Flexible and anisotropically conductive sandwich film by assembly of liquid silicone rubber and cobalt coated glass fiber composites via magnetic field inducement

Abstract In this work, we have prepared electromagnetic cobalt coated glass fiber (Co@GF) composite via electroless plating method firstly. And then a conductive sandwich flexible film consisted of Co@GF composite and liquid silicone rubber (RTV-2) is successfully formed, through tape casting method at room temperature. Based on the perfect coating and excellent electrical conductivity of Co@GF composite, the resultant RTV-2/Co@GF/RTV-2 sandwich flexible film shows high electrical conductivity of 0.264 Ω·cm and can stretch to 100% ( of 4.40 Ω·cm) without obvious fracture. When the magnetic field was applied to the curing process, the electromagnetic Co@GF composite aligned automatically in the RTV-2 matrix on account of its ferromagnetic nature. The as-prepared film shows anisotropy in electrical performance. The volume resistivity parallel to the magnetic field direction is about two times lower than that of perpendicular direction. The maximum difference in volume resistivity (ρ∥ of 0.768 Ω·cm and ρ⊥ of 1.549 Ω·cm) is obtained at magnetic field intensity of 800 mT. In addition, a certain magnetic field intensity at 100mT is helpful to improve the electrical conductivity of the as-obtained sandwich film. The anisotropic RTV-2/Co@GF/RTV-2 sandwich flexible film would be considered as promising flexible electronic sensor where discrepant sensing sensitivity is required in orthogonal directions.