The biphasic effect of ABA triblock copolymers on the self-assembly of surfactants: insight from dissipative particle dynamics

Morphological transition of micelles is significant to the synthesis of mesoporous silica materials, drug delivery, and many other applications of nanotechnology. Here, employing dissipative particle dynamics simulations, the cooperative assembly of surfactants and triblock copolymers is studied. The simulation results illustrate that ABA triblock copolymers with a particular block ratio can produce a "biphasic" effect on surfactant micelles, meaning that the surfactant micelles can be enlarged or shortened by regulating the proportion of ABA triblock copolymers. Further investigation of the free energy and the mean square displacement of premicelles indicates that the fusion barrier and diffusivity of premicelles highly depends on the proportion of ABA triblock copolymers. The denser/loose hydrophilic outer shell is attributed to higher/lower diffusion and lower/higher diffusion capacities, and the micellar morphology is therefore changed. These findings not only enrich our understanding on the self-assembly of surfactants with polymers, but also offer a novel strategy to control micellar structures.