100 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 500 4OO 0 100 150 200 250 300 350 Distance [% of initial] .... befor• treatment -- after bleachlag • after bleaching + treanne•t • after treatment+4 ahamp. Figure 8. The effect of bleaching and treatment with 0.2% polyquaternium-ll (procedure A) on the combing curves of virgin, dark brown hair. VIRGIN, BROWN HAIR The effect of a cationic polymer, applied through the windows in the treatment frame, on virgin, brown hair is presented in Figure 4. The analysis of the combing traces suggests that after the first treatment and rinsing, the conditioning effect of the adsorbed layer of the polymer is relatively small. The lowering of combing forces, in comparison to untreated hair, is evident in tress sections corresponding to both windows, and is of the order of 10-20 G (Figure 4). Subsequent shampooing leads to an increase in combing forces in the areas that were not treated with the polymer. One possible explanation of this increase can be a progressive removal of sebum and/or hair lipids that form a lubricating layer on the fiber surface. Another contributing factor could be a progressive damage to hair, such as the abrasion of cuticle cells, incurred in the process of sham- pooing as a result of rubbing and handling the hair. This phenomenon is well docu- mented in the literature (7,8). The combing forces in treated sections of the fibers increase to a smaller extent, and the two combing force minima are clearly evident after shampooing. This suggests that the adsorbed polymer is not removed completely by exposure to anionic surfactants. Also, the formation of a polymer-surfactant complex may enhance the lubricating properties of the treated sections of the fibers. The subse- quent, second, treatment of the same tress with the polymer solution (through the windows combing traces not shown) reduces the combing force values again, to a level characteristic for untreated hair. The traces obtained after shampooings following the second treatment display the same pattern as those obtained after the first treatment,

SPATIALLY RESOLVED COMBING ANALYSIS 101 2000 1500 1000 50O 1418+83 .................................................................... 433 ................ ....... 308-4-14 39•-I- 10 ................. 607..+._7O Untreated After After After 1 After 4 Brown Hair Bleaching Treatment Shampooing Shampooings Figure 9. The combing work of bleached, virgin, dark brown hair after each, consecutive treatment or shampooing. The figure summarizes the data presented in Figure 8. with an evident increase in combing forces in untreated sections of hair. The data are summarized in a bar graph plot illustrating the variation of combing work after treat- ments and shampooings in relation to untreated hair (Figure 5). The results presented in Figure 5 emphasize again a small conditioning effect of polyquaternium-11 and an increase of combing forces after repeated shampooings. DYED HAIR To assess the effect of the cationic polymer on oxidatively dyed hair, untreated brown hair was first dyed through windows with a black shade of an oxidative hair dye (procedure A). This results in a significant increase in combing forces in the dyed sections of hair (Figure 6). Exposure of the whole tress modified in such a way to a 0.2% solution ofpolyquaternium-11 results in an adsorption of the polymer and a decrease in the combing force values to a level similar to that characteristic for untreated hair. However, subsequent shampooings desorb the polymer and produce a significant in- crease of friction, especially in the damaged portions of hair. A conditioning layer of the polymer is partially removed by one shampooing and completely stripped by two shampooings, as shown by the data in Figure 6. The ensuing, second, treatment of the same tress with a solution of the conditioning agent reduced the combing forces again, and a subsequent shampooing partially removed a conditioning layer of the polymer