Preparation of High-Performance Ionogels with Excellent Transparency, Good Mechanical Strength, and High Conductivity.

Ionogels offer great potential for diverse electric applications. However, it remains challenging to fabricate high-performance ionogels with both good mechanical strength and high conductivity. Here, a new kind of transparent ionogel with both good mechanical strength and high conductivity is designed via locking a kind of free ionic liquid (IL), i.e., 1-ethyl-3-methylimidazolium dicyanamide ([EMIm][DCA]), into charged poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS)-based double networks. On the one hand, the charged PAMPS double network provides good mechanical strength and excellent recovery property. On the other hand, the free [EMIm][DCA] locked in the charged double network through electrostatic interaction offers ionic conductivity as high as ≈1.7-2.4 S m at 25 °C. It is demonstrated that the designed ionogel can be successfully used for a flexible skin sensor even under harsh conditions. Considering the rationally designed chemical structures of ILs and the diversity of charged polymer networks, it is envisioned that this strategy can be extended to a broad range of polymer systems. Moreover, functional components such as conducting polymers, 0D nanoparticles, 1D nanowires, and 2D nanosheets can be introduced into the polymer systems to fabricate diverse novel ionogels with unique functions. It is believed that this design principle will provide a new opportunity to construct next-generation multifunctional ionogels.