Recyclable Ionogel with Shape Memory-Assisted Healing Microstructure for Highly Sensitive Ionotronic Pressure Sensor

Surface microstructures have been widely employed in pressure sensors to enhance sensitivity. However, the microstructures are susceptible to irreversible collapse under prolonged cyclic loading, leading to device failure. This work develops a recyclable ionogel (PUF/IL) with shape memory-assisted healing microstructure for highly sensitive ionotronic pressure sensor. Hydrogen bond units (UPy) and fluorinated chain extenders (OHD) are used to regulate the various properties of PUF/IL. Benefiting from the ion-dipole interactions between OHD and ionic liquids (IL), IL can be firmly stabilized in the ionogel network. PUF/IL exhibits exceptional shape-memory properties, demonstrating fixation and recovery rates of 99% and 86%, respectively. More importantly, when the microstructure is mechanically damaged during long-term use, it can be fully recovered through a shape-memory process. Due to the dynamic interactions, PUF/IL shows remarkable recyclability. The mechanical properties, shape memory performance, and pressure-sensing capabilities of recycled PUF/IL retain over 95% of their initial values. Overall, the strategy of healing collapsed microstructures via the shape-memory effect of PUF/IL, combined with its recyclability, effectively improves the long-term reliability and sustainability of pressure sensors. This work provides a solid foundation and creative design ideas for the development of next-generation durable, sustainable, highly sensitive pressure sensors.