Phase Behavior Of Phasmidic Mesogen-Jacketed Liquid Crystalline Polymers Displaying Chain Bundling

Phasmidic mesogens generally consist of a long rod core and two dendronized end-groups possessing three alkyl tails. Mesogen-jacketed liquid crystalline polymers (MJLCPs) represent an important class of shape-persistent polymers. Here, we synthesized two phasmidic molecules (MS-n, n = 8, 12, where n is the carbon number of each alkyl tail). More importantly, using MS-n as side chains, we synthesized two families of phasmidic MJLCPs (PE-n and PNB-n) for the first time. The side-chain grafted density of the PE backbone is about twice that of the PNB backbone. MS-n (n = 8, 12) can form a hexagonal Phi phase (Phi(H)). From n = 8 to 12, phase structures (molecular shapes) of PE-n and PNB-n change from smectic (ribbon-like) to OH (cylinder-like). For their (Ns, we conducted a comparative analysis of molecular packing among phasmidic molecules, phasmidic MJCLPs, and previous MJLCPs. The result shows that PE-12 and PNB-12 form a double-chain and four-chain column, respectively, whereas most previous MJLCPs render a single chain column. The single-chain versus multichain packing behavior of MJLCPs was theoretically predicted. This work provides a strategy for manipulating molecular sizes, shapes, packing, and phase structures of side-chain polymers through combined side-chain and main-chain molecular engineering.