Study On Flexible Piezoelectric Polymer Film Of Pyramidal Structure

Piezoelectric sensors as pressure signal transducers of the industry devices have wide range of applications in industrial production and daily life.Comparing with other piezoelectric sensors,Piezoelectric polymer polyvinylidene fluoride-trifluoroethylene(PVDF-Tr FE)sensor has high piezoelectric coefficient,high chemical resistance,high flexibility and so on,which is currently the most widely used piezoelectric sensor.However,with the further development of industry and technology,the requirements on the performance of the piezoelectric sensor are higher.The fabricated process and structure of the piezoelectric sensor still need to be further optimized.In this dissertation,different surface structures of PVDF-Tr FE piezoelectric thin films are simulated using ANSYS software based on the finite element analysis including the planar,quadrangular,triangular,and pyramidal structure.Comparing the strains and output voltages of the four structures,the pyramid structure is found the best piezoelectric structure under the same restraint and pressure load.Under the same pressure,the relationship between strains and output voltages are also discussed.Based on the simulation result,it is found that pyramid structure has the highest strain and the highest piezoelectric output voltage,and planar structure has the smallest strain and the lowest piezoelectric output voltage.Then,in order to further verify the simulation results,the flexible piezoelectric film was experimentally explored.Firstly,the PVDF-Tr FE powder is dissolved in DMF solution by a magnetron vibrating method.Then the PVDF-Tr FE film is fabricated by a spin-coating method.The piezoelectric properties of the PVDF-Tr FE piezoelectric films were characterized by PFM(Pressure Power Microscope)and FTIR(Fourier Transform Infrared Spectroscopy).XRD(X-ray Diffraction)was used to characterize the formation of the ? phase by annealing.The flat and pyramidal structure PVDF-Tr FE films are fabricated.The pyramidalsurface structure of the PVDF-Tr FE film is observed by SEM.The piezoelectric properties of the flat and pyramidal structures were measured on piezoelectric equipment including an oscilloscope and magnetic shaker.Under the same pressure,the voltage output of the polarized pyramidal structure is the highest indicating better piezoelectric performance.