| The self-assembly of macromolecules has become one of the research hotspots inpolymer field in these years. As a kind of special macromolecule, rod-coil blockcopolymer could self-assemble to form a series of different structures since theanisotropy and orientational ordering of rigid chain. These special nanoscale structureshave potential applications in many areas, thus the study on the self-assembly ofrod-coil block copolymers in solvents has been widely concerned.Now the research mainly focuses on the rod-coil diblock copolymer. Rod-coil-rodtriblock and more complex three-arm star rod-coil block copolymer have been littlestudied. In this paper, the self-assembly behaviors of rod-coil-rod triblock copolymer,three-arm star rod-coil block copolymer, and three-arm star rod-coil block copolymer/nanoparticles in selective solvents were studied by dissipative particle dynamics (DPD)method.(1) Using DPD method, the self-assembly of rod-coil-rod triblock (RxCyRx) indifferent solvents was studied, especially focusing on the impact of polymerconcentration and the chain length on the aggregate morphologies. Many kinds ofmicelles, such as spheres, nematic bundles, worms, cylinders, perforated lamellae,lamellae, coil-and rod-aggregated hollow cylinders, networks and several meltedphases, were obtained. In the coil-selective solvent, increasing coil length can defer thephase transition from sphere to other morphologies while increasing rod length canadvance the transition. In the rod-selective solvent, an opposite influence rule is found.Theoretically, these morphologies and morphological transitions are controlled byminimizing the micellar free energy, which drives the rod-coil-rod copolymers to takethe different shape and undergo the phase transition.(2) The self-assembly of three-arm star rod-coil block copolymer (RC)3in differentsolvents were studied, and the impact of polymer concentration and chain length on theself-assembled structures were analyzed, too. The corresponding phase diagrams wereobtained and the possible assembly way was speculated. The aggregate morphologieswere generally changed as spheresâ†'cylindersâ†'networksâ†'lamellae with theincreasing of polymer concentration. Compared with the self-assembly of rod-coil-rodthree block, star rod-coil block copolymer generally form micelles which have specialinternal structures, namely “rod-coil-rod-coil...” regions arranged in turn. (3) The co-assembly of (RC)3with nanoparticles were studied, and the impact ofpolymer concentration, repulsive force between nanoparticles and different chainsegments, the shape and concentration of nanoparticles on the co-assembly wereconsidered. Some rules as follows were confirmed: a. rod-coil block copolymers couldregulate the distribution and sorting of nanoparticles, the adding of nanoparticles couldregulate the self-assembled structures of block copolymers as well; b. neutralnanoparticles tended to distribute in two-phase interfacial area, and the rod-friendly (orcoil-friendly) nanoparticles tended to distribute in rod block (or coil block) phase region;c. longer rod-friendly (or coil-friendly) nanorods tended to be located in the center ofthe rod block (or coil block) phase region. |
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