Supramolecular (Hydrogen-Bonded and Halogen-Bonded) Liquid Crystalline Polymers

Abstract

Directional intra-/intermolecular interactions of diverse strengths are of great importance for the construction of supramolecular self-assemblies. Hydrogen bonding and halogen bonding are the most important categories of noncovalent interactions that have been investigated to this end. As an analogous counterpart of the hydrogen bonding, halogen bonding is the noncovalent interaction between halogen atoms (Lewis acids) and neutral or anionic Lewis bases. It represents a type of novel noncovalent bonding as effective as hydrogen bonding for driving highly specific intermolecular interactions. The binding features and the structural properties of these two types of noncovalent interactions provide a new approach for the construction of a variety of supramolecular assemblies, especially polymeric liquid crystals. By tuning the chemical structures of the monomeric building blocks used for the hydrogen or halogen bonded assemblies, the mesomorphic properties of the self-assembled polymers could be conveniently adjusted and thus the resulting polymeric materials can be used as various types of materials. A recent advance on hydrogen-bonded and halogen-bonded liquid crystalline polymeric materials and their applications is summarized herein.