400 JOURNAL OF COSMETIC SCIENCE �SH-AL-1 _,._ PQ-67 (0.5%) -a-PQ-70 (1%) Jo-Guar (0.5%) -e-PQ-10 (0.2%) 1.15 ._ 1.10 LL 1.05 a, J! 1.00 rn · a! 0.95 � -a 0.90 'i§ £ 0.85 0.80 0 50 100 150 Equilibrium Time (Minutes) 200 Figure 6. H 2 RF of different shampoos at various equilibrium times. 250 the shampoo containing PQ-70 showed higher humidity resistance factors. Even after 4 hours of equilibrium time, the remained elasticity is still 6% higher than that of the untreated hair. Shampoos containing PQ-67 or Guar did not show any benefits on hair humidity resistance. Hair treated with the shampoo containing PQ-10 showed decrease in hair remaining elasticity this is an indication of hair moisturization. Unfortunately, the moisturized hair exhibited higher wet combing force due to the absorption of extra water. HAIR IMAGES OF FRIZZY HAIR AT DIFFERENT RH Digital images of frizzy hair tresses were taken at 50% and 80% RH and presented in Figure 7. It is clearly shown that there were significant changes in hair volume and curvature of a fizzy hair sample due to an increase in the environmental humidity. In order to understand the mechanism of hair frizz, the average ellipticity (the ratio of maximum diameter to minimum diameter of a hair fiber) of different types of hair fibers was determined using a Laser Scanning Micrometer LSM-5000. It is observed that naturally curly and kinky hairs have higher average ellipticity than other types of hair such as oriental hair and Caucasian hair. Data are presented in Table II. Due to the large differences in two main diameters on hair cross-section, moisture has pronounced effects on hair curvature and volume, and therefore, naturally-curly and kinky hair is the frizziest hair among all types of hairs. Image Analysis is a very useful tool to see the difference of hair under various environ- mental RH and used for evaluations of anti-frizz performance of hair care formulation by comparing images of hair samples at different humidity before and after cosmetic treatments. Figure 8 shows images of a frizzy hair tress at 50% and 80% RH before and

2006 TRI/PRINCETON CONFERENCE 401 7-1 Untreated frizzy hair at 50%RH 7-2 Untreated frizzy hair at 80%RH Hair type *CSD, µm (Average) Ellipticity Shape of hair shaft Shape Figure 7. Change in the appearance of a frizzy hair sample. Table II Shape and Ellipticity of Different Types of Hairs Caucasian Black Oriental 29-96 (70) 46-120 (90) 36-125 (92) 1.17-1.41 1.68-1.98 -1.25 Oval Flat Round Straight to Wavy to Straight to wavy/curly very curly wavy * CSD: Cross-sectional diameter. Hispanic 30-120 (70-92) 1.17-1.98 Oval-flat-round Straight/wavy to very curly after treatment with a PQ-70-containing shampoo. Before the shampoo treatment, the hair tress became volume-expanded and curlier when the RH increased from 50% to 80%. After the shampoo treatment, the changes in hair volume and curvature were reduced. Figure 9 shows images of a frizzy hair tress at 50% and 80% RH before and after treatment with a PQ-10-containing shampoo. Before the shampoo treatment, the frizzy hair tress became volume-expanded and curlier when the RH increased from 50% to 80%. After the shampoo treatment, the changes in hair volume and curvature with an increase in the environmental humidity did not show any improvement. Comparing theses images, it can be concluded that the PQ-70 shampoo did show better anti-frizz performance compared to other tested shampoo formulations.