Next Article in Journal / Special Issue
Known and Unknown Features of Hair Cuticle Structure: A Brief Review
Previous Article in Journal
Effects of a Phenol-Enriched Purified Extract from Olive Mill Wastewater on Skin Cells
Previous Article in Special Issue
Stiffness of Human Hair Correlates with the Fractions of Cortical Cell Types
Open AccessReview

Degradation of Hair Surface: Importance of 18-MEA and Epicuticle

1
R&D—Hair Care Products Research, Kao Corporation, Tokyo 131-8501, Japan
2
R&D—Analytical Science Research, Kao Corporation, Wakayama 640-8580, Japan
*
Author to whom correspondence should be addressed.
Cosmetics 2019, 6(2), 31; https://doi.org/10.3390/cosmetics6020031
Received: 25 March 2019 / Revised: 22 April 2019 / Accepted: 5 May 2019 / Published: 9 May 2019
(This article belongs to the Special Issue Recent Advance in Hair Science and Hair Care Technologies)
In this paper, surface degradation of hair is reviewed. Surface properties such as hydrophobicity and surface friction change as surface structures of hair fiber, that is, 18-methyleicosanoic acid (18-MEA) and epicuticle, degrade. Comparison of contact angle and amount of 18-MEA from root to tip of the sampled hair fibers clarified the contribution of not only 18-MEA but also epicuticle to surface properties. It was found that chemical treatment by itself, such as bleaching, is not enough to cause complete loss of hydrophobic nature even after 18-MEA is removed. Additional weathering processes, such as repeatedly shampooing, are required. A technology for the deposition of a persistent hydrophobicity to bleached and weathered hair surfaces using 18-MEA is presented. Combination of 18-MEA with specific cationic surfactants (Stearoxypropyldimethylamine: SPDA) made the bleached and weathered hair surface hydrophobic, and its hydrophobicity was maintained even after shampooing. Characterization of adsorbed layers of 18-MEA/SPDA on a mica surface, as a possible hydrophilic surface model, was performed using atomic force microscopy (AFM) and angle-resolved X-ray photoelectron spectroscopy (AR-XPS). The effects of the anteiso-branch moiety of 18-MEA to create a persistent hydrophobicity with 18-MEA/SPDA were investigated using controlled AFM. It was revealed that the anteiso-branch moiety of 18-MEA in the 18-MEA/SPDA system produces a persistent hydrophobicity by providing higher fluidity to the upper region of the 18-MEA/SPDA layer. The contribution to hair beauty and sensory feeling as one of the practical functions of the hair surface is described in this paper. The hydrophobic nature of the hair surface reduces surface friction in a wet state, which reduces hair disorder alignment. It is also revealed that the moisturized or dried out feeling strongly depends on the hair shape (meandering and diameter) which depends on hair surface properties in a wet environment. View Full-Text
Keywords: 18-MEA; epicuticle; hair surface 18-MEA; epicuticle; hair surface
Show Figures

Figure 1

MDPI and ACS Style

Tokunaga, S.; Tanamachi, H.; Ishikawa, K. Degradation of Hair Surface: Importance of 18-MEA and Epicuticle. Cosmetics 2019, 6, 31.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop