Interactions between Crossed Hair Fibers at the Nanoscale

• 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.

Subject headings

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Keyword

atomic-force microscopy

electrical double-layer

hydrophobic surfaces

micellar-solutions

colloidal forces

spring constants

silica surfaces

keratin fibers

friction

adhesion

Chemistry

Kemi

Publication and Content Type

ref (subject category)

art (subject category)