Self‐assembly of main chain liquid crystalline polymers via heteromeric hydrogen bonding

Abstract

Complexation between pyridines and carboxylic acids is driven by hydrogen bonding. This simple, single hydrogen bond is shown to be capable of serving concomitantly as both the agent of liquid crystallinity and as the coupling bond generating an extended linear chain structure. Three such complexes made from an aromatic diacid and three structurally different bis pyridyls were prepared. In each case the association complex self‐assembles into an organized liquid crystalline phase. Discussion of this complexation as a step‐growth polymerization process is presented along with an examination of the suitability of various methods for characterizing these materials.

Functional liquid-crystalline polymers and supramolecular liquid crystals

“…38,39,[64][65][66] LC polymeric complex 12 was prepared through the formation of triple hydrogen bonds. 38,65 The influence of chirality on the mesomorphic behavior of the supramolecular polymers was studied.…”

“…The complex exhibited nematic and smectic phases. 39 LC polymeric merocyanine dye assemblies exhibiting columnar phases were also obtained by combining triple hydrogen bonds and π-π aggregation. 66 Use of multifunctional components for the formation of noncovalent interactions can produce supramolecular LC network structures.…”

“…The concept of hydrogen-bonded liquid crystals [29][30][31][32][33][34][35][36][37][38][39][40] has been extended to halogen-bonded LC complexes [73][74][75] because of the similarities of these non-covalent interactions. Halogen-bonded main-chain LC polymers were obtained by self-assembly of bifunctional halogen-bonding molecules.…”

“…In addition to hydrogen bonds, [29][30][31][32][33][34][35][36][37][38][39][40] halogen bonds, 74,75 and ionic interactions, 15,[86][87][88][89][90][91][92][93][94] charge-transfer interactions were applied for the preparation of supramolecular LC polymers. 95,96 Ringsdorf et al 95 used charge-transfer interactions between electron-rich triphenylene and 2,4,7-trinitrofluorenone units to produce LC discotic polymers.…”

“…1,2,29,30 Supramolecular hydrogen-bonded LC polymers emerged by introducing supramolecular chemistry into the design of LC polymers. [31][32][33][34][35][36][37][38][39] These polymers were firstly prepared through the formation of complementary hydrogen bonds by Kato and Frechet 37 and Lehn, 38 respectively. They exhibit LC phases in their bulk states.…”