The invention relates to the technical field of flexible sensors, in particular to a gradient
hierarchical porous structure flexible piezoresistive sensor and a preparation method thereof. The sensor is of a laminated structure and comprises an upper flexible packaging
protection layer, a lower flexible packaging
protection layer, a conductive fabric
electrode and a middle piezoresistive sensing layer, and a limiting frame is arranged on the periphery of the sensor. The sensing layer is prepared by adopting a 3D
printing ink direct writing technology, and adopted printing
slurry takes
silicone rubber as a matrix and is uniformly mixed with expanded conductive microspheres and conductive filler. The printing wires are stacked in order to form a macroscopic gradient
porous network structure; after the expanded microspheres are subjected to in-situ foaming, micro closed pores are formed in the material, and a rough
microstructure is constructed on the surface of the wire material, so that hierarchical multi-scale regulation and control of a conductive network are realized cooperatively, contact sites are increased remarkably, and the sensitivity of the sensor is further improved effectively. The flexible piezoresistive sensor prepared by the invention has the advantages of high sensitivity, wide
pressure detection range and high
linearity, and has the commercial values of simple preparation process, high
repeatability, lower cost and the like.