Conditioning by cationic polymers on Asian hair

Many parameters, such as polymer types, molecular weight, cationic charge density, type of silicone emulsion and hair surface damage level, will affect the deposition and conditioning performance. In this study, we have systematically explored the coacervate formation, silicone deposition, and hair wet combing force reduction of the shampoo samples with three cationic polymers (polyquaternium-10, guar hydroxypropyltrimonium chloride and a mixture of GHPTC and acryamidopropyltrimonium chloride/acrylamide copolymer) and three silicone emulsions (small-particle silicone, large-particle silicone and amodimethicone) on Asian undamaged and bleached hair. The mechanism for the difference in deposition and conditioning performance among the samples are discussed and interpreted.

 With the economy growing and the population greying in Asia, more and more consumers are use colouring, perms and styling products to improve their hair appearance. All these treatments along with environmental exposure will damage the hair surface, lead to a loss in natural shine and make hair difficult to comb through.1,2 Whereas a shampoo is used simply to clean hair, a conditioning shampoo is a more attractive choice for many consumers because it combines hair cleansing and conditioning into one step. These types of products are becoming more and more popular in the Asian market. The performance of conditioning shampoo reflects the distribution of cationic polymers and agents such as silicone oils deposited along the hair fibre. The most broadly used deposition technology is based on the complex coacervate formed from cationic polymers and anionic surfactants in conditioning shampoos during the rinse stage. The hydrophobic coacervate will deposit cationic polymers, along with silicone oils encapsulated inside, onto hair and scalp. The deposited silicone will provide hair with combing force reduction, a greater hydrophobic surface, a soft feel, a more lustrous appearance and improved manageability in the dry stage.3,4 Parameters, such as polymer types, molecular weight, cationic charge density, type of silicone emulsion and degree of surface damage will affect the coacervate formation and the deposition efficacy. Selecting an appropriate conditioning polymer for a specific silicone type is very important to formulating a shampoo with excellent conditioning benefits without build-up issue for either undamaged or damaged hair. In this study, three cationic polymers – polyquaternium-10 (PQ-10), guar hydroxypropyltrimonium chloride (GHPTC) and a mixture of GHPTC and acryamidopropyltrimonium chloride/ acrylamide copolymer (polyAPTAC-ACM)5,6 – were formulated in shampoo systems and used to compare conditioning performance on Asian undamaged and bleached hair. The relative surface silicone deposition level (RSSL) of hair treated by the shampoo samples with those polymers and three silicone emulsions inside, was measured by ATR-FTIR method. Three silicone emulsions are small particle silicone (SPS), large particle silicone (LPS) and amodimethicone (ADM). The wet combing force, contact angle and silicone build-up effect on hair after treatment were also evaluated. The mechanism for the difference in conditioning performance among the samples is discussed and interpreted.

 Experiments