Conditioning Agents for Hair and Skin

316
(c)
10 20
Figure 7 Continued.
Jachowicz
C, D, and E, designed for damaged/dyed, regular, and fine hair (42). The data
presented in the figures are consistent with the above-delineated criteria of
performance. Conditioner C, based on most substantive ingredients, produced
the greatest change in zeta potential of hair and also precipitated the thickest
conditioning layer. On the other hand, the use of conditioner E resulted in the
least extensive surface modification, as evidenced by a gradual decrease of zeta
potentials during rinsing with the test solution and a relatively thin layer of
conditioning agents on the hair surface. Conditioner D showed behavior intermediate
between that of conditioners C and E.
DEPA experiments with multiple applications of a conditioner followed by
shampooing can provide information about the removability of conditioner
residues from hair and can be used for the evaluation of buildup parameters.
The results of such an experiment are presented in Figure 8 as plots of zeta
potential, flow rate, and conductivity as a function of time. The conditioner
employed in this study was based on substantive components such as bephenyltrimethylammonium
chloride and silicone emulsion DC 929 and resulted in a
significant modification of hair as reflected by high positive values of zeta potential
and a thick, 3.56-)Ltm layer of the conditioning agent. Subsequent shampooing
washed away most of the adsorbed species, lowering the zeta potentials
and reducing the thickness of the conditioning layer to 0.71 fim. The data from
this experiment can be used to calculate the extent of removability of conditioning
residues in a shampooing step and their buildup as a result of two