Molecular Dynamics Simulation of the Self-Assembly of Rigid Sphere-Rod Amphiphilic Marcomolecules into Onion-Like Assemblies

Self-assembly behaviors of amphiphilic block copolymers have been well explored. When both hydrophilic and hydrophobic domains are rigid, the common rule of self-assembly based on the packing parameter is not applicable because the solvophobic domain cannot collapse into a globule state. Recently, it was found that the T-shaped sphere-rod shaped amphiphiles with the long rods being hydrophobic domains show intriguing self-assembly behavior. In polar solvents they first stack to each other face to face, then such units would further assemble into onion-like structures with uniform size and strictly identical interlayer distance. They respond to the external condition change by changing the number of layers, but not the overall morphology. The self-assembly of these marcomolecules in organic solvent and water mixed solvent results in the spontaneous organization of bilayer structures. Using all-atom molecular dynamics simulations, we investigated the initial stages of the self-assembly process of amphiphilic molecules which will be the focus of this presentation. The investigation is also expanded through coarse-grained simulations and our findings will be discussed as well.