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![Recent advances in flexible and soft gel-based pressure sensors](https://image.oaes.cc/8c0f4715-e09f-449d-9c42-bb8ce8832914/5176.fig.4.jpg)
Figure 4. Schematic illustrating the gel preparation methods. For hydrogels: (A) physical crosslinking; (B) chemical crosslinking; (C) ionizing radiation crosslinking. For ionogels: (D) in-situ reactions in ILs; (E) solvent exchange; (F) direct polymerization of polymerizable ILs. For aerogels: (G) sol-gel and drying method.