1999 ANNUAL SCIENTIFIC MEETING 61 Tensiometer 3, but is not effective for oils, as a correction for viscosity is not provided in the Washburn equation.. Several approaches to sample preparation were explored to obtain flat pigment samples suitable for direct observation of contact angles using the Ram6-Hart Goniometer. Measurements made of water on cakes of pure hydrophobic pigment pressed at 4000 psi were useful, but the differing densities of the cakes among the various surface treatments made values for good wetting, low viscosity fluids questionable. Samples used to obtain the results shown below were obtained by casting 100gm wet films onto glass slides from slurties of 60% pigment by weight dispersed in isopropyl alcohol and drying overnight at room temperature. Roughness of the surface is known to affect contact angle measurements 4, so control of particle size in the alcoholic dispersions is critical to obtaining useful comparative results. Based on visual observation of the time required for drops to spread and that at which absorption began to take place, readings were taken at 0.33 seconds following release of 15gl droplets of the liquids. Pigments used were red iron oxide with methicone, caprylyl silane, reacted dimethicone, and reacted perfluoro treatments. Reported here are values for the following oils: mineral oil/300cs, dimethicone/100cs, cyclomethicone, octyl palmitate, and propylene glycol dicaprylate/dicaprate. Mineral Oil Dimethicone Ds Octyl Prop. Glycol water Palmirate C840 Methicone 21.0 21.5 6.7 16.0 15.0 •07 C, Silane 22.7 22.7 7.8 8.3 20.0 117 Dimethicone 29.7 23.5 4.7 10.0 22.0 119 , , Perfluoro 95.8 34.1 10.5 40.7 64.1 130 Results are considered as a comparison ofwettability among the treatments in each oil. Comparison ofwettability among the different oils cannot be inferred due to the differences in surface tensions between the fluids. Practical Application: Pigments and fillers having each surface treatment were then incorporated into an anhydrous foundation and a water in oil foundation. The anhydrous foundation contained 43% pigment dispersed in octyl palmitate and waxes. Octyl palmitate was the sole oil utilized as the vehicle for the 39% color grind of the water-in-oil foundation. Viscosity measurements, presence or absence of color flotation, and relationship between mass tone and skin tone were the practical indications of pigment wetting. Surface ANHYDROUS W/O EMULSION - COLOR GRIND treatment Mass/Skin Mass/Skin Viscosity 70C Flotation Tone Viscosity RT Flotation Tone Control 30,000 mass light 30,00i) mass dark Methicone 2,900 mass red 4,300 Cs Silane 1,900 good 1,000 good Dimethicone 1,000 none good . . 1,300 .gøød . . Perfluoro 30,000 26,000

62 JOURNAL OF COSMETIC SCIENCE Discussion: As predicted by the contact angle measurements between the pigments and octyl palmitate, the C8 silane and the Dimethicone treated pigments gave the lowest viscosity dispersions in octyl palmitate, indicating better wetting. In the emulsion color grind, the descending order of viscosities was the same as the order for the contact angles with the C8 silane being the lowest. The rank of viscosity for the silane and the dimethicone were reversed in the anhydrous system, indicating an effect from the waxes or the elevated temperature. Absolute values for contact angles will not be obtained from the above method, but useful reproducible data can be collected by controlling experimental parameters. A day spent screening treatments in various vehicles will narrow the number of time consuming experiments that need to be made in the lab to optimize formulations. References: •Hollenberg, J., Price, M.S., Sujet, D., Performance of a Range of Surface Treatments, SCC Annual Scientific Meeting, 12/96. 2young, T., Phil. Trans: Royal Soc. (London), 95, 65 (1805). 3Rulison, C., Technical Notes, Kriiss USA, 1997. *Wenzl, R.N., Ind. Eng. Chem. (Anal.), 28, (1936) 988. Cardre 01/JANE/scc 1299