Solvent-induced self-assembly of polymer-tethered nanorods.

Self-assembly behaviors of polymer-tethered nanorods in the selective solvent are systematically investigated via a dissipative particle dynamics (DPD) simulation method. Three types of polymer-tethered nanorods are considered: one end tethered, both ends tethered, and middle tethered. The solvent-induced diverse morphologies and morphological transitions depend on the topology, rod/tether length ratio, solvent selectivity, and mixed solvent content. In the pure rod-selective solvent (solvent I) or the pure tether-selective solvent (solvent II), the ordered micellar structures include: cylinders, hexagonal cylinders, bilayer lamellae, lamellae/cylinder mixed phases, inverted hollow cylinders, and nematic bundles. These micelles are formed by the competition among the stretching of tethers, liquid crystalline of rods, interfacial energy, and solvent selectivity. In the I/II mixed solvent, with varying mixed solvent content in sequence (i.e., changing the solvent quality for the blocks), the reversible morphological transitions and fantastic intermediate phases (e.g., liquid crystalline phase) are observed, which correspond directly to the case of that induced by varying the rod/tether length ratio in the pure solvent. It is concluded that improving the selective solvent content is equivalent to increasing the soluble block ratio. The present study reveals that the morphology and morphological transition of polymer-tethered nanorods could be significantly manipulated through topology, block length, and solvent, especially the selectivity.