Langmuir, Vol.19, No.21, 8654-8660, 2003
Hybrid threadlike micelle formation between a surfactant and polymer in aqueous solution
The construction of a new type of threadlike micelle called a "hybrid threadlike micelle", formed by surfactant and polymer molecules, was investigated using NMR and viscoelastic measurements in an aqueous system of cetyltrimethylammonium bromide (CTAB), sodium p-toluensulfonate (NapTS), and sodium poly(p-vinylbezoate) (NaPVB) (CTAB:NapTS:NaPVB/W), varying the pH and composition of components. When the molar concentration of NapTS (C-S) is higher than 60% of the concentration of CTAB (C-D), the system constructs hybrid threadlike micelles that are long enough to become entangled with each other and that exhibit pronounced viscoelasticity well described by the behavior of a simple Maxwell model, like an ordinary aqueous threadlike micellar system without polymers (CTAB:NapTS/W). At a pH lower than the pK(a) of the polymer, the viscoelastic relaxation time and strength of the CTAB:NapTS: NaPVB/W system become greater than those of the ordinary threadlike micellar system. These findings suggest that incorporation of long polymers into the hybrid threadlike micelle effectively hinders the crossing-through reaction between two micelles at an entanglement point (which releases the entanglement) and that it causes the rigidity of the hybrid threadlike micelle to be greater than that of the ordinary threadlike micelle.