32 HAIR STYLING
Figure 4: Scanning electron microscopy of hair from Strand 2 & detail of the cuticles
Figure 5: Scanning electron microscopy of hair from Strand 3 & detail of the cuticles
Figure 6: Scanning electron microscopy of hair from Strand 3 & detail of the cuticles
and oxidised, forming sulfur oxides (S=O). These changes in functional groups can be observed in an infrared (IR) spectrum and are used to evaluate the capillary damage caused by oxidation. During this oxidation process, part of the hair
hydrolyses the sebum that protects the cuticle. The resulting saponification of sebum decrease sebum, and hair becomes parched, more porous and brittle, resulting in loss of traction resistance and elasticity.
Evaluating hair damage associated with bleaching-scanning electron microscopy ■ Obective: To establish establish the level of hair damage as observed to different strands of hair treated with bleaching powder without additives and bleaching powder added with different concentrations of the powdered liposome (1%, 2% and 3%).
■ Method Five virgin hair locks (without previous treatment) (Figure 1); Each tress except for the control is bleached with the following combinations:
Test products Strand 1: Control without treatment Strand 2: Bleaching powder Strand 3: Bleaching powder + powdered liposome 1% Strand 4: Bleaching powder + powdered liposome 2% Strand 5: Bleaching powder + powdered liposome 3%
Each hair of the tested hair strands was observed under the scanning electronic microcope (SEM) to evaluate their superficial condition, especially the cuticles.
PERSONAL CARE November 2021
Figure 7: Scanning electron microscopy of hair from Strand 4 hair & detail of the cuticles
■ Equipment & materials: l
Cressington. Model: 108 l
SEM. Brand: Carl Zeiss. Model: Leica S440 l Gold/Palladium Metalliser. Brand:
Digital micrometer (Digimess)
l Untreated dark auburn female virgin hair l Bleaching powder
l 40 vol hydrogen peroxide l Hair dryer
■ Protocol: 1. Five dark brown natural virgin hair locks were prepared, without dying or bleaching, of 3 grams each. 2. Four strands were bleached by mixing 10 grams of the appropriate bleaching powder with 20 ml of 40-volume hydrogen peroxide. The discoloration time is 60 minutes. The treated locks were rinsed with plenty of warm water for two minutes 3. They were dried with a clean towel first, and then using the hot air blow dryer at medium temperature for three minutes 4. Each lock was bleached in the same manner for four cycles 5. The treated locks were left to rest for 24 hours in an environment at a temperature of 20°C and constant humidity of 50%. 6. Six hairs were selected from each strand, and 2 cm were taken from their middle part to place them in the object holder. The samples were metallised with palladium gold for four minutes 7. The selected hairs were observed under the scanning electron microscope
■ Results Analysis of the photos taken by the SEM 1. The untreated strand 1 control hair (Figure 2) is in good condition, with intact and hydrated cuticles.
2. In strand 2, hair treated with bleaching powder without additives (Figures 3 & 4), the cuticles have been mostly swept during bleaching and the cortex is exposed due to the alkaline hydrolysis suffered by the proteins that comprise it. Remains of broken and dehydrated cuticles are observed. 3. In strand 3, hair treated with bleaching powder plus 1% powdered liposome (Figures 5 and 6), the cuticles have been partially swept away during bleaching and there are some areas where the cortex is exposed. The degree of hydrolysis observed seems to be less than that experienced by strand 2. There are some remains of damaged cuticles and dehydrated ends. The general condition of these strands is better than those of strand 2. 4. In strand 4, hair treated with bleaching powder plus 2% powdered liposome (Figures 7 & 8), it is observed that the cuticles look healthy and line the hair fibre. They are seen with certain prominence, as if they were dehydrated. 5. In strand 5, hair treated with bleaching powder with 3% powdered liposome (Figures 9 & 10), it is observed that the cuticles look healthy and line the entire hair fibre. There is some degree of damage and the relief is similar to the untreated control hair. 6. At the ends of strand 2, treated with bleaching powder (without additives), the hydrolysis of the keratin occurs. The hair sticks together, making it impossible to comb without breaking it. 7. The ends of strand 3, treated with bleaching powder added with 1% powdered liposome, can be combed with extraordinarily little hair breakage. In this strand, the hair has not stuck to each other, due to the degree of lubrication that the powdered liposome provides.
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