A curved multimodal sensing device and its preparation method

Abstract

The present invention provides a curved multimodal sensing device and a preparation method thereof. The water molecules present between the stacked layers of the elastic sensor substrate support layer increase the adhesion and ductility between the films. The elastic sensor substrate adhesion layer and the elastic sensor substrate support layer are connected by hydrogen bonds, which increases the stretchability of the film. In other words, the curved multimodal sensing device of the present invention is obtained by utilizing a curving process induced by the interaction force between waterborne polyurethane (WPU) and MXene-based two-dimensional materials. This can easily realize the integration of multimodal sensors, greatly reduce the complexity of the sensor preparation process, and further expand the application scenarios of curved devices. Compared with traditional process devices, the cost is lower.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible sensors, and in particular relates to a curved multimodal sensing device and a preparation method thereof. Background Art

[0002] Monitoring various physiological signals of the human body plays a very important role in clinical diagnosis and treatment. However, existing equipment such as desktop tonometers and B-ultrasound monitors generally have problems such as high equipment cost and complex operation. In addition, rigid sensor modules are usually unable to be conformed during examinations of the eyes and brain, which not only leads to a poor medical experience for patients, but also inaccurate monitoring results. Therefore, there is an urgent need to develop sensor monitoring equipment that can be conformed to curved surfaces.

[0003] With the continuous breakthroughs in core technologies in the field of flexible electronics, wearable flexible medical devices have gradually entered the front line of clinical diagnosis and treatment, greatly promoting the progress of related equipment. Flexible electronic sensing technology is a cutting-edge cross-disciplinary technology that mainly involves new materials (including two-dimensional semiconductor materials, new organic materials, etc.), new processes (such as 3D printing processes, face-to-face water transfer processes, etc.), and new systems (such as MEMS systems, etc.). It is achieved by making traditional rigid electronic modules flexible or performing flexible packaging to obtain stretchable and bendable flexible electronic devices for use in the sensing field. Compared with traditional sensing equipment, they generally have advantages such as wearing comfort and strong conformability.

[0004] Existing multimodal flexible sensing devices typically utilize flexible packaging made of rigid materials, which only allows for small-angle bending and is unable to maintain a curved conformal state for extended periods. Because the sensing module in curved sensing devices must remain bent for extended periods, they often suffer from low product yields and unstable performance. Consequently, in areas requiring curved conformal monitoring, such as the eye and brain, monitoring accuracy and long-term stability cannot be guaranteed. Summary of the Invention

[0005] To solve the above problems, the present invention provides a curved multimodal sensing device and a preparation method thereof, which has good ductility and stretchability, and can ensure monitoring accuracy and long-term stability.

[0006] A curved multimodal sensing device comprises, from top to bottom, a first flexible packaging layer 11, a sensor electrode functional unit 3, an elastic sensor substrate 2, and a second flexible packaging layer 12; wherein the elastic sensor substrate 2 comprises, from top to bottom, an elastic sensor substrate adhesion layer 22 and an elastic sensor substrate support layer 21;

[0007] The first flexible encapsulation layer 11 and the second flexible encapsulation layer 12 are used to encapsulate the sensor electrode functional unit 3 and the elastic sensor substrate 2; the elastic sensor substrate 2 is used to support the sensor electrode functional unit 3, wherein the elastic sensor substrate support layer 21 is an elastic film formed by stacking multiple layers of sheet-like water-based polyurethane material, and water molecules exist between each layer of the sheet-like water-based polyurethane material and are connected by hydrogen bonds; at the same time, the upper surface of the elastic sensor substrate adhesion layer 22 is connected to the supporting sensor electrode functional unit 3 through hydrogen bonds, and the lower surface is connected to the elastic sensor substrate support layer 21 through hydrogen bonds;

[0008] The lower surface of the second flexible packaging layer 12 is used to bond to the object under test that requires curved conformal monitoring. The measured signal generated by the object under test is transmitted to the sensor electrode functional unit 3 through the second flexible packaging layer 12 and the elastic sensor substrate 2, and is led out to the host computer through the external wire interface set on the sensor electrode functional unit 3.

[0009] Furthermore, the sensor electrode functional unit 3 is made of MXene-based materials.

[0010] Furthermore, the external wire interface of the sensor electrode functional unit 3 is a serpentine wire electrode, an interdigitated electrode or a bridge electrode.

[0011] Furthermore, the material of the first flexible encapsulation layer 11 and the second flexible encapsulation layer 12 is polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT) or hydrogel.

[0012] Furthermore, the thickness of the elastic sensor substrate adhesion layer 22 is smaller than the thickness of the elastic sensor substrate support layer 21 .

[0013] Furthermore, the thickness of the elastic sensor substrate adhesion layer 22 is 100 to 500 nm; and the thickness of the elastic sensor substrate support layer 21 is 1500 to 5000 nm.

[0014] Furthermore, the elastic sensor substrate adhesion layer 22 and the elastic sensor substrate support layer 21 are integrally formed.

[0015] A method for preparing a curved multimodal sensing device comprises the following steps:

[0016] S1: spraying a polymer release agent on a glass sheet a and heating and drying;

[0017] S2: Spin-coating a polymer or hydrogel solution on the glass sheet a treated with a release agent, and obtaining a second flexible encapsulation layer 12 thin film after drying;

[0018] S3: treating the second flexible encapsulation layer 12 film with oxygen plasma to temporarily modify the film surface and improve its hydrophilicity;

[0019] S4: spin-coating an aqueous polyurethane solution on the modified second flexible encapsulation layer 12 film and heating and drying it to obtain an elastic sensor substrate 2 attached to the second flexible encapsulation layer 12 film;

[0020] S5: The glass sheet a is transferred to a heating platform and heated, a mask with an electrode structure is covered on the elastic sensor substrate 2, and a MXene-based conductive material is sprayed with a spray gun to obtain a sensor electrode functional unit 3;

[0021] S6: dripping a hydrophilic solution of a sensitive material onto the sensor electrode functional unit 3, wherein different hydrophilic solutions of sensitive materials correspond to different sensing properties;

[0022] S7: Spin-coating a polymer or hydrogel solution on the sensor electrode functional unit 3, and drying to obtain a first flexible encapsulation layer 11 thin film;

[0023] S8: The packaged integrated film is removed from the glass sheet a, placed in a mold for hot pressing and molding, and the preparation of the curved multimodal sensing device is completed.

[0024] Furthermore, in step S6, the hydrophilic solution of the sensitive material to be drop-coated is a photoelectric material, a thermoelectric material or a piezoelectric material.

[0025] Furthermore, in step S2 and step S7, the spin coating solution is polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT) or a hydrogel solution.

[0026] Beneficial effects:

[0027] 1. The present invention provides a curved multimodal sensing device. The water molecules present between the stacked layers of the elastic sensor substrate support layer increase the adhesion and ductility between the films. The elastic sensor substrate adhesion layer and the elastic sensor substrate support layer are connected by hydrogen bonds, which increases the stretchability of the film. In other words, the curved multimodal sensing device of the present invention is obtained by using a curvature process induced by the interaction force between waterborne polyurethane (WPU) and MXene-based two-dimensional materials. This can easily realize the integration of multimodal sensors, greatly reduce the complexity of the sensor preparation process, and further expand the application scenarios of curved devices. Compared with traditional process devices, the cost is lower.

[0028] 2. The present invention provides a method for preparing a curved multimodal sensing device. The elastic sensor substrate formed by a waterborne polyurethane (WPU) two-dimensional material solution has better ductility and stretchability. This is because the film formed by the stacking of WPU molecules is formed by stacking two-dimensional sheet material groups. The gaps in the middle are filled with immobile water molecules, which greatly enriches the hydroxyl groups in the WPU film, resulting in stronger hydrogen bond interaction forces. In other words, the curved surface process induced by the interaction force between waterborne polyurethane (WPU) and MXene-based two-dimensional materials can achieve a higher product yield compared with traditional processes, and the prepared sensor has better long-term stability.

[0029] 3. The present invention provides a method for preparing a curved multimodal sensing device, in which sensor electrode units are patterned by a simple mask spraying method, MXene-based two-dimensional materials are used as sensor electrode modules, and after the sensitive material is drop-coated, the curved multimodal sensing device is prepared by hot pressing. Compared with the preparation process of traditional curved wearable sensing devices, this method is simpler and more process-compatible, and can quickly integrate multimodal sensors with different functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 1 is a schematic diagram of the structure layering of a curved multimodal sensing device according to an embodiment of the present invention;

[0031] Figure 2 Schematic diagram of the functional unit structure of an elastic sensing substrate and sensor electrodes in a curved multimodal sensing device according to an embodiment of the present invention;

[0032] Figure 3 This is an XPS test result diagram of the interaction force between the elastic sensing substrate and the sensor electrode functional unit in a curved multimodal sensing device according to an embodiment of the present invention;

[0033] Figure 4 1 is a schematic diagram of a process flow of a method for preparing a curved multimodal sensing device in an embodiment of the present invention (taking an eye-entering curved multimodal sensing device as an example). DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0035] like Figure 1As shown, a curved multimodal sensing device comprises, from top to bottom, a first flexible packaging layer 11, a sensor electrode functional unit 3, an elastic sensor substrate 2, and a second flexible packaging layer 12; wherein the elastic sensor substrate 2 comprises, from top to bottom, an integrally formed elastic sensor substrate adhesion layer 22 and an elastic sensor substrate support layer 21;

[0036] The first flexible encapsulation layer 11 and the second flexible encapsulation layer 12 are used to encapsulate the sensor electrode functional unit 3 and the elastic sensor substrate 2, that is, the elastic sensor substrate support layer 21, the elastic sensor substrate adhesion layer 22, and the sensor electrode functional unit 3 are located between the second flexible encapsulation layer 12 and the first flexible encapsulation layer 11; the elastic sensor substrate 2 is used to support the sensor electrode functional unit 3, wherein, Figure 2 As shown, the elastic sensor substrate support layer 21 is an elastic film formed by stacking multiple layers of sheet-like waterborne polyurethane (WPU) materials, and water molecules exist between the layers of sheet-like waterborne polyurethane materials and are connected by hydrogen bonds. At the same time, the upper surface of the elastic sensor substrate adhesion layer 22 is connected to the supporting sensor electrode functional unit 3 through intermolecular interactions such as hydrogen bonds, and the lower surface is connected to the elastic sensor substrate support layer 21 through intermolecular interactions such as hydrogen bonds. That is, the elastic sensor substrate adhesion layer 22 is located on the surface above the elastic sensor substrate support layer 21.

[0037] The lower surface of the second flexible packaging layer 12 is used to bond to the object under test that requires curved conformal monitoring. The measured signal generated by the object under test is transmitted to the sensor electrode functional unit 3 through the second flexible packaging layer 12 and the elastic sensor substrate 2, and is led out to the host computer through the external wire interface set on the sensor electrode functional unit 3; wherein, the shape of the external wire interface includes but is not limited to a serpentine wire electrode, an interdigitated finger electrode, a bridge electrode, etc.

[0038] It should be noted that the sensor electrode functional unit 3 is a resistive electrode, which itself can serve as a sensor or as a supporting layer for a sensitive dielectric material; the sensor electrode functional unit 3 is composed of a MXene-based material, including but not limited to Ti3T2Cx MXene, Mo2TiC2 MXene, etc.; the sensor electrode functional unit 3 is located on the elastic sensor substrate 2, that is, the elastic sensor substrate 2 is used to support the sensor electrode functional unit 3.

[0039] The materials used for the second flexible encapsulation layer 12 and the first flexible encapsulation layer 13 include, but are not limited to, polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT), and hydrogel.

[0040] The thickness of the elastic sensor substrate adhesion layer 22 is less than the thickness of the elastic sensor substrate support layer 21; the thickness of the elastic sensor substrate adhesion layer 22 is 100 to 500 nm; the thickness of the elastic sensor substrate support layer 21 is 1500 to 5000 nm; the thickness of the curved multimodal sensing device is 100 to 2500 μm.

[0041] The curved multimodal sensing device of the present invention was subjected to a mechanism test, focusing on detecting the interaction force relationship between the elastic sensor substrate support layer 21 and the elastic sensor substrate adhesion layer 22 and between the elastic sensor substrate adhesion layer 22 and the sensor electrode functional unit 3 .

[0042] The contact layer was tested by X-ray photoelectron spectroscopy (XPS test), and the results were as follows: Figure 3 As shown in Figure 3, a certain interaction force exists between Ti3C2Tx MXene and waterborne polyurethane (WPU). Deconvolution of the XPS spectra of N and O elements in WPU and Ti3C2Tx MXene / WPU revealed the presence of hydrogen bonding forces based on NH and OH between Ti3C2Tx MXene and WPU, which is based on N-Ti static forces. This synergistic force positively influences the tight adhesion of Ti3C2Tx MXene nanosheets to the WPU surface, demonstrating the responsive behavior of the conductive layer after strain on the elastic substrate.

[0043] Compared to films formed from traditional two-dimensional sheet-like material solutions, films formed from waterborne polyurethane (WPU) two-dimensional material solutions exhibit superior ductility and stretchability. This is due to the fact that films formed from stacked two-dimensional sheet-like material groups are formed by stacking WPU molecules. The interstices between them contain immobile water molecules, which greatly enrich the hydroxyl groups in the WPU film and thus create stronger hydrogen bonding interactions. The surface layer of the WPU film also exhibits strong hydrogen bonding interactions with the Ti3C2Tx MXene due to the abundant hydroxyl and N-rich groups, which enhances the stability and elasticity of the sensor substrate.

[0044] Furthermore, the present invention provides a method for preparing a curved multimodal sensing device, such as Figure 4 As shown, the following steps are included:

[0045] S1: Spray a polymer release agent onto a clean glass sheet a and heat dry it;

[0046] S2: Spin-coating a polymer or hydrogel solution on the glass sheet a treated with a release agent, and obtaining a second flexible encapsulation layer 12 thin film after drying;

[0047] S3: treating the second flexible encapsulation layer 12 film with oxygen plasma to temporarily modify the film surface and improve its hydrophilicity;

[0048] S4: spin-coating an aqueous polyurethane solution on the modified second flexible encapsulation layer 12 film and heating and drying it to obtain an elastic sensor substrate 2 attached to the second flexible encapsulation layer 12 film;

[0049] S5: The glass sheet a is transferred to a heating platform and heated, a mask with an electrode structure is covered on the elastic sensor substrate 2, and a MXene-based conductive material is sprayed with a spray gun to obtain a sensor electrode functional unit 3;

[0050] S6: dripping other sensitive material hydrophilic solutions on the sensor functional unit 3 to obtain functional modules with different sensing performances;

[0051] S7: Spin-coating a polymer or hydrogel solution on the sensor functional unit 3, and drying to obtain a first flexible encapsulation layer 11 thin film;

[0052] S8: removing the encapsulated integrated film from the glass sheet a, placing it into a mold for hot pressing and molding, thereby completing the preparation of a contact lens-type intraocular pressure monitoring device with adjustable sensitivity;

[0053] In step S1, the polymer release agent sprayed is a polysiloxane spray, a fluoropolymer spray, or the like; the release agent is dried at a temperature of 110-135°C for 5-15 minutes. For example, one implementation of step S1 is to spray a fluoropolymer release agent onto a clean glass sheet a and heat-dry it at 120°C for 20 minutes to obtain a dense protective layer.

[0054] In step S2, the spin coating solution is a polymer solution or hydrogel solution such as polydimethylsiloxane (PDMS) or polybutylene adipate terephthalate (PBAT). At the same time, the rotation speed of the spin coating polymer or hydrogel solution to form a film is 400-3500 rpm, and the time is 12-25 seconds. The temperature for drying the second flexible encapsulation layer film is 80-120°C, and the time is 15-45 minutes. For example, one implementation method of step S2 is: spin coating polybutylene adipate terephthalate (PBAT) solution on glass sheet a treated with a release agent at 2000 rpm for 15 seconds, and heating and drying on a heating table at 170°C for 30 minutes to obtain the first flexible encapsulation layer 11 film after drying.

[0055] In step S3, the oxygen plasma treatment is performed under vacuum conditions for 5-20 minutes. For example, one implementation of step S3 is as follows: the second flexible encapsulation layer 12 film is subjected to oxygen plasma treatment under vacuum conditions for 10 minutes to temporarily modify the film surface and improve its hydrophilicity;

[0056] In step S4, the polymer solution is spin-coated at a speed of 500-2500 rpm for 5-30 seconds. The elastic sensor substrate film is dried at a temperature of 25-66°C for 15-45 minutes. For example, one implementation of step S4 is as follows: the aqueous polyurethane solution is spin-coated at 1500 rpm for 10 seconds on the modified second flexible encapsulation layer 12 film, and then heated and dried at 35°C for 20 minutes to obtain the elastic sensor substrate 2 attached to the second flexible encapsulation layer 12 film.

[0057] In step S5, when spraying the functional material, the glass sheet should be placed on a heating platform at a temperature of 55-85°C, and the distance between the spray gun and the glass sheet should be 20-40 cm. For example, one implementation of step S5 is as follows: the glass sheet a is transferred to the heating platform and heated at 60°C, a mask with an electrode structure is covered on the elastic sensor substrate 2, and Ti3T2C is sprayed with a spray gun. x MXene conductive material, to obtain sensor electrode functional unit 3;

[0058] In step S6, the sensitive materials to be drop-coated include but are not limited to optoelectronic materials (such as aqueous perovskite solutions, etc.), thermoelectric materials, piezoelectric materials, etc.

[0059] In step S7, the spin coating solution is a polymer solution or hydrogel solution such as polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT). The rotation speed of the spin coating polymer or hydrogel solution to form a thin film is 400-3500 rpm, and the time is 12-25 seconds. The temperature for drying the first flexible encapsulation layer film is 80-120°C, and the time is 15-45 minutes. For example, one implementation of step S7 is: spin coating polybutylene adipate-terephthalate (PBAT) solution on the sensor functional unit 3 at 2000 rpm for 15 seconds, and heating and drying on a heating table at 170°C for 30 minutes, and obtaining the first flexible encapsulation layer 11 film after drying;

[0060] In step S8, the curvature of the hot pressing molding is 8mm-2500mm, including but not limited to the commonly used curvatures of 8.4mm, 8.6mm, 8.8mm and 9.0mm for the eye-into-type curved multimodal sensing device, and the commonly used curvatures of 1000mm, 1500mm, 2000mm and 2500mm for the brain-computer interface type curved multimodal sensing device. In step S8, the temperature of the hot pressing molding is 115-190°C, and the time is 25-45min. For example, one implementation method of step S8 is: remove the encapsulated integrated film from the glass sheet a, place it in a hot pressing mold with a curvature of 8.8mm for hot pressing molding, and hot press in a 160°C oven for 25min to complete the preparation of the curved multimodal sensing device.

[0061] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may of course make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A curved multimodal sensing device, characterized in that: From top to bottom, it comprises a first flexible packaging layer (11), a sensor electrode functional unit (3), an elastic sensor substrate (2), and a second flexible packaging layer (12); wherein the elastic sensor substrate (2) comprises, from top to bottom, an elastic sensor substrate adhesion layer (22) and an elastic sensor substrate support layer (21); The first flexible encapsulation layer (11) and the second flexible encapsulation layer (12) are used to encapsulate the sensor electrode functional unit (3) and the elastic sensor substrate (2); the elastic sensor substrate (2) is used to support the sensor electrode functional unit (3), wherein the elastic sensor substrate support layer (21) is an elastic film formed by stacking multiple layers of sheet-like waterborne polyurethane materials, and water molecules exist between each layer of sheet-like waterborne polyurethane materials and are connected by hydrogen bonds; at the same time, the upper surface of the elastic sensor substrate adhesion layer (22) is connected to the supporting sensor electrode functional unit (3) by hydrogen bonds, and the lower surface is connected to the elastic sensor substrate support layer (21) by hydrogen bonds; The lower surface of the second flexible packaging layer (12) is used to be bonded to a test object requiring curved conformal monitoring, and a test signal generated by the test object is transmitted to the sensor electrode functional unit (3) through the second flexible packaging layer (12) and the elastic sensor substrate (2), and is then led out to a host computer through an external wire interface provided on the sensor electrode functional unit (3).

2. The curved multimodal sensing device according to claim 1, wherein: The sensor electrode functional unit (3) is composed of MXene-based materials.

3. The curved multimodal sensing device according to claim 1, wherein: The external wire interface of the sensor electrode functional unit (3) is a serpentine wire electrode, an interdigitated electrode or a bridge electrode.

4. The curved multimodal sensing device according to claim 1, wherein: The materials of the first flexible encapsulation layer (11) and the second flexible encapsulation layer (12) are polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT) or hydrogel.

5. The curved multimodal sensing device according to claim 1, wherein: The thickness of the elastic sensor substrate adhesion layer (22) is smaller than the thickness of the elastic sensor substrate support layer (21).

6. The curved multimodal sensing device according to claim 5, characterized in that: The thickness of the elastic sensor substrate adhesion layer (22) is 100 to 500 nm; the thickness of the elastic sensor substrate support layer (21) is 1500 to 5000 nm.

7. The curved multimodal sensing device according to claim 1, wherein: The elastic sensor substrate adhesion layer (22) and the elastic sensor substrate support layer (21) are integrally formed.

8. A method for preparing a curved multimodal sensing device, characterized in that: The following steps are involved: S1: spraying a polymer release agent on a glass sheet a and heating and drying; S2: spin coating a polymer or hydrogel solution on a glass sheet a treated with a release agent, and obtaining a second flexible encapsulation layer (12) film after drying; S3: treating the second flexible encapsulation layer (12) film with oxygen plasma to temporarily modify the film surface to improve its hydrophilicity; S4: spin-coating an aqueous polyurethane solution on the modified second flexible encapsulation layer (12) film and heating and drying the solution to obtain an elastic sensor substrate (2) attached to the second flexible encapsulation layer (12) film; S5: The glass sheet a is transferred to a heating table and heated, a mask having an electrode structure is covered on the elastic sensor substrate (2), and a MXene-based conductive material is sprayed with a spray gun to obtain a sensor electrode functional unit (3); S6: dripping a hydrophilic solution of a sensitive material onto the sensor electrode functional unit (3), wherein different hydrophilic solutions of sensitive materials correspond to different sensing properties; S7: Spin-coating a polymer or hydrogel solution on the sensor electrode functional unit (3), and obtaining a first flexible encapsulation layer (11) thin film after drying; S8: The packaged integrated film is removed from the glass sheet a, placed in a mold for hot pressing and molding, and the preparation of the curved multimodal sensing device is completed.

9. The method for preparing a curved multimodal sensing device according to claim 8, wherein: In step S6, the hydrophilic solution of the sensitive material to be drop-coated is a photoelectric material, a thermoelectric material or a piezoelectric material.

10. The method for preparing a curved multimodal sensing device according to claim 8, wherein: In step S2 and step S7, the spin coating solution is polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT), or a hydrogel solution.

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