Self-Assembly Behavior of Triphenylene-Based Side-Chain Discotic Liquid Crystalline Polymers

We constructed a generic coarse-grained model of triphenylene-based side-chain discotic liquid crystalline polymers (SDLCPs). Then dissipative particle dynamics (DPD) simulation was employed to systematically study how composition and structural factors of SDLCPs such as molecular weight, main chain, spacer and aliphatic tails, and the incompatibility between mesogenic core and its substituents influence their mesophases and self-assembly behavior. Eight mesophases were obtained by changing the factors mentioned above. The eight phases are hexagonal columnar-amorphous (Col(h)-Am), nematic columnar-amorphous (Col(ne)-Am), nematic columnar-clustered (Col(ne)-Clu), nematic columnar-columnar (Col(ne)-Col), random columns-amorphous (Col(ran)-Am), random columnar-clustered (Col(ran)-Clu), amorphous-amorphous (Am-Am), and sphere-amorphous (Sph-Am). The name of mesophase is denoted as assembly of discogens-aggregation of backbone. By checking conformation of molecules, the intracolumnar self-assembling patterns based on the discrete columnar stack (DCS) were observed in Col(h)-Am, Col(ne)-Am, and Col(ne)-Clu, while Col(ne)-Col and Sph-Am adopted different packing modes. Moreover, molecular weight effect and positive coupling of spacer were discolosed, which matches well with experiments. Moderate or strong incompatibility between mesogenic cores and substituents and proper peripheral aliphatic tails are needed for SDLCPs to form ordered mesophases. The in-depth understranding of their superstructures may offer inspiring guidance for rational polymer design, preparation, and further exploration in optoelectronic field.