▎ 摘　　要

NOVELTY - Three-dimensional porous flexible composite material comprises carbon nanotubes and polydimethylsiloxane (PDMS), where the mass ratio of carbon nanofibers and graphene in the composite material is 1-8:1. USE - The composite material is useful for flexible strain sensor e.g. human-computer interaction device, and robot electronic skin and human body monitoring module. ADVANTAGE - The method: adopts a synergistic conductive network of one-dimensional two-dimensional conductive fillers; and improves the conductivity and thermal stability of the sensor. The porous flexible sensor with synergistic conductive network has higher sensitivity and wider strain detection range. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: a three-dimensional porous flexible strain sensor comprising three-dimensional porous flexible composite material and interdigitated electrodes and conductive silver paste; a method for preparing three-dimensional porous flexible composite material comprising (1) mixing polydimethylsiloxane (PDMS) and paraffin and completely dissolve in the naphtha solution, and mixing uniformly to obtain solution A, (2) adding carbon nanotubes and graphene to the solution A described in step (1), and carrying out ultrasonic dispersion to solution B, (3) adding the curing agent to the solution, pouring into the mold after magnetic stirring to solidify to obtain the composite conductive material, (4) adding composite conductive material into the Soxhlet extractor that is equipped with naphtha and is extracted and processed to remove paraffin and drying to obtain a three-dimensional porous carbon nanotube-graphene/polydimethylsiloxane (PDMS)composite material; and a method for preparing a three-dimensional porous flexible strain sensor comprising (1) mixing polydimethylsiloxane and paraffin and completely dissolve in the naphtha solution, and mixing uniformly to obtain solution A, (2) adding carbon nanotubes and graphene to solution A, and performing ultrasonic dispersion to obtain solution B, (3) adding the curing agent to the solution B, pouring it into the mold after magnetic stirring to solidify to obtain the composite conductive material, (4) adding the composite conductive material into the Soxhlet extractor that is equipped with naphtha and is extracted and processed to remove paraffin, and drying to obtain a three-dimensional porous carbon nanotube-graphene/polydimethylsiloxane composite material, and (5) cutting the three-dimensional porous carbon nanotube-graphene/polydimethylsiloxane composite material into a sample size of a desired size, attaching one side coated with conductive silver paste and the wires of the interdigitated electrodes, and packaging to obtain a three-dimensional porous carbon nanotube-graphene/PDMS flexible strain sensor.