Influence of Backbone Regioregularity on the Optoelectronic and Mechanical Response of Conjugated Polyelectrolyte-Based Hydrogels

Emerging Potential of Conjugated Polyelectrolytes beyond Boundaries

Conjugated polyelectrolytes (CPEs) constitute a distinct class of materials defined by a π-conjugated backbone and ionic side chains. The delocalized π electrons offer distinct electronic and optical properties, while the presence of ionic moieties enables precise adjustments of hydrophilicity, pH neutrality, self-doping, and ionic conductivity. A recent proliferation of applications for CPEs underscores their dual nature, marking a notable expansion in their potential in technological innovation. The ability to fine-tune both electronic and ionic traits broadens horizons for their utility, spanning organic/inorganic optoelectronics, electrochemical transistors, photocatalytic water splitting, thermoelectric devices, and energy storage systems. This review highlights recent advancements in CPE research, emphasizing synthetic strategies for integrating a wide range of structural units that can tailor optoelectronic and ion transport functions. It also explores innovative applications across diverse domains and discusses a range of operational mechanisms. Additionally, the review addresses persistent challenges and prospects in the field, contributing to ongoing progress toward the implementation of CPEs in emerging technological opportunities.

A Perspective Looking Backward and Forward on the 25th Anniversary of Conjugated Polyelectrolytes

Conjugated polyelectrolytes are π-conjugated polymers that contain ionic charged groups such as sulfonate (R-SO3-), carboxylate (R-COO-), or ammonium (R-NR3+) combined with a π-conjugated backbone. This perspective provides a summary review of the key developments in the field, starting from the first reports of their synthesis and properties to application-focused developments. The applications include optical sensors for molecular and biomolecular targets, organic electronic applications, and specific biological applications including cellular imaging and photodynamic therapy. This perspective concludes with a discussion of where the field of conjugated polyelectrolytes is expected to lead in the coming years.