A dielectric elastomer material based on the structure of dihydromyricetin, its preparation method and applications

Abstract

The present invention discloses a dielectric elastomer material based on the structure of dihydromyricetin, its preparation method and applications, belonging to the technical field of organic synthesis. In the present invention, dihydromyricetin is used as a cross-linking agent to coordinate with metal organic salts to construct a bio-based polyurethane network with room-temperature self-healing properties. The DMY molecule contains multiple polar groups, which can enhance the interfacial polarization effect and increase the dielectric constant, enabling the material to have excellent properties under high-frequency and high-voltage conditions. Metal coordination further enhances the polarity and dielectric response. By optimizing the cross-linking structure, the elastic modulus is effectively reduced, and the driving deformation ability is improved, solving the problems of high modulus and low breakdown strength of traditional polyurethanes. The antioxidant property of dihydromyricetin combined with the dynamic network design endows the material with excellent room-temperature self-healing properties and improves the problems of difficult recycling and slow degradation of traditional materials. This material has the characteristics of low modulus, high dielectric, good self-healing and environmental protection, and has broad application prospects in the fields of flexible electronics, intelligent drive devices, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a dielectric elastomer material based on the structure of dihydromyricetin, a preparation method thereof, and an application thereof. Background Art

[0002] At present, dielectric elastomers (DEs) have important application values in the fields of flexible electronics, bionic actuation, etc., but their performance still faces many challenges. Due to the limitation of the main chain structure of traditional polyurethane-based DEs, their dielectric constants are generally low, resulting in a need for a higher driving electric field. Secondly, although the introduction of inorganic fillers or metal coordination bonds can improve the dielectric properties, this often significantly increases the elastic modulus of the material (usually > 2 MPa) due to filler agglomeration or coordination rigidity strengthening the network, while reducing its breakdown strength (< 30 kV / mm). Finally, although existing dynamic bonds (such as disulfide bonds, hydrogen bonds) endow the material with self-healing properties, most of them have a low repair efficiency at room temperature (for example, the 3-hour repair efficiency in Application No. CN202111454793.0 is only 80 - 90%), and there are few technologies that can regulate the mechanical properties while improving the dielectric properties.

[0003] Therefore, how to provide a dielectric elastomer material that can regulate the mechanical properties while improving the dielectric properties is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0004] To solve the above technical problems, the present invention proposes a dielectric elastomer material based on the structure of dihydromyricetin, a preparation method thereof, and an application thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A preparation method of a dielectric elastomer material based on the structure of dihydromyricetin, using dihydromyricetin as a bio-based monomer for crosslinking, and simultaneously adding a metal organic salt for coordination to construct a bio-based polyurethane network that can achieve self-healing at room temperature.

[0007] Preferably, it specifically includes the following steps:

[0008] Pre-polymerize polyetheramine and a diisocyanate in an organic solvent to obtain a prepolymer, then mix and react the prepolymer with a chain extender, add dihydromyricetin and continue the reaction, and finally add a metal organic salt for a coordination reaction. After the reaction is completed, remove the solvent to obtain the room-temperature self-healing dielectric elastomer material.

[0009] Beneficial effects: The present invention proposes an innovative solution from the perspective of molecular design and dynamic network regulation. First, the present invention makes a breakthrough by selecting dihydromyricetin (DMY) as a multifunctional crosslinker. Traditional coordination bond design mostly relies on the combination of a single metal ion and a carboxylic acid group (such as Fe 3+ -COOH), the coordination site density is low and it is easy to cause rigid aggregation areas. The dihydromyricetin in the present invention is a natural polyphenol compound, which contains 5 phenolic hydroxyl groups, 1 carbonyl group and conjugated double bond structure in its molecule. It can achieve technical advantages through the following mechanisms: First, the multi-coordination effect of dihydromyricetin is achieved by coordinating with metal ions (such as Al 3+ 、Zn 2+ ) form high-density, evenly distributed ion clusters, which significantly enhance the interfacial polarization of the material. Compared with the single-coordination system (such as iron-carboxylic acid complex), the dielectric constant can be increased to above 9.9; at the same time, the dynamic reversibility of the coordination bond avoids local stress concentration caused by filler agglomeration or bonding fixation, so that the elongation at break of the material remains above 1876%; secondly, the benzene ring structure and conjugated system of dihydromyricetin greatly increase the molecular dipole moment, and as a network cross-linking point, it enhances the inherent polarization ability of the polyurethane main chain, thereby making the dielectric loss significantly lower than that of conventional composite systems.

[0010] Secondly, the present invention further improves the self-healing performance of the material through the synergistic repair mechanism of disulfide p-phenylenediamine chain extender and antioxidant. Existing self-healing elastomers based on dynamic disulfide bonds (such as patent CN202111454793.0) generally rely on single sulfur bond exchange and require high temperature (>60°C) or photoactivation to achieve repair (room temperature efficiency <50%). The present invention utilizes the antioxidant properties of dihydromyricetin. Its phenolic hydroxyl group can react with oxygen free radicals to form ketone intermediates, triggering the dynamic exchange reaction of the disulfide bond in the chain extender, thereby enabling the material to be rapidly repaired at room temperature. The repair efficiency can reach >98% within 3 hours, and the breakdown strength recovery rate after repair exceeds 90%, which is significantly better than the traditional dynamic bond system.

[0011] Finally, this invention also emphasizes the bio-based and biodegradable properties of the material. Traditional polyurethane DE (DE) is difficult to degrade due to its backbone (e.g., application number CN202111454793.0), which can easily cause environmental damage. However, this invention significantly reduces the degradation difficulty of polyurethane by leveraging the natural degradability of dihydromyricetin and a dynamic network design, effectively alleviating environmental pollution. This bio-based polyurethane material not only exhibits excellent driving performance but also conforms to current design concepts of environmental friendliness and sustainable development, offering new possibilities for the application of green materials.

[0012] Preferably, the molar ratio of the polyetheramine, diisocyanate, chain extender, dihydromyricetin and metal organic salt is 4:30:2.5:2.5:(1-5).

[0013] Beneficial effects: The amino groups and ether groups in the above polyetheramines provide polarity for the polyurethane material, enabling it to have good dielectric response under the action of an external electric field. Especially in materials with high dielectric constants, the polar groups can promote the interfacial polarization of the material and improve its dielectric properties.

[0014] Preferably, the diisocyanate is isophorone diisocyanate.

[0015] Preferably, the organic solvent includes one of tetrahydrofuran, N,N-dimethylformamide, and toluene.

[0016] Preferably, the temperature of the prepolymerization reaction is 60 - 80 °C, and the time is 0.5 - 4 h.

[0017] Preferably, the chain extender is dithio-4,4'-diaminodiphenyl.

[0018] Beneficial effects: The dynamic exchange characteristics of the disulfide bond in the chain extender enable the material to achieve self-healing at room temperature, while reducing the modulus and increasing the deformation amount, enhancing the interfacial polarization and increasing the dielectric constant, making the dielectric elastomer exhibit more excellent electro-deformation ability.

[0019] Preferably, the temperature of the reaction of mixing the prepolymer and the chain extender is 60 - 80 °C, and the time is 0.5 - 1.5 h.

[0020] Preferably, the temperature of the continued reaction is 60 - 80 °C, and the time is 0.5 - 2 h.

[0021] Preferably, the metal organic salt is zinc acetate or zinc acetate dihydrate.

[0022] Beneficial effects: In the present invention, the coordination of Zn 2+ -dihydromyricetin (Zn 2+ -DMY) promotes the interfacial polarization and enhances the molecular dipole moment, significantly improving the dielectric properties of the material. Moreover, the dynamic crosslinking involving Zn 2+ improves the self-healing property and durability of the material, making it perform better in the fields of flexible electronics and intelligent actuators.

[0023] Preferably, the temperature of the coordination reaction is 20 - 60 °C, and the time is 0.1 - 12 h.

[0024] A dielectric elastomer material based on the structure of dihydromyricetin prepared by the above preparation method.

[0025] An application of a dielectric elastomer material based on the structure of dihydromyricetin in the field of electronic wearables.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] The present invention has developed a multifunctional cross-linked network material around dihydromyricetin (DMY). First, the hydroxyl groups and carbonyl groups in the DMY molecule form strong polar groups, significantly enhancing the synergistic effect of interfacial polarization and dipole polarization, enabling the dielectric constant of the material to be adjusted to 9.9 - 11, and the increase in elastic modulus is limited. At the same time, DMY can coordinate with a variety of metal ions, further enhancing dipole polarization and increasing the dielectric constant. Secondly, by introducing a chain extender of dithiodiphenylamine, a dynamic disulfide bond network is constructed. Combining with the antioxidant effect of DMY, efficient self-healing at room temperature is achieved, with a healing efficiency exceeding 98% and a healing time of less than 3 hours. In addition, the flexible structure of DMY and the dynamic network act synergistically to maintain the low modulus of the material, and the breakdown strength meets the requirements of high-field driving. The material also has environmental friendliness and recyclability. Both DMY and dithiodiphenylamine are derived from renewable resources, with a bio-based content > 24.7%, and can be recycled up to 3 times, and the retention rate of mechanical properties is significantly higher than that of traditional petroleum-based elastomers. The present invention proposes an innovative solution from the perspectives of molecular design and dynamic network regulation, successfully achieving the coordinated regulation of dielectric properties and mechanical properties, providing a more efficient and sustainable material solution for fields such as flexible electronics and bionic driving, effectively solving the problems of traditional polyurethane dielectric elastomers such as high elastic modulus, low breakdown strength, limited driving deformation, and difficulty in recycling and degradation, and having broad applications in the field of electronic wearables. Description of the Drawings

[0028] The drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0029] Figure 1 The stress-strain curve diagrams of the room-temperature self-healing dielectric elastomer material (initial) prepared in Example 1 and the repaired polyurethane dielectric elastomer material (after repair at 25°C);

[0030] Figure 2 The stress-strain curve diagrams of the room-temperature self-healing dielectric elastomer material (initial) prepared in Example 2 and the repaired polyurethane dielectric elastomer material (after repair at 25°C);

[0031] Figure 3 The stress-strain curve diagrams of the room-temperature self-healing dielectric elastomer material (initial) prepared in Example 3 and the repaired polyurethane dielectric elastomer material (after repair at 25°C);

[0032] Figure 4 The stress-strain curve diagrams of the room-temperature self-healing dielectric elastomer material (initial) prepared in Example 4 and the repaired polyurethane dielectric elastomer material (after repair at 25°C);

[0033] Figure 5 The stress-strain curve graphs of the room-temperature self-healing dielectric elastomer material (initial) prepared in Comparative Example 1 and the repaired polyurethane dielectric elastomer material (after repair at 25°C);

[0034] Figure 6 The stress-strain curve graphs of the room-temperature self-healing dielectric elastomer material (initial) prepared in Comparative Example 2 and the repaired polyurethane dielectric elastomer material (after repair at 25°C);

[0035] Figure 7 The dielectric constant curve graphs of the room-temperature self-healing dielectric elastomer materials prepared in Examples 1-4 and Comparative Examples 1-2;

[0036] Figure 8 The dielectric loss curve graphs of the room-temperature self-healing dielectric elastomer materials prepared in Examples 1-4 and Comparative Examples 1-2;

[0037] Figure 9 The schematic diagram of the potential application of the room-temperature self-healing dielectric elastomer material in flexible electronic devices. Detailed implementation manners

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0039] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0040] Unless otherwise specified, the raw materials in the embodiments of the present invention are all obtained through commercial channels;

[0041] Among them, the molecular weight of the polyetheramine is 2000.

[0042] Unless otherwise specified, the room temperature or normal temperature in the embodiments of the present invention refers to 25±3°C.

[0043] Example 1

[0044] A preparation method of a dielectric elastomer material based on the structure of dihydromyricetin, comprising the following steps:

[0045] (1)Synthesis of prepolymer: Polyetheramine (8 g, 4 mmol) was mixed with 10 mL of toluene, and purged with nitrogen and heated with stirring at 120 °C for 2 h to remove excess moisture. Then isophorone diisocyanate (6.67 g, 30 mmol) was added, and the reaction was carried out at 70 °C for 1 h to obtain the prepolymer;

[0046] (2)Chain extension: Chain extender dithio-4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) was added to the obtained prepolymer, and the reaction was carried out at 70 °C for 2 h. Then dihydromyricetin (0.8 g, 2.5 mmol) was added and the reaction was carried out at 70 °C for 4 h;

[0047] (3)Zinc acetate dihydrate (0.22 g, 1.2 mmol) that can form a coordination bond with dihydromyricetin was added to the reaction system obtained in step (2), and the reaction was carried out at 60 °C for 0.5 h. After the reaction, the solvent was removed in an oven to obtain a room-temperature self-healing dielectric elastomer material with self-healing and recyclable functions and a high dielectric constant.

[0048] Technical effects:

[0049] According to GB / T 10401-2006, the above-obtained room-temperature self-healing dielectric elastomer material was cut into dumbbell-shaped specimens to test its properties. The stress-strain curves of the room-temperature self-healing dielectric elastomer material (initial) and the repaired polyurethane dielectric elastomer material (after room-temperature repair) prepared in this example are shown in Figure 1 From Figure 1 it can be seen that the initial stress was 1.86 MPa and the strain was 2790%; the stress after repair at 25 °C was 1.77 MPa and the strain was 2722%.

[0050] The room-temperature self-healing dielectric elastomer material prepared in this example was cut into wafers with a diameter of 1 cm, and conductive electrodes were coated on both the front and back sides. The Solartron, SI1260 instrument was used to measure its dielectric constant and dielectric loss. The obtained dielectric constant curve is shown in Figure 7 and the dielectric loss curve is shown in Figure 8 . It can be seen that the self-healing capabilities of the tensile strength and elongation at break of the PU-DMYBDBA polyurethane prepared in this example were 95.2% and 97.6% respectively, and the dielectric constant and dielectric loss were 9.9 (@100 HZ) and 0.1 (@100 HZ) respectively.

[0051] Example 2

[0052] A preparation method of a dielectric elastomer material based on the structure of dihydromyricetin, comprising the following steps:

[0053] (1) Synthesis of prepolymer: Polyetheramine (8 g, 4 mmol) was mixed with 10 mL of toluene, purged with nitrogen, heated and stirred at 120 °C for 2 h to remove excess moisture. Then isophorone diisocyanate (6.67 g, 30 mmol) was added and reacted at 70 °C for 1 h to obtain the prepolymer;

[0054] (2) Chain extension: In the obtained prepolymer, chain extender dithio - 4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) was added and reacted at 70 °C for 2 h. Then dihydromyricetin (0.8 g, 2.5 mmol) was added and reacted at 70 °C for 4 h;

[0055] (3) Zinc acetate dihydrate (0.44 g, 2.4 mmol) that can form a coordination bond with dihydromyricetin was added to the reaction system obtained in step (2) and reacted at 60 °C for 0.5 h. After the reaction, the solvent was removed in an oven to obtain a room - temperature self - healing dielectric elastomer material with high dielectric constant and the functions of self - healing and recyclability.

[0056] Technical effects:

[0057] According to GB / T 10401 - 2006, the above - obtained room - temperature self - healing dielectric elastomer material was cut into dumbbell - shaped specimens, and its properties were tested. The stress - strain curves of the room - temperature self - healing dielectric elastomer material (initial) and the repaired polyurethane dielectric elastomer material (after room - temperature repair) prepared in this example are shown in Figure 2 From Figure 2 it can be seen that the initial stress is 2.78 MPa and the strain is 2062%; the stress after repair at 25 °C is 2.67 MPa and the strain is 2047%.

[0058] The room - temperature self - healing dielectric elastomer material prepared in this example was cut into wafers with a diameter of 1 cm, and conductive electrodes were coated on both the front and back sides. The Solartron, SI1260 instrument was used to measure its dielectric constant and dielectric loss. The obtained dielectric constant curve is shown in Figure 7 and the dielectric loss curve is shown in Figure 8 . It can be seen that the self - healing capabilities of the tensile strength and elongation at break of the PU - DMYBDBA polyurethane prepared in this example are 96% and 99.3% respectively, and the dielectric constant and dielectric loss are 10.8 (@100 HZ) and 0.1 (@100 HZ) respectively.

[0059] Example 3

[0060] A preparation method of a dielectric elastomer material based on the structure of dihydromyricetin, comprising the following steps:

[0061] (1)Synthesis of prepolymer: Polyetheramine (8 g, 4 mmol) was mixed with 10 mL of toluene, purged with nitrogen, heated and stirred at 120 °C for 2 h to remove excess moisture, then isophorone diisocyanate (6.67 g, 30 mmol) was added, and the reaction was carried out at 70 °C for 1 h to obtain the prepolymer;

[0062] (2)Chain extension: Chain extender dithio-4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) was added to the obtained prepolymer, and the reaction was carried out at 70 °C for 2 h. Then dihydromyricetin (0.8 g, 2.5 mmol) was added and the reaction was carried out at 70 °C for 4 h;

[0063] (3)Zinc acetate dihydrate (0.88 g, 4.8 mmol) that can form a coordination bond with dihydromyricetin was added to the reaction system obtained in step (2), and the reaction was carried out at 60 °C for 0.5 h. After the reaction, the solvent was removed in an oven to obtain a room-temperature self-healing dielectric elastomer material with self-healing and recyclable functions and a high dielectric constant.

[0064] Technical effects:

[0065] According to GB / T 10401-2006, the above-obtained room-temperature self-healing dielectric elastomer material was cut into dumbbell-shaped specimens to test its properties. The stress-strain curves of the room-temperature self-healing dielectric elastomer material (initial) and the repaired polyurethane dielectric elastomer material (after room-temperature repair) prepared in this example are shown in Figure 3 From Figure 3 it can be seen that the initial stress is 3.58 MPa and the strain is 2407%; the stress after repair at 25 °C is 3.45 MPa and the strain is 2392%.

[0066] The room-temperature self-healing dielectric elastomer material prepared in this example was cut into wafers with a diameter of 1 cm, and conductive electrodes were coated on both the front and back sides. The Solartron, SI1260 instrument was used to measure its dielectric constant and dielectric loss. The obtained dielectric constant curve is shown in Figure 7 and the dielectric loss curve is shown in Figure 8 . It can be seen that the self-healing capabilities of the tensile strength and elongation at break of the PU-DMYBDBA polyurethane prepared in this example are 96.4% and 99.4% respectively, and the dielectric constant and dielectric loss are 11.0 (@100HZ) and 0.08 (@100HZ) respectively.

[0067] Example 4

[0068] A preparation method of a dielectric elastomer material based on the structure of dihydromyricetin, comprising the following steps:

[0069] (1)Synthesis of prepolymer: Polyetheramine with a molecular weight of 2000 (6 g, 3 mmol), polyetheramine with a molecular weight of 400 (0.4 g, 1 mmol) and 10 mL of toluene were mixed, purged with nitrogen, heated and stirred at 120 °C for 2 h to remove excess moisture, then isophorone diisocyanate (6.67 g, 30 mmol) was added, and the reaction was carried out at 70 °C for 1 h to obtain the prepolymer;

[0070] (2)Chain extension: Chain extender dithio-4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) was added to the obtained prepolymer, and the reaction was carried out at 70 °C for 2 h. Then dihydromyricetin (0.8 g, 2.5 mmol) was added and the reaction was carried out at 70 °C for 4 h;

[0071] (3)Zinc acetate dihydrate (0.44 g, 2.4 mmol) that can form a coordination bond with dihydromyricetin was added to the reaction system obtained in step (2), and the reaction was carried out at 60 °C for 0.5 h. After the reaction, the solvent was removed in an oven to obtain a room-temperature self-healing dielectric elastomer material with self-healing and recyclable functions and a high dielectric constant.

[0072] Technical effects:

[0073] According to GB / T 10401-2006, the above-obtained room-temperature self-healing dielectric elastomer material was cut into dumbbell-shaped specimens, and its properties were tested. The stress-strain curves of the room-temperature self-healing dielectric elastomer material (initial) and the repaired polyurethane dielectric elastomer material (after room-temperature repair) prepared in this example are shown in Figure 4 It can be seen from Figure 4 that the initial stress is 6.14 MPa and the strain is 1876%; the stress after repair at 25 °C is 5.97 MPa and the strain is 1858%.

[0074] The room-temperature self-healing dielectric elastomer material prepared in this example was cut into a wafer with a diameter of 1 cm, and conductive electrodes were coated on both the front and back sides. The Solartron, SI1260 instrument was used to measure its dielectric constant and dielectric loss. The obtained dielectric constant curve is shown in Figure 7 and the dielectric loss curve is shown in Figure 8 . It can be seen that the self-healing capabilities of the tensile strength and elongation at break of the PU-DMYBDBA polyurethane prepared in this example are 97.2% and 99.0% respectively, and the dielectric constant and dielectric loss are 10.4 (@100 HZ) and 0.11 (@100 HZ) respectively.

[0075] Comparative Example 1

[0076] A preparation method of a room-temperature self-healing dielectric elastomer material, which is different from Example 1 only in that: zinc acetate dihydrate in step (3) is replaced by manganese acetylacetonate, and its addition amount is limited, and the remaining process steps and parameters are the same as those in Example 1. The specific steps are as follows:

[0077] (1) Synthesis of prepolymer: Mix polyetheramine (8 g, 4 mmol) with 10 mL of toluene, heat and stir under nitrogen purge at 120 °C for 2 h to remove excess moisture, then add isophorone diisocyanate (6.67 g, 30 mmol), and react at 70 °C for 1 h to obtain a prepolymer;

[0078] (2) Chain extension: Add chain extender dithio-4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) to the obtained prepolymer, react at 70 °C for 2 h, then add dihydromyricetin (0.8 g, 2.5 mmol) and react at 70 °C for 4 h;

[0079] (3) Add manganese acetylacetonate (0.85 g, 2.4 mmol) that can form a coordination bond with dihydromyricetin to the reaction system obtained in step (2), and react at 60 °C for 0.5 h. After the reaction, place it in an oven to remove the solvent to obtain a room-temperature self-healing dielectric elastomer material.

[0080] Technical effect:

[0081] According to GB / T 10401-2006, the above-obtained room-temperature self-healing dielectric elastomer material was cut into dumbbell-shaped specimens, and its properties were tested. The stress-strain curves of the room-temperature self-healing dielectric elastomer material (initial) and the repaired polyurethane dielectric elastomer material (after room-temperature repair) prepared in this comparative example are shown in Figure 5 , from Figure 5 it can be seen that the initial stress is 10.8 MPa and the strain is 730.2%; the stress after repair at 25 °C is 9.9 MPa and the strain is 730%.

[0082] The room-temperature self-healing dielectric elastomer material prepared in this comparative example was cut into a 1 cm diameter wafer, and conductive electrodes were coated on both the front and back sides. The Solartron, SI1260 instrument was used to measure its dielectric constant and dielectric loss. The obtained dielectric constant curve is shown in Figure 7 , and the dielectric loss curve is shown in Figure 8 . It can be seen that the self-healing capabilities of the tensile strength and elongation at break of the PU-DMYBDBA polyurethane prepared in this comparative example are 90.7% and 99.9% respectively, and the dielectric constant and dielectric loss are 8.0 (@100 HZ) and 0.06 (@100 HZ) respectively.

[0083] Comparative Example 2

[0084] A preparation method of a room-temperature self-healing dielectric elastomer material, which is only different from Example 1 in that zinc acetate dihydrate in step (3) is replaced by iron acetylacetonate, and its addition amount is limited, and the remaining process steps and parameters are the same as those in Example 1, specifically including the following steps:

[0085] (1) Synthesis of prepolymer: Mix polyetheramine (8 g, 4 mmol) with 10 mL of toluene, heat and stir under nitrogen purge at 120 °C for 2 h to remove excess moisture, then add isophorone diisocyanate (6.67 g, 30 mmol), and react at 70 °C for 1 h to obtain a prepolymer;

[0086] (2) Chain extension: Add chain extender dithio-4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) to the obtained prepolymer, react at 70 °C for 2 h, then add dihydromyricetin (0.8 g, 2.5 mmol) and react at 70 °C for 4 h;

[0087] (3) Add iron acetylacetonate (0.85 g, 2.4 mmol) that can form a coordination bond with dihydromyricetin to the reaction system obtained in step (2), and react at 60 °C for 0.5 h. After the reaction is completed, place it in an oven to remove the solvent to obtain a room-temperature self-healing dielectric elastomer material.

[0088] Technical effects:

[0089] According to GB / T 10401-2006, the above-obtained room-temperature self-healing dielectric elastomer material was cut into dumbbell-shaped specimens to test its properties. The stress-strain curves of the room-temperature self-healing dielectric elastomer material (initial) and the repaired polyurethane dielectric elastomer material (after room-temperature repair) prepared in this comparative example are shown in Figure 6 , from Figure 6 it can be seen that the initial stress is 3.42 MPa and the strain is 382%; the stress after repair at 25 °C is 3.26 MPa and the strain is 380%.

[0090] Cut the room-temperature self-healing dielectric elastomer material prepared in this comparative example into a wafer with a diameter of 1 cm, coat conductive electrodes on both the front and back sides, and use a Solartron, SI1260 instrument to measure its dielectric constant and dielectric loss. The obtained dielectric constant curve is shown in Figure 7 , and the dielectric loss curve is shown in Figure 8 . It can be seen that the self-healing capabilities of the tensile strength and elongation at break of the PU-DMYBDBA polyurethane prepared in this comparative example are 95.3% and 99.5% respectively, and the dielectric constant and dielectric loss are 7.8 (@100 HZ) and 0.17 (@100 HZ) respectively.

[0091] Figure 9Schematic diagram of the potential application of the room-temperature self-healing dielectric elastomer material in flexible electronic devices, showing its application prospect as a flexible pressure sensor. Among them, the high dielectric constant of the dielectric elastomer material in the present invention is reflected in its ability to improve the sensing sensitivity, and even a small deformation can significantly change the capacitance; the low modulus characteristic is reflected in its suitability for skin-fitting and bendable deformation scenarios; the low dielectric loss is reflected in ensuring signal stability and avoiding energy dissipation; the room-temperature self-healing property is reflected in its ability to self-heal microcracks, improving the device life and stability; the bio-based environmental protection characteristic is reflected in its adaptation to the trend of wearable and green materials. The material provided by the present invention can achieve signal response through the change of dielectric constant when subjected to external mechanical stimuli. Combining its low modulus, high dielectric constant and self-healing performance, it is suitable for intelligent material fields such as wearable devices and electronic skin.

[0092] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A preparation method of a dielectric elastomer material based on the structure of dihydromyricetin, characterized in that, A bio-based monomer using dihydromyricetin as a cross-linking agent, and a metal-organic salt is added for coordination to construct a bio-based polyurethane network that can achieve self-healing at room temperature; The room temperature is 25 ± 3 °C; Specifically, it includes the following steps: Polyetheramine and a diisocyanate are subjected to a prepolymerization reaction in an organic solvent to obtain a prepolymer. Then, after mixing and reacting the prepolymer with a chain extender, dihydromyricetin is added and the reaction continues. Finally, a metal-organic salt is added for a coordination reaction. After the reaction is completed, the solvent is removed to obtain a room-temperature self-healing dielectric elastomer material; The chain extender is 4,4'-diaminodiphenyl disulfide; The metal-organic salt is zinc acetate or zinc acetate dihydrate.

2. The preparation method of a dielectric elastomer material based on the structure of dihydromyricetin according to claim 1, characterized in that, The molar ratio of the polyetheramine, diisocyanate, chain extender, dihydromyricetin, and metal-organic salt is 4:30:2.5:2.5:(1.2 - 4.8).

3. The preparation method of a dielectric elastomer material based on the structure of dihydromyricetin according to claim 1, characterized in that, The temperature of the prepolymerization reaction is 70 °C and the time is 1 h.

4. The preparation method of a dielectric elastomer material based on the structure of dihydromyricetin according to claim 1, characterized in that, The temperature of the reaction of mixing the prepolymer and the chain extender is 70 °C and the time is 2 h; and / or, The temperature of the continued reaction is 70 °C and the time is 4 h.

5. The preparation method of a dielectric elastomer material based on the structure of dihydromyricetin according to claim 1, characterized in that The temperature of the coordination reaction is 60 °C and the time is 0.5 h.

6. A dielectric elastomer material based on the structure of dihydromyricetin prepared by the preparation method according to any one of claims 1-5.

7. Application of the dielectric elastomer material based on the structure of dihydromyricetin according to claim 6 in the field of electronic wearables.

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