Preparation Of Flexible Ni@Cu/rGO/PVDF Composite Film And Its Microwave Absorption Property

In this paper,Ni@Cu-based composite microwave absorption materials were designed.Then,the influence of different compositions of Ni@Cu-based composites on electromagnetic absorption property was investigated.Firstly,a core-shell structural composite with copper as core and nickel as shell was prepared by a hydrothermal method,and its growth mechanism was explored.The results showed that the minimum reflection loss value(RL_min)of Ni@Cu composite is-32.2 dB.The excellent microwave absorbing property was mainly stemmed from the the point charge caused by one-dimensional structure and the interfacial polarization behavior of the Ni@Cu core-shell structure.In addition,by simplifying the preparation conditions,one-dimensional Ni@Cu-two dimensional rGO)sandwich structured composites were successfully prepared.When the thickness of the Ni@Cu/rGO absorber is 2.5 mm,the minimum reflection loss can reach-41.2 dB at 8.8 GHz.TThe transmission and attenuation mechanisms of electromagnetic waves in composite materials are revealed.Furthermore the relationship between the microstructure of materials and electromagnetic parameters was investigated.This paves a guideway for the practical application of composite materials.Finally,a flexible Ni@Cu/rGO/PVDF（polyvinylidene fluoride）film was prepared.The Ni@Cu/rGO/PVDF film has the characteristics of flexibility.Besides,when the film thickness is 2.5 mm,the minimum reflection loss is-45.07 dB in the frequency range of 18-26.5 GHz,and the effective absorption bandwidth（RL<-10 dB）can reach 8.5 GHz.The ternary composite film can be used as a high-efficiency and flexible portable electromagnetic wave-absorbing material in combination with features of dielectric loss,magnetic loss,interfacial polarization effect,reflection and scattering effect,and flexibility.By designing and controllable preparation of Ni@Cu-based electromagnetic wave absorbing material components,a flexible Ni@Cu/rGO/PVDF composite film with excellent electromagnetic wave absorption performance was finally prepared.The novelty of this thesis is that we investigated the interaction of composite materials with various constituents and electromagnetic wavesand provided a theoretical basis for the research and application of lightweight high-strength microwave absorbing materials.