Friction and Tactile Sensation of Index Finger Skin on Textured Glass Surfaces During Swipe Motion

Sensory evaluation techniques have been used to investigate rich tactile sensations experienced by humans. Sensory evaluations typically incorporate quantitative measurement methods that rely on the subjective judgment of participants to assess tactile sensations. Although the relation between friction coefficient, skin surface and fingertip, contact surface, and the effect on tactile perception for various materials and textures is a critical topic of research, such underlying mechanisms are yet to be understood comprehensively. In this study, the frictional properties and tactile sensations of the human index finger on textured glass surfaces were investigated during swipe motions. Friction tests were conducted using a six-axis force sensor to measure the coefficient of friction (CoF) across textured and flat glass surfaces. Surface texturing reduced the CoF by decreasing the real contact area. Furthermore, the sliding direction of the finger influenced the CoF. Using the semantic differential method, sensory evaluations revealed higher tactile scores for the textured glass surfaces regarding smoothness, lightness, and silkiness than those for flat surfaces. The findings demonstrated a strong correlation between frictional behaviour and tactile sensations, providing insights for designing textured glass in touch-based applications.