Finger Friction Measurements on Coated and Uncoated Printing Papers

• Published in: Tribology letters 2010-02, Vol.37 (2), p.389-399
• Main Authors: Skedung, Lisa, Danerlöv, Katrin, Olofsson, Ulf, Aikala, Maiju, Niemi, Kari, Kettle, John, Rutland, Mark W
• Format: Article
• Language: English
• Subjects: Biotribology; Chemistry; Chemistry and Materials Science; Coated paper; Coefficient of friction; Corrosion and Coatings; Finger friction; Finger friction measurements on coated and uncoated printing papers Friction test methods; Friction; Friction test methods; Kemi; Lipids; Materials Science; Nanotechnology; NATURAL SCIENCES; NATURVETENSKAP; Organic chemistry; Original Paper; Paper friction; Perception; Photoelectrons; Physical Chemistry; Piezoelectricity; Pulp & paper industry; Skin friction; skin friction paper friction; Surface roughness; Surfaces and Interfaces; Tactile feel; Theoretical and Applied Mechanics; Thin Films; Tribology; Uncoated paper
• ISSN: 1023-8883; 1573-2711; 1573-2711
• DOI: 10.1007/s11249-009-9538-z

A macroscopic finger friction device consisting of a piezoelectric force sensor was evaluated on 21 printing papers of different paper grades and grammage. Friction between a human finger and the 21 papers was measured and showed that measurements with the device can be used to discriminate a set of similar surfaces in terms of finger friction. When comparing the friction coefficients, the papers group according to paper grade and the emerging trend is that the rougher papers have a lower friction coefficient than smoother papers. This is interpreted in terms of a larger contact area in the latter case. Furthermore, a decrease in friction coefficient is noted for all papers on repeated stroking (15 cycles back and forth with the finger). Complementary experiments indicate that both mechanical and chemical modifications of the surface are responsible for this decrease: (1) X-ray photoelectron spectroscopy measurements show that lipid material is transferred from the finger to the paper surface, (2) repeated finger friction measurements on the same paper sample reveal that only partial recovery of the frictional behaviour occurs and (3) profilometry measurements before and after stroking indicate small topographical changes associated with repeated frictional contacts.