BEHAVIOR OF SILICONE SURFACTANTS 97 A 5000 •o -- I.LI n 4000. --n-- ABILWE0• 1•'C --o-- ABIL WE 0• ,,,, --A-- ABIL WE 0• 40ø(3 ,.•. - -V -• ABIL WE 0• i I I I ' I i i , 0 5 10 15 20 25 30 SHEAR RATE (1/S) ,, %' H':I .... FI- [] i ,, ,, o ,, A• .... o.-- o .............. '.'•- -V .... V .............. V ........................ --El-- DC Q2-5200 15"C --O-- DC Q2-5200 30"C --A-- DC Q2-5200 40øC --V-' DC Q2-5200 50"C I '"" • ' I' ' I ' I ' I ' I ' I 0 5 10 15 20 25 30 35 SHEAR RATE (1/S) Figure 6. a. Changes in viscosity of Abil WE 90 at 15 ø, 30 ø, 40 ø, and 50øC. B. Changes in viscosity of DC Q2-5200 at 15 ø, 30 ø, 40 ø, and 50øC. To determine the effect of glycol concentration on surfactant viscosity, we tested dif- ferent concentrations of PG at 15 øC. Figures 8A and 8B show the rheograms of mixtures prepared with different concentrations of this glycol. Mixtures with Abil WE 09 showed increasing viscosity as the proportion of glycol increased, with values ranging from 400 cP or higher (lower concentration of glycol) to 1200 cP or higher (higher concentration of glycol). However, the opposite was found for mixtures with DC Q2-5200: the lower

98 JOURNAL OF COSMETIC SCIENCE 0 30000, 03 --El-- ABIL 50% + PG 50% --O--. ABIL50% + gty•efine50% -- 'A-- I ABIL50% + PEG50% I ' I ' I ' I ' I 10 15 20 25 30 SHEAR RATE (1/S) I I •: --,•:: = =m'- .......... = = --El ........ I ' I ' I ' I ' I 0 5 10 15 20 SHF_AR RATE I ' I ' I Figure 7. A. Changes in viscosity with shear rate in mixtures of Abil WE 90 with 50% propylene glycol (PG), glycerine, or polyethylene glycol (PEG) at constant temperature (15 o _+ 1 øC). B. Changes in viscosity with shear rate in mixtures of DC Q2-5200 with 50% propylene glycol (PG), glycerine, or polyethylene glycol (PEG) at constant temperature (15 ø + iøC). the concentration of glycol, the higher the viscosity of the mixture. In 5/5 mixtures, viscosity was around 1000 cP or higher in 9/1 mixtures of PG, viscosity at 15øC was 8500 cP or higher. Mixtures with the other two glycols yielded results similar to those obtained with PG.