Dissipative particle dynamics is applied to study the crossing dynamics at an entanglement point of surfactant thread-like micelles in an aqueous solution. This chapter investigates the possibility of a phantom crossing, which is the relaxation mechanism for the pronounced viscoelastic behavior of a surfactant thread-like micellar solution. When two thread-like micelles are encountered at an entanglement point under a condition close to thermal equilibrium, they fuse to form a four-armed branch point. Then, a phantom crossing reaction occurs occasionally, or one micelle is cut down at the branch point. When increasing the repulsive forces between hydrophilic parts of the surfactants, fusion occurs less and the thread-like micelle is frequently broken down at an entanglement point. In these three schemes (i.e., a phantom crossing, a cut at the branch point, and a break at the entanglement point), the breakage occurs somewhere along the thread-like micelle. The breakage is considered as an essential process in the relaxation mechanism, and a phantom crossing can be seen as a special case of these processes. To explain the experimental evidence that a terminal of thread-like micelles is scarcely observed, a mechanism is also proposed where the generated terminal merges into the connected micelle part between two entanglement points owing to thermal motion.
!!!All Science Journal Classification (ASJC) codes
- 化学 (全般)