Conditioning Agents for Hair and Skin

304 Jachowfcz
Another class of raw materials for hair conditioners is cationic polymers.
This class of compounds tends to impart a different feel to hair than quaternary
surfactants, and their substantivity can be controlled by a selection of
monomers, degree of quaternization, etc. They may also be deposited onto
hair effectively from formulations containing a large excess of anionic or amphoteric
surfactants, such as shampoos, oxidative hair dye lotions, etc. Early
work on the interaction of hair with cationic polymers was reported by Chow
(10), Woodward (11), and Goddard (12). These authors have demonstrated
that strong interactions exist between hair keratin and cationic polymers such
as polyethyleneimine, cationic cellulose, poly(dimethyldiallylammonium chloride),
and co(vinylpyrrolidone-methacryloxyethyltrimethylammonium methosulfate).
A variety of different techniques were used to perform fundamental
studies on a polymer's affinity to hair. Radio-tracer techniques with ''*C-labeled
compounds (11-13) and colloid polymer titration methods (14) were
employed for quantitative sorption studies, while X-ray photoelectron spectroscopy
(15), electron spectroscopy for chemical analysis ESCA (16), wettability
(17), and electrokinetic measurements (14,15,18) were used to characterize
the surface of hair after modification with polymers.
Finally, proteins constitute an important class of conditioner raw materials.
They are claimed to impart softness to the hair, increase tensile strength, add
body and gloss, enhance springiness, and improve the overall look and feel of
hair. While there is little peer-review literature to support the effect of proteins
on the physicochemical properties of hair, the substantivity of polypeptides to
hair keratin is well established. Quantitative sorption work has been reported
by Karjalla et al. (19), Turowski et al. (20), Mintz et al. (21), and other authors.
II. REVIEW OF TESTING METHODOLOGIES
A. Instrumental Techniques
1. Combing Analysis
Quantitative combing measurements are frequently used to evaluate the effectiveness
of hair care products. The development of this technique can be
attributed to Newman et al. (22), Tolgyesi et al. (23), Garcia et al. (24), and
Kamath et al. (25). A variation of the method, termed spatially resolved combing
analysis, has been recently presented by Jachowicz et al. (26). Figure 1
presents a photograph of an experimental setup based on a Diastron miniature
tensile tester. In the usual procedure, a comb is passed through a hair tress
and the force is measured as a function of distance. The experimental variables
include the dimensions of a tress, the density of combing teeth, and the type
of comb material. Most of the work reported in scientific and patent literature
relates to hair tresses with a length in the range of 6-7 in., a weight of 1-3 g,