ABC線性多塊狀雙親性共聚合物在對A塊狀具有選擇性的溶劑下之微胞行為衍變

Abstract

The ability of ABC amphiphilic multiblock terpolymers to self-assemble into multicompartment micelles in dilute solutions is of great current interest. We used three-dimensional self-consistent mean-field theory to investigate the micellization behavior of ABC amphiphilic multiblock terpolymers in the presence of a solvent that is selective to the terminal A block. Firstly, we have explored systematically the morphologies adopted by a particular block terpolymer architecture, A-b-(B-alt-C)n, where the A block is solvophilic and B and C blocks are solvophobic. In particular, we focused on the effects of the incompatibility parameter between B and C, hBC, and the composition of the solvophilic A block, fA, on the formation of micelles from ABC triblock and A(BC)3 multiblock terpolymers, respectively. We observed a general trend that a segmented packing of B- and C-layers along the axial direction of the micelles is favored than the coaxial packing with the increasing of hBC or decreasing of fA. The separation of B and C blocks within a micelle leads to the formation of a variety of multicompartment micelle morphologies, such as core-shell-corona spherical micelles, hamburgers, and bump-surface micelles, in the ABC triblock copolymers. In the A(BC)3 multiblock terpolymers, we discovered more fascinating micelles by implementing the SCFT simulation than by the DPD simulation. Besides the BC-segmented worm-like micelles, which have been found in the DPD simulation work, concentric multilayer spheres and vesicles can be formed by the solvent-induced effect when the solvophilic A block is a majority component. In the A(BC)3A multiblock terpolymers, a series of fascinating micellar structures are observed, such as B- and C-disk segmented vesicles, BC-segmented hollow cylinders, BC-segmented toroidal micelles, infinite BC-segmented cylindrical micelles and BC-mixed toroidal micelles. By the limitation of B and C blocks are all joined to A block, the segmented packing way of B and C layers is along the axial direction of the structures. With the decreasing of fA, the structural transition is from vesicles to micelles in the A(BC)3A multiblock terpolymers. It is opposite result compared to the A(BC)3 multiblock terpolymers system (micelles → vesicles). The SCFT method provides an efficient way to screen promising molecular architectures for the ability to self-assemble into technologically promising hierarchical structures.