A flexible pressure sensor based on PDMS and a preparation method thereof

Abstract

The application relates to the technical field of pressure sensors, in particular to a flexible pressure sensor based on PDMS and a preparation method thereof, the flexible pressure sensor based on PDMS comprises a flexible substrate, a bottom electrode and a top electrode arranged from bottom to top, and further comprises a PDMS dielectric layer, the PDMS dielectric layer is composed of two pieces of PDMS films with different surface microstructures, and the PDMS dielectric layer is located between the bottom electrode and the top electrode or on both sides. On one hand, the method can one-time prepare two pieces of PDMS with complementary surface microstructures based on petal templates, effectively increases the contact and deformation of the PDMS microstructure, and improves the sensitivity of the pressure sensor; on the other hand, a plurality of low-cost molds are arranged in a specific manner, a PDMS with a series of microstructures and a large size can be obtained, and various applications of the PDMS capacitive pressure sensor or the PDMS resistance pressure sensor with different sizes and microstructures in different scenes can be realized.

Description

Technical Field

[0001] This invention relates to the field of pressure sensor technology, and in particular to a flexible pressure sensor based on PDMS and its fabrication method. Background Technology

[0002] Flexible pressure sensors can not only convert pressure or stress into specific electrical signals (such as voltage, current, capacitance, or resistance) to achieve pressure detection, but also have the characteristics of being lightweight, thin, flexible, stretchable, highly sensitive, and wearable. They have broad application prospects in fields such as human-computer interaction systems, electronic skin, medical and health care, smart homes, and environmental monitoring.

[0003] PDMS (Polydimethylsiloxane) is the most commonly used dielectric layer material in flexible pressure sensors, possessing excellent tensile strength, insulation, and transparency. Due to the limited deformation range of planar PDMS structures, it is often necessary to design and fabricate PDMS with special microstructures to improve the sensitivity of flexible pressure sensors, such as strip structures, pyramid structures, cylindrical and hemispherical structures, etc.

[0004] However, current common PDMS surface structures are mainly created by casting using different templates or molds, such as sandpaper templates, 3D printed templates, and specific photolithographic templates to construct a single surface microstructure. These methods can only produce a single surface structure and are insufficient to meet the flexible application needs in different situations. For example, sandpaper templates are relatively inexpensive and can be used for large-area PDMS fabrication, but the surface microstructures are irregular and prone to introducing impurities; while 3D printed templates and specific photolithographic templates can achieve various surface microstructure designs, the manufacturing process of fine templates is relatively complex, and large-area fine templates are even more expensive. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a flexible pressure sensor based on PDMS and its fabrication method.

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

[0007] A flexible pressure sensor based on PDMS includes a flexible substrate, a bottom electrode, and a top electrode arranged from bottom to top, and also includes a PDMS dielectric layer. The PDMS dielectric layer is composed of two PDMS films with different surface microstructures and is located between or on both sides of the bottom electrode and the top electrode.

[0008] Preferably, when the PDMS dielectric layer is located between the bottom electrode and the top electrode, the side of the PDMS film with the surface microstructure corresponds to the bottom electrode; when the PDMS dielectric layer is located on both sides of the bottom electrode and the top electrode, the surface microstructure of one PDMS film is attached to the bottom electrode, and the surface microstructure of the other PDMS film is attached to the top electrode.

[0009] Preferably, a protective layer is provided at the upper end of the top electrode.

[0010] Preferably, a method for fabricating a flexible pressure sensor based on PDMS includes the following steps:

[0011] S1: Prepare two templates with different surface microstructures: template 1 and template 2;

[0012] S2: Mix the base polymer and curing agent for preparing the PDMS solution at a mass ratio of 10-12:1 to prepare a bubble-free PDMS solution;

[0013] S3: Place the templates 1 and 2 prepared in S1 into the molding tank and spray a layer of silicone oil release agent; pour the PDMS solution into the molding tank so that the PDMS solution covers the templates 1 and 2, heat and cure at 50-65℃, and then let it stand at room temperature.

[0014] S4: Remove the cured PDMS film from the molding tank, and remove template 1 and template 2; clean and dry the PDMS film to obtain PDMS films with different surface microstructures;

[0015] S5: Cut the PDMS film obtained in S4 to obtain two PDMS films of the same size but with different surface microstructures, namely PDMSⅠ corresponding to template 1 and PDMSⅡ corresponding to template 2.

[0016] S6: Attach PDMSⅠ to the bottom electrode;

[0017] S7: Attach PDMSⅡ to the top electrode;

[0018] S8: Assemble the top electrode and bottom electrode obtained in S6 and S7 to form a flexible pressure sensor, wherein the side of PDMSⅠ with surface microstructure corresponds to the side of PDMSⅡ with surface microstructure.

[0019] Preferably, in step S1, plant petals are used to prepare template 1 and template 2.

[0020] Preferably, the plant petals are one of the following: rose petals, Chinese rose petals, peony petals, peach blossom petals, and cherry blossom petals.

[0021] Preferably, in step S1, the specific steps for preparing two templates with different surface microstructures are as follows: placing cleaned plant petals between two flat glass plates, applying a pressure of 8-20N to flatten them, using the petals with raised structures as template 1, spraying a layer of release agent on the surface of template 1; pouring a PVA solution with a mass fraction of 14%-18% onto template 1, and then heating and curing to obtain template 2 with a surface structure complementary to that of template 1.

[0022] Preferably, in step S1, after the plant petals are flattened, they are cut into regular shapes to obtain template 1.

[0023] Preferably, the thickness of template 2 is close to the thickness of template 1.

[0024] Preferably, in step S2, the curing agent is one of the following: anhydride curing agent, isocyanate, or silane coupling agent. After the base polymer and the curing agent are mixed, ultrasonic treatment is performed for 10-30 minutes.

[0025] The beneficial effects of this invention are as follows: Firstly, this method can prepare two complementary PDMS surface microstructures in a single process using a petal template, effectively increasing the contact and deformation of the PDMS microstructures and improving the sensitivity of the pressure sensor. Secondly, by arranging multiple low-cost molds in a specific manner, large-size PDMS with a series of microstructures can also be obtained, enabling various applications of capacitive or resistive pressure sensors based on PDMS of different sizes and microstructures in different scenarios. This preparation method not only allows for the simultaneous preparation of PDMS films with two different structures, effectively improving mold design, efficiency, and flexibility, and reducing PDMS manufacturing costs, but also meets the requirements of different applications for PDMS structure and size, making it particularly suitable for flexible pressure sensors or other flexible wearable devices based on PDMS. Attached Figure Description

[0026] Figure 1 This is the fabrication process in Example 1 of the flexible pressure sensor based on PDMS proposed in this invention;

[0027] Figure 2 This is a schematic diagram of the template 1, template 2, and their corresponding PDMSⅠ and PDMSⅡ used in the fabrication process of a flexible pressure sensor based on PDMS proposed in this invention;

[0028] Figure 3 This is a schematic diagram of the structure of a flexible pressure sensor based on PDMS proposed in this invention;

[0029] Figure 4The images show microscopic images of two different PDMS membrane surface microstructures in a flexible pressure sensor based on PDMS proposed in this invention. The scale bar in the images is 50 micrometers.

[0030] In the figure: 1 Flexible substrate, 2 Protective layer, 3 Bottom electrode, 4 Top electrode, 5 PDMSⅠ, 6 PDMSⅡ. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0032] Reference Figure 1-4 A flexible pressure sensor based on PDMS includes a flexible substrate 1, a bottom electrode 3, and a top electrode 4 arranged from bottom to top, and also includes a PDMS dielectric layer. The PDMS dielectric layer is composed of two PDMS films with different surface microstructures. The PDMS dielectric layer is located between or on both sides of the bottom electrode and the top electrode. When the PDMS dielectric layer is located between the bottom electrode and the top electrode, the side of the PDMS film with the surface microstructure corresponds to the bottom electrode. When the PDMS dielectric layer is located on both sides of the bottom electrode and the top electrode, the surface microstructure of one PDMS film is attached to the bottom electrode, and the surface microstructure of the other PDMS film is attached to the top electrode. A protective layer 2 is provided at the upper end of the top electrode.

[0033] Example 1:

[0034] A flexible pressure sensor structure based on PDMS comprises a flexible substrate 1, a bottom electrode 3, a middle PDMS dielectric layer, a top electrode 4, and a protective layer 2. The middle PDMS dielectric layer consists of two PDMS layers, PDMSⅠ5 and PDMSⅡ6. One surface of PDMSⅡ6 has a regular protrusion structure similar to the surface of a rose, while one surface of PDMSⅠ has a recessed microstructure complementary to that of PDMSⅡ. The specific fabrication method includes the following steps:

[0035] S1: Prepare templates 1 and 2 with different surface microstructures: Place clean rose petals between two flat glass plates and flatten them by applying 10N pressure. Use the petals with relatively regular raised structures as template 1. Spray a layer of release agent on the surface of the petal template 1. Pour a 15% PVA (polyvinyl alcohol) solution onto template 1 and then heat to cure it to obtain a PVA template 2 with a surface structure complementary to that of the petal template 1. The thickness of the PVA template 2 is close to the thickness of the petal template 1. Alternatively, lotus petals, peach petals, or cherry blossom petals can be used as template 1.

[0036] S2: Preparation of PDMS solution: The two precursor materials of PDMS (basic polymer component and curing agent, the curing agent is an acid anhydride curing agent) are mixed in a mass ratio of 12:1. After stirring for ten minutes, the solution is placed in an ultrasonic cleaner to remove air bubbles, and then left to stand for ten minutes.

[0037] S3: Place petal template 1 and PVA template 2 in a polytetrafluoroethylene molding tank and spray a layer of release agent on their surface; pour the PDMS solution after S2 has been allowed to stand into the molding tank onto petal template 1 and PVA template 2, and heat the poured PDMS in a 50-65℃ oven for 1 hour; the thickness of the PDMS can be adjusted by the amount of PDMS liquid poured in.

[0038] S4: After standing at room temperature for 24 hours, the PDMS with the template is turned over in the PTFE molding tank and poured out. Then, the petal template 1 and PVA template 2 are removed respectively. The PDMS is cleaned and dried to obtain a PDMS film with two complementary microstructures on the surface.

[0039] S5: The PDMS obtained in S4 was observed under a microscope and then cut from the region between the two different microstructures to obtain PDMSⅠ5 and PDMSⅡ6, which are complementary to the surface structures of petal template 1 and PVA template 2, respectively.

[0040] S6: Place PDMSⅠ5 on the bottom electrode 3 with a flexible substrate 1, wherein the side of PDMSⅠ5 without surface microstructure is attached to the bottom electrode 3; and attach the flat side of PDMSⅡ6 to the top electrode 4 on the protective layer.

[0041] S7: Assemble the PDMS with electrodes in S5 and S6, with the side of PDMSⅠ5 with microstructure corresponding to the side of PDMSⅡ6 with microstructure, to obtain a capacitive flexible pressure sensor based on PDMS.

[0042] Example 2:

[0043] A flexible pressure sensor structure based on PDMS comprises a flexible substrate 1, a bottom electrode 3, a middle PDMS dielectric layer, a top electrode 4, and a protective layer 2. The middle PDMS dielectric layer consists of two PDMS layers, PDMS I5 and PDMS II6. One surface of PDMS II6 has a series of protrusions and depressions, and one surface of PDMS I5 has a microstructure complementary to that of PDMS II6. The specific fabrication method includes the following steps:

[0044] S1: Prepare templates 1 and 2 with different surface microstructures: Place clean rose petals between two flat glass plates and flatten them by applying 8N pressure. Use the petals with raised microstructures as template 1. Spray a layer of release agent on the surface of the petal template 1. Pour a 14% PVA (polyvinyl alcohol) solution onto template 1 and then heat to cure it to obtain a PVA template 2 with a surface structure complementary to that of the petal template 1. The thickness of the PVA template 2 is close to the thickness of the petal. Alternatively, a substrate with an inverted pyramidal pit array structure can be used as template 1. Alternatively, a substrate with an inverted hemispherical pit array structure can be used as template 1.

[0045] S2: Preparation of PDMS solution: The two precursor materials of PDMS (basic polymer component and curing agent, the curing agent is isocyanate) are mixed in a mass ratio of 11:1. After stirring for ten minutes, the solution is placed in an ultrasonic cleaner to remove air bubbles, and then left to stand for fifteen minutes.

[0046] S3: Place four petal templates 1 and four PVA templates 2 sequentially into a polytetrafluoroethylene molding tank, and spray a layer of release agent on their surfaces; pour the PDMS solution after S2 has settled onto the petal templates 1 and PVA templates 2 in the molding tank, place the poured PDMS in a 60℃ oven and heat for 1 hour, then let it stand at room temperature for 20-24 hours; the PDMS thickness can be adjusted by the amount of PDMS liquid poured in.

[0047] S4: Turn the PDMS in the polytetrafluoroethylene molding tank in S3 over and pour out the PDMS with multiple templates. Then remove all templates 1 and 2 respectively. Clean and dry the PDMS to obtain a PDMS film with two complementary microstructures arranged regularly.

[0048] S5: The PDMS obtained in S4 is observed under a microscope, and a suitable area is selected for segmentation to obtain PDMSⅠ5 and PDMSⅡ6, which are complementary to the surface structures of template 1 and template 2.

[0049] S6: Place PDMSⅠ5 on the bottom electrode 3 with the flexible substrate 1, wherein the side of PDMSⅠ5 without microstructure is attached to the bottom electrode 3; and attach the flat side of PDMSⅡ6 to the top electrode 4 on the protective layer.

[0050] S7: Assemble the PDMS with electrodes in S5 and S6, with the side of PDMSⅠ5 with microstructure corresponding to the side of PDMSⅡ6 with microstructure, to obtain a capacitive flexible pressure sensor based on PDMS.

[0051] Example 3:

[0052] A flexible pressure sensor structure based on PDMS includes a protective layer 2, a PDMS I5 dielectric layer, a bottom electrode 3, a top electrode 4, a PDMS II6 dielectric layer, and the protective layer 2. One surface of the PDMS II6 layer has a series of raised microstructures, and the PDMS I5 layer has a series of recessed microstructures. The specific fabrication method of the flexible pressure sensor based on PDMS includes the following steps:

[0053] S1: Prepare template 1 and template 2 with different surface microstructures: Place clean rose petals between two flat glass plates and apply 20N pressure to flatten them. Use the petals with relatively regular raised structures as template 1. Spray a layer of release agent on the surface of the petal template 1. Pour a 15% PVA (polyvinyl alcohol) solution onto template 1 and then heat to cure it to obtain PVA template 2 with a surface structure complementary to that of petal template 1.

[0054] S2: Preparation of PDMS solution: The two precursor materials of PDMS (basic polymer component and curing agent, the curing agent is silane coupling agent KH550) are mixed in a mass ratio of 10:1. After stirring for ten minutes, the solution is placed in an ultrasonic cleaner to remove air bubbles, and then left to stand for twenty minutes.

[0055] S3: Place two petal templates 1 and two PVA templates 2 alternately in a polytetrafluoroethylene molding tank, and spray a layer of release agent on their surface; pour the PDMS solution after S2 into the petal templates 1 and PVA templates 2 in the molding tank, and heat the poured PDMS in a 65℃ oven for 1 hour; the PDMS thickness can be adjusted by the amount of PDMS liquid poured in; alternatively, place petal templates 1 and PVA templates 2 in two polytetrafluoroethylene molding tanks respectively, pour the PDMS solution after standing in each tank, place them in a 50-65℃ oven for 1 hour, and then let them stand at room temperature for 24 hours; alternatively, heat the poured PDMS in a 30℃ oven for 4 hours, and then let it stand at room temperature for 24 hours.

[0056] S4: Turn the polytetrafluoroethylene molding tank over and pour out the PDMS with the template. Then remove template 1 and template 2 respectively. Clean and dry the PDMS to obtain a PDMS film with two complementary microstructures.

[0057] S5: The PDMS obtained in S4 was observed under a microscope and then divided from the region between the two different microstructures to obtain PDMSⅠ5 and PDMSⅡ6, which are approximately complementary to the surface structures of template 1 and template 2, respectively.

[0058] S6: A conductive layer is prepared by spin-coating a conductive colloidal material onto the microstructured side of PDMSⅠ5, such as silver paste, carbon paste, or high-concentration modified PEDOT:PSS. Alternatively, a metal electrode layer can be prepared on the microstructured side of PDMSⅠ5 by sputtering or evaporation, and a metal electrode layer can be prepared on the microstructured side of PDMSⅡ6 by sputtering or evaporation as the top electrode 4.

[0059] S7: Assemble the PDMS with electrodes in S5 and S6. The top electrode 4 on the microstructure of PDMSⅡ6 corresponds to the bottom electrode 3 on the microstructure of PDMSⅠ5. Then, attach the protective layer 2 to the side of PDMSⅠ5 and PDMSⅡ6 without microstructures to obtain a resistive flexible pressure sensor based on PDMS.

[0060] Example 4:

[0061] A flexible pressure sensor structure based on PDMS includes a protective layer 2, a PDMS I5 dielectric layer, a bottom electrode 3, a top electrode 4, a PDMS II6 dielectric layer, and the protective layer 2. PDMS I5 and PDMS II6 have similar but differently arranged surface microstructures. The specific fabrication method of the PDMS-based flexible pressure sensor includes the following steps:

[0062] S1: Prepare templates 1 and 2 with different surface microstructures: Place clean rose petals between two flat glass plates and flatten them by applying 15N pressure. Use the petals with raised microstructures as template 1. Spray a layer of release agent onto the surface of the petal template 1. Pour a 15% PVA (polyvinyl alcohol) solution onto template 1 and then heat to cure it to obtain a PVA template 2 with a surface structure complementary to that of the petal template 1. The thickness of the PVA template 2 is close to the thickness of the petal. Alternatively, a substrate with an inverted pyramidal pit array structure can be used as template 1. Alternatively, a substrate with an inverted hemispherical pit array structure can be used as template 1. Alternatively, peach blossom petals or cherry blossom petals can be used as template 1.

[0063] S2: Preparation of PDMS solution: Mix the two precursor materials of PDMS (basic polymer component and curing agent) in a mass ratio of 10:1, stir for ten minutes, put them into an ultrasonic cleaner to remove air bubbles in the solution, and then let them stand for ten minutes.

[0064] S3: Place four petal templates 1 and four PVA templates 2 sequentially into a polytetrafluoroethylene molding tank, and spray a layer of release agent on their surfaces; pour the PDMS solution after S2 has settled onto the petal templates 1 and PVA templates 2 in the molding tank, place the poured PDMS in a 65℃ oven and heat for 1 hour, then let it stand at room temperature for 20-24 hours; the PDMS thickness can be adjusted by the amount of PDMS liquid poured in.

[0065] S4: Turn the PDMS in the polytetrafluoroethylene molding tank in S3 over and pour out the PDMS with multiple templates. Then remove all templates 1 and 2 respectively. Clean and dry the PDMS to obtain a PDMS film with two complementary microstructures arranged regularly.

[0066] S5: The PDMS obtained in S4 is observed under a microscope, and a suitable area is selected for segmentation to obtain PDMSⅠ5 and PDMSⅡ6, which are complementary to the surface structures of template 1 and template 2.

[0067] S6: A conductive layer is fabricated by spin-coating a conductive colloidal material onto the microstructured side of PDMSⅠ5, such as silver paste, carbon paste, or high-concentration modified PEDOT:PSS. Alternatively, a metal electrode layer can be fabricated on the microstructured side of PDMSⅠ5 by sputtering or evaporation. A conductive colloidal material is also spin-coated onto the microstructured side of PDMSⅡ6 to create an upper conductive layer, such as silver paste, carbon paste, or high-concentration modified PEDOT:PSS. Alternatively, a metal electrode layer can be fabricated on the microstructured side of PDMSⅡ6 by sputtering or evaporation.

[0068] S7: Assemble the PDMS with electrodes in S5 and S6. The top electrode 4 on the microstructure of PDMSⅡ6 corresponds to the bottom electrode 3 on the microstructure of PDMSⅠ5. Then, attach the protective layer 2 to the side of PDMSⅠ5 and PDMSⅡ6 without microstructures to obtain a resistive flexible pressure sensor based on PDMS.

[0069] In Examples 1-4, the plant petals are one of the following: rose petals, Chinese rose petals, lotus petals, peach petals, and cherry blossom petals.

[0070] In S1, after flattening the plant petals, the plant petals can be cut into regular shapes to obtain template 1.

[0071] In S2, the curing agent is one of the following: acid anhydride curing agent, isocyanate, or silane coupling agent. After the base polymer and curing agent are mixed, they are subjected to ultrasonic treatment for 10-30 minutes.

[0072] In S3, the heating temperature and time of the cast PDMS are: 50-65℃ for 1 hour, or 30-35℃ for 4-8 hours.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A flexible pressure sensor based on PDMS, comprising a flexible substrate, a bottom electrode, and a top electrode arranged from bottom to top, characterized in that, It also includes a PDMS dielectric layer, which consists of two PDMS films with different surface microstructures, and the PDMS dielectric layer is located between or on both sides of the bottom electrode and the top electrode.

2. The flexible pressure sensor based on PDMS according to claim 1, characterized in that, When the PDMS dielectric layer is located between the bottom electrode and the top electrode, the side of the PDMS film with the surface microstructure corresponds to the bottom electrode; when the PDMS dielectric layer is located on both sides of the bottom electrode and the top electrode, the surface microstructure of one PDMS film is attached to the bottom electrode, and the surface microstructure of the other PDMS film is attached to the top electrode.

3. A flexible pressure sensor based on PDMS according to claim 1, characterized in that, A protective layer is provided at the upper end of the top electrode.

4. A method for fabricating a flexible pressure sensor based on PDMS according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Prepare two templates with different surface microstructures: template 1 and template 2; S2: Mix the base polymer and curing agent for preparing the PDMS solution at a mass ratio of 10-12:1 to prepare a bubble-free PDMS solution; S3: Place the templates 1 and 2 prepared in S1 into the molding tank and spray a layer of silicone oil release agent; pour the PDMS solution into the molding tank so that the PDMS solution covers the templates 1 and 2, and heat and cure at 50-65℃. S4: Remove the cured PDMS film from the molding tank, and remove template 1 and template 2; clean and dry the PDMS film to obtain PDMS films with different surface microstructures; S5: Cut the PDMS film obtained in S4 to obtain two PDMS films of the same size but with different surface microstructures, namely PDMSⅠ corresponding to template 1 and PDMSⅡ corresponding to template 2. S6: Attach PDMSⅠ to the bottom electrode; S7: Attach PDMSⅡ to the top electrode; S8: Assemble the top electrode and bottom electrode obtained in S6 and S7 to form a flexible pressure sensor, wherein the side of PDMSⅠ with surface microstructure corresponds to the side of PDMSⅡ with surface microstructure.

5. The method for fabricating a flexible pressure sensor based on PDMS according to claim 1, characterized in that, In S1, at least one set of templates, template 1 and template 2, is a plant petal template or a template prepared from plant petals.

6. The method for fabricating a flexible pressure sensor based on PDMS according to claim 5, characterized in that, The plant petals mentioned are one of the following: rose petals, Chinese rose petals, peony petals, peach blossom petals, and cherry blossom petals.

7. The method for fabricating a flexible pressure sensor based on PDMS according to claim 6, characterized in that, In step S1, the specific steps for preparing two templates with different surface microstructures are as follows: placing cleaned plant petals between two flat glass plates and applying a pressure of 8-20N to flatten them; using the petals with raised structures as template 1; spraying a layer of release agent on the surface of template 1; pouring a PVA solution with a mass fraction of 14%-18% onto template 1; and then heating and curing to obtain template 2 with a surface structure complementary to that of template 1.

8. The method for fabricating a flexible pressure sensor based on PDMS according to claim 7, characterized in that, In step S1, after the plant petals are flattened, they are cut into regular shapes to obtain template 1.

9. The method for fabricating a flexible pressure sensor based on PDMS according to claim 7, characterized in that, The thickness of template 2 is controlled to be close to that of template 1.

10. The method for fabricating a flexible pressure sensor based on PDMS according to claim 4, characterized in that, In S2, the curing agent is one of the following: anhydride curing agent, isocyanate, and silane coupling agent. After the base polymer and the curing agent are mixed, they are stirred and ultrasonically treated for 10-30 minutes.

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