A triboelectric material with high toughness and self-repairing performance, and a preparation method and application thereof
Patent Information
- Application Number
- CN202611478939.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-22
- Publication Date
- 2026-10-27
Smart Images
Figure CN122978382A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of triboelectric materials technology, specifically relating to a triboelectric material with both high toughness and self-healing properties, its preparation method, and its application. Background Technology
[0002] Triboelectric nanogenerators (TENGs), as an emerging micro-nano energy harvesting technology, utilize the principles of triboelectricity and electrostatic induction, exhibiting excellent harvesting capabilities for low-frequency mechanical energy. They hold broad application prospects in areas such as distributed sensor networks for the Internet of Things (IoT), wearable electronics, and environmental monitoring. TENGs typically consist of a triboelectric layer and an electrode layer, possessing a relatively simple structure yet powerful functionality. The triboelectric layer, as the key component for generating triboelectricity, directly impacts power generation efficiency through its material selection; the electrode layer is responsible for collecting and conducting the generated charge, enabling efficient energy output. Factors influencing the triboelectric performance of TENGs primarily include the inherent properties of the material, its surface condition, and environmental conditions.
[0003] Polyurethane (PU) has become an important matrix for constructing functional polymer materials due to its excellent mechanical flexibility, good film-forming properties, and designable molecular structure. PU is generally composed of alternating soft segments (usually polyether or polyester polyol) and hard segments (polyisocyanates and small amounts of small molecule chain extenders). By adjusting the selection, ratio, and aggregation state of the soft and hard segments, different physical properties can be achieved. The presence of numerous polar groups such as urethane and urea groups on the PU molecular chain gives it a positive charge, making it suitable as a TENG (Temperature Engyling) positive friction layer material.
[0004] However, during actual service, the friction layer material of TENGs experiences surface wear or cracking due to prolonged relative sliding friction, repeated deformation, mechanical scratches, and harsh conditions. This leads to a significant reduction in surface charge, a sharp decrease in electrical output, and even renders the entire device malfunctioning. While polyurethane can be endowed with self-healing capabilities by introducing reversible dynamic interactions, traditional self-healing polyurethanes are mainly used in coatings and thin film materials, and often rely on a single dynamic bond network. This makes it difficult to simultaneously consider the material's mechanical strength, self-healing efficiency, and electrical properties as a friction material.
[0005] For example, while PU systems relying solely on hydrogen bonds possess some self-healing capabilities, the recovery rate of mechanical properties after repair is low. After 24 hours of repair at 100°C, such materials can recover approximately 90% of their elongation at break, but the fracture strength can only recover to 75% of its original value, indicating that the individual hydrogen bond network is insufficient. Therefore, there is an urgent need to develop a triboelectric material that combines high strength, high toughness, and efficient self-healing properties. Summary of the Invention
[0006] To address the challenge of simultaneously achieving high mechanical properties and self-healing efficiency in existing self-healing triboelectric materials, this invention provides a triboelectric material with both high toughness and self-healing properties, along with its preparation method and applications. This invention utilizes the addition of a diaminoglyoxime chemical crosslinking agent, leveraging its tetrafunctionality to form a dual dynamic network with adipic acid dihydrazide and prepolymer through multiple hydrogen bonds. In this dual dynamic network, the chemical crosslinking points provide structural support to ensure high strength, while the multiple hydrogen bonds endow the material with rapid recombination capabilities for efficient self-healing. The synergistic effect of these two factors effectively solves the problem of performance imbalance in a single network, enabling the material to maintain excellent triboelectric output while possessing outstanding toughness and damage recovery capabilities, significantly extending the lifespan of devices. This provides a new material foundation for the development of high-performance self-healing electronic skin and flexible sensors.
[0007] This invention is achieved through the following technical solution:
[0008] A method for preparing a triboelectric material with both high toughness and self-healing properties includes the following steps:
[0009] (1) Polytetrahydrofuran ether diol (PTMG), isophorone diisocyanate (IPDI) and dibutyltin dilaurate (DBTDL) catalyst are mixed and reacted at 60~120℃ for 2~6h under inert gas protection to obtain a prepolymer;
[0010] (2) Dissolve adipic acid dihydrazide (ADH) in a solvent and add it to the prepolymer obtained in step (1), and continue to react at 40~60℃ for 6~24h;
[0011] (3) After dissolving diaminoglyoxime (DAG) in a solvent, add it to the reaction system of step (2) and continue to react at 70~90℃ for 6~24h to obtain a polyurethane elastomer solution;
[0012] (4) The polyurethane elastomer solution obtained in step (3) is heated to form a film, and then dried to obtain a triboelectric material with both high toughness and self-healing properties.
[0013] Further, in step (1), the polytetrahydrofuran ether diol is first pretreated by vacuum dehydration. The dehydration conditions are vacuuming at 80~160℃ for 0.5~3h, with a vacuum degree of 0~20KPa. The molar ratio of polytetrahydrofuran ether diol (PTMG) to isophorone diisocyanate (IPDI) is 1:0.25~5. The molar ratio of dibutyltin dilaurate (DBTDL) catalyst to polytetrahydrofuran ether diol (PTMG) is 0.03~0.1:1.
[0014] Further, in step (2), the amount of adipic dihydrazide (ADH) added is 0.1~0.3:1 in molar ratio with isophorone diisocyanate (IPDI).
[0015] Further, in step (3), the molar ratio of diaminoglyoxime (DAG) to the molar amount of isophorone diisocyanate (IPDI) is 0.1~0.3:1.
[0016] Furthermore, in steps (2) and (3), the solvent is dimethylacetamide (DMAc).
[0017] Further, in step (4), the heating to form a film is performed by heating at 60~160℃ for 6~48h; the drying is performed by drying the polyurethane elastomer after film formation in a vacuum oven at 60~120℃ for 6~48h.
[0018] The triboelectric material prepared by the method of the present invention has both high toughness and self-healing properties. The tensile strength of the triboelectric material is 33-55 MPa, the elongation at break is 800-960%, and the toughness is 74-175 MJ / m³.
[0019] The triboelectric material of this invention, possessing both high toughness and self-healing properties, can be applied to triboelectric nanogenerators. When applied to triboelectric nanogenerators, a vertical contact-separation mode is adopted, with the positive electrode material being the triboelectric material film of this invention and the negative electrode material being a fluorinated ethylene propylene copolymer (FEP) film.
[0020] When the triboelectric material of the present invention, which combines high toughness and self-healing properties, is applied to triboelectric nanogenerators, the open-circuit voltage of the triboelectric nanogenerator can reach 130~163 V, the short-circuit current can reach 4~6.5 μA or more, and the transferred charge can reach 6~9 nC / cm² or more; after being cut off and repaired at 80℃ for 12 hours, its output repair rate reaches 98%.
[0021] The triboelectric nanogenerator of this invention can be applied in self-powered sensing or smart packaging. It can be developed into a highly sensitive sensor for monitoring the transportation status of packaged goods.
[0022] The reaction principle of the present invention is as follows: (1) Polytetrahydrofuran ether diol (PTMG) is used as a soft segment to give the material flexibility, and isophorone diisocyanate (IPDI) is used as a hard segment to combine with adipate dihydrazide (ADH) chain extender and diaminoglyoxime (DAG) tetrafunctional crosslinking agent to form hard segment microdomains.
[0023] The equimolar ratio of adipic dihydrazide (ADH) to diaminoglyoxime (DAG) ensures the optimal match between the multiple hydrogen bond network and the tetrafunctional chemical cross-linking points. The chemical cross-linking points provided by diaminoglyoxime (DAG) serve as the network backbone, while the multiple hydrogen bonds generated by adipic dihydrazide (ADH) serve as reinforcing units. They self-assemble within the hard segment microregions to form a ladder structure similar to DNA base pairs.
[0024] (2) The tetrafunctional chemical cross-linking points in diaminoglyoxime (DAG) form a stable framework, preventing creep and plastic deformation caused solely by hydrogen bond networks; the combined action of adipic dihydrazide (ADH) and diaminoglyoxime (DAG) produces an ordered hard segment aggregation state, which can play a good role in stress transfer; the synergistic effect of a large number of hydrogen bonds and dynamic oxime bonds gives the polymer excellent self-healing ability.
[0025] (3) Increased temperature can induce dynamic dissociation of the hydrogen bond network at the polyurethane damage interface, releasing molecular chain segments that gain sufficient mobility to achieve diffusion and entanglement across the damage interface. When the temperature decreases, hydrogen bond interactions are re-established at the interface, thereby completing the damage healing process.
[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0027] 1. This invention constructs a polyurethane elastomer material based on the synergistic effect of adipic dihydrazide (ADH) and diaminoglyoxime (DAG). The material utilizes the tetrafunctional chemical crosslinking of DAG and the multiple hydrogen bonds of ADH to form a dual dynamic network. The prepared material exhibits excellent mechanical properties, with a tensile strength reaching 53.23 MPa, an elongation at break of 950%, and a toughness of 174.32 MJ / m³, significantly superior to the basic PU system containing only hydrogen bonds (tensile strength 26 MPa, toughness 85 MJ / m³).
[0028] 2. The polyurethane elastomer prepared by this invention has a high self-healing ability. Thanks to its dual dynamic network, the material can achieve a self-healing rate of 90.7% under 80℃ / 12h conditions. Based on this material, the TENG, after being cut, can achieve an output performance repair rate of over 98% after 80℃ / 12h repair, which is far superior to the repair effect of the basic system.
[0029] 3. Based on the material of this invention as the positive electrode, the TENG has an open-circuit voltage of up to 162 V, a short-circuit current of 6.50 μA, a transfer charge of 8.78 nC / cm², stable performance after 4000s of continuous operation, and an open-circuit voltage drop of only 1.2%; after being cut off and repaired at 80℃ for 12 hours, its output repair rate reaches 98%.
[0030] 4. The polyurethane elastomer prepared by this invention has good recyclability. After three hot-press recycling cycles, the stress-strain curves almost overlap, and the strength retention rate after the first recycling reaches 94.2%.
[0031] 5. The TENG prepared by this invention has good triboelectric and mechanical properties, and can be used to develop a highly sensitive sensor for monitoring the transportation status of packaged goods. The output voltage is 18V, 39V, 55V, and 66V corresponding to a drop height of 10-40cm, with a linear relationship R²=0.9787, which realizes accurate perception of the changes in the status of packaged goods during transportation. Attached Figure Description
[0032] Figure 1 The images show the FTIR spectra of the material samples from Examples 1-5. Figure 1 (a) Wavenumber 4000-500 cm -1 ; Figure 1 (b) Wavenumber 1750-1500 cm -1 ; Figure 1 (c) Wavenumber 3500-3000 cm -1 .
[0033] Figure 2 The images show the XRD patterns of the material samples from Examples 1-5.
[0034] Figure 3 The thermal performance analysis spectra of the material samples in Examples 1-5 are shown below. Figure 3 (a) is a TGA curve graph; Figure 3 (b) is a DTG curve.
[0035] Figure 4 The images show the temperature-dependent infrared spectra of PU 2.5 in Example 1 at different wavenumber ranges. Figure 4 (a) is 3050-3500 cm -1 Variable-temperature infrared spectra within the wavenumber range; Figure 4 (b) is 1500-1800 cm -1 Variable temperature infrared (VT-FTIR) spectra within the wavenumber range.
[0036] Figure 5 For example, PU 2.5 in Example 1 was heated to 1760-1600 cm. -1 The 2D-COS spectrum is obtained from two-dimensional correlation spectral analysis of the spectrum. Figure 5 (a) is the synchronous spectrum; Figure 5 (b) is an asynchronous spectrum.
[0037] Figure 6 For example, PU 2.5 in Example 1 is at 2280-2260 cm.-1 Variable-temperature infrared spectrum within the wavenumber range.
[0038] Figure 7 The figures show the mechanical properties of the material samples from Examples 1-5. Figure 7 (a) is a stress-strain curve diagram; Figure 7 (b) is a bar chart of tensile strength-elongation at break-toughness.
[0039] Figure 8 This is a cyclic tensile test diagram of PU 2.5 in Example 1. Figure 8 (a) is a graph of five cycles of tensile testing at 400% strain; Figure 8 (b) is a loading-unloading cycle curve when the strain increases from 100% to 500%.
[0040] Figure 9 The figures show the results of PU 2.5 being repaired at 80°C for different times in Example 1. Figure 9 (a) Stress-strain curves after repair at 80℃ for different times; Figure 9 (b) is a bar chart showing the self-healing efficiency after different repair times at 80°C.
[0041] Figure 10 The figures show the mechanical properties of PU 2.5 after 12 hours of repair at different temperatures in Example 1. Figure 10 (a) Stress-strain curves after 12 h of repair at different temperatures; Figure 10 (b) Bar chart of self-healing efficiency after 12 h of repair at different temperatures.
[0042] Figure 11 The stress-strain curves of PU 1 before and after repair at 100℃ for 24 h are shown in Comparative Example 1.
[0043] Figure 12 The image shows the stress-strain curves of PU 2.5 before and after three hot-pressing recycling processes in Example 1.
[0044] Figure 13 The electrical output performance of PU in different proportions in the material samples of Examples 1-5 is shown. Figure 13 (a) is the open-circuit voltage; Figure 13 (b) represents the short-circuit current; Figure 13 (c) represents the amount of charge transferred during short circuit (test area is 9 cm²). 2 ).
[0045] Figure 14 The output voltage of PU 2.5 under different conditions in Example 1 is shown. Figure 14 (a) represents different contact areas; Figure 14 (b) represents different stretch ratios.
[0046] Figure 15 This refers to the long-term electrical stability of PU 2.5 in Example 1 over 4000 seconds.
[0047] Figure 16 The TENG sensor assembled from the PU 2.5 sample in Example 1 is shown as the output voltage when dropped from different heights onto the packaging. Figure 16 (a) is a surface drop; Figure 16 (b) is a fall from the sill. Detailed Implementation
[0048] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of protection of the present invention.
[0049] Example 1
[0050] A method for preparing a triboelectric material with both high toughness and self-healing properties includes the following steps:
[0051] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Then dissolve 2.7785 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add it to the three-necked flask with a syringe. The reaction system is mechanically stirred at 80 °C for 3 h under a nitrogen atmosphere and then cooled to 40 °C to obtain an isocyanate-terminated prepolymer.
[0052] (2) Dissolve 0.4355g of adipic dihydrazide (ADH) in 20ml of dimethylacetamide (DMAc), add it to the prepolymer system of step (1) with a syringe, and react at 45°C for 12h.
[0053] (3) Dissolve 0.2952g of diaminoglyoxime (DAG) in 30ml of dimethylacetamide (DMAc), add it to the reaction system of step (2) and continue the reaction for 12h at a reaction temperature of 80℃ to obtain a polyurethane elastomer solution (referred to as: PU 2.5 solution).
[0054] (4) Pour the PU 2.5 solution into a glass petri dish and heat it on an 80°C heating plate for 24 hours to dry the solvent and form a film. Then dry it in an 80°C vacuum oven for 24 hours to completely remove the solvent. Finally, a PU 2.5 polyurethane elastomer film is obtained, which is a triboelectric material with both high toughness and self-healing properties (denoted as: PU 2.5).
[0055] Example 2
[0056] A method for preparing a triboelectric material with both high toughness and self-healing properties includes the following steps:
[0057] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Dissolve 1.9450 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add the solution to the three-necked flask using a syringe. The reaction system is mechanically stirred at 80 °C for 3 h under a nitrogen atmosphere and then cooled to 40 °C to obtain an isocyanate-terminated prepolymer.
[0058] (2) Dissolve 0.2177g of adipic dihydrazide (ADH) in 20ml of dimethylacetamide (DMAc), add it to the prepolymer system of step (1) with a syringe, and react at 45°C for 12h.
[0059] (3) Dissolve 0.1476g of diaminoglyoxime (DAG) in 30ml of dimethylacetamide (DMAc), add it to the reaction system of step (2) and continue the reaction for 12h at a reaction temperature of 80℃ to obtain a polyurethane elastomer solution (referred to as: PU 1.75 solution).
[0060] (4) Pour the PU 1.75 solution into a glass petri dish and heat it on an 80°C heating table for 24 hours to dry the solvent and form a film. Then dry it in a vacuum oven at 80°C for 24 hours to completely remove the solvent. Finally, a PU 1.75 polyurethane elastomer film is obtained, which is a triboelectric material with both high toughness and self-healing properties (denoted as: PU 1.75).
[0061] Example 3
[0062] A method for preparing a triboelectric material with both high toughness and self-healing properties includes the following steps:
[0063] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Dissolve 2.2229 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add it to the above three-necked flask with a syringe. The reaction system is mechanically stirred at 80 °C for 3 h under a nitrogen atmosphere and then cooled to 40 °C to obtain an isocyanate-terminated prepolymer.
[0064] (2) Dissolve 0.2903g of adipic dihydrazide (ADH) in 20ml of dimethylacetamide (DMAc), add it to the prepolymer system of step (1) with a syringe, and react at 45°C for 12h.
[0065] (3) Dissolve 0.1968g of diaminoglyoxime (DAG) in 30ml of dimethylacetamide (DMAc), add it to the reaction system of step (2) and continue the reaction for 12h at a reaction temperature of 80℃ to obtain a polyurethane elastomer solution (denoted as: PU 2 solution).
[0066] (4) Pour the PU 2 solution into a glass petri dish and heat it on an 80°C heating table for 24 hours to dry the solvent and form a film. Then dry it in a vacuum oven at 80°C for 24 hours to completely remove the solvent. Finally, a PU 2 polyurethane elastomer film is obtained, which is a triboelectric material with both high toughness and self-healing properties (denoted as: PU 2).
[0067] Example 4
[0068] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Dissolve 2.5008 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add it to the above three-necked flask with a syringe. The reaction system is mechanically stirred at 80 °C for 3 h under a nitrogen atmosphere and then cooled to 40 °C to obtain an isocyanate-terminated prepolymer.
[0069] (2) Dissolve 0.3629 g of adipic dihydrazide (ADH) in 20 ml of dimethylacetamide (DMAc), add it to the prepolymer system of step (1) with a syringe, and react at 45 °C for 12 h.
[0070] (3) Dissolve 0.2460g of diaminoglyoxime (DAG) in 30ml of dimethylacetamide (DMAc), add it to the reaction system of step (2) and continue the reaction for 12h at a reaction temperature of 80℃ to obtain a polyurethane elastomer solution (referred to as: PU 2.25 solution).
[0071] (4) Pour the PU 2.25 solution into a glass petri dish and heat it on an 80°C heating plate for 24 hours to dry the solvent and form a film. Then dry it in a vacuum oven at 80°C for 24 hours to completely remove the solvent. Finally, a PU 2.25 polyurethane elastomer film is obtained, which is a triboelectric material with both high toughness and self-healing properties (denoted as: PU 2.25).
[0072] Example 5
[0073] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Dissolve 3.0565 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add it to the above three-necked flask with a syringe. The reaction system is mechanically stirred at 80 °C for 3 h under a nitrogen atmosphere and then cooled to 40 °C to obtain an isocyanate-terminated prepolymer.
[0074] (2) Dissolve 0.5080g of adipic dihydrazide (ADH) in 20ml of dimethylacetamide (DMAc), add it to the prepolymer system of step (1) with a syringe, and react at 45°C for 12h.
[0075] (3) Dissolve 0.3444g of diaminoglyoxime (DAG) in 30ml of dimethylacetamide (DMAc), add it to the reaction system of step (2) and continue the reaction for 12h at a reaction temperature of 80℃ to obtain a polyurethane elastomer solution (referred to as: PU 2.75 solution).
[0076] (4) Pour the PU 2.75 solution into a glass petri dish and heat it on an 80°C heating plate for 24 hours to dry the solvent and form a film. Then dry it in an 80°C vacuum oven for 24 hours to completely remove the solvent. Finally, a PU 2.75 polyurethane elastomer film is obtained, which is a triboelectric material with high toughness and self-healing properties (denoted as: PU 2.75).
[0077] Example 6
[0078] A method for preparing a triboelectric material with both high toughness and self-healing properties includes the following steps:
[0079] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Then dissolve 2.7785 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add it to the above three-necked flask with a syringe. The reaction system is mechanically stirred at 60 °C for 6 h under a nitrogen atmosphere and then cooled to 50 °C to obtain an isocyanate-terminated prepolymer.
[0080] (2) Dissolve 0.4355g of adipic dihydrazide (ADH) in 20ml of dimethylacetamide (DMAc), add it to the prepolymer system of step (1) with a syringe, and react at 40℃ for 24h.
[0081] (3) Dissolve 0.2952g of diaminoglyoxime (DAG) in 30ml of dimethylacetamide (DMAc), add it to the reaction system of step (2) and continue the reaction for 24h at a reaction temperature of 70℃ to obtain a polyurethane elastomer solution.
[0082] (4) Pour the PU 2.5 solution into a glass petri dish and heat it on a 60°C heating table for 48 hours to dry the solvent and form a film. Then dry it in a 60°C vacuum oven for 48 hours to completely remove the solvent. Finally, a polyurethane elastomer film is obtained, which is a triboelectric material with both high toughness and self-healing properties.
[0083] Example 7
[0084] A method for preparing a triboelectric material with both high toughness and self-healing properties includes the following steps:
[0085] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Then dissolve 2.7785 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add it to the three-necked flask with a syringe. The reaction system is mechanically stirred at 120 °C for 2 h under a nitrogen atmosphere and then cooled to 60 °C to obtain an isocyanate-terminated prepolymer.
[0086] (2) Dissolve 0.4355g of adipic dihydrazide (ADH) in 20ml of dimethylacetamide (DMAc), add it to the prepolymer system of step (1) with a syringe, and react at 60℃ for 6h.
[0087] (3) Dissolve 0.2952g of diaminoglyoxime (DAG) in 30ml of dimethylacetamide (DMAc), add it to the reaction system of step (2) and continue the reaction for 6h at a reaction temperature of 90℃ to obtain a polyurethane elastomer solution.
[0088] (4) Pour the PU 2.5 solution into a glass petri dish and heat it on a heating table at 160°C for 6 hours to dry the solvent and form a film. Then dry it in a vacuum oven at 120°C for 6 hours to completely remove the solvent. Finally, a polyurethane elastomer film is obtained, which is a triboelectric material with both high toughness and self-healing properties.
[0089] Comparative Example 1
[0090] The preparation method of a basic PU elastomer containing only hydrogen bond networks includes the following steps:
[0091] (1) Place 10.0 g of polytetrahydrofuran ether diol (PTMG) in a 250 ml three-necked flask and dehydrate it under vacuum at 110 °C for 1 h. Dissolve 2.2228 g of isophorone diisocyanate (IPDI) and 160 mg of dibutyltin dilaurate (DBTDL) catalyst in 10 ml of dimethylacetamide (DMAc) and add the solution to the three-necked flask using a syringe. The reaction system is mechanically stirred at 80 °C for 3 h under a nitrogen atmosphere and then cooled to 40 °C to obtain an isocyanate-terminated prepolymer.
[0092] (2) Dissolve 0.871 g of adipic dihydrazide (ADH) in 20 ml of dimethylacetamide (DMAc), and add it to the prepolymer system of step (1) using a syringe. React at 40 °C for 12 h. In this comparative example, no diaminoglyoxime (DAG) crosslinking agent was added to prepare a basic PU system containing only hydrogen bond networks (denoted as: PU 1).
[0093] (3) Pour the solution after the reaction into a glass petri dish, heat it on an 80°C heating plate for 24 hours to dry the solvent, and then dry it in an 80°C vacuum oven for 24 hours to completely remove the solvent, thus obtaining the basic PU elastomer film.
[0094] I. Material Characterization Analysis
[0095] (I) FTIR spectral analysis
[0096] The structural characterization of the material samples prepared in Examples 1-5 was performed using Fourier transform infrared spectroscopy. The results are as follows: Figure 1 As shown, at 2275 cm -1 The -N=C=O group at the corresponding position completely disappears in the polymer network, indicating that the isocyanate groups in isophorone diisocyanate (IPDI) have been completely consumed, and the reaction is complete. The peak values are located at 3326 cm⁻¹. -1 and 1717cm -1 These were assigned as tensile vibrations of -NH- and C=O, respectively, consistent with the formation of polyurethane groups. The highest peaks were 1533 cm⁻¹ and 1533 cm⁻¹, respectively. -1 and 954 cm -1 The presence of diaminoglyoxime (DAG) in the polymer network was confirmed by the stretching and bending vibrations of the -C=N- and NO groups, respectively.
[0097] (II) XRD Analysis
[0098] The material samples prepared in Examples 1-5 were analyzed by X-ray diffraction, and the results are as follows: Figure 2As shown, the synthesized polyurethane elastomer film material exhibits typical amorphous or amorphous structural characteristics. No sharp crystalline diffraction peaks were observed in its diffraction pattern; only a broad and diffuse diffraction peak was observed near 2θ≈20°. This is due to the amorphous peak characteristic of amorphous polymers caused by the short-range ordered arrangement within the polyurethane molecular chains. The alicyclic structure of isophorone diisocyanate (IPDI) inhibits long-range crystallization of the hard segments, while the branching topological effect of the four-arm crosslinking chain extender diaminoglyoxime (DAG) further breaks the linear regularity of the molecular chains, reinforcing the amorphous characteristics of the material.
[0099] (III) TGA Analysis
[0100] Thermogravimetric analysis was performed on the material samples prepared in Examples 1-5, and the results are as follows: Figure 3 As shown, the synthesized polyurethane exhibits good overall thermal stability. The material decomposes in three stages: the first stage (250-370℃) is the pyrolysis of the urethane in the hard segment; the second stage (370-450℃) is the thermal oxidative pyrolysis of the polyether soft segment polytetrahydrofuran ether diol (PTMG); and the third stage (450-630℃) is the further pyrolysis of the residue. The T5% of the material samples in Examples 1-5 are all greater than 288℃, which meets the basic requirements for heat resistance in subsequent use.
[0101] (iv) VT-FTIR and 2D-COS analysis
[0102] The PU 2.5 prepared in Example 1 was studied using variable-temperature Fourier transform infrared spectroscopy (VT-FTIR), and the results are as follows: Figure 4 As shown, this indicates that as the temperature rises from 30℃ to 120℃, 3321 cm -1 The absorption peak gradually shifts to higher wavenumbers and weakens in intensity, indicating that heating causes the hydrogen bond network in the system to dissociate.
[0103] The PU 2.5 prepared in Example 1 was analyzed using two-dimensional correlation spectroscopy (2D-COS). Figure 5 As shown, the response order of hydrogen-bonded groups with increasing temperature is: 1703 cm⁻¹ -1 Orientation 1713 cm -1 To transform, and then move towards 1639 cm -1 The transformations correspond to the C=O stretching vibrations of hydrogen-bonded urethane, free urethane, and hydrogen-bonded urea groups, respectively, indicating that the hydrogen bond network breaks in a hierarchical manner.
[0104] At the same time Figure 6 It can be seen that the PU 2.5 prepared in Example 1 has a diameter of 2267 cm. -1The presence of distinct absorption peaks at the wavelength range, which are attributed to the stretching vibrations of the isocyanate groups, confirms that the urethane bonds in the system undergo reversible dissociation under the synergistic effect of the oxime bond and high temperature.
[0105] The above results indicate that increasing temperature induces dynamic dissociation of the hydrogen bond network at the damaged interface of polyurethane, releasing molecular chain segments that gain sufficient mobility to diffuse and entangle across the damaged interface. When the temperature decreases, hydrogen bond interactions are re-established at the interface, thus completing the damage healing process. Therefore, the main reason why the material possesses both high mechanical strength and high repair efficiency is that the high-density multi-hydrogen bond network formed in the hard segment microregions constructed from ADH and DAG exhibits significant thermal response dynamic characteristics. Heating activates the reversible breakage and recombination of hydrogen bonds, providing conditions for chain segment movement; after cooling, the hydrogen bond network reforms, restoring mechanical properties. The self-healing ability of PU 2.5 mainly stems from the dynamic reversible characteristics of the multi-hydrogen bond network and its synergistic effect with dynamic oxime bonds.
[0106] II. Material Performance Testing and Analysis
[0107] (I) Mechanical property testing and analysis
[0108] Tensile tests were performed on the material samples prepared in Examples 1-5 using a vertical tensile testing machine. The results are shown in Table 1 and... Figure 7 As shown.
[0109] Table 1 Comparison of mechanical properties of material samples from Examples 1-5
[0110]
[0111] As shown in Table 1 above, with the increase of chain extender content, the hardness and strength of the material samples show a trend of first increasing and then decreasing. From PU 1.75 to PU 2.5, the tensile strength continuously increases, reaching a maximum of 53.23 MPa at PU 2.5, which is about 693% higher than that of PU 1.75. At PU 2.75, the tensile strength can still be maintained at 50.56 MPa.
[0112] The elongation at break gradually decreased from 1123% for PU 1.75 to 803% for PU 2.75.
[0113] Toughness also shows a trend of first increasing and then decreasing with the increase of chain extender content. It is optimal at PU 2.5, reaching 174.32 MJ / m³. The toughness of PU 2.75 can still be maintained at 138.38 MJ / m³.
[0114] To further verify the material properties of PU 2.5 obtained in Example 1, cyclic tensile tests were performed on it, and the results are as follows: Figure 8 As shown. By Figure 8 (a) It can be seen that after five cycles of tensile testing at 400% strain, the tensile strength remains at 3.12 MPa, which is 30.67% of the original strength. Figure 8 (b) It can be seen that the tensile strength of the material can reach 10.48 MPa when the strain increases from 100% to 500%. It can be observed that as the given strain gradually increases, the loading curves at various strains all rise along the envelope of a single tensile curve, and there is a certain residual strain after unloading, which increases with the given strain. This indicates that there is a hierarchical energy dissipation mechanism within the material. In the low strain range (100%-200%), the breaking and formation of weak hydrogen bonds are the main processes, resulting in less energy dissipation and a smaller residual strain. When the strain increases to 300%-400%, strong hydrogen bonds begin to participate in the breaking process, enhancing the energy dissipation capacity and significantly increasing the residual strain. Under the maximum strain condition (500%), a small number of chemical crosslinking points may be irreversibly damaged or the chain segments may undergo relative displacement, resulting in significant energy dissipation. Furthermore, the hysteresis loop area also continuously increases with increasing strain at each different strain. This is because energy can be dissipated well under different deformation degrees, which is the result of the combined action of multiple dynamic bonds.
[0115] (II) Self-healing performance test analysis
[0116] (1) The PU 2.5 sample prepared in Example 1 was subjected to self-healing tests at 80°C for different times. The results of the self-healing tests are as follows: Figure 9 As shown, the self-healing effect is better with increasing repair time. After 12 hours, the self-healing rate can reach 90.7%, and the tensile strength remains at 48.29 MPa.
[0117] (2) A temperature gradient test was conducted on the PU 2.5 sample prepared in Example 1, and the results are as follows: Figure 10 As shown. From Figure 10 It can be seen that the mechanical properties of the sample were improved to some extent after repair at 60℃ for 12 hours, but not ideally; the tensile strength and elongation at break were improved after repair at 70℃ for 12 hours; and the best self-healing effect was obtained after repair at 80℃ for 12 hours.
[0118] (3) The performance of the original material and its self-healing material in Comparative Example 1 were compared, and the results are as follows: Figure 11 It can be seen that after repairing at 100℃ for 24 hours, the elongation at break of the basic PU 1 system prepared in Comparative Example 1 recovered to about 90%, but the tensile strength only recovered to 75%, indicating that the single hydrogen bond network has limitations in achieving efficient self-repair.
[0119] (III) Recyclability Performance Testing and Analysis
[0120] The PU 2.5 sample film prepared in Example 1 was subjected to three breakage-hot pressing cycle experiments, and the results are as follows: Figure 12 As shown, the stress-strain curves almost completely overlap. The initial tensile strength of the sample was 48.2 MPa, and after one hot-press recovery, the strength was still 45.4 MPa, with a strength retention rate of 94.2%. In the subsequent two cycles, the elastic modulus, elongation at break, and strength showed almost no change, indicating that the system has good structural resilience and chemical stability for hot working.
[0121] (iv) Triboelectric performance testing and analysis
[0122] TENG was prepared using a vertical contact-separation method. The positive electrode was a 3×3 cm² PU 2.5 film bonded to copper adhesive from Example 1, and the negative electrode was a 3×3 cm² FEP film bonded to copper adhesive. Both were fixed on an acrylic substrate, and then triboelectric properties were tested.
[0123] (1) The material samples obtained in Examples 1-5 were tested, and the results are shown in Table 2 and... Figure 13 (a) and Figure 13 As shown in (b).
[0124] Table 2 Comparison of TENG triboelectric properties of material samples prepared in Examples 1-5
[0125]
[0126] From Table 2, Figure 13 (a) and Figure 13 (b) It can be seen that the triboelectric output performance of PU changes systematically with the change of the formulation ratio. Among them, PU 2.5 exhibits the best triboelectric output performance, with a peak open-circuit voltage of 162 V, a short-circuit current of 6.50 μA, and a short-circuit transferred charge of 8.78 nC / cm. 2 The transferred charge of PU 2.5 was 169% higher than that of PU 1.75. This performance difference can be attributed to the influence of the material's dynamic network structure on its charge capture and storage capabilities: a suitable ratio allows for the formation of a relatively complete multiple hydrogen bond network in PU 2.5, enabling a large number of polar groups to effectively capture and store charge during friction; simultaneously, a suitable crosslinking density ensures appropriate mobility of molecular chain segments, which is beneficial for sufficient contact at the friction interface. When the dynamic bond density is too low, the number of polar groups is insufficient, limiting the charge capture capability; when the dynamic bond density is too high, the overly dense crosslinking network may restrict the movement of molecular chain segments, affecting the effective contact area of the friction interface, which is detrimental to charge accumulation and transfer. These results indicate that by adjusting the ratio to optimize the dynamic network structure of PU 2.5, its triboelectric output performance can be effectively improved, providing experimental evidence for the application of the material in self-powered sensors and energy harvesting devices.
[0127] After the PU 2.5 sample prepared in Example 1 was completely cut open, the triboelectric test results showed an open-circuit voltage of only 75V, with an output reduction of approximately 50%, indicating that the integrity of the triboelectric layer is a crucial factor affecting the output. After the completely cut PU 2.5 sample was repaired at 80℃ for 12 hours, the material recovered to its original output performance, with the open-circuit voltage returning to 159V, achieving a repair rate exceeding 98%. This demonstrates its excellent repair characteristics in practical use.
[0128] (2) The output voltage performance of the PU 2.5 sample prepared in Example 1 was tested under different conditions. From Figure 14 (a) shows that the open-circuit voltage is directly proportional to the effective contact area, based on the test results under different triboelectric contact areas. Figure 14 (b) The test results of different stretching ratios show that as the stretching ratio increases, the open circuit voltage gradually increases and remains stable. Under 400% stretching, the open circuit voltage is 90V, indicating that the material has good stretchability.
[0129] (3) During the continuous operation of the PU 2.5 sample prepared in Example 1 for 4000s, the open circuit voltage remained stable at around 160V, decreasing by only 1.2% (e.g., Figure 15 (As shown).
[0130] (v) Application of packaging drop detection
[0131] The TENG sensor assembled from the PU 2.5 sample prepared in Example 1 was fixed to the packaging and drop tests were conducted from four heights: 10cm, 20cm, 30cm, and 40cm.
[0132] Surface drop test results as follows Figure 16 As shown in (a), it can be seen that as the drop height increases from 10cm to 40cm, the output voltage shows a significant upward trend, with values of 18V, 39V, 55V and 66V respectively, and the linear relationship is R²=0.9787.
[0133] Drop test results as follows Figure 16 As shown in (b), it can be seen that it is similar to the surface drop test. As the drop height increases, the output voltage shows a significant upward trend, but the output waveform characteristics are different.
[0134] therefore, Figure 16 (a) and Figure 16 (b) The comparison shows that by analyzing the voltage output waveform characteristics, the two different drop types, surface drop and edge drop, can be effectively distinguished. This also effectively demonstrates that the triboelectric material of this invention can be applied to TENGs and achieves good results.
[0135] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a triboelectric material possessing both high toughness and self-healing properties, characterized in that, Includes the following steps: (1) Mix polytetrahydrofuran ether diol, isophorone diisocyanate and dibutyltin dilaurate catalyst, and react under inert gas protection at 60~120℃ for 2~6h to obtain prepolymer; (2) After dissolving adipic acid dihydrazide in a solvent, add it to the prepolymer obtained in step (1) and continue to react at 40~60℃ for 6~24h; (3) Dissolve diaminoglyoxime in a solvent and add it to the reaction system of step (2). Continue to react at 70~90℃ for 6~24h to obtain a polyurethane elastomer solution. (4) The polyurethane elastomer solution obtained in step (3) is heated to form a film and then dried to obtain a triboelectric material with both high toughness and self-healing properties.
2. The method for preparing the triboelectric material with both high toughness and self-healing properties according to claim 1, characterized in that, In step (1), the polytetrahydrofuran ether diol is first pretreated by vacuum dehydration at 80-160°C for 0.5-3 hours; the molar ratio of polytetrahydrofuran ether diol PTMG to isophorone diisocyanate IPDI is 1:0.25-5; the molar ratio of dibutyltin dilaurate to polytetrahydrofuran ether diol is 0.03-0.1:
1.
3. The method for preparing the triboelectric material with both high toughness and self-healing properties according to claim 1, characterized in that, In step (2), the molar ratio of adipic acid dihydrazide to isophorone diisocyanate is 0.1~0.3:
1.
4. The method for preparing the triboelectric material with both high toughness and self-healing properties according to claim 1, characterized in that, In step (3), the molar ratio of diaminoglyoxime to isophorone diisocyanate is 0.1~0.3:
1.
5. The method for preparing the triboelectric material with both high toughness and self-healing properties according to claim 1, characterized in that, In step (4), the heating to form a film is performed by heating at 60~160℃ for 6~48h; the drying is performed by drying the polyurethane elastomer after film formation in a vacuum oven at 60~120℃ for 6~48h.
6. A triboelectric material with both high toughness and self-healing properties, prepared by the method according to any one of claims 1 to 5.
7. The triboelectric material with both high toughness and self-healing properties according to claim 6, characterized in that, The triboelectric material has a tensile strength of 33-55 MPa, an elongation at break of 800-960%, and a toughness of 74-175 MJ / m³.
8. The application of the triboelectric material with high toughness and self-healing properties as described in claim 7 in triboelectric nanogenerators.
9. The application of the triboelectric material with high toughness and self-healing properties as described in claim 8 in triboelectric nanogenerators, characterized in that, The triboelectric nanogenerator adopts a vertical contact-separation mode, with the positive electrode material being the triboelectric material film and the negative electrode material being the fluorinated ethylene propylene copolymer film.
10. The application of the triboelectric material with high toughness and self-healing properties as described in claim 1 in triboelectric nanogenerators, characterized in that, The open-circuit voltage of the triboelectric nanogenerator is 130~163 V, the short-circuit current is 4~6.5μA or more, and the transferred charge is 6~9nC / cm² or more; after being cut off and repaired at 80℃ for 12 hours, its output repair rate reaches 98%.