A Flexible and Recyclable Polybenzoxazine Vitrimer Ionogel

High Resolution Image Download MS PowerPoint Slide Ionogels, an emerging class of solid polymer electrolytes (SPEs), break ground in the field of soft electronics combining ionic conductivity with the mechanical resilience of elastomeric polymer networks. To support the integration of ionogels into the next generation of flexible electronics devices, recent research efforts showcased the potential of covalent adaptable networks (CANs) to prolong their operational lifetime. In this study, we present the design of a flexible and recyclable ionogel based on a stretchable polybenzoxazine vitrimer containing dynamic ester bonds. Ionic conductivity is imparted by swelling the vitrimer matrix with an ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMImTFSI) at various swelling ratios (from 50 to 150 wt.%). The influence of EMImTFSI uptake on the ionogel properties has been investigated with ionic conductivities in the range of 0.1 to 2 mS·cm –1 and α-mechanical relaxation temperatures ranging from −31 to −58 °C. The advantages of vitrimer chemistry through internally catalyzed transesterification reactions were highlighted by their stress relaxation as short as 10 s at 170 °C, enabling fast mechanical reprocessing. At low IL content, recycled vitrimer ionogels retain identical ionic, thermal, mechanical, and dynamic properties over multiple reprocessing cycles, showcasing excellent compatibility between the cross-linked network and the ionic species. Finally, the vitrimer ionogel was successfully incorporated into the design of an electrostimulated actuator, illustrating its potential to serve as a sustainable and high-performance material for advanced soft electronic applications.