Nonlinear Synergistic Coupling of Poisson Deformation and Crack Engineering Enables Linear Mechanosensing up to 4 MPa

Reliable and accurate physiological mechanosensing requires tactile sensors that maintain linearity across ultrawide ranges, yet most reported devices saturate below 500 kPa due to strain hardening and deformation saturation of elastic microstructures. Balancing this long-standing trade-off between sensitivity and linearity demands an alternative design strategy. Here, we present a nonlinear synergistic coupling strategy that combines the strain-hardening behavior of cylindrical elastomers with the crack-propagation behavior of crack-based films. Under compression, Poisson expansion transforms vertical stress into lateral tensile strain, contributing to progressive crack evolution while avoiding strain saturation typically observed in conventional planar configurations. Finite element simulations and experimental results confirm that the matched nonlinear synergistic coupling of elastomer deformation and crack propagation. Our tactile sensor achieves a record sensitivity of 3.8 MPa-1 across a ultrawide linear range up to 4 MPa, far exceeding conventional mechanosensors. This nonlinear coupling strategy provides a route to ultrawide-linear mechanosensing, with broad potential in healthcare, biomechanics, and intelligent robotic manipulation.