Curved multi-mode sensing device and preparation method thereof

Abstract

According to the curved multi-mode sensing device and the preparation method thereof provided by the invention, water molecules existing between sheet layers formed by stacking the elastic sensor substrate supporting layer increase the adhesive force and ductility between films, and the elastic sensor substrate adhesion layer and the elastic sensor substrate supporting layer are connected through a hydrogen bond. The stretchability of the film is improved; that is to say, the curved multi-modal sensing device is obtained by utilizing a curved process induced by interaction force between the waterborne polyurethane (WPU) and the MXene-based two-dimensional material, integration of the multi-modal sensor can be simply and conveniently realized, the complexity of a sensor preparation process flow is greatly reduced, and meanwhile, the production cost is reduced. And the application scene of the curved device can be further expanded, and compared with the traditional process device, 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 multi-modal sensing device and a preparation method thereof. Background Art

[0002] The monitoring of 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 not conformable 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 conformally tested on 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-cutting technology, mainly involving 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 flexible packaging, and then obtaining stretchable and bendable flexible electronic devices for use in the sensing field. Compared with traditional sensing equipment, they generally have the advantages of comfortable wearing and strong conformity.

[0004] In the existing technology, multimodal flexible sensing devices usually use flexible packaging made of hard materials, which can only achieve small-angle bending and cannot be curved for a long time. Because the sensing function module of curved sensor devices must remain in a bent state for a long time, there are generally problems such as low product yield and unstable performance. Therefore, in areas such as the eyes and brain that require curved conformal monitoring, the accuracy and long-term stability of monitoring cannot be guaranteed. Summary of the invention

[0005] In order 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 the accuracy of monitoring and long-term stability.

[0006] A curved multi-modal sensing device, comprising, 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 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;

[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, a finger 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; 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 the solution to obtain an elastic sensor substrate 2 attached to the second flexible encapsulation layer 12 film;

[0020] S5: transferring the glass sheet a to a heating platform and heating it, covering the elastic sensor substrate 2 with a mask having an electrode structure, and spraying a MXene-based conductive material with a spray gun to obtain a sensor electrode functional unit 3;

[0021] S6: dripping a hydrophilic solution of a sensitive material on 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 obtaining a first flexible encapsulation layer 11 thin film after drying;

[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, in which water molecules existing between stacked layers of an elastic sensor substrate support layer increase the adhesion and extensibility between thin films, and the elastic sensor substrate adhesion layer and the elastic sensor substrate support layer are connected by hydrogen bonds, thereby increasing the stretchability of the thin film; that is, 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, which 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, making the cost lower than that of traditional process devices.

[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 due to the fact that the film formed by the stacking of WPU molecules is formed by stacking of two-dimensional sheet material groups. The gaps in the middle are filled with immobile water molecules, which greatly enrich the hydroxyl groups in the WPU film, resulting in stronger hydrogen bond interaction forces. In other words, the present invention utilizes the curved surface process induced by the interaction force between waterborne polyurethane (WPU) and MXene-based two-dimensional materials, and compared with the traditional process, a higher product yield can be obtained, 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 the sensor electrode unit is patterned by a simple mask spraying method, MXene-based two-dimensional materials are used as sensor electrode modules, and after the sensitive material is dripped, the curved multimodal sensing device is prepared by hot pressing molding. Compared with the preparation process of traditional curved wearable sensing devices, the method is simpler and has process compatibility, and can quickly integrate multimodal sensors with different functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of the structure layering of a curved multi-modal sensing device in an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of a functional unit structure of an elastic sensing substrate and a sensor electrode in a curved multi-modal 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 multi-modal sensing device in an embodiment of the present invention;

[0033] Figure 4 It is a process flow diagram of a method for preparing a curved multi-modal sensing device in an embodiment of the present invention (taking an eye-entering curved multi-modal 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 multi-modal sensing device includes, 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 includes, 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 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 through intermolecular interaction forces such as hydrogen bonds, and the lower surface is connected to the elastic sensor substrate support layer 21 through intermolecular interaction forces such as hydrogen bonds, that is, the elastic sensor substrate adhesion layer 22 is located on the surface layer 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, a 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 be used as a sensor or as a supporting layer for a sensitive medium material; the sensor electrode functional unit 3 is composed of MXene-based materials, 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), hydrogel, and the like.

[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 multi-modal sensing device of the present invention is subjected to a mechanism test, with a focus 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 subjected to an X-ray photoelectron spectroscopy test (XPS test), and the results were as follows: Figure 3 As shown. There is a certain interaction force between Ti3C2Tx MXene and waterborne polyurethane (WPU). By deconvolving the XPS graphs of WPU and Ti3C2Tx MXene / WPU for N and O elements, the results show that there is a hydrogen bonding force based on NH and OH between Ti3C2Tx MXene and WPU based on N-Ti static force. This synergistic force has a positive effect on the tight adhesion of Ti3C2Tx MXene nanosheets on the WPU surface, proving the responsive behavior of the conductive layer after strain on the elastic substrate.

[0043] Compared with the film formed by the traditional two-dimensional sheet material solution, the film formed by the waterborne polyurethane (WPU) two-dimensional material solution has better ductility and stretchability. This is due to the fact that the film formed by the stacking of WPU molecules is formed by the stacking of two-dimensional sheet material groups. The gaps in the middle seal the immobile water molecules, which greatly enriches the hydroxyl groups in the WPU film, thus there is a stronger hydrogen bond interaction force. The surface of the WPU film is also due to the strong hydrogen bond interaction between the rich hydroxyl groups and N-rich groups and Ti3C2Tx MXene, which improves the stability and elasticity of the sensor substrate.

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

[0045] S1: spraying a polymer release agent on a clean glass sheet a and heating and drying;

[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 the solution to obtain an elastic sensor substrate 2 attached to the second flexible encapsulation layer 12 film;

[0049] S5: transferring the glass sheet a to a heating platform and heating it, covering the elastic sensor substrate 2 with a mask having an electrode structure, and spraying a MXene-based conductive material 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 obtaining a first flexible encapsulation layer 11 thin film after drying;

[0052] S8: removing the encapsulated integrated film from the glass sheet a, placing it into a mold for hot pressing and molding, and 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 fluorine-containing polymer spray, etc.; the release agent is dried at a temperature of 110-135°C for 5-15 minutes. For example, one implementation of step S1 is: spray a fluorine-containing polymer release agent on a clean glass sheet a and heat and 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), polybutylene adipate-terephthalate (PBAT), etc. At the same time, the rotation speed of the spin coating polymer or hydrogel solution to form a film is 400-3500rpm, and the time is 12-25s. The temperature for drying the second flexible encapsulation layer film is 80-120°C, and the time is 15-45min. For example, one implementation method of step S2 is: spin coating polybutylene adipate-terephthalate (PBAT) solution at 2000rpm on a glass sheet a treated with a release agent for 15s, and heating and drying on a heating table at 170°C for 30min, and obtaining a 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: subjecting the second flexible encapsulation layer 12 film to oxygen plasma treatment for 10 minutes under vacuum conditions to temporarily modify the film surface and improve its hydrophilicity;

[0056] In step S4, the rotation speed of the spin coating polymer solution is 500-2500rpm, and the time is 5-30s. The temperature of the elastic sensor substrate film is 25-66°C, and the time is 15-45min. For example, one implementation of step S4 is: spin coating the aqueous polyurethane solution on the modified second flexible encapsulation layer 12 film at 1500rpm for 10s, and heating and drying at 35°C for 20min, 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: transfer the glass sheet a to the heating platform and heat it at 60°C, cover the mask with the electrode structure on the elastic sensor substrate 2, and spray Ti3T2C 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 a hydrogel solution such as polydimethylsiloxane (PDMS), polybutylene adipate-terephthalate (PBAT), etc. The rotation speed of the spin coating polymer or hydrogel solution to form a thin film is 400-3500rpm, and the time is 12-25s. The temperature for drying the first flexible encapsulation layer film is 80-120°C, and the time is 15-45min. For example, one implementation of step S7 is: spin coating polybutylene adipate-terephthalate (PBAT) solution on the sensor functional unit 3 at 2000rpm for 15s, and heating and drying on a heating table at 170°C for 30min, 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, put it into 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 certainly 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 multi-modal sensing device, characterized in that: It 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); 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 supporting 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 the sheet-like waterborne polyurethane materials and are connected by hydrogen bonds; at the same time, the upper surface of the elastic sensor substrate adhesive 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 supporting layer (21) by hydrogen bonds; The lower surface of the second flexible packaging layer (12) is used to bond to an object to be tested that requires curved conformal monitoring, and the measured signal generated by the object to be tested 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 a host computer through an external wire interface provided on the sensor electrode functional unit (3).

2. A curved multi-modal sensing device as claimed in claim 1, characterized in that: The sensor electrode functional unit (3) is composed of MXene-based materials.

3. A curved multi-modal sensing device as claimed in claim 1, characterized in that: The external wire interface of the sensor electrode functional unit (3) is a serpentine wire electrode, a finger electrode or a bridge electrode.

4. The curved multi-modal sensing device according to claim 1, characterized in that: 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 multi-modal sensing device according to claim 1, characterized in that: The thickness of the elastic sensor substrate adhesion layer (22) is smaller than the thickness of the elastic sensor substrate support layer (21).

6. A curved multi-modal sensing device as claimed in 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 multi-modal sensing device according to claim 1, characterized in that: 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 multi-modal 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 the 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 film to obtain an elastic sensor substrate (2) attached to the second flexible encapsulation layer (12) film; S5: transferring the glass sheet a to a heating table and heating it, covering the elastic sensor substrate (2) with a mask having an electrode structure, and spraying a MXene-based conductive material 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 multi-modal sensing device is completed.

9. The method for preparing a curved multi-modal sensing device according to claim 8, characterized in that: In step S6, the sensitive material hydrophilic solution applied is a photoelectric material, a thermoelectric material or a piezoelectric material.

10. The method for preparing a curved multi-modal sensing device according to claim 8, characterized in that: 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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