数的原因很可能源于作为胶束和发色溶致液晶的组成部分的组件的柔性。