| The research of electric/magnetic dual-response smart materials have become a hot spot in the field of electric/magnetic rheological research.The electric/magnetic dual-response elastomer is composed of dual-response dispersed particles and a polymer matrix.Because it has both electrical and magnetic response properties and the soft substance characteristics of a polymer elastomer,it is a multi-response intelligent soft material,which applicated in biomedical and other fields.Due to the strong magnetoelectric coupling between ferroelectric and ferromagnetic,multiferroic materials have recently attracted the interest of many scientists.There may be a large interface coupling region between ferromagnetic and ferroelectric materials,and the heterostructure of ferroelectric/ferromagnetic core/shell nanocomposites may make it a good candidate for multifunctional response materials.Barium titanate(BT)has been widely studied in electrorheological materials due to its high dielectric constant and low dielectric loss.Ferric oxide(Fe3O4)has strong paramagnetism and low density.In this study,BT and Fe3O4 were used as basic materials to prepare electrical/magnetic dual-responsive composite particles with different shell contents and morphologies to study their electromagnetic response properties dispersed in elastomers.In this thesis,two types of BT particles with different shapes and sizes of about 400-500 nm were prepared by sol gel,soft template method,and hydrothermal reaction.One is a smooth sphere and the other is a flower pattern with large pores assembled from nanosheets.Subsequently,using BT as the core,the in-situ deposition method was used to plant Fe3O4 particles with a particle size of about 10 nm in situ on the surface of BT to obtain BT@Fe3O4 composite particles with different morphologies.Using SEM,TEM,XRD and other methods to characterize the morphology and crystal form of the composite particles.Disperse the prepared particles in gelatin elastomer under the four conditions of without field,electric field(0.8kV/mm),magnetic field(0.01T),electromagnetic double field(0.8kV/mm+0.01T)to prepare a series of particles/gelatin composite elastomer,and the impedance analyzer,laser confocal,and dynamic viscoelastic spectrometer are used to test the microstructure and properties of the elastomer,and the effects of composite particle morphology and shell content on the electromagnetic response performance are analyzed and studied.Experimental results show:(1)For 6 different ratios of spherical composite particles:as the content of Fe3O4 increases,the electrical response of the spherical composite particles increases first and then decreases;The magnetic response performance of spherical composite particles continues to increase;The electromagnetic dual response performance of spherical composite particles continues to increase.When the BT:Fe3O4 mass ratio is 1:1,particle has the largest electrical response performance;When the BT:Fe3O4 mass ratio is 1:2.0,particle has the largest magnetic response performance;When the BT:Fe3O4 mass ratio is 1:2.0,it has the largest electromagnetic dual response performance;(2)For particles with different morphologies:spherical BT has a smooth surface,flower BT has a rough surface,and has a high specific surface area.The response sensitivity of flower BT is 11%,while that of spherical BT is 3%.The electrical response performance of flower composite particle is lower than the spherical composite particle. |
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