Mesogen-Initiated Linear Polyglycerol Isomers: The Ordering Effect of a Single Cholesterol Unit on “Sticky” Isotropic Chains

Synthesis, thermal properties, and the liquid crystalline (LC) order of polymers consisting of a single mesogenic cholesterol unit and flexible, linear polyglycerol (PG) or poly(glyceryl glycerol) (PGG) chains have been investigated. Incorporation of the single mesogen has been achieved by using cholesterol directly as an initiator for the oxyanionic ring-opening polymerization (ROP) of ethoxyethyl glycidyl ether (EEGE) or isopropylidene glyceryl glycidyl ether (IGG). The controlled polymerization allowed the synthesis of a series of peculiar rod–coil type polyethers with molecular weights of 600–2300 g/mol, representing a degree of polymerization (DPn) of 4–30 for both PG and PGG with the polydispersity Mw/Mn in the range of 1.07–1.25. The resulting linear PGs exhibit extremely stable thermotropic LC order in a broad temperature range up to 260 °C, forming mainly layered smectic A (SmA) phases with varying layer thicknesses, depending on the degree of polymerization of the respective polymer structure. L...