2008 TRI/PRINCETON CONFERENCE 235 Table V Total Color Loss of Mannequin Gabrielle Measured by dE, Ruby Red Color PQ-55 3-step anti-fading system Commercial 3-step anti-fading system dE 7.09 10.7 %dE improvement by PQ-55 system over commercial system 33.8% Figure 15. Pictures of mannequin Daphne dyed in red after 10 cycle washes and treatments with PQ-55 anti-fading system (right side) and commercial color lock system (left side). Dyed pre-bleached Asian hair. It is believed that hydrophobically modifi ed cationic polymers such as PQ-55 are able to form a hydrophobic and substantive barrier on hair surface especially on cuticle edges and around the pores, which effectively reduces washing out of hair dye. In order to prove the effect of wash resistant and hydrophobic barrier provided by PQ-55 treatment, water contact angles of dyed hair fi bers were measured after 10× SLES washes and with and without treatment of 2% PQ-55 leave in gel. The difference in water contact angles of treated and untreated hair surface is an indication of hair fi ber surface hydrophobicity changes. Figure 17a is the result of water contact angle measurement of hair fi bers after 10× SLES washes and with or without 10× treatment with 2% PQ-55 leave-in gel. It should be noticed that the treated and untreated hair tresses were the two split halves of a same hair tress before treatment and washes therefore the treated and untreated hair tresses have the same average contact angle before treatment and washes. The results in Figure 17a indicate that the average water contact angles of hair fi ber surface from the treatment with PQ-55 leave-in gel is 60.4° after 10× SLES washes, while the contact an- gle of hair fi bers treated with the gel without PQ-55 after the same washes is 50.4°. These results demonstrate that the hair surface after treatment with 2% PQ-55 leave-in gel is more hydrophobic than the control. The corresponding color protection effect of PQ-55 leave-in treatment is 38% (Figure 5), which is attributed to the increased hydro- phobicity and barrier function of the hair surface. Figure 17b is the water contact angles of hair fi bers after 10× treatment and wash with PQ-55 3 step anti-fading system

JOURNAL OF COSMETIC SCIENCE 236 Figure 17. Water contact angles of hair fi bers. (a) 2% PG-55 leave-in gel treatments vs gel without PQ-55, both after 10× SLES washes. (b) PQ-55 3 step anti-fading system vs commercial color lock shampoo and conditioner system. 10× washes and treatment, dyed bleached dark brown hair, intense red color. Figure 16. Image analysis of darkness of mannequin Daphne dyed in ruby red after 10 cycle washes and treatments with PQ-55 anti-fading system (right side) and commercial color lock system (left side).