Citation: BUREIKO, A., 2013
AbstractExperimental investigations of both bulk and surface rheology of solutions of commercially available polymers Aculyn TM 22 and Aculyn TM 33 in presence of sodium chloride are performed in a wide range of the polymer and salt concentrations. It is shown that the bulk viscosity and the surface viscoelastic modulus of solutions of both polymers increases with the increase of polymer concentration and the decrease of the salt concentration. Solutions of both polymers demonstrate very good foamability and form stable foams. Foam drainage is governed mainly by the bulk viscosity when the latter is in the range of 100-500 mPa·s.
The adhesion force between individual human hair fibers in a crosshair geometry was measured by observing their natural bending and adhesive jumps out of contact, using optical video microscopy. The hair fibers' natural elastic responses, calibrated by measuring their natural resonant frequencies, were used to measure the forces. Using a custom-designed, automated apparatus to measure thousands of individual hair−hair contacts along millimeter length scales of hair, it was found that a broad, yet characteristic, spatially variant distribution in adhesion force is measured on the 1 to 1000 nN scale for both clean and conditioner-treated hair fibers. Comparison between the measured adhesion forces and adhesion forces modeled from the hairs' surface topography (measured using confocal laser profilometry) shows they have a good order-of-magnitude agreement and have similar breadth and shape. The agreement between the measurements and the model suggests, perhaps unsurprisingly, that hair−hair adhesion is governed, to a first approximation, by the unique surface structure of the hairs' cuticles and, therefore, the large distribution in local mean curvature at the various individual contact points along the hairs' lengths. We posit that haircare products could best control the surface properties (or at least the adhesive properties) between hairs by directly modifying the hair surface microstructure.
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