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Poly(ionic liquid)-Based Covalently Adaptable Networks (PIL-CANs): Polar and Dipolar Interactions.
Md Wali Ullah1, Marek W Urban1
1Department of Materials Science and Engineering, Clemson University, Clemson South Carolina 29634, United States.
ACS Macro Letters
|May 14, 2026
Summary
This study introduces poly(ionic liquid)-based covalently adaptable networks (PIL-CANs) that are reprocessable and maintain properties after damage. These advanced materials offer high performance comparable to epoxies but with lower glass transition temperatures.
Area of Science:
- Materials Science
- Polymer Chemistry
- Chemical Engineering
Background:
- Covalently adaptable networks (CANs) offer self-healing and reprocessing capabilities.
- Poly(ionic liquids) (PILs) combine properties of polymers and ionic liquids.
- Developing PIL-CANs with tunable mechanical properties and recyclability is crucial.
Purpose of the Study:
- To synthesize and characterize novel PIL-CANs with variable aliphatic spacer lengths.
- To investigate the reprocessing and self-healing mechanisms of these PIL-CANs.
- To evaluate the thermal stability and mechanical performance of the developed materials.
Main Methods:
- Synthesis of PIL-CANs using imidazolium (Im+)-(bis((trifluoromethyl)sulfonyl)amide) (TFSI-) monomers with acetoacetate (AcAc) end-groups.
- Cross-linking with tris(2-aminoethyl) amine (TREN).
- Mechanical testing (storage modulus) and thermal analysis (glass transition temperature, Tg).
- Reprocessing via compression molding at 120 °C.
Main Results:
- PIL-CANs exhibited high storage modulus (2.5-3.0 GPa).
- Materials were reprocessable multiple times via compression molding after mechanical damage.
- Recovery of properties relies on imine-enamine and keto-enol tautomerism.
- Preservation of storage moduli, junction densities, and entropic energy upon reprocessing.
- Comparable storage moduli to high-performance networks but lower Tg.
Conclusions:
- The synthesized PIL-CANs demonstrate excellent reprocessability and mechanical integrity.
- These materials offer a promising alternative to traditional high-performance polymers.
- Tunable properties through molecular design (spacer length) are feasible.
- The reprocessing mechanism is linked to dynamic covalent chemistry and tautomerism.
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