Material Extrusion-Enabled Soft Multimodal Pressure Sensors With Fabrication-Embedded Stretch-Induced Strain...

Key challenges in stretchable pressure sensors include establishing cost-effective fabrication routes for soft functional materials, achieving strain-insensitive performance under deformation, and enabling seamless integration into soft architectures. Here, electrospinning is combined with liquid-based material extrusion (l-MEX) and melt-based material extrusion (m-MEX) to fabricate stretchable pressure sensors with multimodal sensing capability. The sensing layer is composed of mechanically anisotropic electrospun poly(vinylidene fluoride) / thermoplastic polyurethane composite microfibers sandwiched between l-MEX printed stretchable silver electrodes, exhibiting a Young's modulus as low as 0.5 MPa. A three-dimensional serpentine architecture reconfigures the sensing layer into a compliant geometry and enables system-level stretchability while maintaining stable sensing performance under strain. In the capacitive mode, the optimized sensor achieves 97.6% strain insensitivity under strains up to 30% and a minimum detectable pressure of 0.04 kPa. In the piezoelectric mode, the same device exhibits a sensitivity of 16.5 mV kPa^-1 and a strain-insensitivity ratio of 85.4% at 10% applied strain. A stretchable capacitive sensing matrix enables uniform pressure mapping under strain. Integration of the sensors into a pneumatically actuated soft gripper further demonstrates real-time piezoelectric responses. This work presents a scalable and automatable manufacturing route for integrating soft functional materials into stretchable electronics and soft robotic systems.