Self-powered flexible magnetoelectric therapy fiber and preparation method thereof

Abstract

The present application relates to the field of fiber manufacturing, and particularly relates to a self-powered flexible magnetic electrotherapy fiber and a preparation method thereof, the self-powered flexible magnetic electrotherapy fiber comprises: a piezoelectric unit for generating an electric signal in response to mechanical deformation of the fiber; a magnetic unit comprising at least one magnetic response element capable of changing its state in response to the electric signal; and a conductive unit electrically connected to the piezoelectric unit and the magnetic unit for transmitting the electric signal to the magnetic unit to drive the magnetic response element to change its state; wherein the state change of the magnetic response element causes the magnetic field pattern output by the fiber to change adaptively with the mechanical deformation. Compared with the prior art, the present application realizes true energy self-supply and closed-loop intelligent response, the fiber uses human body movement to generate electricity and directly drives the treatment function, without the need for an external power supply, and the treatment mode can be automatically matched in real time with the user's activity state.

Description

Technical Field

[0001] This invention relates to the field of fiber manufacturing, and in particular to a self-powered flexible magnetoelectric therapy fiber and its preparation method. Background Technology

[0002] In the current field of health monitoring and physical therapy, wearable devices are developing towards greater flexibility, intelligence, and functional integration. Among these, integrating energy harvesting, biosensing, and therapeutic functions into a single flexible carrier, especially textile fibers, is a research direction that has attracted widespread attention.

[0003] Magnetotherapy, a common non-invasive physical therapy method, has effects closely related to the strength, frequency, and mode of action of the magnetic field. Traditional magnetic therapy patches or devices typically rely on embedded permanent magnets or electromagnetic coils that require an external power source. Permanent magnets generate static, constant magnetic fields, and their treatment modes and parameters cannot be adjusted according to the user's real-time condition, lacking dynamic adaptability and personalized intervention capabilities. While devices based on electromagnetic coils can adjust the magnetic field by changing the input current, they usually rely on bulky batteries or external power sources, limiting their potential for long-term, convenient use in wearable scenarios.

[0004] In recent years, with the development of flexible electronics and nanomaterials, researchers have attempted to develop various self-powered systems that harvest mechanical energy from human movement or the environment to power electronic devices. Piezoelectric materials, such as polyvinylidene fluoride (PVDF) and its copolymers, are often used to manufacture fibrous or thin-film energy harvesters due to their excellent flexibility and electromechanical conversion efficiency. Meanwhile, to endow fibers with sensing capabilities, researchers have introduced conductive materials such as carbon nanotubes, graphene, or MXene into fiber systems for monitoring signals such as strain and pressure. However, the main function of these self-powered fibers is usually limited to energy harvesting or sensing. The collected electrical energy is often only used to power or store small sensors, without further use to drive the fiber itself to generate active, controllable therapeutic functions. In other words, there is a disconnect between the "harvesting" of energy and the "output" of therapeutic functions; the fiber itself does not possess the ability to intelligently adjust its therapeutic parameters using the energy it generates.

[0005] On the other hand, some research has attempted to integrate magnetic materials into fibers to achieve magnetotherapy functions. A common method is to directly mix magnetic powders such as ferrite or neodymium iron boron into the fiber spinning solution. While this method can produce magnetic fibers, it also generates a fixed magnetic field. A few studies have attempted to prepare composite fibers containing magnetic particles and conductive materials, hoping to generate a changing electromagnetic field by applying current through an external circuit. However, this is essentially still a "passive" actuator that requires external control signals and has not solved the problems of energy self-sufficiency and closed-loop feedback.

[0006] Furthermore, how to efficiently and stably integrate multiple functional modules, such as energy harvesting, signal transmission, magnetic field generation, and dynamic control, within a single micrometer-scale fiber without compromising fiber flexibility and wearing comfort, and how to ensure that these modules work collaboratively rather than simply being stacked, remains a challenge that requires further exploration. Existing technical solutions often only achieve one or two of the aforementioned functions. When pursuing multifunctional integration, problems such as structural complexity, mutual interference between functions, or incompatibility of manufacturing processes are frequently encountered, leading to compromises in fiber performance, reliability, or comfort.

[0007] In summary, existing magnetic therapeutic fibers or devices still have significant limitations in terms of the dynamic adjustability of the magnetic field, self-supply of energy, and multifunctional integrated intelligence. Developing a flexible intelligent fiber capable of autonomously acquiring energy from daily activities and using that energy to drive its therapeutic functions to adjust in real-time and adaptively according to the user's condition is of great significance for promoting the development of next-generation personalized, wearable health management technologies. Summary of the Invention

[0008] This application aims to overcome the shortcomings of existing magnetoelectric therapy fibers, such as fixed magnetic field modes, reliance on external energy supply, and the inability to adaptively adjust the therapeutic function in real time according to the user's condition. Therefore, it provides a self-powered flexible magnetoelectric therapy fiber and its preparation method to overcome the above-mentioned deficiencies.

[0009] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a self-powered flexible magnetoelectric therapy fiber, comprising: Piezoelectric element, used to generate electrical signals in response to the mechanical deformation of fibers; A magnetic unit includes at least one magnetic response element, which is capable of changing its state in response to an electrical signal; A conductive unit, electrically connected to the piezoelectric unit and the magnetic unit, is used to transmit the electrical signal to the magnetic unit to drive the state change of the magnetic response element; The change in the state of the magnetic response element causes the magnetic field mode output by the fiber to adapt to the mechanical deformation.

[0010] In the fields of magnetotherapy and flexible electronics, existing technologies generally face a difficult-to-reconcile contradiction: on the one hand, obtaining a flexible and adjustable dynamic magnetic field usually requires an external power supply and complex control circuits, which limits the wearability and convenience of the device; on the other hand, while simple solutions based on permanent magnets have a simple structure, the static magnetic field they generate cannot respond to the user's activity state, and its treatment parameters are fixed. Furthermore, although existing research has successfully integrated piezoelectric materials into fibers to achieve mechanical energy harvesting, or incorporated magnetic materials to obtain basic magnetism, these functions often exist independently or simply coexist. For example, a fiber can harvest energy for sensing or simply provide a static magnetic field, but there is a lack of an intrinsic, automatic linkage mechanism between the harvested energy and the fiber's therapeutic output. This means that the fiber's "sensing" and "treatment" are two separate systems, failing to form an autonomous feedback intelligent closed loop.

[0011] Therefore, this invention aims to fundamentally change this situation by constructing a self-contained fiber-based microsystem capable of integrating "sensing-decision-execution." Specifically, the solution explicitly defines a system comprising piezoelectric units, magnetic units, and conductive units, connected through a specific synergistic mechanism. The magnetic units contain "magnetic response elements" that directly respond to electrical signals generated by the piezoelectric units and change their own state, thereby transforming them into a unified entity that acts as both a "control signal" and an "energy source," driving changes in the internal functional structure.

[0012] In terms of technical implementation, this invention brings multi-level advancements. First, it achieves intelligent programmability of magnetic field output. The final magnetic field characteristics generated by the fiber (such as whether it alternates, its frequency, and intensity) are no longer determined by preset fixed parameters, but are determined in real-time by the mechanical deformations actually applied to the fiber by the user (such as the amplitude and frequency of walking, running, and joint bending). Vigorous exercise may encode a high-frequency pulsed magnetic field, while gentle activity corresponds to a low-frequency alternating magnetic field. This achieves dynamic matching between the magnetic therapy mode and the human physiological state, which is impossible for traditional static magnetic therapy devices or external electromagnetic devices that require manual adjustment. Second, it truly achieves self-sufficiency in energy and self-driving of function. The entire magnetic field adjustment process is driven entirely by the biomechanical energy collected by the fiber itself, without any external batteries or wires, solving the problem of continuous power supply for wearable devices and improving the freedom and sustainability of use. Finally, this solution achieves a high degree of integration and miniaturization at the system integration level. It cleverly integrates three functional modules—energy harvester (piezoelectric unit), signal transmission and processing network (conductive unit), and actuator (magnetic unit)—into the microstructure of a single fiber through material selection and structural design. This allows the modules to be tightly integrated in space and deeply synergistic in function, thus realizing the functions that previously required multiple independent devices in combination on a single flexible carrier.

[0013] Therefore, compared to existing magnetic fibers or devices with fragmented functions and passive responses, this invention successfully constructs an intelligent system with tightly coupled internal functions by introducing the core mechanism that "the state of the magnetic response element is controlled by a self-generated electrical signal and ultimately modulates the output magnetic field." This system not only physically unifies energy harvesting and function execution, but also logically achieves adaptive adjustment of the treatment output to the user's state. While enhancing personalized treatment and user experience, it also demonstrates non-obviousness in structural integration and system operating logic.

[0014] Preferably, the piezoelectric unit comprises a piezoelectric polymer film.

[0015] Preferably, the magnetic unit comprises an array of magnetic nanowires arranged along the fiber axis.

[0016] Preferably, the conductive unit comprises a composite conductive network of two-dimensional materials and carbon nanotubes.

[0017] Preferably, the piezoelectric polymer film is polyvinylidene fluoride or a copolymer thereof.

[0018] Preferably, the magnetic nanowire array is iron(III) oxide nanowire or composite nanowire loaded with Fe3O4.

[0019] Preferably, the two-dimensional material is MXene.

[0020] Preferably, the magnetic unit further includes permanent magnet powder, which is dispersed in the conductive unit.

[0021] Preferably, the fiber further includes a flexible encapsulation layer that wraps the piezoelectric unit, magnetic unit, and conductive unit.

[0022] Secondly, the present invention also provides a method for preparing the self-powered flexible magnetoelectric therapy fiber, comprising the following steps: (S.1) Forming the piezoelectric unit; (S.2) Form the magnetic unit; (S.3) Form the conductive unit; (S.4) Integrate the piezoelectric unit, magnetic unit and conductive unit, so that the conductive unit is electrically connected to the piezoelectric unit and the magnetic unit, so as to realize the adaptive driving of the magnetic response element state change with mechanical deformation.

[0023] Preferably, forming the magnetic unit includes constructing a magnetic nanowire array by electrospinning or a template method.

[0024] Preferably, forming the piezoelectric unit includes preparing a piezoelectric polymer film by solution casting or electrospinning.

[0025] Preferably, forming the conductive unit includes dispersing two-dimensional materials, carbon nanotubes, and permanent magnet powder in a flexible resin to form a composite conductive slurry, and then coating it onto the piezoelectric unit.

[0026] Preferably, the permanent magnet powder is neodymium iron boron powder with an insulating layer on its surface.

[0027] Preferably, the integration step further includes a step of polarizing the piezoelectric unit.

[0028] Preferably, the method achieves multi-layer structure integration through coaxial electrospinning or layer-by-layer assembly processes.

[0029] Therefore, the present invention has the following beneficial effects: (1) It achieves true energy self-supply and closed-loop intelligent response. The fiber generates its own power using human movement and directly drives the therapeutic function without the need for an external power source. The therapeutic mode can be matched automatically in real time according to the user's activity status. (2) It realizes the in-situ programmability and adaptive adjustment of magnetic field output. Through the internal conversion chain of "mechanical energy-electrical energy-magnetic structure change", the output magnetic field mode (such as static, alternating, pulse) can be dynamically adjusted according to the intensity and frequency of motion, thereby improving the personalization and targeting of treatment. (3) This scheme integrates multiple functions such as energy harvesting, motion sensing and dynamic magnetoelectric therapy in a single fiber. Through the synergistic design of multi-layer materials and structures, it realizes the synergistic effect of multiple physical fields such as magnetism, electricity and force, and achieves the integration of composite functions in a limited space. (4) The fiber's structural design takes into account both flexibility and durability, and its preparation method is compatible with traditional textile processes, providing a new feasible path for the development of smart fabrics and wearable medical devices. (5) While providing dynamic therapy, the fiber’s piezoelectric signal can also serve as a data source for motion monitoring, achieving “multiple uses for one fiber” and expanding its application potential in the field of health management. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0031] Example 1 This embodiment provides a method for preparing a self-powered flexible magnetoelectric therapy fiber, which specifically includes the following steps: (S.1) Formation of magnetic units: 0.8 g of iron(III) oxide (Fe3O4) nanowires with an average length of 5 μm were dispersed in 20 mL of a deionized aqueous solution containing 8 wt% polyvinylpyrrolidone (PVP, Mw=1,300,000) and ultrasonically treated for 2 hours to obtain a uniform spinning solution A.

[0032] (S.2) Forming piezoelectric units: Dissolve 1.2 g of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE, molar ratio 75 / 25) powder in a mixed solvent of 10 mL of N,N-dimethylformamide (DMF) and 5 mL of acetone, and stir in a water bath at 60 °C for 6 hours until completely dissolved to obtain a spinning solution B with a mass fraction of 8%.

[0033] (S.3) Preliminary integration to form core-sheath fibers: A coaxial electrospinning device was used, with spinning solution A as the core layer and spinning solution B as the sheath layer. Specific parameters were: core layer advance speed 0.8 mL / h, sheath layer advance speed 1.5 mL / h, spinning voltage 18 kV, receiving distance 15 cm, and receiving roller linear speed 12 m / s. During the spinning process, the high-speed rotating roller traction caused the Fe3O4 nanowires in the core layer to be oriented along the fiber axis, resulting in the "Fe3O4 nanowire array / PVDF-TrFE" composite fiber precursor.

[0034] (S.4) Formation of conductive units: 50 mg of few-layer titanium carbide (MXene, Ti3C2T) was added. x Nanosheets and 20 mg of multi-walled carbon nanotubes (CNTs) were dispersed in 10 mL of deionized water and sonicated for 1 hour. Then, 0.5 g of neodymium iron boron (NdFeB) micropowder with an average particle size of 2 μm (coated with a SiO2 insulating layer of about 100 nm thickness) and 2 g of aqueous polyurethane (PU) emulsion were added and magnetically stirred for 4 hours to obtain a uniform conductive magnetic slurry C.

[0035] (S.5) Final integration: The composite fiber precursor obtained in step 3 is immersed in slurry C at a speed of 5 cm / min, and then dried in an oven at 80°C for 30 minutes to form a uniform MXene / CNT / NdFeB-PU composite conductive layer (i.e. conductive unit) with a thickness of about 15 micrometers on the fiber surface.

[0036] (S.6) Polarization treatment: The above fibers are placed in an oven at 120°C for 10 minutes and then polarized for 30 minutes under an electric field strength of 100 MV / m (electrode spacing 1 cm). After that, they are cooled to room temperature while maintaining the electric field to activate the piezoelectricity of PVDF-TrFE.

[0037] (S.7) Encapsulation: The polarized fiber is immersed in the A:B component (1:1 mixture) prepolymer of Ecoflex 00-30 silicone rubber, pulled out and cured at room temperature for 4 hours to form a flexible encapsulation layer with a thickness of about 50 micrometers, and finally the self-powered flexible magnetoelectric therapy fiber F1 is obtained.

[0038] Example 2 This embodiment provides a method for preparing a self-powered flexible magnetoelectric therapy fiber, which specifically includes the following steps: (S.1) Forming magnetic units: 0.5 g of Fe3O4 nanowires with an average length of 10 micrometers and 0.5 g of Bianstone powder with a particle size of 200 nanometers are ball-milled together for 2 hours to form a composite. Then, the composite powder is dispersed in 20 ml of an aqueous solution containing 6% PVP by weight to obtain spinning solution A.

[0039] (S.2) Forming piezoelectric units: Dissolve 1.2 g of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE, molar ratio 75 / 25) powder in a mixed solvent of 10 mL of N,N-dimethylformamide (DMF) and 5 mL of acetone, and stir in a water bath at 60 °C for 6 hours until completely dissolved to obtain a spinning solution B with a mass fraction of 8%.

[0040] (S.3) Preliminary integration to form core-sheath fibers: A coaxial electrospinning device was used, with spinning solution A as the core layer and spinning solution B as the sheath layer. Specific parameters were: core layer advance speed 0.5 mL / h, sheath layer advance speed 1.2 mL / h, spinning voltage 20 kV, receiving distance 15 cm, and receiving roller linear speed 15 m / s. During the spinning process, the high-speed rotating roller traction caused the Fe3O4 nanowires in the core layer to be highly oriented along the fiber axis, thus obtaining the "Fe3O4@Bianstone composite nanowire array / PVDF-TrFE" composite fiber precursor.

[0041] (S.4) Forming conductive units: 80 mg MXene and 10 mg CNT were dispersed in 10 mL of water, followed by the addition of 0.2 g of NdFeB micro powder with a particle size of 5 μm and 1.5 g of aqueous PU to obtain a uniform conductive magnetic slurry C.

[0042] (S.5) Final integration: Using microfluidic spraying, slurry C is uniformly sprayed onto the surface of the fiber precursor, controlling the wet film thickness to be about 100 micrometers, and after drying at 85°C, a conductive layer with a thickness of about 8 micrometers is formed.

[0043] (S.6) Polarization treatment: The above fibers are placed in an oven at 120°C for 10 minutes and then polarized for 30 minutes under an electric field strength of 100 MV / m (electrode spacing 1 cm). After that, they are cooled to room temperature while maintaining the electric field to activate the piezoelectricity of PVDF-TrFE.

[0044] (S.7) Encapsulation: The polarized fiber is immersed in the A:B component (1:1 mixture) prepolymer of Ecoflex 00-30 silicone rubber, pulled out and cured at room temperature for 4 hours to form a flexible encapsulation layer with a thickness of about 50 micrometers, and finally the self-powered flexible magnetoelectric therapy fiber F2 is obtained.

[0045] Example 3 This embodiment provides a method for preparing a self-powered flexible magnetoelectric therapy fiber, which specifically includes the following steps: (S.1) Formation of magnetic units: 0.8 g of iron(III) oxide (Fe3O4) nanowires with an average length of 5 μm were dispersed in 20 mL of a deionized aqueous solution containing 8 wt% polyvinylpyrrolidone (PVP, Mw=1,300,000) and ultrasonically treated for 2 hours to obtain a uniform spinning solution A.

[0046] (S.2) Formation of piezoelectric units: 1.5 g of polyvinylidene fluoride (PVDF, Mw~534,000) was dissolved in a mixed solvent of 9 mL of DMF and 6 mL of acetone to obtain a spinning solution B with a mass fraction of 10%.

[0047] (S.3) Preliminary integration to form core-sheath fibers: A coaxial electrospinning device was used, with spinning solution A as the core layer and spinning solution B as the sheath layer. Specific parameters were: core layer advance speed 0.8 mL / h, sheath layer advance speed 1.5 mL / h, spinning voltage 18 kV, receiving distance 15 cm, and receiving roller linear speed 12 m / s. During the spinning process, the high-speed rotating roller traction caused the Fe3O4 nanowires in the core layer to be oriented along the fiber axis, resulting in the "Fe3O4 nanowire array / PVDF-TrFE" composite fiber precursor.

[0048] (S.4) Formation of conductive units: 30 mg of graphene nanosheets and 30 mg of CNTs were dispersed in 10 mL of ethanol, and 0.8 g of NdFeB micro powder with a particle size of 1 μm and 2.5 g of polyvinyl alcohol (PVA, 10% by mass) aqueous solution were added and stirred to obtain slurry C. A film was formed on the surface of the fiber precursor by dip-coating-coating method, and the thickness of the conductive layer after drying was about 20 μm.

[0049] (S.5) Polarization treatment: The above fibers are placed in an oven at 100°C for 10 minutes and then polarized for 45 minutes under an electric field strength of 80 MV / m (electrode spacing 1 cm). After that, they are cooled to room temperature while maintaining the electric field to activate the piezoelectricity of PVDF-TrFE.

[0050] (S.6) Encapsulation: The polarized fiber is immersed in the A:B component (1:1 mixture) prepolymer of Ecoflex 00-30 silicone rubber, pulled out and cured at room temperature for 4 hours to form a flexible encapsulation layer with a thickness of about 50 micrometers, and finally the self-powered flexible magnetoelectric therapy fiber F3 is obtained.

[0051] Example 4 This embodiment demonstrates a preparation method based on a layer-by-layer assembly process, which differs from coaxial spinning.

[0052] (S.1) Formation of independent magnetic units: using a template-assisted method. Anodized aluminum oxide (AAO) template is immersed in a suspension containing Fe3O4 nanowires (same as spinning solution A in Example 1, without PVP). Vacuum-assisted filtration is used to orient the nanowires within the template channels. The template is then dissolved to obtain an independent Fe3O4 nanowire array film.

[0053] (S.2) Forming piezoelectric units and integrating them for the first time: A DMF solution of PVDF-TrFE (concentration 12%) was cast onto the surface of the nanowire array film obtained in step 1 and dried at 80°C to form a piezoelectric layer with a thickness of about 20 micrometers, thereby combining with the magnetic unit.

[0054] (S.3) Forming and integrating conductive units: MXene / CNT / NdFeB-PU slurry (formulation same as step 4 in Example 1) is screen printed on the piezoelectric layer surface of the composite film obtained in step 2, patterned into strips, and dried to form a strip conductive layer with a width of 500 micrometers and a thickness of 10 micrometers.

[0055] (S.4) Cutting and polarization: Cut the above composite film into fiber strips 1 mm wide. The polarization treatment is the same as step 6 in Example 1.

[0056] (S.5) Encapsulation: The fiber strip is immersed in polydimethylsiloxane (PDMS) prepolymer and cured to obtain fiber F4.

[0057] Example 5 This embodiment provides a method for preparing a self-powered flexible magnetoelectric therapy fiber, which specifically includes the following steps: (S.1) Forming magnetic units: Same as step 1 in Example 2, using Fe3O4@Bianstone composite.

[0058] (S.2) Forming piezoelectric units: Prepare a DMF solution with a concentration of 15% PVDF-TrFE (molar ratio 70 / 30) as spinning solution B.

[0059] (S.3) Preliminary integration to form core-sheath fibers: Coaxial electrospinning parameters are: core layer 0.4 mL / h, sheath layer 2.0 mL / h, voltage 22 kV, receiving distance 20 cm, and roller speed 10 m / s. Composite fibers with a relatively thick sheath layer (piezoelectric layer) are obtained.

[0060] (S.4) Formation of conductive units: Disperse 20 mg MXene and 50 mg CNT in 10 mL of water / ethanol mixed solvent, add 1.0 g of NdFeB micro powder with a particle size of 3 μm and 3.0 g of polyurethane acrylate (PUA) prepolymer, stir and add 1% photoinitiator. Apply the slurry to the fiber surface and cure with a UV lamp to form a conductive layer.

[0061] (S.5) Final integration and post-processing: The polarization and encapsulation steps are the same as in Example 1, to obtain fiber F5.

[0062] Example 6 This embodiment provides a method for preparing a self-powered flexible magnetoelectric therapy fiber, which specifically includes the following steps: (S.1) Forming magnetic units: Same as step 1 in Example 1.

[0063] (S.2) Forming piezoelectric units: Same as step 2 in Example 1.

[0064] (S.3) Preliminary integration to form nucleosheath fibers: Same as step 3 in Example 1.

[0065] (S.4) Forming conductive units: Disperse 100 mg of MXene in 10 ml of water, add 1.5 g of water-based PU, and stir to obtain a pure conductive slurry without permanent magnet powder.

[0066] (S.5) Final integration: The composite fibers are impregnated with the above-mentioned pure conductive paste and dried.

[0067] (S.6) Polarization and encapsulation: Following steps 6 and 7 of Example 1, fiber F6 was obtained. This fiber generates a tunable magnetic field by means of the state change of the Fe3O4 nanowire array driven by the current in the conductive layer, with a relatively weak background static magnetic field.

[0068] Comparative Example 1 This comparative study prepared a static magnetic therapy fiber that does not have the function of "adaptive change".

[0069] (S.1) Repeat steps 1-3 of Example 1 to prepare the "Fe3O4 nanowire array / PVDF-TrFE" composite fiber precursor.

[0070] (S.2) Formation of a static conductive / decorative layer: Mix 2 grams of polydimethylsiloxane (PDMS) prepolymer with 0.2 grams of carbon black, stir to remove bubbles, coat the mixture onto the fiber surface, and cure to form a purely conductive encapsulation layer without magnetic additives. This layer serves only a protective function and cannot drive changes in magnetic units.

[0071] (S.3) The fiber is subjected to polarization treatment.

[0072] The final fiber D1 has a fixed Fe3O4 nanowire array inside. The charge generated by the piezoelectric unit cannot drive any controllable change in the state of the magnetic unit through the conductive unit. Therefore, the output magnetic field mode is fixed.

[0073] Comparative Example 2 This comparative example prepares a magnetoelectric therapy fiber that lacks piezoelectric units and relies on an external power source.

[0074] (S.1) Repeat step 1 of Example 1 to prepare Fe3O4 nanowire array and fix it on the surface of flexible polyester filament with insulating adhesive.

[0075] (S.2) The conductive magnetic paste C prepared in step 4 of Example 1 was directly coated onto the surface of the nanowire array and dried.

[0076] (S.3) Encapsulate with an insulating encapsulation layer.

[0077] The resulting fiber D2, lacking piezoelectric units, relies entirely on an external power source to apply current to the conductive units to drive changes in the magnetic field, and does not possess the ability to be self-powered or respond to human movement.

[0078] Comparative Example 3 This comparative example prepares a piezoelectric sensing fiber lacking a magnetic response element.

[0079] (S.1) Uniaxial electrospinning was used, and pure PVDF-TrFE piezoelectric fibers were obtained by spinning using only PVDF-TrFE solution (same as step 2 in Example 1).

[0080] (S.2) The conductive magnetic paste C (containing NdFeB) prepared in step 4 of Example 1 is coated on the surface of the pure piezoelectric fiber, and then dried, encapsulated and polarized.

[0081] The resulting fiber D3 lacks internal magnetic response elements (such as deflectable magnetic nanowire arrays) that can be driven by electrical signals to change their state. The NdFeB micropowder in the conductive layer is fixed in position within the polymer matrix. When the fiber deforms and generates piezoelectric charges, it can only produce a weak induced electromagnetic field superimposed on a essentially unchanging static magnetic field generated by the fixed NdFeB micropowder, making it impossible to achieve dynamic and adaptive changes in the magnetic field mode.

[0082] Examples 1-6 and Comparative Examples 1-3 were tested. To ensure the comparability and objectivity of the test results, all fiber samples (F1-F6, D1-D3) were subjected to the following tests: 1. Mechanical-Electrical Output Performance Test: A 10 cm long fiber sample was fixed at both ends on a micro-displacement control platform, with the middle portion in contact with an arc-shaped mold with an adjustable radius of curvature. The control platform cyclically drove the fiber to bend at fixed frequencies (1 Hz, 3 Hz, 5 Hz) and fixed deformation amplitudes (bending radius of curvature varying from ∞ to 5 mm). The peak open-circuit voltage (Voc) and peak short-circuit current (Isc) generated by the fiber during cyclic bending were measured using a high-resistance voltmeter (KEITHLEY 6514) and a picoammeter (KEITHLEY 6485), respectively, to evaluate its energy harvesting capability.

[0083] 2. Adaptive Response Test in Magnetic Field Mode: The fiber sample was placed flat. A high-precision triaxial magnetometer (sensitivity ≤ 1 μT) probe was fixed at a distance of 2 mm directly above the surface of the fiber sample.

[0084] Static magnetic field test: When the fiber is at rest, record the background static magnetic field strength (B_static) on its surface.

[0085] Dynamic magnetic field response test: Using the same mechanical drive device as in test 1, the fiber was driven to undergo periodic bending at different frequencies (1 Hz, 5 Hz) and a fixed amplitude. A magnetometer continuously recorded the change curve of the magnetic field intensity on the fiber surface over time. By analyzing this curve, the peak intensity (ΔB) of the alternating magnetic field induced by mechanical deformation and the fundamental frequency (f_magnetic) of this alternating magnetic field were extracted. By comparing the consistency between the mechanical drive frequency (f_mech) and the magnetic field change frequency (f_magnetic), as well as the relationship between ΔB and the drive frequency and amplitude, its "adaptive" and "programmable" capabilities were evaluated.

[0086] 3. Functional Integration Verification Test: An integrated testing system was built. Fiber samples were woven into an elastic wristband and worn on the volunteer's wrist. The volunteer sequentially performed three movements: "stationary," "slow walking" (approximately 1 Hz cadence), and "fast running" (approximately 3 Hz cadence). The following signals were simultaneously acquired: a) the piezoelectric voltage signal generated by the fiber (via a wireless Bluetooth module); b) the change signal of the magnetic field strength at a fixed point on the wristband surface (via a portable magnetometer). By analyzing the correspondence between the two signals in the time and frequency domains, it was verified whether the fiber simultaneously achieved both "mechanical energy harvesting (sensing)" and "dynamic magnetic field modulation (therapy)" functions, and whether it automatically switched according to the movement pattern.

[0087] Test Results Summary Table .

[0088] Through system testing of the embodiments and comparative examples in the table above, the following conclusions can be drawn: All embodiments (F1-F6) successfully achieved the core function of "mechanical deformation - generation of electrical signals - adaptive change of driving magnetic field". The test data clearly shows that the frequency of the generated alternating magnetic field (f_magnetic) is completely consistent with the external mechanical driving frequency (f_mech), and the intensity of the magnetic field change (ΔB) increases with the increase of driving mechanical energy (manifested as an increase in frequency or amplitude). Comparative Example 1 (D1) cannot drive the magnetic unit to change because the conductive unit cannot. Although there is a static magnetic field and piezoelectric output, the magnetic field does not change adaptively, proving that the technical feature of "electrical connection of the conductive unit to drive the state change of the magnetic response element" is a necessary condition for achieving self-adaptation. Comparative Example 2 (D2) completely relies on an external power source and does not have the ability to power itself or respond to spontaneous body movement, which in turn proves the necessity and progress of the present invention in using the piezoelectric unit as a built-in driving source. Comparative Example 3 (D3) lacks a movable "magnetic response element," so its magnetic field hardly changes with deformation, and only has a very weak induced electromagnetic field. This contrasts sharply with the significant effect of the embodiment, proving that "the magnetic response element can change its state in response to an electrical signal" is the key to generating an effective and controllable dynamic magnetic field.

[0089] In summary, the test results fully demonstrate the effectiveness and inventiveness of the technical solution of this invention. All embodiments can achieve the expected adaptive magnetoelectric therapy function, while the comparative examples, from the opposite perspective, verify that omitting or replacing key features of this invention will lead to functional failure or degradation. This invention successfully integrates energy harvesting, sensing, and dynamic therapy functions into a single fiber, achieving a leap from passive static therapy to active adaptive therapy.

[0090] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A self-powered flexible magnetoelectric therapy fiber, characterized in that, include: Piezoelectric element, used to generate electrical signals in response to the mechanical deformation of fibers; A magnetic unit includes at least one magnetic response element, which is capable of changing its state in response to an electrical signal; A conductive unit, electrically connected to the piezoelectric unit and the magnetic unit, is used to transmit the electrical signal to the magnetic unit to drive the state change of the magnetic response element; The change in the state of the magnetic response element causes the magnetic field mode output by the fiber to adapt to the mechanical deformation.

2. The self-powered flexible magnetoelectric therapy fiber according to claim 1, characterized in that, The piezoelectric unit includes a piezoelectric polymer film; The magnetic unit comprises an array of magnetic nanowires arranged along the fiber axis; The conductive unit comprises a composite conductive network of two-dimensional materials and carbon nanotubes.

3. The self-powered flexible magnetoelectric therapy fiber according to claim 2, characterized in that, The piezoelectric polymer film is polyvinylidene fluoride or a copolymer thereof; The magnetic nanowire array is iron(II,III) oxide nanowire or composite nanowire loaded with Fe3O4. The two-dimensional material is MXene.

4. The self-powered flexible magnetoelectric therapy fiber according to claim 1, characterized in that, The magnetic unit also includes permanent magnet micropowder, which is dispersed in the conductive unit.

5. The self-powered flexible magnetoelectric therapy fiber according to claim 1, characterized in that, The fiber also includes a flexible encapsulation layer that wraps the piezoelectric unit, magnetic unit, and conductive unit.

6. A method for preparing the self-powered flexible magnetoelectric therapy fiber as described in any one of claims 1-5, characterized in that, Includes the following steps: (S.1) Forming the piezoelectric unit; (S.2) Form the magnetic unit; (S.3) Form the conductive unit; (S.4) Integrate the piezoelectric unit, magnetic unit and conductive unit, so that the conductive unit is electrically connected to the piezoelectric unit and the magnetic unit, so as to realize the adaptive driving of the magnetic response element state change with mechanical deformation.

7. The method according to claim 6, characterized in that, The magnetic unit is formed by constructing a magnetic nanowire array through electrospinning or a template method; Forming the piezoelectric unit includes preparing a piezoelectric polymer film by solution casting or electrospinning; The conductive unit is formed by dispersing two-dimensional materials, carbon nanotubes and permanent magnet powder in a flexible resin to form a composite conductive slurry, and then coating it onto the piezoelectric unit.

8. The method according to claim 7, characterized in that, The permanent magnet powder is neodymium iron boron powder with an insulating layer on its surface.

9. The method according to claim 6, characterized in that, The integration step also includes a step of polarizing the piezoelectric unit.

10. The method according to claim 6, characterized in that, The method achieves multi-layer structure integration through coaxial electrospinning or layer-by-layer assembly processes.