Facile in-situ synthesis of carbon black@poly(ionic liquid) composites with a smooth U-link chain macrostructure within surfactant-free ionic liquid microemulsions

Poly(ionic liquid)s show tremendous potential in the application of strain sensing. However, their development is limited by tedious fabrication techniques and the instability factor of existing poly(ionic liquid)s-based strain sensing materials. In this work, we in situ synthesized a novel carbon black and poly(ionic liquid) composites (CB@PILs) by performing thiol-ene click reaction within a surfactant-free ionic liquid microemulsion. The successful construction and reaction of the composites were confirmed by FTIR, XRD, XPS, SEM, TG/DSC, strain test, and conductivity analyses. Results demonstrated that a composite that has a smooth U-link chain macrostructure could be prepared by altering the carbon black content at 3 wt%, and the resultant polymer presented good thermal stability and strain sensing performance. The mass ratio between polyethylene glycol diacrylate and hydroxyethyl methacrylate could further improve the conductivity and mechanical properties of CB@PIL composites. This work provides a potential avenue for designing CB@PIL composites, thus making them viable for strain sensing.