Abstract
Interactions between hydrophobically modified polymers (hm-polymers) and surfactants were investigated by steady-state fluorescence as well as rheological experiments. Hydrophobically modified hydroxyethylcellulose (hmHEC) with C16 hydrophobe grafts of 0.9% mole along with tetradecyltrimethylammonium bromide and cetyltrimethylammonium bromide were studied. The presence of C16HEC induced the aggregation of surfactant micelles in aqueous solution at concentrations about one-half times lower than the critical micelle concentration. As surfactant is added, the viscosity of hm-polymer solution first increases due to the bridging of hydrophobe clusters by surfactant micelles to form mixed micelles and later decreases due to the masking of hydrophobes individually by excess micelles. Fluorescence quenching experiments showed that the number of hydrophobes (NH) in a mixed micelle decreases steadily with increasing surfactant concentration due to hydrophobe dilution by the surfactant. NH declines from greater than...
Published Version
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