Supramolecular Side-Chain Liquid Crystalline Polymers with Various Kinked Pendant Groups

Supramolecular side-chain liquid crystalline polymers with various kinked pendant groups are constructed from positional isomers of proton acceptor monomers and donor polymers (with different molecular weights) through hydrogen bonding. Monomer-monomer complexes of similar structures are built to compare the influence of the proton donors bound to the polymer backbones. Due to the bending effects introduced by the positional isomers, we are able to tune the molecular shape and thus to modify the mesogenic properties. New liquid crystalline properties are introduced by the kinked molecular geometry, and their kinked architecture is supported by the quantum mechanical calculations, the powder X-ray diffraction (XRD) patterns, and the deviation temperatures (¢T). Mesogenic properties of monomer- polymer complexes have similar trends as those of monomer-monomer complexes. Compared with analogous hydrogen-bonded (H-bonded) monomer-monomer complexes, higher isotropization tempera- tures and broader ranges of mesogenic phases (e.g., SA phase) are observed in the kinked supramolecular polymers. Significantly, H-bonded positional isomerism leads to dissimilar structures and properties of supramolecular side-chain liquid crystalline polymers.