Scale lifting

The cell membrane complex and the endoctitide are the most vulnerable to the attack by shampoos, to build-up and even to stretching and cracking. If build-up gets beneath the scales, it can cause scale lifting a type of scale damage that makes the hair feel dry, coarse and look dull... 

This scale-lifting phenomenon is due primarily to the penetration of cationic and anionic surfactant into the endocuticle and the cell membrane complex and the subsequent deposition and buildup of a hydrophobic anionic-cationic complex layer. When this layer is sufficiently large, a lifting... 

Figure 5-16. Scale lifting caused by vigorous combing of hair tresses.

Figure 5-17. Chipping, scale lifting, and tearing of large sections of cuticle by vigorous combing.

Figure 5-18. Tearing or breaking off of large sections of a single cuticle scale after scale lifting.

Figure 5-38. Scale lifting by alternating treatments with triethanol ammonium lauryl sulfate and stearalkonium chloride. Hair previously permed on a live head and subsequently treated in the laboratory. Light micrographs illustrate scale lifting in the wet state.

Figure 5-41. Schematic of light scattering curves illustrating a normal untreated hair fiber (solid fine) and a fiber with scales lifted (dashed line).

Another interesting technique for artifically generating scale lifting and splits has been described by Kon et al. [149]. This technique involves extraction of proteins from the fiber via enzyme digestion followed by freeze drying. This method has been used to study damage prevention by polymers. 

Figure 5 3. Micrographs illustrating scale hfting by a leading U.S. two-in-one shampoo. Top Control treatment by a two-in-one shampoo that does not cause scale lifting. Bottom A two-in-one shampoo sold in the United States that caused scale lifting. This formula is no longer being sold.

Figure 8-5. (A) Control hair fiber near the scalp illustrating cuticle scales that have not been lifted. (B) Hair fiber extended at low relative humidity. Note the scale lifting from extension. Micrographs kindly provided by Sigrid Ruetsch of Textile Research Institute/Princenton.

Figure 8-11. Scale lifting caused by extension cycling to 10% at 10% RH, (la) to 50 cycles, (lb) to 100 cycles, and (Ic) to 200 cycles. Reprinted with permission of the Journal of the Society of Cosmetic Chemists [67].

Inhibition or promotion of scale lifting and hair fragmentation by isolated polymers or ingredients can be informative in terms of helping to explain the mechanism of fiber degradation from stretching and abrasive actions. However, such treatments are often of limited use in product for-... 

Figure 8-17. Hair fiber chemically bleached with alkaline peroxide, fatigued 100,000 times with 30-g load, and then extended. Note the extensive scale lifting and fracturing underneath the scales at the weakened cell membrane complex. Electron micrographs kindly provided by Sigrid Ruetsch of Textile Research...

Figure 8-19. Both hair fibers extension cycled 200 times to 20% extension at 10% RH, put into water, and knotted. Fiber on the right treated with 3% cystine poly-siloxane prior to knotting. Note the lack of scale lifting from the polysiloxane-treated fiber. Reprinted with permission of the Journal of Cosmetic Science [67].

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