The Synthetic Double-Helical Polyelectrolyte PBDT: From Molecular Conformation to Advanced Materials

Inspired by the iconic structure of DNA, the creation of synthetic polymers that adopt a stable double-helical conformation is a significant frontier in materials science. However, maintaining such ordered structures in high molecular weight polymers across diverse environments remains a formidable challenge. As a canonical example of this class, poly(2,2′-disulfonyl-4,4′-biphenyleneterephthalamide) (PBDT), a rigid-rod polyelectrolyte, stands out as one of the few experimentally confirmed synthetic double-helical macromolecules. Its exceptional molecular rigidity and conformational order translate into remarkable performance features that are pivotal for functional materials. The double-helical structure enhances its chain alignment capabilities, enabling the formation of anisotropic hydrogel networks; it imparts excellent mechanical strength and thermal stability to solid polymer electrolytes, where it forms fibrous networks that create highly efficient ion transport channels; and it drives the formation of thermoreversible fibrous gels. This review systematically chronicles the development of PBDT, focusing on the confirmation of its unique conformation, the methodologies for its structural characterization, and its burgeoning applications. We aim to provide a comprehensive reference and theoretical insights that may inspire the future design of synthetic double-helical macromolecules for next-generation materials.