Freeze-casted aerogel-based piezoresistive pressure sensors: materials, structures, and applications

Flexible piezoresistive pressure sensors have emerged as vital components for wearable electronics, soft robotics, and biomedical monitoring. However, simultaneously achieving high sensitivity, a wide detection range, and long-term durability for these sensors remains challenging. Among the various approaches, freeze-casted aerogel-based sensors have garnered significant attention owing to their exceptional properties, such as ultralow density, high porosity, and customizable microstructures. This review summarizes the recent advances in such sensors, with emphasis on material selection, structural design, and practical applications. The integration of one-dimensional, two-dimensional, and hybrid nanomaterials offers synergistic enhancements in electrical conductivity, mechanical robustness, and sensing performance. Advanced structural engineering strategies, including anisotropic pore alignment, gradient architecture, and biomimetic designs, have enabled improved sensitivity, a broader detection range, and enhanced durability. Representative applications in real-time physiological monitoring and human–machine interfaces demonstrate the potential of these sensors in real-world scenarios. This review provides insight into rational design strategies that harness both materials and architecture to improve the performance and applicability of next-generation aerogel-based pressure sensors.