Fabrication and performance of bidirectional cantilever sensor with conductive Thermoplastic Polyurethane porous foams.

• Flexible TPU is modified by different conductive nanoparticles. • Porous foam sensors with good durability, high sensitivity and excellent lightweigh. • Bidirectional sensing performance achieved by a simple asymmetric sandwich structure. • Adjustable by the structure and performance of the inner and outer layers. Cantilever sensors are widely used in many application areas due to their bidirectional sensing performances. In this paper, we propose a bidirectional cantilever sensor with asymmetric sandwich structure via the simple low-temperature template casting and freeze-drying methods. The high sensitivity TPU porous foams are embedded in the low sensitivity foams, which changes the conductivity and sensitivity of asymmetric sandwich structure in different bending direction. Here, direction of the deformation in the cantilever beam can be detected by the piezoresistive behaviors. The results of the experiments demonstrate the asymmetric sandwich structure cantilever sensor exhibits good flexibility, excellent stability, rapid response speed, and remarkable bidirectional sensing. [ABSTRACT FROM AUTHOR]