Conditioning By Cationic Polymers On Asian Hair-3

Sample evaluations
A coacervation study was conducted using the following steps: 2% polymer solution was prepared with the ratio of 0.2/12/2/1 for polymer/SLES/CAPB/NaCl. The solution was diluted in a ratio of up to 20 times. The transparency percentage of solution was measured at the wavelength of 600 nm by UV-visible spectrophotometer (Agilent Cary 300). The ATR-FTIR (Thermo Nicolet 380) technique was employed in this study to use the ratio of silicone peak height near 796.5 cm–1 (tangent baseline) to a hair reference peak area from 940.1 cm–1 to 919.9 cm–1 (tangent baseline) to determine the RSSL of hair samples, as shown in Equation 1.6,7 Hair tip-root silicone selectivity was defined as the ratio of the RSSL for bleached hair to the RSSL for undamaged hair since undamaged hair represent the hair in root, while bleached hair represent the damaged hair in tip. The combing force of bleached hair was evaluated by TA.XTPlus texture analyser with a combing force adaptor from Stable Micro Systems Ltd. The combing speed was 5 mm/s. Each sample was measured three times to calculate an average. The contact angle of hair tresses was measured by the method reported in the literature.7

Results and discussion
Coacervate formation
Cationic polymers were soluble in the undiluted shampoo but became insoluble during the massage and rinsing stage, the polymer surfactant complex precipitated out of solution and deposited onto the hair through the coacervation process. Other actives such as silicone or ZPT in shampoo will be encapsulated inside the coacervate and deposit on hair simultaneously. Because the water-insoluble coacervate affects the turbidity of the diluted shampoo, per cent transmittance is an appropriate means of measuring the coacervate formation of cationic polymers in shampoo systems. The dilution of 1 to 5 times represents the real-life shampoo massage stage, and 5 to 20 times represent the rinsing stage. The increased depth and breadth of the transparency curve indicate a more effective formula for deposition and conditioning purposes. The coacervate formation of three polymers after a serial dilution (up to 20 times) is shown in Figure 1. All three polymers tested formed coacervate, with the solution transparency decreasing initially and then increasing during dilution. It is worth noting that the PolyAPTAC-ACM/ GHPTC mixture had the deepest and broadest peak, reflecting the largest amount of coacervate formed early during the massage stage. The coacervation decreased rapidly later during the rinse stage. It has been reported that the more coacervate that forms early in the dilution stage, the more deposition of cationic polymers and silicone will occur onto hair, leading to better conditioning performance during the wet and dry stages. The rapid decrease of the coacervate amount later in the rinse stage indicates that excess polymers could be easily rinsed off without build-up on hair fibre. This excellent conditioning effect during all stages for wet and dry hair can be achieved as a result.

Source from https://www.personalcaremagazine.com