Mechanical buckling assisted formation of 3D conductive composite meso-structure for highly sensitive piezoresistive pressure sensor

With the advancement of robotics and wearable devices related research fields, enhancing the sensitivity of piezoresistive pressure sensor is the first demand of the related research to sense the subtle stimuli. To improve sensitivity, a material tailoring approach using the nature of different materials and an introduction of novel structures made by processing existing materials have been studied. Such latter mechanical exploration has the unique advantage of obtaining performance beyond the nature of the material. This study introduces a 3D meso-structured piezoresistive pressure sensor, which exhibits remarkably improved sensitivity of 450 times compared with that of a conventional 2D sensor, manufactured through simple mechanical buckling assisted 3D structure formation. The principle of sensitivity improvement is related to the developed tensile strain in the sensor and both numerical and experimental analyses show that the maximum principal strain plays a crucial role as a governing parameter to determine the sensitivity. Classical mechanics-based analyses further show that performances can be easily tuned by adjusting its thickness. The present sensor has excellent durability and reliability (stable over 10,000 operating cycles). Consequently, the use of a highly sensitive sensor with a digital twin application is demonstrated for real-time and virtual stress monitoring in a cantilever.