Surfactant film rigidity is a ubiquitous general concept that is quantified into two different units. We show here how to convert the bending rigidity from reduced units of a virtual infinitely thin film (not made of molecules) into the chemical unit (kJ.mol⁻¹) of a realistic film of monomolecular thickness. In most cases, molecular lengths are not negligible versus curvature radius. Two bending constants for the elasticity of thin-shelled solids can be defined, as introduced by Gauss, whereas only one physical bending constant taking into account that the film cannot be torn has been introduced in the 1990s by Hyde and Ninham. The explicit conversion depends on the topology and is different in the quasi-planar approximation, as well as the ‘direct’ oil in water (o/w) or ‘reverse’ water in oil (w/o) case of spherical or cylindrical micelles. We show some examples for classical and nonclassical micelles and microemulsions of different compositions.

表面活性剂膜的硬度是普遍存在的概念，可以量化为两个不同的单位。我们在这里展示如何将抗弯刚度从虚拟无限薄膜（不是由分子组成）的还原单位转换为化学单位（kJ.mol ^-1））的单分子厚度的真实薄膜。在大多数情况下，分子长度相对于曲率半径不可忽略。正如高斯所介绍的那样，可以定义两个用于薄壳固体弹性的弯曲常数，而在1990年代，海德和宁纳姆只引入了一个考虑到薄膜不能撕裂的物理弯曲常数。显式转换取决于拓扑，并且在准平面近似中以及球形或圆柱形胶束的情况下，“直接”在水中的油（o / w）或“反向”在水中的油（w / o）不同。我们展示了不同组成的经典和非经典胶束和微乳液的一些实例。