Research On Environmentally Friendly BT-based Flexible Piezoelectric Material

Piezoelectric material is a special functional material that can convert electrical and mechanical energy into each other.Piezoelectric flexible composites have been widely studied by many scholars because of their good flexibility that commonly used piezoelectric ceramics do not have,and they are used in sensors,wearable energy harvesting devices,hydrophones and so on.In this paper,barium calcium zirconate titanate（BCZT）ceramic particles and short rods with different structures were synthesized by solid-phase method,hydrothermal method and electrospinning method as fillers,reinforced polyvinylidene fluoride（PVDF）or microcrystalline cellulose（MCC）.The polymer matrix was prepared by solution casting and other methods to prepare an environmentally friendly BCZT/PVDF composite membrane and an environmentally friendly and degradable BCZT/MCC composite membrane.Through the structural characterization,mechanical properties and electrical properties testing of the composite film,the influence of the piezoelectric flexible film on the preparation process of different fillers,film laying process and drying process is discussed.The main research of this paper includes the following four aspects:（1）BCZT ceramic powders were prepared by pre-sintering at 1200 ℃ by solid-phase method,and the median particle size was 500 nm.Five kinds of BCZT ceramic powders were prepared by hydrothermal method under different reaction conditions,and the median particle size was between 2.2μm and 6.7μm.Four kinds of BCZT rods with diameters ranging from 0.3μm to 0.8μm were prepared by electrostatic spinning by changing the concentration of acetic acid in BCZT precursor solution.The microstructure and microstructure of the material were analyzed by XRD,SEM,XPS,thermogravimetric methods,etc.It is believed that the three synthesis methods can obtain ceramic powder or short rod with perovskite structure,and its size can be used as filler for preparing piezoelectric flexible composite films.（2）Through the exploration of different film laying,drying and electrode preparation processes,it was found that a smooth and continuous BCZT/PVDF composite film can be prepared by solution casting film laying,vacuum drying film forming and thermal evaporation method.The experimental results show that the electrical properties and stimulated output electrical signals of the flexible composite membranes reinforced by ceramic fillers are better than those of pure PVDF membranes;the addition of ceramic fillers will reduce the tensile strength of the composite membranes;the properties of type 1-3 composite membranes Better than0-3 type composite membrane.The experimental results show that the BCZT fiber membrane was spun from 4 m L BCZT precursor solution and calcined at 1250 ℃.The ceramic rods were used to strengthen the composite film samples,d₃₃ is 19 p C/N,which is 9 p C/N compared with pure PVDF film 2.1 times higher.Under the impact of 3 N,the output voltage of the composite membrane is 1.32 V,which is 2.3 times higher than that of pure PVDF（0.58V）.（3）Through the exploration of different film laying,drying and electrode preparation processes,it was found that BCZT/MCC composite films by solution casting method,non-solvent induced phase separation（NIPS）film forming and thermal evaporation method,electrodes with relatively flat and continuous surface can be prepared.The experimental results show that the electrical properties and stimulated output electrical signals of the flexible composite films reinforced by ceramic fillers are better than those of pure MCC films;the addition of ceramic fillers can improve the tensile strength of the composite films;the properties of type 1-3composite films Better than 0-3 type composite membrane.The experimental results showed that 9 m L acetate BCZT precursor solution was spun out of BCZT fiber membrane and calcined at 1000 ℃ to obtain ceramic rods for strengthening the composite film samples,d33 is 24p C/N andεr is 85.87,which is relatively pure.The0.8 p C/N of the cellulose membrane is 30 times higher.Under the shock of 3 N,the output voltage of the composite film was 60.3 m V,which was 2.3 times higher than that of pure cellulose（26.4 m V）.（4）Through the research in this paper,an environmentally friendly BCZT/PVDF composite membrane with excellent performance and an environmentally friendly and degradable BCZT/MCC composite membrane were prepared.PVDF-based composite membranes have better performance than cellulose-based composite membranes,but both can meet the requirements of piezoelectric flexible membranes in the fields of sensors,biomedical imaging,and non-destructive testing.