Silicone oil is used as a regulator in hair and skin care products. They give hair a soft, combed and shiny appearance. Different polymers are added to shampoos and conditioners to improve silicone deposition on hair. As the size of the polymer increases, the interaction between the polymer and the hair matrix increases, resulting in the deposition of silicone resin.
Secondly, a total of 24 kinds of anionic polymers and neutral polymers were used. The anionic polymer showed less substance to the hair due to its electrostatic repulsion with the hair surface, while the neutral polymer showed weaker interaction with the hair and less deposition of silicone resin.
Application of cationic polymers
Various cationic polymers are used as thickeners in shampoos and conditioners to improve silicone deposition on the hair surface. The molecular weight, surface charge and charge density of cationic polymers have important effects on silicon deposition.
Influence of molecular weight
01
Quaternary ammonium compounds have strong interaction with silicone oil and can be used as bridging agents to promote the deposition of silicone oil on hair. With the increase of polymer molecular weight, the interaction is also enhanced, which is conducive to the deposition of Si 55. The interaction between large molecular weight polymer and small molecular weight polymer is stronger, which is beneficial to the deposition of silicone oil. Molecular weight plays an important role in the deposition of organosilicon.
Surface charge effect
02
The surface charge of the polymer showed greater improvement in silicon deposition on the hair. The amount of silicone oil deposited in untreated hair was significantly reduced, while the amount of silicone oil deposited in the hair sample treated with positive surface charge was significantly increased. Therefore, the electrostatic interaction between the negative surface of hair and the positive surface charge of silicone oil droplets is beneficial to improve the deposition of silicone oil on hair.
Charge density effect
03
Silicone deposition was significantly higher in hair samples treated with a PQ-67 shampoo than in hair samples treated with a cationic guar gum shampoo. The charge density of polymer has a great influence on the deposition of organosilicone on hair.


Proteins are used to improve organosilicon deposition
Using protein can also improve silicone deposits in hair. Applying these lotions to the surface of the hair can significantly improve the deposition of organosilicon and help repair damaged hair skin scales. Because silicone resin has a variety of ions and polar sites, the interaction between protein and silicone resin is strong, resulting in increased viscosity of the emulsion, which is conducive to further improve the deposition of silicone resin on hair.


Improvement of organosilicon deposition process by liquid crystal colloidal structure
Another successful method to increase silicone deposition on hair is a liquid crystal (LC) colloidal structure of shampoo produced by a cationic polymer [polydiallyldimethylammonium chloride] and a negatively charged surfactant. The liquid crystal structure is deposited on the hair surface through electrostatic and hydrophobic action, which leads to the increase of hydrophobicity on the hair surface and the increase of organosilicate deposition.


Improvement of organosilicon deposition by silicon emulsion with uniform size control
Although the deposition rate of silicone oil can be improved by using the above methods, the size and uniformity of silicone oil emulsion have not been controlled until the last ten years. In 2011, Nazir et al. used SPG film emulsification technology to prepare silicone oil emulsion with uniform and controllable size. Add these lotions to the model shampoo and conditioner and store for 1 year. Hair samples were treated with fresh and 1-year stored shampoos and conditioners and compared with a control sample containing a widely distributed emulsion. The effects of emulsion particle size uniformity and storage stability on the deposition of organosilicon were systematically studied


With the decrease of droplet size, the amount of organosilicon deposition on the hair surface increases. In addition, fresh droplets of uniform size and 1-year storage drops are almost similar due to their good storage stability. However, in the case of non-uniform droplets, the deposition of the samples stored for one year was significantly reduced due to the poor storage stability. These results indicate that droplet size and uniformity are important for improving hair stability and organosilicon deposition.