Interactions between Crossed Hair Fibers at the Nanoscale

• Published in: Langmuir Vol. 26; no. 24; pp. 18909 - 18915
• Main Authors: Mizuno, Hiroyasu, Luengo, Gustavo S, Rutland, Mark W
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 21.12.2010
• Subjects: adhesion; Adhesives - chemistry; Adhesives - metabolism; Air; atomic-force microscopy; Biological Interfaces: Biocolloids, Biomolecular and Biomimetic Materials; Chemistry; colloidal forces; electrical double-layer; Exact sciences and technology; Female; Friction; General and physical chemistry; Hair - chemistry; Hair - drug effects; Hair - metabolism; Hair Bleaching Agents - pharmacology; Humans; hydrophobic surfaces; Interactions between crossed hair fibers at the nanoscale ATOMIC-FORCE MICROSCOPY ELECTRICAL DOUBLE-LAYER HYDROPHOBIC SURFACES MICELLAR-SOLUTIONS COLLOIDAL FORCES SPRING CONSTANTS SILICA SURFACES KERATIN FIBERS FRICTION ADHESION; Kemi; keratin fibers; micellar-solutions; Microscopy, Atomic Force; Nanotechnology - methods; NATURAL SCIENCES; NATURVETENSKAP; silica surfaces; Solutions; spring constants; Surface physical chemistry; Human; Attraction; Atomic force microscopy; Separation; Force; Fiber; Cationic surfactant; Air; Surfactant; Ionic surfactant; Adhesion; Dispersion; Heterogeneity; Adsorption; Friction; Bleaching; Friction coefficient; Lubrication
• ISSN: 0743-7463; 1520-5827; 1520-5827
• DOI: 10.1021/la103001s

The atomic force microscope fiber probe is used to directly measure the forces and friction between two human hairs under various conditions. It is shown that the forces between the hair fibers in solution can be well explained by a DLVO interaction and that cationic surfactant modifies the interactions in a manner entirely consistent with current views of adsorption behavior. A Coulombic attraction occurs between the crossed hair fibers in air due to the heterogeneity of the surface, and at shorter separations a clear dispersion interaction is observed. Exposure of the hair to a bleaching solution leads to the removal of the adhesion and solely a double-layer interaction. Two crossed hair fibers obey Amontons’ classic law of friction, with a linear relation between applied load and frictional force, allowing the determination of a friction coefficient; positively charged surfactant adsorption is shown to reduce the friction coefficient between the fibers in a manner consistent with boundary lubrication by a palisade layer.