540 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS will report data on the adsorption of Polymer JR onto human hair from sim- ple aqueous solution, and also from a number of aqueous surfactant solutions of potential interest as shampoo ingredients, under conditions simulating shampooing in practice. Results on the adsorption of the polymer in vitro on- to various mammalian skin stratum corneum surfaces are also reported, to- gether with electron microscopic (EM) results of skin washed with soap with and without the polymer. EXPERIMENTAL Bleached and virgin-brown human hair was obtained from DeMeo Bros.* For adsorption experiments, small swatches weighing 100 mg each were cut and placed in 1-oz counting vials. Ten ml of a water solution of radio-tagged Polymer JR were piperted into the vials, were left there to contact the hair for a given time, and then the solution was poured off. The hair was then given a brief rinse with distilled water, which was sufficient to remove any entrained radioactive solution. The hair was dried to remove excess mois- ture, and dissolved with 1 ml of Unisol? tissue solubilizer. This was followed by addition of 0.5 ml of methanol to solubilize any water present and 10 ml of a toluene-based scintillation liquid. The vials were then counted by the nor- mal scintillation method. Counts at 100 per cent efficiency were calculated by a tagging procedure involving addition of small amounts of a standard radio- active toluene sample. For the shampoo experiments, 5 g of hair tresses were washed with 2 g of shampoo for 30 to 45 sec, and rinsed 3 times in 1 1. quantities of 40øC tap wa- ter. The wash/rinse was repeated, and the tress was then dried. The sham- poo, rinse, and drying treatment was repeated for the desired number of cy- cles. The amount of polymer on the hair after a given shampoo cycle was de- termined by weighing 100 mg of hair into a counting vial and dissolving and counting in the manner outlined above for the adsorption experiments. Each shampoo consisted of a 15 per cent solution of the surfactant, 2 per cent of a fatty amide (Onyx Super Amide L-9C), and 1.5 per cent of Polymer JR 400. The surfactants used were as follows: Tergitol© 15-S-9:S 9 mole ethoxylate of a secondary Cn to C•5 alcohol Miranol CM-SF:a a dicarboxylic coconut imidazolinium derivative Standapol T:** triethanolamine lauryl sulfate Stan- dapol AB-45:** lauryl dimethyl betainc Standapol ES-2: ** sodium salt of the *New York, N.Y. 10003. ?Isolabs, Inc., Akron, Ohio 44321. SUnion Carbide Corp., New York, N.Y. •Miranol Chemical Co., Irvington, N.J. 07111. **Henkel Inc., Teaneck, N.J. 07666.

ADSORPTION OF POLYMER JR 541 sulfated 2-mole ethoxylate of lauryl alcohol F-90:* sodium salt of linear do- decyl benzene sulfonate and potassium laurate: made in the laboratory by neutralization of lauric acidi with potassium hydroxide. In the case of the skin, samples of mammalian stratum corneum were pre- pared in our laboratory from whole skin. For the porcine membranes we used hairless fetal pigskin which was obtained frozen.$ Upon warming, the stratum corncure layer could be peeled readily by hand from the whole skin. In the case of calfskin, the starting material was dehaired pickled calfskin. ø The skin was hydrated by soaking it in water overnight and by putting it into a solu- tion of 0.2 per cent trypsin, 2 molar urea, and 0.1 per cent tris (hydroxymeth- yl) aminomethane. This solution was then warmed for about 4 hours to 50øC. At the end of this period, the stratum corncure could be worked off by hand with some difficulty. Treatment with radio-tagged Polymer JR was the same as described previously for the hair samples. RESULTS AND DISCUSSION Adsorption of Polymer JR on bleached hair was determined for 0.1 per cent concentration. The data are given in two figures because of the ,vide range of time involved Fig. 1 is in hours, Fig. 2 in days. It can be seen that there is a fast initial reaction leading to nearly i per cent pickup in an hour however, attainment of equilibrium takes at least a week. Such a lengthy process differs from the behavior of polymers on typical inorganic substrates like glass, metal, and powdered oxides. In such cases, adsorption is largely completed in less than an hour. It is interesting to note that Polymer JR shows relatively fast and limited adsorption on clean glass slides (2) hence, there is a presumption that the character of the hair substrate is responsible for the slow adsorption in Fig. 2. An investigation of the literature shows precedents for this, although litfie has been reported specifically for the action of polymers on hair. An earlier study, which has features in common with our results, is the work of Scott and coworkers (3), who measured the adsorption of cetyltrimethyl ammonium bromide on natural and bleached hair. Under conditions of acid and neutral pH, a continuing adsorption was observed, which did not reach equilibrium even in 24 hours. Their results on bleached hair and 0.1 concentration are shown by the dotted line in Fig. 1. *Pilot Chemical Co., Los Angeles, Calif. ?Matheson, Colman and Bell, Rensellaer, N.Y. tPelFreez, Rogers, Arkansas. 0Barrett Corporation, Newark, N.J.