CUTICLE DECEMENTATION AND BUCKLING 221 8b Figure 8. Surfaces of decemented cuticles treated with a 3% aqueous solution of polyethylenimide (PEI) after three cycles of wetting/blow drying. 8a x770 8b x2500. to cause severe cuticle shape distortion. In Figures 8a and 8b are shown decemented cuticles treated with PEI after three cycles of wetting/blow drying. In these figures it can be clearly seen that after blow/drying the decemented cuticles appear severely distorted. From these observations it can be inferred that decemented cuticles can be distorted or reglued depending on the mechanical properties of the dry polymer. CONCLUSIONS The experiments show that strain cycles at low extensions in dry hair fibers produce lifting and buckling at the cuticle edges. Strain-cycling experiments with swollen fibers indicate that decementation and buckling of the cuticles is caused by circular compres- sion stresses on the cuticular envelope. It is also shown that this type of damage can be prevented and repaired by using appropriate hair swelling actives or by pretreating the fibers with appropriate polymeric substances capable of recementing the cuticles. ACKNOWLEDGMENTS The author wishes to thank Ann Harder for her valuable technical assistance and Herb Eldestein for his helpful discussions. REFERENCES (1) J. A. Swift Fine details on the surface of human hair, Int. J. Cosmet. Sci., 13, 143-159 (1991). (2) 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, 695-702 (1972).

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