Study On Preparation Of High Dielectric Composite Materials By Electrospinning

Dielectric materials have been used in many fields,and the rapidly developing technology has put higher requirements on the dielectric properties of the materials.Electrospinning technology has been extensively used in the field of dielectric due to its adaptability and ease of operation.In this paper,combined with the electrospinning process,the synthesis and application of co-doped titanium dioxide with a huge dielectric constant are studied,and the multi-dimensional application of high dielectric materials is realized.The paper is divided into three parts:(1)The high-temperature solid-phase method is a common way to prepare co-doped titanium dioxide ceramics,and the sol-gel method has received much attention because of its homogeneous chemical composition,mild experimental conditions and easy doping at the molecular level.Therefore,La+Nb co-doped titanium dioxide(LNTO)ceramic particles with large dielectric constants were successfully prepared using the sol-gel method by investigating the experimental conditions.The one-dimensional material has the advantages of high aspect ratio and low specific surface area,and the LNTO nanofibers(LNTO NFs)with fibrous morphology were prepared by combining the electrostatic spinning process to control their morphology.The intrinsic permittivity was tested and the LNTO ceramic material with 2%doping content reached a dielectric constant of 2.76×10~4 at 1 k Hz with a dielectric loss of 0.4,an improvement of about two orders of magnitude over pure titanium dioxide.(2)Based on the above experiments,high dielectric composites were prepared by using the giant dielectric constant of LNTO and special fiber morphology to composite with PVDF and PDMS,and assembled friction generators with them to expand the applications of high dielectric composites.It was found that using LNTO as high dielectric filler can effectively enhance the dielectric constant of the composites,and the LNTO NFs/PVDF composites have more excellent dielectric properties compared with LNTO/PVDF composites.The dielectric constant of 1-LNTO NFs/PVDF composite is 40when the content of 1-LNTO NFs is 60 wt%,and the dielectric loss is 0.12.The dielectric constant of 1-LNTO/PDMS is 4.75 when the addition of 1-LNTO is20 wt%,and the friction generator assembled by this composite obtains the maximum output voltage and output current at this time,and the maximum output voltage is 350 V.(3)Flexible LNTO nanofiber films were successfully prepared by tuning the electrostatic spinning process conditions to overcome the brittleness drawback of inorganic materials,explore their dielectric properties,and use them to explore their intact fiber film applications.The LNTO/PVDF composites with 3D networks were prepared by vacuum impregnation,and the dielectric properties of the composites were improved by using the complete filler network reinforcement,and the dielectric constant of the composites reached 25 when the filler network content was 10 wt%,which was 1.7 times higher than that of conventional composites.By exploring the optimal process conditions to obtain flexible inorganic fiber membranes,it was found that the LNTO nanofiber membranes with high dielectric constant and good flexibility after heat treatment at 700°C were used as a dielectric layer to assemble sensors,and this sensor can generate current signals under different pressures,which can be applied to the field of body-worn electronic devices.