Study On The Preparation And Properties Of Nanocomposite Polyvinylidene Fluoride With High Dielectric

Composites with high dielectric constant and low dielectric loss have important applications in the microelectronics industry,especially in the field of embedded capacitors.Polymer matrix composites have the advantages of good flexibility,convenient processing,light weight and low cost,and can meet the requirements of microelectronics miniaturization.Polymer composites filled with conductive and ceramic fillers can obtain very high dielectric constant,but inevitably the material itself will be accompanied by a large increase in dielectric loss,which is a fatal disadvantage for its practical application.In this paper,polyvinylidene fluoride（PVDF）was used as polymer matrix to design and prepare packing materials with core-shell structure Si C@PDA and MXene@CTAB.Compared with the traditional mixing method,the shell layer has many advantages,which can improve the dispersion,dielectric property and interface compatibility between the filler and the polymer matrix.PVDF/Si C,PVDF/Si C@PDA and PVDF/MXene@CTAB composites were prepared by solution blending method.Compared with PVDF/Si C composites,the interface binding ability of PVDF/Si C@PDA composites is improved,which can significantly inhibit dielectric loss and ac conductivity while maintaining high dielectric constant.The dielectric constant,dielectric loss and conductivity of40wt%PVDF/Si C at 1000Hz were 2240,71.53 and 1.9×10^-3S/m,respectively,while the PVDF/Si C@PDA-b were 50.4,0.048 and 1.0×10^-5S/m,respectively,proving that PDA coating can effectively inhibit the dielectric loss caused by interface polarization and ion relaxation polarization.In addition,the dielectric constant,dielectric loss and conductivity of PVDF/Si C@PDA-a are 61.2,0.056 and 1.3×10^-5s/m,respectively.By designing PVDF/MXene@CTAB nanocomposites,dielectric materials with high dielectric constant and low dielectric loss can be obtained.At the frequency of 100Hz and1000Hz,the permittivity of PVDF-10 is 323 and 164 respectively,which is 32.3 times and 16.9times higher than that of pure PVDF.In the whole frequency range,the tangent value of pvdf-10 is within 0.9 and reaches 0.51 at 1000Hz,which is higher than that of pure PVDF（0.02）,but it can still be used in dielectric applications.The main innovation of this paper is the preparation of core-shell fillers by a simple method.The effect of the organic-inorganic interface on the dielectric behavior of composite materials is studied.Compared with the traditional inorganic material components,the shell layer has many advantages.It can improve the filler in The dispersion in the polymer matrix,the dielectric properties and the interface compatibility of the filler and the polymer matrix,in order to achieve the best balance of dielectric constant and dielectric loss,the thickness of the shell layer must be adjusted reasonably for the future Advanced energy storage materials provide new ideas.