Department of Applied Chemistry, Chemical Engineering, and Biochemical Engineering, Graduate School of Science and Engineering, Yamagata University.
Department of Resin Processing Research, Division of Polymer Solution, Denka Company Limited.
J Oleo Sci. 2024;73(5):801-811. doi: 10.5650/jos.ess23245.
Hair shape affects the frictional properties and tactile sensation of hair. In this study, we evaluated the friction associated with the rubbing of straight, curly, or wavy hair by a contact probe equipped in a sinusoidal motion friction evaluation system. This system provides dynamic information such as the velocity dependence and hysteresis of the frictional force. In the case of hair fibers fixed at 1 mm intervals on a glass plate, a stable friction pattern was observed, in which the friction coefficient was almost constant during the dynamic friction process. The friction coefficients in the inward direction toward the hair root for straight, curly, and wavy hair were 0.47 ± 0.04, 0.51 ± 0.02, and 0.54 ± 0.04, respectively. As wavy hair is thick and has a larger true contact area with the contact probe, the friction coefficient was larger. When the finger model rubbed the straight or curly hair bundle in the inward direction, an oscillation pattern was observed, with the friction coefficient fluctuating at 20 ms intervals and the kinetic friction coefficient evaluated at 0.67 and 0.64, respectively. For the surface of straight hair, containing densely arranged cuticles, a large oscillation was observed in the direction against the cuticles. Meanwhile, no oscillation phenomenon was observed in wavy hair, which is characterized by a smooth cuticle and complex hair flow. Because wavy hair, which is frizzy, has fewer points of contact between hairs, impeding the occurrence of cooperative fluctuations in the frictional force.
发型会影响头发的摩擦特性和触感。在这项研究中，我们通过配备在正弦运动摩擦评估系统中的接触探头，评估了直发、卷发和波浪发之间摩擦的相关情况。该系统提供了动态信息，如摩擦力对速度的依赖性和滞后性。在将头发纤维以 1 毫米的间隔固定在玻璃板上的情况下，观察到了稳定的摩擦模式，在该模式中，在动态摩擦过程中摩擦系数几乎保持不变。对于发根方向的直发、卷发和波浪发，摩擦系数分别为 0.47±0.04、0.51±0.02 和 0.54±0.04。由于波浪发较厚，与接触探头的实际接触面积较大，因此摩擦系数较大。当手指模型在向内方向摩擦直发或卷发束时，观察到了一种振荡模式，摩擦系数以 20 毫秒的间隔波动，动摩擦系数分别评估为 0.67 和 0.64。对于含有紧密排列的角质层的直发表面，在与角质层相反的方向上观察到了较大的振荡。同时，在具有光滑角质层和复杂发流的波浪发中没有观察到振荡现象。由于卷曲的波浪发发间接触点较少，阻碍了摩擦力的协同波动的发生。
