Structures and Properties of Supramolecular Liquid-Crystalline Side-Chain Polymers Built through Intermolecular Hydrogen Bonds

Abstract

The design, structure, and properties of supramolecular liquid-crystalline side-chain polymers are described. In particular, we show how several simple H-bonding building blocks can be used for the formation of various liquid-crystalline structures. Poly[4-(6-(acryloyloxy)hexyl- and -undecyloxy)benzoic acid] (PmOBA; m = 6, 11) have been employed as polymer components. A variety of supramolecular mesogenic “copolymers” based on one polymeric component have been designed and prepared by simple self-assembly. Cooperation of the hydrogen bond and electron donor−acceptor interactions results in the mesophase stabilization for the “copolymeric” supramolecular structures of PmOBA with a mixture of trans-4-methoxy-4‘-stilbazole (1OSz) and trans-4-cyano-4‘-stilbazole (SzCN) or trans-4-nitro-4‘-stilbazole (SzNO2). When a bifunctional molecule, 4,4‘-bipyridine (BPy), is used as a component for “copolymeric” structures, supramolecular copolymeric networks based on PmOBA have been formed by self-assembly. The networks exhibit stable mesomorphic behavior and reversible phase transitions due to the dynamics of the hydrogen bonds.