104 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 8OO 600 u. 400 :200 0 Bleached and Dyed Hair Treatment with 0.2% solution of polyquaternium-11 Combing Work [Gcm] Before treat. - 5233 .............. 7 - '•f[ 7. ....... ,- .................. After treat. - 679 / After treat. + I shamp. - 1194 After treat. + 4 shamp. - 2319 0 50 100 150 200 250 300 350 Distance [% of initial] -- before treatment after treatment after treatment + 4 shampooings Figure 12. The effect of treatment with 0.2% polyquaternium-ll (procedure B) and subsequent sham- pooings on the combing curves of twice bleached and dyed hair. was found that cationic polymer adsorbs on the fiber surface in an irreversible fashion and cannot be removed by repeated shampooings. As shown by the data presented in Figure 12, the combing forces are reduced in the treated sections by factors of 20 and 40, in the first and second windows, respectively. Combing forces corresponding to untreated sections of hair are also significantly reduced, an effect probably related to the mechanism of fiber disentanglement in the neighboring low and high friction areas of a tress. Four and eight shampooings result in an increase in the combing forces, espe- cially in untreated sections of hair, although to a level significantly lower than that characteristic for unconditioned hair. CONCLUSIONS Spatially resolved combing analysis was applied to study the properties of hair damaged by the use of chemical treatments. The technique was capable of (a) quantifying the surface damage as a result of dyeing, bleaching, and perming, and (b) demonstrating the conditioning properties of a cationic polymer, polyquaternium-11. The substantivity of the polymer to hair could be assessed by the measurements performed after the condi- tioning treatment as well as after subsequent shampooings. The study demonstrates that the extent of hair conditioning by the polymer depends on the state of the hair surface. While undamaged hair was not significantly improved by the use of polyquaternium-11,

SPATIALLY RESOLVED COMBING ANALYSIS 105 its effect on chemically modified and raspy hair was very pronounced. In addition to this, the conditioning effect was found to be durable since an adsorbed layer of a cationic polymer could not be removed, from either virgin or damaged hair, by shampooing. ACKNOWLEDGEMENTS The authors acknowledge useful discussions with J. Kosiek and K. Krummel. REFERENCES (1) W. Newman, G. L. Cohen, and C. Hayes, A quantitative characterization of combing force, J. Soc. Cosmet. Chem., 24, 773 (1973). (2) W. S. Tolgyesi, E. Cottington, and A. Fookson, Mechanics of hair combing. Presented at the Sym- posium on Mechanics of Fibrous Structures, Fiber Society, Inc., Atlanta, May 14, 1975. (3) M.L. Garcia and J. Diaz, Combability measurements on human hair, J. Sot'. Cosmet. Chem., 27, 379 (1976). (4) Y. K. Kamath and Hans-Dietrich Weigmann, Measurement of combing forces,J. Soc. Cosmet. Chem., 37, 11 (1986). (5) E.J. Murphy, Cationic polymer conditioner evaluation, Soaps, Cosmetics, Chemical Specialties, Feb- ruary 1980. (6) P. Hossel and E. Pfrommer, Test methods for hair conditioning polymers, Conj•rence Proceedings, In-Cosmetics, Barcelona, March 1994, p. 133. (7) J. A. Swift and A. C. Brown, The critical determination of fine changes in the surface architecture of human hair due to cosmetic treatment,J. Soc. Cosmet. Chem., 23, 695 (1972). (8) M. L. Garcia, J. A. Epps, and R. S. Yare, Normal cuticle-wear patterns in human hair, J. Soc. Cosmet. Chem., 29, 155 (1976).