Breakspear Steven, Noecker Bernd, Popescu Crisan
Kao European Research Laboratories, KAO Germany GmbH, Darmstadt D-64297, Germany (S.B., B.N., C.P.).
J Cosmet Sci. 2018 Sep/Oct;69(5):305-314.
Hair fibers were examined by atomic force microscopy, nanoindentation. By indenting along (longitudinal) and across (transversal) the fiber, we evaluated the Young's modulus and its dependence on the moisture content (relative humidity) of the environment. The ratio of the two values collected for Young's modulus, at a given relative humidity, is defined as the anisotropy index () of the fiber and the acquired results give the evolution of the index of anisotropy with the relative humidity. The use of the model of composite materials allowed us to relate the anisotropy index to the fiber internal architecture. The evaluation of the results acquired on the components of the fiber, within the frame of this model, ultimately points to a possible micro-structure of exocuticle, hindered under usual circumstances by its heavy cross-linking and only noticeable when the absorbed moisture swells the surrounding network and annuls, in this way, its effect.
通过原子力显微镜、纳米压痕法对毛发纤维进行了检测。通过沿纤维的纵向和横向进行压痕，我们评估了杨氏模量及其对环境湿度（相对湿度）的依赖性。在给定相对湿度下，收集的两个杨氏模量值的比值定义为纤维的各向异性指数（），所获得的结果给出了各向异性指数随相对湿度的变化情况。复合材料模型的使用使我们能够将各向异性指数与纤维内部结构联系起来。在该模型框架内对纤维成分所获得结果的评估最终指向了外表皮可能的微观结构，这种结构在通常情况下由于其大量交联而受到阻碍，只有当吸收的水分使周围网络膨胀并消除其影响时才会显现出来。
