30 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 1 0.1 O. 0.01 0.001 ........ 0.001 0.01 0.1 1 Sodium dodecyl sulfate, % Figure 5. Observed maximum precipitation pattern for the three systems. Symbols indicate: ...... DQNNED ........ MQNNED - Polyquaternium 10. The second region is attributed to the binding of mixed surfactant micelies within the complex, as the high percentage of Octoxynol will shield the polymer molecules from each other, resulting in intramolecular polymer-micelle complexation. At high concentrations of polymer and surfactant, Yc necessary to cause precipitation is independent of extension from the chain for a monoquaternary derivative. However, Yc appears to be influenced by the number of cationic charges on the graft, as DQNNED requires a lower micelie charge density to cause precipitation than does MQNNED. FLUORESCENCE Pyrene is a strongly hydrophobic molecule whose water solubility is very low (2-3 mM). Changes in the vibronic fine structure intensities of the pyrene fluorescence spectra result from changes in the micro-environment encountered by pyrene (28). The ratio of the I•/I 3 bands is high when pyrene is solubilized in a hydrophilic medium, whereas the I•/I 3 ratio is low for pyrene in hydrophobic medium (Figure 7). Aqueous solutions of the polymers were examined for the presence of hydrophobic domains in the polymer molecules. The I•/I 3 ratio indicates that pyrene is solubilized in a hydrophilic environ- ment (Table I). A ratio of 1.7:1 indicates that pyrene molecules reside in the solvation shell of the polymer molecules. In miceliar and macromolecule systems, pyrene is preferentially solubilized in the hy- drophobic regions, and the intensity of the I•/I 3 band ratio for pyrene in micelies should decrease (28). Pyrene fluorescence intensity in micelles of 0.10% SDS/0.90% Octoxynol and 1% Octoxynol exhibits a ratio of 1.2:1 (Table I). As the I•/I3 ratio is greater than

POLYMER-SURFACTANT INTERACTION 31 (A) DQNNED MQNNED g0000 Polyquat 10 1.0 0.8 0.6 0.4 0.2 0.1 01.0 % SDS t I I I I I 0.0 0.2 0.4 0.6 0.8 0.9 1.0 % Octoxynol Surfactant concentration ( 1% total ) (e) DQNNED MQNNED Polyquat 10 0.20 0.18 0.16 0.14 0.12 0.10 %SDS 0.80 0.82 0.84 0.86 0.88 0.90 % Octoxynol Surfactant concentration ( 1% total ) Figure 6. Phase diagrams for the systems 1% polymer/sodium dodecyl sulfate/Octox•vnol, varying the ratio of the two surfactants. Symbols indicate: • clear precipitate and clear supernatant ..• white precipitate and clear supernatant [] hazy solution [] clear one-phase solution. (A) Concentration of sodium dodecyl sulfate 0.0% to 1.0%. (B) Concentration of sodium dodecyl sulfate 0.10% to 0.20% to accurately determine Yo