The conditioning performance of a formulation reflects the distribution of cationic conditioning polymers and agents such as silicone oils along the hair fiber. Thus, to deposit conditioners as well as fragrances, actives and other materials onto hair surfaces from cleansing and conditioning formulas, various deposition technologies have been developed. In cleansing formulations, the most broadly used deposition technology is based on the complex coacervate formed from a combination of cationic polymers and anionic surfactants. Alternatively, pearlized wax networks provide deposition in cleansing formulations.
In order to target the deposition of materials, innovative methods are required to assess the delivery of conditioning agents to the fiber surface and damaged ends. One such spectroscopic technique, generally used with flat film substrates, is called attenuated total reflectance-infrared spectroscopy (ATR-IR). ATR-IR has effectively been used to monitor the migration of low molecular weight silicone polymers through a silicone matrix. In the present study, ATR-IR is used to map silicone polymer depositions along the length of hair fibers from conditioning shampoo formulations. In addition, a combination of confocal laser scanning (CLS), fluorescent microscopy and atomic force microscopy (AFM) are used to define the corresponding distributions of cationic polymers along hair fiber surfaces.
Materials and Methods
For the present study, three conditioning polymers were used: guar hydroxypropyltrimonium chloride (GHPTC), acrylamidopropyltrimonium chloride/acrylamide copolymer (APTAC-Acm), and a developmental polymer system combining the two—i.e., GHPTC (and) APTAC-Acm. All three polymers had high molecular weights, ≥ 1 MM kdaltons. GHPTC and the developmental polymer system also exhibited a medium charge density, 0.5–1.1 meq/g, whereas APTAC-Acm had a high charge density, 1.5–3.0 meq/g.
GHPTC is well-known for delivering conditioning benefits to keratin substrates from cleansing formulations. In addition, cationic acrylamide polymers are known for their conditioning performance. In the present work, APTAC-Acm was redesigned for further improved deposition performance. As a result, the developmental polymer system and APTAC-Acm were found to provide uniform conditioning along the hair fiber as well as targeted conditioning to the damaged ends of the hair fibers, as will be shown.
Lab Practical: Formulating with Cationic Polymers
- Formulate with 0.05% w/w polymer for lighter conditioning.
- Formulate with 0.2% w/w polymer for deeper conditioning.
- Amphoteric surfactants and nonionic surfactants can be added to the water phase, followed by anionic surfactants and an emulsion stabilizer.
- Add conditioning oil to desired level.