Effects of surfactant solutions on hair fiber friction

Abstract

Synopsis A capstan method using the Instron Tensile Tester © is described for measuring friction of hair fibers on various reference surfaces. Other test variables examined include fiber tension, rubbing speed, fiber diameter and hair condition. The method was developed to evaluate effects of SURFACTANTS on HAIR FIBERS as part of a longer range objective to predict hair fiber assembly behavior from single fiber properties. Accordingly, frictional results are supplemented with qualitative combing tests on tresses. Cationic surfactants differ for frictional effects on hair rubbed against hard rubber or wool. Some produce friction minima as concentration is reduced, while others of higher molecular weight maintain low frictien. The existence of FRICTION MINIMA was confirmed by qualitative combing tests. With anionic surfactants, friction of hair fibers on hard rubber decreases with increasing concentration. The addition of metallic ions to TEA-lauryl sulfate can either raise or lower friction, depending on their mode of complexing with TEA. Shampoos of different types can be distinguished by frictional measurements, using a controlled rinse procedure.