Dielectric elastomer material based on dihydromyricetin structure and preparation method and application thereof

Abstract

The invention discloses a dielectric elastomer material based on a dihydromyricetin structure and a preparation method and application thereof, and belongs to the technical field of organic synthesis. According to the invention, dihydromyricetin is used as a cross-linking agent and is coordinated with metal organic salt, so that a room-temperature self-repairing bio-based polyurethane network is constructed. DMY molecules contain a plurality of polar groups, so that the interface polarization effect can be enhanced, the dielectric constant is improved, and the material has excellent performance under high frequency and high voltage. The polarity and dielectric response are further improved through metal coordination, by optimizing a cross-linked structure, the elastic modulus is effectively reduced, the driving deformation capacity is improved, and the problems that traditional polyurethane is high in modulus, low in breakdown strength and the like are solved. The oxidation resistance of dihydromyricetin is combined with dynamic network design, so that the material is endowed with excellent room-temperature self-repairing performance, and the problems that a traditional material is difficult to recover and slow to degrade are solved. The material has the characteristics of low modulus, high dielectric, good self-repairing and environmental protection, and has wide application prospects in the fields of flexible electronics, intelligent driving devices and the like.

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) and reduces its breakdown strength (<30 kV / mm) due to filler aggregation or coordination rigidification of the network. Finally, although existing dynamic bonds (such as disulfide bonds and 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 of a cross-linking agent, 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, the method 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 coordination reaction. After the reaction is completed, the solvent is removed to obtain the room-temperature self-healing dielectric elastomer material.

[0009] Beneficial effects: The present invention proposes an innovative solution from the perspectives of molecular design and dynamic network regulation. First, the present invention breakthroughly selects dihydromyricetin (DMY) as a multifunctional crosslinking agent. Traditional coordination bond design mostly relies on the binding of a single metal ion to a carboxylic acid group (such as Fe 3+ -COOH), with a low coordination site density and prone to rigid aggregation regions. However, dihydromyricetin in the present invention, as a natural polyphenol compound, contains 5 phenolic hydroxyl groups, 1 carbonyl group and a conjugated double bond structure in its molecule, and can achieve technical advantages through the following mechanisms: First, the multiple coordination of dihydromyricetin forms high-density and uniformly distributed ion clusters through dynamic coordination with metal ions (such as Al 3+ , Zn 2+ ), significantly enhancing 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 more than 9.9; at the same time, the dynamic reversibility of the coordination bond avoids local stress concentration caused by filler agglomeration or bond fixation, keeping the elongation at break of the material above 1876%; Second, the benzene ring structure and conjugated system of dihydromyricetin greatly increase the molecular dipole moment, and as a network crosslinking point, improve 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 chain extender of p-phenylenediamine disulfide and the antioxidant synergistic repair mechanism. Existing self-healing elastomers based on dynamic disulfide bonds (such as patent CN202111454793.0) generally rely on a 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, and its phenolic hydroxyl group can react with oxygen free radicals to generate a keto intermediate, triggering the dynamic exchange reaction of the disulfide bond in the chain extender, and then enabling the material to achieve rapid repair 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, the present invention also focuses on the bio-based and degradable characteristics of the material. Traditional polyurethane DE is difficult to degrade due to its main chain (such as application number CN202111454793.0), which is likely to cause an environmental burden. The present invention greatly reduces the degradation difficulty of polyurethane and effectively reduces environmental pollution problems by utilizing the natural degradability of dihydromyricetin and dynamic network design. This bio-based polyurethane material not only has excellent driving performance, but also conforms to the current design concept of environmental friendliness and sustainable development, providing new possibilities for the application of green materials.

[0012] Preferably, the molar ratio of the polyetheramine, the diisocyanate, the chain extender, the dihydromyricetin and the 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 bonds 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 mixing reaction of 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 drive.

[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 in the DMY molecule form strong polar groups with the carbonyl 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. Second, by introducing dithiodiphenylenediamine chain extender, 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 dithiodiphenylenediamine 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 realizing 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 high elastic modulus, low breakdown strength, limited driving deformation, and difficulty in recycling and degradation of traditional polyurethane dielectric elastomers, and having wide applications in the field of electronic wearables. Description of the Drawings

[0028] The drawings constituting 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 It is the stress-strain curve diagram of the room-temperature self-healing dielectric elastomer material (initial) prepared in Example 1 and the polyurethane dielectric elastomer material after repair (after repair at 25°C);

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

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

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

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

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

[0035] Figure 7 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 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 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 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 shall fall within the protection scope of the present invention.

[0039] 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 with reference to the accompanying drawings and specific implementation manners.

[0040] Unless otherwise specified, the raw materials in the embodiments of the present invention are 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, 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;

[0046] (2) Chain extension: Chain extender dithio-4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) was added to the obtained prepolymer, 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;

[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 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 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 is 1.86 MPa and the strain is 2790%; the stress after repair at 25 °C is 1.77 MPa and the strain is 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 are 95.2% and 97.6% respectively, and the dielectric constant and dielectric loss are 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: Chain extender dithio - 4,4'-diaminodiphenyl (0.62 g, 2.5 mmol) was added to the obtained prepolymer, 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), 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 self - healing and recyclable functions and high dielectric constant.

[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 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 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 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, 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 3 From Figure 3 it can be seen that the initial stress was 3.58 MPa and the strain was 2407%; the stress after repair at 25 °C was 3.45 MPa and the strain was 2392%.

[0066] The room - temperature self - healing dielectric elastomer material prepared in this example was cut into discs 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 96.4% and 99.4% respectively, and the dielectric constant and dielectric loss were 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) were 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;

[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 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 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 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 97.2% and 99.0% respectively, and the dielectric constant and dielectric loss are 10.4 (@100HZ) and 0.11 (@100HZ) 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, specifically including the following steps:

[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 different from Example 1 only 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, 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] The room-temperature self-healing dielectric elastomer material prepared in this comparative 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 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 is reflected in its suitability for skin adhesion and bendable deformation scenarios; the low dielectric loss is reflected in ensuring signal stability and avoiding energy dissipation; the room-temperature repairability 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 conceived 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 method for preparing a dielectric elastomer material based on a dihydromyricetin structure, characterized in that: Using dihydromyricetin as a bio-based monomer for cross-linking, and adding metal organic salts for coordination, a bio-based polyurethane network that can achieve self-healing at room temperature is constructed; The room temperature is 25±3°C.

2. The method for preparing a dielectric elastomer material based on a dihydromyricetin structure according to claim 1, characterized in that: The specific steps include: The polyetheramine and diisocyanate are prepolymerized in an organic solvent to obtain a prepolymer, and the prepolymer is mixed with a chain extender for reaction, and then dihydromyricetin is added to continue the reaction, and finally a metal organic salt is added for coordination reaction. After the reaction is completed, the solvent is removed to obtain the room temperature self-healing dielectric elastomer material.

3. The method for preparing a dielectric elastomer material based on a dihydromyricetin structure according to claim 2, 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).

4. The method for preparing a dielectric elastomer material based on a dihydromyricetin structure according to claim 2, characterized in that: The prepolymerization reaction was carried out at a temperature of 70° C. and for a period of 1 h.

5. The method for preparing a dielectric elastomer material based on a dihydromyricetin structure according to claim 2, characterized in that: The chain extender is disulfide-4,4'-diaminodiphenyl.

6. The method for preparing a dielectric elastomer material based on a dihydromyricetin structure according to claim 2, characterized in that: The prepolymer and the chain extender are mixed and reacted at a temperature of 70° C. for 2 hours; and / or, The temperature of the continued reaction is 70° C. and the time is 4 hours.

7. The method for preparing a dielectric elastomer material based on a dihydromyricetin structure according to claim 2, characterized in that: The metal organic salt is zinc acetate or zinc acetate dihydrate.

8. The method for preparing a dielectric elastomer material based on a dihydromyricetin structure according to claim 2, characterized in that: The temperature of the coordination reaction is 60° C. and the time is 0.5 h.

9. The dielectric elastomer material based on the dihydromyricetin structure prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the dielectric elastomer material based on the dihydromyricetin structure as claimed in claim 9 in the field of electronic wearables.

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