Self-healing flexible biomimetic composite material with high tear resistance and preparation method thereof

Abstract

The application discloses a self-repairing flexible bionic composite material with high tear resistance and a preparation method thereof. The method is characterized in that a room-temperature self-repairing flexible polyurea elastomer SSPU is prepared by reacting THI, DBI and PDMS. The self-repairing flexible bionic composite material with high tear resistance is prepared by physically mixing the room-temperature self-repairing flexible polyurea elastomer SSPU and a gallium-indium-tin liquid alloy. The self-repairing flexible bionic composite material has the advantages of not affecting the flexibility of the material, greatly improving the tear resistance of the material, and having excellent photo-thermal response characteristics and fast photo-thermal repair capacity, and is suitable for preparing various stretchable and functional devices.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials and relates to a self-healing flexible biomimetic composite material with high tear resistance and its preparation method. Background Technology

[0002] Flexible polymer materials (including elastomers and gels) have attracted widespread attention in important cutting-edge fields such as wearable electronics, soft robotics, and biomedical devices due to their excellent flexibility, high ductility, good conformability, and light weight. To extend their lifespan in dynamic application environments, weak non-covalent interactions are often introduced into existing flexible polymer networks to enable efficient self-healing capabilities without compromising their inherent flexibility. However, these weak interactions inevitably limit the upper limit of the material's fracture energy. This limitation causes flexible self-healing materials to easily fracture along microcracks during deformation, severely reducing or even eliminating the operational reliability of their integrated stretchable devices. As predicted by Lake and Thomas, the critical fracture energy (the minimum energy required to break the elastomer network) of covalent elastomers is limited by the chemical energy of each covalent bond (J. Appl. Polym. Sci. 1965, 9, 1233-1251). Therefore, the stronger the bond strength, the tougher the elastomer theoretically becomes; however, this usually limits the material's self-healing ability, and vice versa (Nat. Rev. Mater. 2020, 5, 562-583). To overcome this contradiction, the fracture energy can be improved to some extent by introducing covalent cross-linked networks (Adv. Mater. 2017, 29, 1702616); combining rigid but incompatible polymers / oligomers to form nano / micro-scale phase-separated structures (Phys. Rev. Lett. 2018, 121, 185501); and embedding meso / macro-scale rigid fillers into the polymer matrix to transfer local stress (Nat. Commun. 2021, 12, 1291). However, these methods often significantly reduce the material's compliance. Developing materials that balance excellent compliance, high ductility, high fracture energy, and self-healing capability remains a significant technical challenge with substantial application value.

[0003] The soft yet resilient smooth muscle tissue in animal small blood vessels can withstand drastic changes in blood pressure without breaking during continuous contraction and relaxation. Vascular smooth muscle is composed of spindle-shaped smooth muscle cells (approximately 20 μm long axis and 8 μm short axis) dispersed in the intercellular matrix (J. Biomech. 2012, 45, 745-755). These smooth muscle cells have a typical nucleoshell structure, with a thin outer shell wrapped by relatively strong cytoskeletal filaments, while the interior is filled with a fluid-like cellular matrix. During passive stretching, the breakage of the external cytoskeletal network of the smooth muscle cells increases the dissipation of mechanical energy near the crack. Simultaneously, the internal fluid properties help to blunt the crack tip under high strain, causing the crack to deflect or even evolve into a longitudinal crack, thus resisting the propagation of cracks perpendicular to the stretching direction and preventing the smooth muscle from failing even in the presence of defects. Moreover, due to the extremely low modulus of the fluid-like cellular matrix, it essentially maintains the inherent softness of the vascular smooth muscle. This unique structure endows vascular smooth muscle with excellent flexibility and high fracture toughness, providing a new approach for the development of high fracture energy self-healing flexible materials. Summary of the Invention

[0004] This invention provides a self-healing flexible biomimetic composite material with high tear resistance and its preparation method. The method employs a strategy of disrupting crystallization behavior to construct "dynamic hard domains" to synthesize a room-temperature self-healing flexible polyurea elastomer (SSPU). Subsequently, gallium indium tin alloy particles with a core-shell structure mimicking smooth muscle cells are filled using a rotational shearing method. These particles function similarly to vascular smooth muscle cells, deforming along the tensile direction with the SSPU matrix, leading to transverse crack branching in the composite material and eventual longitudinal deflection and propagation until the material fractures. Compared to the unfilled polymer matrix SSPU, the prepared smooth muscle-like composite material SSPUGIT exhibits fracture toughness and crack resistance increased by 34.9 times and 12.2 times, respectively, while the increase in Young's modulus is not significant. Combined with the excellent photothermal properties of the gallium indium tin particle filler, SSPUGIT achieves ultra-fast self-healing within 1 minute under 808nm near-infrared (NIR) laser irradiation, with a repair efficiency of ~98.13% ± 1.93%. This method facilitates the toughening design of flexible self-healing materials, resulting in a composite material with extremely high fracture toughness suitable for various stretchable and functional devices.

[0005] The room temperature self-healing flexible polyurea elastomer (SSPU) of this invention has the following structural formula:

[0006]

[0007] X and Y represent the percentage of each structural unit in the polymer, where n = 50–80, X = 0.3–0.5, Y = 0.5–0.7, and X+Y = 100%.

[0008] The preparation method of the room temperature self-healing flexible polyurea elastomer SSPU according to the present invention includes the following steps:

[0009] Step 1: Dissolve aminopropyl-terminated polydimethylsiloxane (PDMS) in an organic solvent and stir until homogeneous to obtain a PDMS solution;

[0010] Step 2: Trimethylhexamethylene diisocyanate (THI) and 4,4'-diisocyanate-3,3'-dimethylbiphenyl (DBI) are mixed and dissolved in an organic solvent at a molar ratio of 7:3 to 5:5. The mixture is then added dropwise to a PDMS solution under a nitrogen atmosphere. The mixture is heated to 55-65°C and stirred continuously to obtain a polymer solution.

[0011] Step 3: Pour the polymer solution into a mold to form and dry to obtain room temperature self-healing flexible polyurea elastomer (SSPU).

[0012] Preferably, in step 1, the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 3000-5000 Da.

[0013] Preferably, in step 1, the concentration of the PDMS solution is 0.1–0.15 mmol / ml.

[0014] Preferably, in step 2, the total molar amount of trimethylhexamethylene diisocyanate and 4,4'-diisocyanate-3,3'-dimethylbiphenyl is the same as the molar amount of aminopropyl-terminated polydimethylsiloxane.

[0015] Preferably, in step 1 or 2, the organic solvent is chloroform, acetone, or tetrahydrofuran.

[0016] Preferably, in step 2, the molar ratio of trimethylhexamethylene diisocyanate and 4,4'-diisocyanate-3,3'-dimethylbiphenyl is 6:4.

[0017] Preferably, in step 2, the reaction time is 1 to 6 hours.

[0018] Preferably, in step 3, the drying procedure is to first dry at room temperature for 6 to 12 hours, and then dry at 60°C for 12 to 24 hours.

[0019] Furthermore, the present invention provides a self-healing flexible biomimetic composite material with high tear resistance, which is composed of room temperature self-healing flexible polyurea elastomer SSPU and gallium indium tin liquid alloy.

[0020] The present invention also provides a method for preparing the above-mentioned self-healing flexible biomimetic composite material with high tear resistance, the specific steps of which are as follows:

[0021] A viscous polymer solution was obtained by dissolving room temperature self-healing flexible polyurea elastomer SSPU in an organic solvent. Then, gallium indium tin liquid alloy was added dropwise in proportion and stirred until uniformly mixed. The solution was then poured into a mold to obtain a self-healing flexible biomimetic composite material with high tear resistance (SSPUGIT-x, where x is the mass ratio of gallium indium tin liquid alloy to SSPU).

[0022] Preferably, the organic solvent is chloroform, acetone or tetrahydrofuran.

[0023] Preferably, the stirring speed is 500-1000 rpm and the stirring time is 30-60 minutes.

[0024] Preferably, the mass ratio of gallium indium tin liquid alloy to SSPU elastomer is 2 to 4:1, more preferably 3:1.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) The self-healing flexible composite material of the present invention greatly improves the tear resistance of the material without significantly affecting its flexibility. The cracked sample can be stretched to the same strain as the intact sample, and the fracture energy can reach up to 111.16 kJ / m. 2 The corresponding tear resistance strain is 1541.75%, which is 34.9 times and 12.2 times higher than that of pure polyurea elastomer.

[0027] (2) The self-healing flexible composite material of the present invention possesses excellent photothermal response characteristics and rapid photothermal repair capability, at 1.99 W / m 2 Under irradiation with 808nm near-infrared laser, the ambient temperature rises to 117.10℃ within 2 seconds, and the mechanical properties can be completely restored within 1 minute, and the puncture hole can be restored to its original state within 2 minutes. Attached Figure Description

[0028] Figure 1 Here is a schematic diagram of the vascular smooth muscle structure (a) and a SEM image of SSPUGIT-3 (b).

[0029] Figure 2 Infrared spectrum of colorless and transparent room temperature self-healing polyurea elastomer SSPU.

[0030] Figure 3 DSC curves of colorless, transparent, room-temperature self-healing polyurea elastomer SSPU.

[0031] Figure 4 DSC curves of crystalline polyurea elastomers: a) SSPU-D; b) SSPU-T.

[0032] Figure 5Small-angle X-ray scattering (SAXS) spectrum of colorless, transparent, room-temperature self-healing polyurea elastomer (SSPU).

[0033] Figure 6 The room temperature self-healing stress-strain curve of colorless and transparent room temperature self-healing polyurea elastomer SSPU.

[0034] Figure 7 Stress-strain curves for a complete SSPU sample and an SSPU sample with a pre-fabricated 1 / 3 width notch in the width direction.

[0035] Figure 8 Stress-strain curves for a complete SSPUGIT-1 sample and an SSPUGIT-1 sample with a pre-fabricated 1 / 3 width notch in the width direction.

[0036] Figure 9 Stress-strain curves for a complete SSPUGIT-2 sample and an SSPUGIT-2 sample with a pre-fabricated 1 / 3 width notch in the width direction.

[0037] Figure 10 Stress-strain curves for a complete SSPUGIT-3 sample and an SSPUGIT-3 sample with a pre-fabricated 1 / 3 width notch in the width direction.

[0038] Figure 11 Stress-strain curves for a complete SSPUGIT-4 sample and an SSPUGIT-4 sample with a pre-made 1 / 3 width notch in the width direction.

[0039] Figure 12 This is a comparison chart of the Young's modulus of each sample.

[0040] Figure 13 Stress-strain curves for a complete SSPUGIT-3-C sample and a SSPUGIT-3-C sample with a pre-fabricated 1 / 3 width notch in the width direction.

[0041] Figure 14 The images show physical samples of SSPU, SSPUGIT-3-C, and SSPUGIT-3 with a pre-fabricated 1 / 3 notch in the width direction under different tensile strains.

[0042] Figure 15 The tear strain and fracture energy variation curves of composite materials filled with gallium indium tin alloys of different mass ratios.

[0043] Figure 16 The stress-strain curves of SSPUGIT-3 after photothermal repair under 808nm near-infrared laser are shown.

[0044] Figure 17A photograph of an SSPUGIT-3 sample with a puncture hole undergoing photothermal repair under an 808nm near-infrared laser. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0046] In the following examples, the aminopropyl-terminated polydimethylsiloxane was purchased from Gelest (USA), the trimethylhexamethylene diisocyanate and 4,4'-diisocyanate-3,3'-dimethylbiphenyl were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and the gallium indium tin liquid alloy was purchased from Zhenjiang Pan-Asia Technology Co., Ltd.

[0047] Example 1

[0048] A method for preparing a self-healing flexible biomimetic composite material with high tear resistance includes the following steps:

[0049] Step 1: Dissolve 2 mmol of aminopropyl-terminated polydimethylsiloxane in 15 ml of chloroform and stir until homogeneous to obtain a PDMS solution;

[0050] Step 2: Mix 1.2 mmol of trimethylhexamethylene diisocyanate and 0.8 mmol of 4,4'-diisocyanate-3,3'-dimethylbiphenyl in 15 ml of chloroform, and add the mixture dropwise to the PDMS solution under a nitrogen atmosphere. Stir continuously at 60 °C for 2 hours to obtain a polymer solution.

[0051] Step 3: Pour the polymer solution into a mold to form and dry to obtain a colorless and transparent polyurea elastomer SSPU with room temperature self-healing function;

[0052] Step 4: Dissolve 4g SSPU in 10ml chloroform to obtain a viscous polymer solution. Add 8g gallium indium tin liquid alloy dropwise to the solution. Stir continuously at a high speed of 600 rpm for 1 hour until a uniform gray-black color is achieved. Then pour the solution into a polytetrafluoroethylene mold.

[0053] Step 5: Dry at room temperature for 12 hours to evaporate the solvent, then tear off and place in a desiccator to obtain SSPUGIT-2, a self-healing flexible biomimetic composite material with high tear resistance.

[0054] Example 2

[0055] A method for preparing a self-healing flexible biomimetic composite material with high tear resistance includes the following steps:

[0056] Step 1: Dissolve 2 mmol of aminopropyl-terminated polydimethylsiloxane in 15 ml of chloroform and stir until homogeneous to obtain a PDMS solution;

[0057] Step 2: Mix 1.2 mmol of trimethylhexamethylene diisocyanate and 0.8 mmol of 4,4'-diisocyanate-3,3'-dimethylbiphenyl in 15 ml of chloroform, and add the mixture dropwise to the PDMS solution under a nitrogen atmosphere. Stir continuously at 60 °C for 2 hours to obtain a polymer solution.

[0058] Step 3: Pour the polymer solution into a mold to form and dry to obtain a colorless and transparent polyurea elastomer SSPU with room temperature self-healing function;

[0059] Step 4: Dissolve 4g SSPU in 10ml chloroform to obtain a viscous polymer solution. Add 12g gallium indium tin liquid alloy dropwise to it. Stir continuously at high speed of 600 rpm for 1 hour with a mechanical stirrer until it turns a uniform gray-black color. Then pour it into a polytetrafluoroethylene mold.

[0060] Step 5: Dry at room temperature for 12 hours to evaporate the solvent, then tear off and place in a desiccator to obtain SSPUGIT-3, a self-healing flexible biomimetic composite material with high tear resistance.

[0061] Example 3

[0062] A method for preparing a self-healing flexible biomimetic composite material with high tear resistance includes the following steps:

[0063] Step 1: Dissolve 2 mmol of aminopropyl-terminated polydimethylsiloxane in 15 ml of chloroform and stir until homogeneous to obtain a PDMS solution;

[0064] Step 2: Mix 1.2 mmol of trimethylhexamethylene diisocyanate and 0.8 mmol of 4,4'-diisocyanate-3,3'-dimethylbiphenyl in 15 ml of chloroform, and add the mixture dropwise to the PDMS solution under a nitrogen atmosphere. Stir continuously at 60 °C for 2 hours to obtain a polymer solution.

[0065] Step 3: Pour the polymer solution into a mold to form and dry to obtain a colorless and transparent polyurea elastomer SSPU with room temperature self-healing function;

[0066] Step 4: Dissolve 4g SSPU in 10ml chloroform to obtain a viscous polymer solution. Add 16g gallium indium tin liquid alloy dropwise to the solution. Stir continuously at a high speed of 600 rpm for 1 hour until a uniform gray-black color is achieved. Then pour the solution into a polytetrafluoroethylene mold.

[0067] Step 5: Dry at room temperature for 12 hours to evaporate the solvent, then tear off and place in a desiccator to obtain SSPUGIT-4, a self-healing flexible biomimetic composite material with high tear resistance.

[0068] like Figure 1 As shown, the blood vessel wall is composed of numerous spindle-shaped core-shell smooth muscle cells, which endow smooth muscle with excellent flexibility and tear resistance. In the composite material SSPUGIT-3, the gallium indium tin liquid alloy exhibits a spindle shape similar to the smooth muscle cell structure.

[0069] like Figure 2 As shown, infrared spectroscopy confirms the successful preparation of the desired self-healing transparent polyurea elastomer material SSPU.

[0070] like Figure 3 As shown, the DSC curve of SSPU shows that no obvious melting endothermic peak was found in the heating cycle and no obvious crystallization exothermic peak was found in the cooling cycle, indicating that SSPU has an amorphous structure.

[0071] like Figure 5 As shown, the small-angle X-ray scattering curve of SSPU indicates that SSPU exhibits a typical microphase separation structure.

[0072] like Figure 6 As shown, SSPU can almost completely restore mechanical properties within 24 hours at room temperature.

[0073] like Figure 7-10 , Figure 15 As shown, with the gradual increase of the proportion of gallium indium tin alloy in the composite material, the tear strain of the composite material increased from 121% to 1542%, and the fracture energy increased from 3.18 kJ / m. 2 Increased to 111.16 kJ / m 2 .

[0074] like Figure 11 , Figure 15 As shown, as the proportion of gallium indium tin alloy continues to increase, the tear strain of the material decreases slightly, indicating that as a low-modulus liquid filler, excessive filling of gallium indium tin alloy will have a negative impact.

[0075] like Figure 12 As shown, the Young's modulus of composite materials filled with different proportions of gallium indium tin alloy are all between 0.71 and 0.86 MPa, with only slight differences compared to the unfilled SSPU polyurea elastomer matrix, indicating that this composite method has little impact on the material's flexibility.

[0076] Comparative Example 1

[0077] Step 1: Dissolve 2 mmol of aminopropyl-terminated polydimethylsiloxane in 15 ml of chloroform and stir until homogeneous to obtain a PDMS solution;

[0078] Step 2: Mix 1.2 mmol of trimethylhexamethylene diisocyanate and 0.8 mmol of 4,4'-diisocyanate-3,3'-dimethylbiphenyl in 15 ml of chloroform, and add the mixture dropwise to the PDMS solution under a nitrogen atmosphere. Stir continuously at 60 °C for 2 hours to obtain a polymer solution.

[0079] Step 3: Pour the polymer solution into a mold to form and dry to obtain a colorless and transparent polyurea elastomer SSPU with room temperature self-healing function;

[0080] Step 4: Dissolve 4g SSPU in 10ml chloroform to obtain a viscous polymer solution. Add 4g gallium indium tin liquid alloy dropwise to the solution. Stir continuously at high speed of 600 rpm for 1 hour with a mechanical stirrer until a uniform gray-black color is achieved. Then pour the solution into a polytetrafluoroethylene mold.

[0081] Step 5: Dry at room temperature for 12 hours to evaporate the solvent, then tear off and place in a desiccator to obtain SSPUGIT-1, a self-healing flexible biomimetic composite material with high tear resistance.

[0082] like Figure 8 , Figure 15 As shown, with a small amount of gallium indium tin alloy filling, the stress and fracture strain of the material are improved, but the tear strain is not significantly improved compared to the unfilled polyurea elastomer SSPU. Cracks can still easily propagate perpendicular to the tensile direction until complete tearing.

[0083] Comparative Example 2

[0084] Step 1: Dissolve 2 mmol of aminopropyl-terminated polydimethylsiloxane in 15 ml of chloroform and stir until homogeneous to obtain a PDMS solution;

[0085] Step 2: Mix 1.2 mmol of trimethylhexamethylene diisocyanate and 0.8 mmol of 4,4'-diisocyanate-3,3'-dimethylbiphenyl in 15 ml of chloroform, and add the mixture dropwise to the PDMS solution under a nitrogen atmosphere. Stir continuously at 60 °C for 2 hours to obtain a polymer solution.

[0086] Step 3: Pour the polymer solution into a mold to form and dry to obtain a colorless and transparent polyurea elastomer SSPU with room temperature self-healing function;

[0087] Step 4: Dissolve 4g SSPU in 10ml chloroform to obtain a viscous polymer solution. Add 12g gallium indium tin liquid alloy dropwise to it. Stir continuously at high speed of 600 rpm for 1 hour with a mechanical stirrer until it turns a uniform gray-black color. Then pour it into a polytetrafluoroethylene mold.

[0088] Step 5: Dry at room temperature for 12 hours to evaporate the solvent, then tear off and place in a desiccator to obtain SSPUGIT-3, a self-healing flexible biomimetic composite material with high tear resistance.

[0089] Step 6: Cut SSPUGIT-3 into small pieces and pile them randomly between two pieces of hot-pressing paper. Press them into a dense composite film at 80°C and 1.5MPa. After cooling to room temperature, peel them off and place them in a desiccator to obtain a composite material SSPUGIT-3-C with the same gallium indium tin alloy ratio as SSPUGIT-3, but whose biomimetic microstructure is destroyed under pressure.

[0090] like Figure 13 As shown, after the biomimetic microstructure is damaged, the stress and fracture strain of SSPUGIT-3-C decrease significantly compared to SSPUGIT-C, and the tear resistance strain also decreases significantly. The tensile strain of the pre-notched sample cannot be consistent with that of the intact sample.

[0091] like Figure 14 As shown, during tensile strain, the three types of pre-notched samples exhibited the following characteristics: the unfilled pure polyurea elastomer SSPU notch tore rapidly; the crack direction of SSPUGIT-3-C, which was filled with gallium indium tin alloy but had its biomimetic microstructure damaged, deflected but could not prevent the crack from extending laterally, and the material still fractured rapidly; for SSPUGIT-3, which was filled with gallium indium tin alloy and whose filler maintained its biomimetic microstructure, the lateral extension of the crack was very small, evolving into a longitudinal crack, forming a straight interface at the original notch, and easily achieving the same large strain as the intact sample.

[0092] like Figure 16 As shown, SSPUGIT-3 has an extremely fast photothermal repair rate. Under irradiation with an 808nm near-infrared laser, it can completely repair the mechanical properties of materials in 1 minute, with a repair efficiency of 98.13% ± 1.93%.

[0093] like Figure 17 As shown, under irradiation with an 808nm near-infrared laser, the puncture hole can be completely repaired within 2 minutes and will not break under significant stretching.

[0094] Comparative Example 3

[0095] Step 1: Dissolve 2 mmol of aminopropyl-terminated polydimethylsiloxane in 15 ml of chloroform and stir until homogeneous to obtain a PDMS solution;

[0096] Step 2: Dissolve 2 mmol of 4,4'-diisocyanate-3,3'-dimethylbiphenyl in 15 ml of chloroform, and add it dropwise to the PDMS solution under a nitrogen atmosphere. Stir continuously at 60 °C for 2 hours to obtain a polymer solution.

[0097] Step 3: Pour the polymer solution into a mold to form and dry to obtain white, translucent polyurea elastomer SSPU-D.

[0098] Comparative Example 4

[0099] Step 1: Dissolve 2 mmol of aminopropyl-terminated polydimethylsiloxane in 15 ml of chloroform and stir until homogeneous to obtain a PDMS solution;

[0100] Step 2: Dissolve 2 mmol of trimethylhexamethylene diisocyanate in 15 ml of chloroform, and add it dropwise to the PDMS solution under a nitrogen atmosphere. Stir continuously at 60 °C for 2 hours to obtain a polymer solution.

[0101] Step 3: Pour the polymer solution into a mold to form and dry to obtain white, translucent polyurea elastomer SSPU-T.

[0102] The prepared SSPU-D and SSPU-T exhibited obvious crystallization behavior and significantly increased hardness, but basically lacked room temperature self-healing function.

[0103] like Figure 4 As shown, obvious endothermic peaks during crystal melting and exothermic peaks during crystallization can be found in the DSC curves of both SSPU-D and SSPU-T, indicating that they have obvious crystallization behavior, and the migration ability of molecular chains is therefore greatly limited.

Claims

1. A room temperature self-healing flexible polyurea elastomer (SSPU), characterized in that, The structure is as follows: ， X and Y represent the percentage of each structural unit in the polymer, where n = 50~80, X = 0.3~0.5, Y = 0.5~0.7, and X+Y = 100%.

2. The method for preparing room temperature self-healing flexible polyurea elastomer (SSPU) according to claim 1, characterized in that, Includes the following steps: Step 1: Dissolve aminopropyl-terminated polydimethylsiloxane in an organic solvent and stir until homogeneous to obtain a PDMS solution; Step 2: Trimethylhexamethylene diisocyanate and 4,4'-diisocyanate-3,3'-dimethylbiphenyl are mixed and dissolved in an organic solvent at a molar ratio of 7:3 to 5:

5. The mixture is then added dropwise to a PDMS solution under a nitrogen atmosphere. The mixture is heated to 55-65 °C and stirred continuously to obtain a polymer solution. Step 3: Pour the polymer solution into a mold to form and dry to obtain room temperature self-healing flexible polyurea elastomer (SSPU).

3. The preparation method according to claim 2, characterized in that, In step 1, the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 3000~5000 Da, and the concentration of the PDMS solution is 0.1~0.15 mmol / ml.

4. The preparation method according to claim 2, characterized in that, In step 2, the total molar amount of trimethylhexamethylene diisocyanate and 4,4'-diisocyanate-3,3'-dimethylbiphenyl is the same as the molar amount of aminopropyl-terminated polydimethylsiloxane; in step 1 or 2, the organic solvent is chloroform, acetone or tetrahydrofuran.

5. The preparation method according to claim 2, characterized in that, In step 2, the molar ratio of trimethylhexamethylene diisocyanate and 4,4'-diisocyanate-3,3'-dimethylbiphenyl is 6:

4.

6. The preparation method according to claim 2, characterized in that, In step 2, the reaction time is 1-6 hours; in step 3, the drying procedure is to first dry at room temperature for 6-12 hours, and then dry at 60 °C for 12-24 hours.

7. A self-healing flexible biomimetic composite material with high tear resistance, characterized in that, It is composed of room temperature self-healing flexible polyurea elastomer SSPU as described in claim 1 and gallium indium tin liquid alloy.

8. The method for preparing the self-healing flexible biomimetic composite material with high tear resistance according to claim 7, characterized in that, The specific steps are as follows: A viscous polymer solution was obtained by dissolving room temperature self-healing flexible polyurea elastomer SSPU in an organic solvent. Then, gallium indium tin liquid alloy was added dropwise in proportion and stirred until uniformly mixed. The solution was then poured into a mold to obtain a self-healing flexible biomimetic composite material with high tear resistance.

9. The preparation method according to claim 8, characterized in that, The organic solvent is chloroform, acetone or tetrahydrofuran, the stirring speed is 500~1000 rpm, and the stirring time is 30~60 minutes.

10. The preparation method according to claim 8, characterized in that, The mass ratio of gallium indium tin liquid alloy to SSPU elastomer is 2~4:

1.

11. The preparation method according to claim 8, characterized in that, The mass ratio of gallium indium tin liquid alloy to SSPU elastomer is 3:1.

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