A ptmf hydrogel force-magnetic dual-mode sensor and a preparation method thereof

Abstract

This invention discloses a PTMF hydrogel dual-mode force-magnetic sensor and its fabrication method, belonging to the field of flexible sensor technology. It aims to solve the problem that existing flexible sensors have limited functionality and are unable to simultaneously sense mechanical signals and non-contact magnetic field signals. This invention includes: fabricating MXene (Ti3C2T… x Solid powder; polyvinyl alcohol, dimethyl sulfoxide, and deionized water are mixed in a predetermined mass ratio and heated and stirred. Then, tannic acid, iron(III) oxide, and methylenebisacrylamide are added sequentially and stirred until homogeneous to obtain a composite solution. The prepared MXene (Ti3C2T) powder is then added to the mixture. x Solid powder is added to a composite solution and subjected to freeze-thaw treatment to obtain a PTMF hydrogel. Electrodes are respectively placed on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure. This technical solution has both good mechanical flexibility and electrical conductivity, and can sense mechanical signals by changing resistance caused by external force, and can also induce magnetic induction response by changing magnetic field.

Description

Technical Field

[0001] This invention relates to the field of flexible sensor fabrication technology, and in particular to a PTMF hydrogel force-magnetic dual-mode sensor and its fabrication method. Background Technology

[0002] Currently, most flexible sensors employ the piezoresistive principle, sensing pressure or strain by changing the resistance of a conductive network under external force. However, these sensors are often single-function, responding only to contact-based mechanical signals, and suffer from insufficient sensing dimensions in complex environments. For example, in interactive scenarios requiring simultaneous monitoring of contact pressure and object proximity (characterized by changes in magnetic fields), single-mode sensors are inadequate.

[0003] To expand sensing capabilities, researchers are dedicated to developing force-magnetic dual-mode sensors that can simultaneously sense contact pressure and changes in magnetic fields (e.g., magnetic field disturbances caused by the proximity of a magnetic object). The key to realizing such sensors lies in developing a composite material that combines good flexibility, stable conductivity, and magnetic responsiveness. Existing methods typically introduce conductive fillers (such as MXene and silver nanowires) and magnetic particles (such as Fe3O4) into an elastic polymer matrix, but this still faces the following challenges: First, ensuring the uniform and stable dispersion of conductive fillers and magnetic particles within the polymer matrix, avoiding agglomeration, is fundamental to achieving high-performance sensing. Second, commonly used chemical crosslinking or complex synthesis processes can lead to decreased material flexibility, cumbersome preparation processes, or high costs. Third, how to organically combine conductive network construction, magnetic function integration, and flexible matrix molding through a relatively simple and controllable process remains a problem that needs optimization.

[0004] Therefore, developing a simple fabrication method that can effectively integrate a highly flexible matrix, a high-performance conductive network, and a magnetic response unit to stably achieve high-sensitivity force-magnetic dual-mode sensing has significant practical application value. Summary of the Invention

[0005] The technical problem to be solved and the technical task proposed by this invention is to improve and refine existing technical solutions, and to provide a PTMF hydrogel force-magnetic dual-mode sensor and its preparation method, so as to simplify the process and simultaneously achieve high-sensitivity force-magnetic dual-mode sensing. To this end, this invention adopts the following technical solution.

[0006] In a first aspect, the present invention provides a method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor, the method comprising:

[0007] Preparation of MXene (Ti3C2T) x Solid powder; Polyvinyl alcohol, dimethyl sulfoxide and deionized water were mixed in a predetermined mass ratio and heated and stirred. Then, tannic acid, iron oxide and methylenebisacrylamide were added in sequence and stirred evenly to obtain a composite solution. The prepared MXene (Ti3C2T) x ) Solid powder is added to a composite solution and then subjected to freeze-thaw treatment to obtain PTMF hydrogel; Electrodes are disposed on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure.

[0008] This technical solution utilizes the excellent gelling properties and biocompatibility of polyvinyl alcohol (PVA), the polyphenol bonding and reinforcing ability of tannic acid, the high conductivity and two-dimensional structure of MXene, and the magnetism of iron oxide (Fe3O4) to provide a material basis for realizing force-magnetic dual-mode sensing. The freeze-thaw process avoids complex chemical reactions, better preserves the intrinsic properties of each component, and tends to form a hydrogel with a porous, uniformly interpenetrating network structure. This is beneficial for stress transmission, conductive pathway construction, and magnetic particle dispersion, laying the foundation for high sensitivity and good flexibility of the sensor. Through a solution mixing-freeze-thaw process, the three-way unification of flexible matrix molding, conductive network construction, and magnetic function integration is achieved. The prepared PTMF hydrogel itself is a sensing unit with complete force-magnetic response capabilities, simplifying the subsequent sensor assembly process. This method mainly involves basic operations such as mixing, stirring, and freeze-thaw, which are easy to repeat and scale up. The mild freeze-thaw conditions help protect the functional integrity of MXene and iron oxide. PTMF hydrogel abbreviations: P-polyvinyl alcohol (PVA), T-tannic acid (TA), M-MXene (Ti3C2T) x ), F-Fe3O4, are named by combining the first letters of the above four core components.

[0009] As a preferred technical means: the preparation of MXene (Ti3C2T) x The steps for producing solid powders include: Lithium fluoride was added to a hydrochloric acid solution and stirred to obtain an emulsion solution; Titanium aluminum carbide powder was added to the emulsion solution and stirred, followed by washing and centrifugation to obtain multilayer MXene (Ti3C2T). x )precipitation; The multilayer MXene precipitate was dispersed in deionized water and subjected to ultrasonic treatment, followed by freeze-drying to obtain MXene (Ti3C2T). x Solid powder.

[0010] As a preferred technical means, the mass ratio of titanium aluminum carbide to lithium fluoride is 1:1.5.

[0011] As a preferred technical means: after adding lithium fluoride to the hydrochloric acid solution, the solution is magnetically stirred in a 35°C water bath for 2 hours to form an emulsion solution; and after adding titanium aluminum carbide powder to the emulsion solution, the solution is stirred at 35°C for 40 hours.

[0012] As a preferred technical means: in the composite solution, the mass ratio of polyvinyl alcohol, dimethyl sulfoxide and deionized water is x:6:4, where the value of x ranges from 0.4 to 1.

[0013] As a preferred technical means: in the composite solution, the mass ratio of tannic acid, iron(III) oxide, methylenebisacrylamide and polyvinyl alcohol is 1:y:0.1:1, where the value of y ranges from 0.2 to 0.4.

[0014] As a preferred technical means, the mixed solution of polyvinyl alcohol, dimethyl sulfoxide and deionized water is stirred at 120°C until the polyvinyl alcohol is completely dissolved.

[0015] As a preferred technical means: when preparing PTMF hydrogel, MXene (Ti3C2T) of the composite solution is added. x The mass fraction of the solid powder is 1 wt%.

[0016] As a preferred technical means, the freeze-thaw treatment includes freezing the composite solution containing MXene at -20°C for 10 hours, followed by thawing at room temperature for 2 hours.

[0017] In a second aspect, the present invention provides a PTMF hydrogel force-magnetic dual-mode sensor, which is prepared by the aforementioned method. The sensor comprises: PTMF hydrogel, a first electrode layer, a second electrode layer, a first encapsulation layer, and a second encapsulation layer; wherein the first encapsulation layer, the first electrode layer, the PTMF hydrogel, the second electrode layer, and the second encapsulation layer are stacked sequentially in the vertical direction.

[0018] Beneficial Effects: This invention prepares a novel force-magnetic dual-mode sensing hydrogel by compounding polyvinyl alcohol, tannic acid, MXene, and iron oxide, and then molding it using a freeze-thaw method. This method is simple, operates under mild conditions, and yields a hydrogel with excellent flexibility, conductivity, and magnetic responsiveness, enabling it to simultaneously and with high sensitivity sense pressure and magnetic field signals. Attached Figure Description

[0019] Figure 1 This is a flowchart of the preparation method of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the PTMF hydrogel force-magnetic dual-mode sensor of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] Example 1 like Figure 1 As shown, a method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor is provided, comprising: (1) Preparation of MXene (Ti3C2T) x Solid powder: Lithium fluoride was added to a hydrochloric acid solution and stirred to obtain an emulsion solution; Titanium aluminum carbide powder was added to the emulsion solution and stirred, then washed and centrifuged to obtain multilayer MXene (Ti3C2T). x )precipitation; The multilayer MXene precipitate was dispersed in deionized water and subjected to ultrasonic treatment, followed by freeze-drying to obtain MXene (Ti3C2T). x Solid powder.

[0023] (2) Mix polyvinyl alcohol, dimethyl sulfoxide and deionized water in a predetermined mass ratio and heat and stir. Then add tannic acid, iron oxide and methylenebisacrylamide in sequence and stir until uniform to obtain a composite solution.

[0024] (3) The prepared MXene (Ti3C2T) x Solid powder is added to a composite solution and then subjected to freeze-thaw treatment to obtain PTMF hydrogel.

[0025] (4) Electrodes are set on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure.

[0026] Example 2 A method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor includes: (1) Preparation of MXene (Ti3C2T) x Solid powder; Lithium fluoride (LiF) was added to a hydrochloric acid (HCl) solution and stirred to obtain an emulsion solution. 4.5 g of lithium fluoride (LiF) was dissolved in 100 ml of a 9 mol / L hydrochloric acid (HCl) solution and magnetically stirred in a 35°C water bath for 2 hours until a uniformly dispersed emulsion solution was formed.

[0027] Titanium aluminum carbide (Ti3AlC2) powder was added to an emulsion solution and stirred to obtain MXene (Ti3C2T). x The mixture contained titanium aluminum carbide (Ti3AlC2) and lithium fluoride (LiF) in a mass ratio of 1:1.5. 3g of titanium aluminum carbide (Ti3AlC2) powder was slowly added to the emulsion solution and stirred at 35°C for 40 hours.

[0028] MXene (Ti3C2T) x The mixture was first washed with deionized water and then centrifuged. Through repeated washing and centrifugation, multilayer MXene (Ti3C2T) was obtained. x MXene (Ti3C2T) precipitation. x The mixture was first washed with deionized water and then centrifuged, and the process was repeated 5 times.

[0029] Multilayer MXene (Ti3C2T) x The precipitate disperses in deionized water, forming MXene (Ti3C2T). x MXene (Ti3C2T) dispersion. x The dispersion was subjected to ultrasonic treatment, and then the dispersion was freeze-dried for a period of time to obtain MXene (Ti3C2T). x ) solid powder. MXene (Ti3C2T) x After freeze-drying the dispersion for 24 hours, MXene (Ti3C2T) was obtained. x Solid powder.

[0030] (2) Polyvinyl alcohol (PVA), dimethyl sulfoxide (DMSO), and deionized water were mixed at a mass ratio of x:6:4 and stirred until the PVA was completely dissolved. Then, tannic acid (TA), iron(III) oxide (Fe3O4), and methylenebisacrylamide (MBA) were added sequentially and stirred until homogeneous to obtain a composite solution. The mass ratio of tannic acid (TA), iron(III) oxide (Fe3O4), methylenebisacrylamide (MBA), and polyvinyl alcohol (PVA) was 1:y:0.1:1. The value of y ranged from 0.2 to 0.4, and the value of x ranged from 0.4 to 1.

[0031] (3) MXene (Ti3C2T) x Solid powder is added to deionized water to form MXene (Ti3C2T) x The composite solution was cooled, and then MXene (Ti3C2T) with a mass fraction of 1 wt% was added. x The dispersion was added to the composite solution, and then quickly poured into a mold for freezing. After thawing, PTMF hydrogel was obtained.

[0032] (4) Electrodes are respectively placed on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure.

[0033] Example 3 A method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor includes: (1) Preparation of MXene (Ti3C2T) x Solid powder; (2) Mix polyvinyl alcohol, dimethyl sulfoxide and deionized water in a predetermined mass ratio and heat and stir. Then add tannic acid, iron oxide and methylenebisacrylamide in sequence and stir until uniform to obtain a composite solution.

[0034] (3) The prepared MXene (Ti3C2T) x Solid powder is added to a composite solution and then subjected to freeze-thaw treatment to obtain PTMF hydrogel.

[0035] (4) Cut PTMF hydrogel according to actual needs, and then set an electrode on the upper and lower surfaces of the PTMF hydrogel to obtain a PTMF hydrogel force-magnetic dual-mode sensor, which can simultaneously measure pressure and magnetic field. The size of the electrode is set according to the PTMF hydrogel, and the material of the electrode is selected according to actual needs. For example, cut PTMF hydrogel with a length, width and height of 2cm, 2cm and 0.5cm respectively, and set a copper sheet as an electrode on the upper and lower surfaces of the PTMF hydrogel.

[0036] Example 4 A method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor includes: (1) Preparation of MXene (Ti3C2T) x Solid powder.

[0037] (2) Mix 0.3g polyvinyl alcohol (PVA), 3mL dimethyl sulfoxide (DMSO) and 2mL deionized water at 120°C. o Stirring at C for 3 hours to completely dissolve polyvinyl alcohol (PVA), then adding 0.3g tannic acid (TA), 0.09g iron(III) oxide (Fe3O4), and 0.03g methylenebisacrylamide (MBA) in sequence and stirring until homogeneous to obtain a composite solution.

[0038] (3) After the composite solution has cooled, add 2 ml of MXene (Ti3C2T) with a mass fraction of 1 wt%. x The dispersion was then quickly poured into a mold and frozen at -20°C for 10 hours, followed by thawing at room temperature for 2 hours to obtain PTMF hydrogel.

[0039] (4) Electrodes are set on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure.

[0040] Example 5 A method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor includes: (1) Preparation of MXene (Ti3C2T) x Solid powder.

[0041] (2) Mix 0.2g polyvinyl alcohol (PVA), 3mL dimethyl sulfoxide (DMSO) and 2mL deionized water at 120°C. o Stirring at C for 3 hours to completely dissolve polyvinyl alcohol (PVA), then adding 0.3g tannic acid (TA), 0.06g iron(III) oxide (Fe3O4), and 0.03g methylenebisacrylamide (MBA) in sequence and stirring until homogeneous to obtain a composite solution.

[0042] (3) The prepared MXene (Ti3C2T) x Solid powder is added to a composite solution and then subjected to freeze-thaw treatment to obtain PTMF hydrogel.

[0043] (4) Electrodes are set on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure.

[0044] Example 6 A method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor includes: (1) Preparation of MXene (Ti3C2T) x Solid powder.

[0045] (2) Mix 0.4 g polyvinyl alcohol (PVA), 3 mL dimethyl sulfoxide (DMSO) and 2 mL deionized water at 120 °C. o Stirring at C for 3 hours to completely dissolve polyvinyl alcohol (PVA), then adding 0.3g tannic acid (TA), 0.12g iron(III) oxide (Fe3O4), and 0.03g methylenebisacrylamide (MBA) in sequence and stirring until homogeneous to obtain a composite solution.

[0046] (3) The prepared MXene (Ti3C2T) x Solid powder is added to a composite solution and then subjected to freeze-thaw treatment to obtain PTMF hydrogel.

[0047] (4) Electrodes are set on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure.

[0048] Examples 4-6 use the same operating steps, but different parameters are used to conduct experiments according to the parameter range described in this invention, and sensors with different magnetic field sensing sensitivities are obtained. The following are the corresponding experimental comparison results.

[0049] Comparative Example 1 When x is 0.3g (i.e., 0.3g of polyvinyl alcohol (PVA)) and y is 0.09g (i.e., 0.09g of iron(III) oxide (Fe3O4), the PTMF hydrogel force-magnetic dual-mode sensor has a pressure sensing sensitivity of 0.3kPa within a pressure range of 0-500Pa.-1 Within a magnetic field range of 5-50 mT, the sensitivity of the magnetic field sensor is 0.32 T. -1 .

[0050] Comparative Example 2 When x is 0.2g (i.e., 0.2g of polyvinyl alcohol (PVA)) and y is 0.06g (i.e., 0.06g of iron(III) oxide (Fe3O4), the PTMF hydrogel force-magnetic dual-mode sensor has a pressure sensing sensitivity of 0.18kPa within a pressure range of 0-500Pa. -1 Within a magnetic field range of 5-50 mT, the sensitivity of the magnetic field sensor is 0.25 T. -1 .

[0051] Comparative Example 3 When x is 0.4g (i.e., 0.4g of polyvinyl alcohol (PVA)) and y is 0.12g (i.e., 0.12g of iron(III) oxide (Fe3O4), the PTMF hydrogel force-magnetic dual-mode sensor has a pressure sensing sensitivity of 0.25kPa within a pressure range of 0-500Pa. -1 Within a magnetic field range of 5-50 mT, the sensitivity of the magnetic field sensor is 0.28 T. -1 .

[0052] Example 7 A PTMF hydrogel force-magnetic dual-mode sensor is provided.

[0053] like Figure 2 As shown, a PTMF hydrogel force-magnetic dual-mode sensor includes a PTMF hydrogel 1, a first electrode layer 3, a second electrode layer 4, a first encapsulation layer 2, and a second encapsulation layer 5; the first encapsulation layer 2, the first electrode layer 3, the PTMF hydrogel 1, the second electrode layer 4, and the second encapsulation layer 5 are stacked sequentially in the vertical direction. The PTMF hydrogel is prepared using any of the aforementioned embodiments.

[0054] In this embodiment, both the first electrode layer 3 and the second electrode layer 4 can be metal sheets, such as copper sheets.

[0055] The above are specific embodiments of the present invention, which demonstrate the substantial features and progress of the present invention. Equivalent modifications can be made to them according to actual usage needs, under the guidance of the present invention, and all such modifications are within the scope of protection of this solution.

Claims

1. A method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor, characterized in that: The method includes: Preparation of MXene (Ti3C2T) x Solid powder; Polyvinyl alcohol, dimethyl sulfoxide and deionized water were mixed in a predetermined mass ratio and heated and stirred. Then, tannic acid, iron oxide and methylenebisacrylamide were added in sequence and stirred evenly to obtain a composite solution. The prepared MXene (Ti3C2T) x ) Solid powder is added to a composite solution and then subjected to freeze-thaw treatment to obtain PTMF hydrogel; Electrodes are disposed on the upper and lower surfaces of the PTMF hydrogel to form a sensor structure.

2. The method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor according to claim 1, characterized in that: The preparation of MXene (Ti3C2T) x The steps for producing solid powders include: Lithium fluoride was added to a hydrochloric acid solution and stirred to obtain an emulsion solution; Titanium aluminum carbide powder was added to the emulsion solution and stirred, followed by washing and centrifugation to obtain multilayer MXene (Ti3C2T). x )precipitation; The multilayer MXene precipitate was dispersed in deionized water and subjected to ultrasonic treatment, followed by freeze-drying to obtain MXene (Ti3C2T). x Solid powder.

3. The method for preparing a PTMF hydrogel force-magnetic dual-mode sensor according to claim 2, characterized in that: The mass ratio of titanium aluminum carbide to lithium fluoride is 1:1.

5.

4. The method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor according to claim 2, characterized in that: After lithium fluoride is added to the hydrochloric acid solution, it is magnetically stirred in a 35°C water bath for 2 hours to form an emulsion solution. Furthermore, after adding titanium aluminum carbide powder to the emulsion solution, the mixture is stirred at 35°C for 40 hours.

5. The method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor according to claim 1, characterized in that: In the composite solution, the mass ratio of polyvinyl alcohol, dimethyl sulfoxide, and deionized water is x:6:4, where the value of x ranges from 0.4 to 1.

6. The method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor according to claim 5, characterized in that: In the composite solution, the mass ratio of tannic acid, iron(III) oxide, methylenebisacrylamide, and polyvinyl alcohol is 1:y:0.1:1, where the value of y ranges from 0.2 to 0.

4.

7. The method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor according to claim 5, characterized in that: The mixture of polyvinyl alcohol, dimethyl sulfoxide, and deionized water was stirred at 120°C until the polyvinyl alcohol was completely dissolved.

8. The method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor according to claim 1, characterized in that: When preparing the PTMF hydrogel, MXene (Ti3C2T) of the composite solution was added. x The mass fraction of the solid powder is 1 wt%.

9. The method for fabricating a PTMF hydrogel force-magnetic dual-mode sensor according to claim 1, characterized in that: The freeze-thaw process includes freezing the composite solution containing MXene at -20°C for 10 hours, followed by thawing at room temperature for 2 hours.

10. A PTMF hydrogel force-magnetic dual-mode sensor, characterized in that: The sensor is prepared by any one of the methods described in claims 1 to 9, and comprises: PTMF hydrogel, a first electrode layer, a second electrode layer, a first encapsulation layer, and a second encapsulation layer; wherein the first encapsulation layer, the first electrode layer, the PTMF hydrogel, the second electrode layer, and the second encapsulation layer are stacked sequentially in the vertical direction.

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