278 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 0.6 0.5 0.4 0.3 0.2 0.1 dry i i i i I i I I 20 24 28 32 36 •'c (dyn/cm) Figure 2. Plots of kinetic frictional coefficient vs critical surface tension for dry hair: a, clean bleached hair b, clean normal hair c, n-C•sTAC d, n-C22TAC e, 2n-C•sDAC f, g-C28TAC (&, reference 1) g, PDMS (A). O. 20 O. 18 O. 16 ::l O. 14 O. 12 O. 10 10 2 10 a mount of P•lS depos i t ion ( # g/ghair as S i ) Figure 3. Effects of amount of PDMS (Mw = 22 X 104) deposition on the kinetic frictional coefficient of dry hair fibers.

CONDITIONING AGENTS 279 Table II HLB Values and Solution Behaviors of POES Surface Dimethylsiloxane Polyoxyethylene Ethylene HLB value Solubility in tension units: m units: n oxide mole: a calc.* water at 25øC (dyn/cm) 60 3 4 3 Insoluble (oil) -- 75 3 11 5 Dispersible (L.C.**) 20.2 45 3 11 6 Dispersible (L. C. **) 20.2 25 3 11 8 Dispersible (emulsion) 20.7 6 3 14 13 Soluble (clear) 22.0 * Calculation of HLB: (weight percent of polyoxyethylene units) •- 5. ** L.C., liquid crystal. with its low IXk. The mechanism of the IXk increases and then suddenly decreases in relation to the growing Mw values, and this may be explained by the effect of the viscosity. With increasing viscosity, Ixu also increases, but after exceeding the critical point where the PDMS films take on more solid-like form, the values start to decrease. The relation between the IXu and critical surface tension (•/c) of hair fibers treated with cationic surfactants (1) and PDMS is plotted in Figure 2. The surface energy decreases, causing low adhesion and consequently low Ixu, when coverage of the hair surface with lubricant is complete. In the case of the hair surfaces treated with cationic surfactants, the effect on Ixu decrease was explained in terms of the amount of surfactant sorbed onto the hair (1). It is clearly shown that PDMS, forming hydrophobic and lubricating thin 120 60 20 o (insoluble) (dispersible) (soluble) I I I I I I I I I ! I I I • 0 5 10 1tLB value(ealuelated) Figure 4. Plots of amount of POES deposition vs HLB value. The hair samples were treated with model shampoo (disodium polyoxyethylenelaurylethersulfosuccinate/amidoaminoacid triethanolamine/POES = 12/8/4 wt%).