Poly(Ionic Liquid) Technologies in Polymer Science

Poly(ionic liquids) (PILs) represent a versatile class of functional polymers in which ionic liquid moieties are covalently incorporated into macromolecular backbones or side chains. By combining the intrinsic conductivity, thermal stability and ion-solvation properties of ionic liquids with the processability and mechanical robustness of polymers, PILs offer a modular platform for advanced materials design. Synthetic approaches—including controlled radical polymerisation, atom transfer radical polymerisation and photopolymerisation—enable precise tuning of molecular weight, charge density and architecture. This structural control underpins diverse applications in energy storage and conversion, electrochemical devices, stimuli-responsive membranes, separation technologies and soft actuators. Recent advances have focused on the creation of nanoporous morphologies, development of polycarbene-bearing networks for ultrasensitive sensing and the formulation of gel electrolytes for all-solid-state capacitors. The global significance of PIL technologies is emphasised by their role in sustainable energy systems, environmental remediation and next-generation smart materials.

Research from Nature Portfolio

Recent studies have introduced cyclopropenium-based polyelectrolytes that exhibit high ionic conductivity and thermal resilience, demonstrating their potential for ion-conducting membranes in fuel cells and batteries. Porous polycarbene-bearing membrane actuators, constructed via ionic complexation of PILs with multivalent acids, have achieved ultrasensitive detection of weak acids and enabled real-time monitoring of proton-involved reactions through dual structural gradients in electrostatic complexation and carbene distribution. In parallel, chemically crosslinked PIL gel electrolytes have been formulated by in situ entrapment of ionic liquids within acrylate networks, yielding mechanically robust, flexible films suitable for all-solid-state electrochemical double-layer capacitors with enhanced capacitance and cycling stability.

Research from all publishers

Emerging reports have highlighted a new generation of poly(1,2,4-triazolium)s, distinguished by ring-position hydrogen bonding, N4 lone-pair interactions and the capacity to form polycarbenes, which confer unique supramolecular behaviour and broaden applications in catalysis and separation. Advances in the design of nanoporous PILs have produced materials with well-defined pore architectures and tunable electrostatic environments, facilitating high-performance gas sorption, selective catalysis and improved ion transport in energy conversion devices. These developments underscore the synergy between pore engineering and ionic functionalities, paving the way for tailored PILs in environmental sensing and sustainable energy technologies.

Poly(Ionic Liquid) Technologies in Polymer Science publication trend

The graph below shows the total number of articles in poly(ionic liquid) technologies in polymer science across all publications each year (not limited to Nature Index journals).

Technical terms

Poly(ionic liquid) (PIL): A polymer in which ionic liquid monomers are polymerised to yield materials combining ionic conductivity with polymeric mechanics.

Ionic liquid: A salt that is liquid at or near room temperature, noted for negligible vapour pressure and high ion mobility.

Polyelectrolyte: A polymer bearing ionisable groups that dissociate in solution to yield charged macromolecules and counter-ions.

Cyclopropenium ion: A three-membered aromatic cation employed in PILs to enhance charge delocalisation and conductivity.

Polycarbene: A polymeric network featuring carbene functionalities, arising from deprotonation of triazolium or imidazolium rings, enabling unique catalytic and responsive behaviour.

Nanopore: A pore with dimensions in the nanometre range, engineered within PIL matrices to control mass transport and surface interactions.

References

1. Poly(1,2,4-triazolium)s as the rising generation of functional poly(ionic liquid)s. Progress in Polymer Science (2025).
2. The evolution of cyclopropenium ions into functional polyelectrolytes. Nature Communications (2015).
3. Porous polycarbene-bearing membrane actuator for ultrasensitive weak-acid detection and real-time chemical reaction monitoring. Nature Communications (2018).
4. A Poly(ionic liquid) Gel Electrolyte for Efficient all Solid Electrochemical Double-Layer Capacitor. Scientific Reports (2018).
5. Poly(ionic liquid)s with engineered nanopores for energy and environmental applications. Polymer (2020).
6. Controlled radical polymerization and in-depth mass-spectrometric characterization of poly(ionic liquid)s and their photopatterning on surfaces. Polymer Chemistry (2016).