Magnetoelectric composite soft material and preparation method thereof

Abstract

The application discloses a magneto-electric composite soft material and a preparation method thereof. The magneto-electric composite material comprises a piezoelectric elastomer layer and a magnetoelastic layer. The piezoelectric elastomer layer and the magnetoelastic layer are spin-coated and solidified together to form an integrated structure with a double-layer material. The electrical output and the magneto-electric coupling coefficient of the magneto-electric composite material are controlled by the doping amount of piezoelectric ceramic powder in the piezoelectric elastomer, the amplitude and the frequency of an external magnetic field. The application further discloses a preparation method of the magneto-electric composite material. The preparation method is simple, has a wide application range and low cost, and can be applied to the fields of magneto-electric sensors, flexible robots, energy capturing and self-powered devices.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, specifically relating to a novel magnetoelectric composite soft material and its preparation method. Background Technology

[0002] The magnetoelectric effect refers to the magnetization effect produced by an electric field or the polarization effect produced by a magnetic field. Magnetoelectric composite materials, as functional materials in magnetoelectric coupling effects, have extremely important application prospects in data storage, magnetoelectric sensing, biotherapy, energy harvesting, and even flexible robotics. Magnetization is often found in metallic materials, while polarization exists in dielectric materials. Therefore, materials with intrinsic magnetoelectric effects are extremely rare in nature. Moreover, the magnetoelectric effect of these materials is particularly weak at room temperature, and they can only function normally at extremely low temperatures, greatly limiting the widespread application of magnetoelectric materials.

[0003] Therefore, research over the past half-century has mainly focused on multiphase magnetoelectric composite materials, which are co-fired or strongly bonded together with piezoelectric and magnetostrictive materials and coupled together by stress at the interface. However, such composite materials are often hard materials with high operating frequencies, and in order to ensure a high magnetoelectric coupling coefficient under a weak magnetic field, an external DC magnetic field is usually required. At the same time, such composite materials have strict requirements on the bonding strength of the interface.

[0004] Therefore, it is urgent to develop a magnetoelectric composite material that is simple to manufacture, has low modulus, low operating frequency, and does not require an external DC magnetic field. Summary of the Invention

[0005] To overcome the existing technical problems, the present invention provides a magnetoelectric composite soft material and its preparation method. The magnetoelectric composite soft material has a high room temperature magnetoelectric coupling coefficient and requires a low frequency and low amplitude magnetic field for operation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A magnetoelectric composite soft material includes a piezoelectric elastomer layer 1 and a magnetoelectric elastomer layer 2. The piezoelectric elastomer layer 1 comprises piezoelectric ceramic powder and a silicone rubber polymer, with the piezoelectric ceramic powder uniformly dispersed in the silicone rubber polymer. The magnetoelectric elastomer layer 2 comprises magnetic particles and a silicone rubber polymer, with the magnetic particles uniformly dispersed in the silicone rubber polymer. The piezoelectric elastomer layer 1 and the magnetoelectric elastomer layer 2 are grown together by spin coating and curing to form a compact bilayer composite structure. The magnetoelectric coupling coefficient of the magnetoelectric composite soft material is 0.8 Vcm. -1 Oe -1 ~5.9Vcm -1 Oe -1The output charge and magnetoelectric coupling coefficient of the magnetoelectric composite material are controlled by adjusting the doping ratio of piezoelectric ceramic powder and the amplitude and frequency of the applied magnetic field. The magnetic field required for the operation of the magnetoelectric composite soft material has a frequency of 1Hz to 7Hz and an amplitude of 0.5Oe to 2.5Oe.

[0008] The piezoelectric elastomer layer 1 is a silicone rubber polymer with piezoelectric ceramic powder uniformly dispersed inside. By doping the silicone rubber polymer with piezoelectric ceramic powder, the polymer material, which originally had no electromechanical coupling ability, can generate an electrical response under deformation. The magnetoelastic layer 2 is a silicone rubber polymer with magnetic particles uniformly dispersed inside, so that the silicone rubber polymer can acquire the ability of magnetostrictive deformation.

[0009] The piezoelectric ceramic powder includes barium titanate, barium strontium titanate, or PZT ceramic powder; the silicone rubber polymer is polydimethylsiloxane (PDMS) or platinum-catalyzed silicone rubber Ecoflex; and the magnetic particles are metal particles such as hydroxyl iron powder, hydroxyl nickel powder, or hydroxyl neodymium iron boron (NdFeB).

[0010] The method for preparing a magnetoelectric composite soft material involves first selecting a glass plate or acrylic plate as a substrate, doping magnetic particles into a silicone rubber polymer to obtain a pre-magnetic elastomer polymer, pouring the pre-magnetic elastomer polymer onto the substrate, spin-coating it using a spin coater, and then curing it at a high temperature to obtain a magnetoelastic layer 2. Then, piezoelectric ceramic powder is doped into the silicone rubber polymer to obtain a pre-piezoelectric elastomer polymer, which is then poured onto the cured magnetoelastic layer 2, spin-coated again using a spin coater, and then cured at a high temperature to form a piezoelectric elastomer layer 1 on the magnetoelastic layer 2. Finally, a tightly structured double-layer magnetoelectric composite material is formed.

[0011] The doping method is physical doping, in which uncured silicone rubber polymer is mixed with magnetic particles or piezoelectric ceramic powder in a certain proportion and stirred thoroughly.

[0012] The curing process involves heating and curing within a range of room temperature to 90°C.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. Diverse material system options.

[0015] 2. It has a high room temperature magnetoelectric coupling coefficient, and the magnetic field required for operation is low frequency and low amplitude.

[0016] 3. The magnetoelectric coupling performance of magnetoelectric composite materials is easy to control. The magnetoelectric effect can be controlled by adjusting the mass ratio of doped piezoelectric ceramic powder and by changing the amplitude and frequency of the applied magnetic field.

[0017] 4. The preparation process used in this invention is simple, highly applicable, and does not have interface problems. It can be used for complex preparations such as 3D printing. The prepared magnetoelectric composite material can be used in fields such as energy harvesting, magnetoelectric sensing, and flexible robots. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a magnetoelectric composite soft material structure proposed in this invention;

[0019] Figure 2 This is a flowchart illustrating the preparation process of magnetoelectric composite materials.

[0020] Figure 3 The relationship between the output charge and magnetoelectric coupling coefficient of the magnetoelectric composite material and the doping ratio of the piezoelectric ceramic powder in the experiment;

[0021] Figure 4 This shows the relationship between the output charge and magnetoelectric coupling coefficient of the magnetoelectric composite material and the amplitude of the applied magnetic field in the experiment.

[0022] Figure 5 This represents the relationship between the output charge and magnetoelectric coupling coefficient of the magnetoelectric composite material and the frequency of the applied magnetic field in the experiment. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific examples, but this is not intended to limit the scope of the invention.

[0024] like Figure 1 As shown, this invention provides a specific embodiment of a novel magnetoelectric composite soft material and its preparation method. The novel magnetoelectric composite soft material includes a piezoelectric elastomer layer 1 and a magnetoelectric elastomer layer 2. The piezoelectric elastomer layer 1 includes piezoelectric ceramic powder and a silicone rubber polymer, with the piezoelectric ceramic powder uniformly dispersed in the silicone rubber polymer. The magnetoelectric elastomer layer 2 includes magnetic particles and a silicone rubber polymer, with the magnetic particles uniformly dispersed in the silicone rubber polymer. The piezoelectric elastomer layer 1 and the magnetoelectric elastomer layer 2 are grown together by spin coating and curing to form a dense bilayer composite structure.

[0025] like Figure 2 As shown, a glass plate was selected as the substrate, and magnetic particles were doped into the silicone rubber polymer to prepare a pre-magnetic elastomer polymer. The pre-magnetic elastomer polymer was poured onto the substrate and spin-coated using a spin coater. Then, it was cured at a high temperature to obtain a magnetoelastic layer 2. Piezoelectric ceramic powder was doped into the silicone rubber polymer to prepare a pre-piezoelectric elastomer polymer. The pre-piezoelectric elastomer polymer was then poured onto the cured magnetoelastic layer 2 and spin-coated again using a spin coater. Then, it was cured at a high temperature to form a piezoelectric elastomer layer 1 on the magnetoelastic layer 2. Finally, a tightly structured double-layer magnetoelectric composite material was formed.

[0026] In this specific embodiment, the selected silicone rubber polymer is Ecoflex0020, wherein liquid A and liquid B are mixed in equal proportions, and the piezoelectric ceramic powder is selected as barium strontium titanate (Ba). 0.67 Si 0.33 TiO3 with a particle size of 70 nm, and the magnetic particles are selected from rubidium iron boron powder with a particle size of 30 micrometers. Hard magnetic particles are selected and magnetized under a strong magnetic field after preparation.

[0027] After the material was prepared, according to the definition of magnetoelectric coupling, the magnetoelectric coupling coefficient of the magnetoelectric composite material was obtained by measuring the output charge and equivalent capacitance of the magnetoelectric composite soft material:

[0028]

[0029] Where, α ME Where is the magnetoelectric coupling coefficient, E is the electric field, and h is the electric field. e The external magnetic field is dQ, the output charge is L, the thickness of the magnetoelectric composite material is C eff The equivalent capacitance of the magnetoelectric composite material is given by formula (1). The magnetoelectric coupling coefficient of the magnetoelectric composite material is measured in the experiment.

[0030] like Figure 3 As shown, the output charge and magnetoelectric coupling coefficient first increase and then decrease with the frequency of the applied magnetic field. At 5 Hz, the output charge and magnetoelectric coupling coefficient reach their maximum, and resonance occurs near this frequency.

[0031] like Figure 4 As shown, when the frequency of the controlled magnetic field is around 5Hz, the output charge increases linearly with the applied magnetic field, and the magnetoelectric coupling coefficient does not change with the amplitude of the applied magnetic field.

[0032] like Figure 5 As shown, the frequency and amplitude of the controlled magnetic field, the output charge and the magnetoelectric coupling coefficient vary with the doping ratio of the piezoelectric ceramic powder, and increase with the increase of the piezoelectric ceramic powder.

Claims

1. A magnetoelectric composite soft material, characterized in that: The material comprises a piezoelectric elastomer layer (1) and a magnetoelastic layer (2), which are naturally grown together by spin coating and curing to form a two-layer composite structure; the magnetoelectric coupling coefficient of the magnetoelectric composite soft material is 0.8 Vcm. -1 Oe -1 ~5.9Vcm -1 Oe -1 The charge output and magnetoelectric coupling coefficient of the magnetoelectric composite material are controlled by adjusting the doping ratio of piezoelectric ceramic powder and the amplitude and frequency of the applied magnetic field; the frequency of the magnetic field required for the operation of the magnetoelectric composite soft material is 1Hz to 7Hz, and the amplitude is 0.5Oe to 2.5Oe. The piezoelectric elastomer layer (1) is made of silicone rubber polymer with piezoelectric ceramic powder uniformly dispersed inside. By doping the silicone rubber polymer with piezoelectric ceramic powder, the silicone rubber polymer, which originally had no electromechanical coupling ability, can generate an electrical response under deformation. The silicone rubber polymer is platinum-catalyzed silicone rubber Ecoflex; the piezoelectric ceramic powder is barium titanate and barium strontium titanate Ba. 0.67 Si 0.33 TiO3; The magnetoelastic layer (2) is made of silicone rubber polymer with magnetic particles uniformly dispersed inside, so that the silicone rubber polymer can acquire the ability of magnetostriction.

2. The magnetoelectric composite soft material according to claim 1, characterized in that, The silicone rubber polymer is polydimethylsiloxane (PDMS) or platinum-catalyzed silicone rubber Ecoflex; the magnetic particles are hydroxyl iron powder, hydroxyl nickel powder, or hydroxyl neodymium iron boron (NdFeB).

3. A method for preparing a magnetoelectric composite soft material according to claim 1 or 2, characterized in that, First, magnetic particles are doped into silicone rubber polymer to prepare a pre-magnetic elastomer polymer. The pre-magnetic elastomer polymer is poured onto a substrate and spin-coated using a spin coater. Then, it is cured at high temperature to obtain a magnetoelastic layer (2). Piezoelectric ceramic powder is doped into silicone rubber polymer to prepare a pre-piezoelectric elastomer polymer. Then, the pre-piezoelectric elastomer polymer is poured onto the cured magnetoelastic layer (2) and spin-coated using a spin coater. Then, it is cured at high temperature to form a piezoelectric elastomer layer (1) on the magnetoelastic layer (2). Finally, a tightly structured double-layer magnetoelectric composite material is formed.

4. The preparation method according to claim 3, characterized in that, The doping method is physical doping, in which uncured silicone rubber polymer is mixed with magnetic particles or piezoelectric ceramic powder in a certain proportion and stirred thoroughly.

5. The preparation method according to claim 3, characterized in that, The curing process involves heating and curing within a range of room temperature to 90 degrees Celsius, with a curing time of 20 minutes to 3 hours.

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