102 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 600 500 300 200 100 0 50 100 150 200 250 300 350 Distance [% of initial] .... untreated hair after perming (incl. neutralization) Figure 10. The effect of perming with a nonconditioning formulation and shampooing (procedure A) on the combing curves of virgin, dark brown hair. from the hair. The same sequence of conditioning and shampooing repeated for the third time yielded the same result. The combing data are summarized in Figure 7, which shows the combing work of the dyed sections of the tress after each treatment. It demonstrates the conditioning effect of the polymer and its removability from hair as a result of one or two shampooings. The data also provide indirect evidence of the lack of polymer buildup after consecutive applications. This presumption is supported by the fact that no decrease in combing values is evident after the second and third polymer treatment, which suggests no additional deposition of polymer on hair. BLEACHED OR PERMED HAIR The conditioning of bleached hair is illustrated by the data presented in Figure 8. One hour bleaching of hair results in a three- to fourfold increase in combing forces as compared to the untreated control. Subsequent treatment with a 0.2% polymer solution brings about a reduction of combing forces, especially pronounced in the bleached sections of a tress. The shape of the combing trace after polymer treatment, with two minima corresponding to the bleached section of hair, suggests that the cationic polymer is more substantive to damaged hair, and its adsorption reduces the combing friction to a level below that characteristic for untreated hair. In addition to this, a modifying layer of polymer cannot be removed by subsequent multiple shampooings. While combing

SPATIALLY RESOLVED COMBING ANALYSIS 103 300 • 150 ]- .......................... --3/:,/•74--\•.:/'¾•,• .... o 0 50 100 150 200 250 300 350 Distance [% of initial] after perming (incl. neutr./cond.) Figure 11. The effect of perming with a conditioning formulation (0.2% polyquaternium-11 in a neu- tralizer procedure A) on the combing curves of virgin, dark brown hair. forces increase after one and four shampooings, they remain at a relatively low level, close to that measured for untreated hair, as evident from both combing force traces (Figure 8) and from the calculated combing work values (Figure 9). Perming, which consists of hair reduction with a mercaptan and its subsequent oxidation (neutralization) with hydrogen peroxide, also results in the damage of hair surface. Figure 10 shows a four- to fivefold increase in combing forces corresponding to the permed sections of fibers. Incorporation of a cationic polymer in the neutralizer prevents hair from becoming raspy by lowering the combing forces (Figure 11). Clearly, the treated sections are characterized by lower friction than the untreated portions of hair, which suggests high substantivity of polyquaternium-11 to perm-damaged fiber surface. The effect is permanent, and the conditioning persists through four shampooings. In contrast to this, when perming was performed by employing a neutralizer containing a low-molecular-weight conditioning agent such as quaternium-52, a smaller extent of combing force reduction was evident. In this case, the conditioning effect was also not durable, and disappeared completely after a single shampooing. BLEACHED/DYED HAIR The effect of the polymer on hair damaged by a combination of two bleachings and oxidative dyeing was also studied by employing procedure B. As with bleached hair, it