Flexible magnetic hydrogel pressure sensors show promise for various applications, including self-sensing materials, wearable electronics, artificial electronic skin, and bionic soft robots. However, current hydrogel pressure distribution sensors have limited applications due to their low resolution and complicated array-type structure with wiring. In this study, we present a highly flexible, touch-sensitive, and mechanically robust pressure sensor. We achieved this by using a hydrogel matrix with added magnetic particles. Magnetic hydrogels were synthesized by polymerizing and crosslinking acrylamide using free radicals. We evaluated the performance of the magnetic hydrogel tactile sensor for continuous sensing by measuring electrical impedance tomography (EIT). We investigated the influence of particle volume fraction on morphology and sensitivity to distributed strain. Additionally, we prepared magnetic hydrogels as hydrogel pressure-sensitive substrates and confirmed the feasibility of using them as sensitive elements for hydrogel pressure distribution sensors through mechanical properties tests. Moreover, EIT accurately captured and distinguished different numbers of points and shapes, with lower volume fractions (3vol%) being more sensitive. These results demonstrate the potential of using tomographic methods for tactile imaging and distributed strain sensing in magnetic hydrogel composites. Overall, our study provides important insights into the development of flexible, high-resolution pressure sensors with potential for a wide range of applications in the fields of robotics, wearable technology, and healthcare.

magnetic hydrogel, electrical impedance tomography, flexible tacticle sensor