Supramolecular gel with self-repairability and thixotropy and preparation method of supramolecular gel
Through the formation of an interpenetrating nanofiber network based on organic molecules based on tetrastyrene derivatives, the problem of insufficient self-healing performance of supramolecular gels at room temperature and imbalance in mechanical and dynamic performance is solved, and the rapid self-healing and high stable thixotropy of low temperature are achieved, which is suitable for a variety of solvent environments.
Patent Information
- Application Number
- CN202510562554.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2025-08-08
AI Technical Summary
The existing supramolecular gels have insufficient self-repair performance at room temperature, difficult to balance mechanical and dynamic performance, complex preparation process and limited solvent selection, which limits their application in different environments.
Using organic molecules based on tetrastyrene derivatives, an interpenetrating nanofiber network is formed through supramolecular assembly, and π-π stacking and hydrogen bonding are used to improve the thermal stability and self-healing ability of the gel, which is suitable for a variety of organic solvents.
It achieves rapid self-healing and high stable thixotropy at low temperatures. It is suitable for a variety of solvents and is suitable for self-healing materials, flexible electronic devices and biomedical materials.
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Figure CN120441456A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a supramolecular gel with self-repairing and thixotropic properties and a preparation method thereof, belonging to the technical field of organic molecular materials. Background Art
[0002] Supramolecular gels are a class of soft materials formed by the self-assembly of small molecules through non-covalent interactions (such as hydrogen bonding, π-π stacking, and van der Waals forces). Due to their unique dynamic reversibility and stimulus responsiveness, they have shown broad application prospects in self-healing materials, flexible electronic devices, biomedical materials, and smart coatings. However, existing supramolecular gel materials still face the following challenges in practical applications:
[0003] 1. Insufficient self-healing performance: The self-healing ability of many supramolecular gels depends on external stimuli such as heating, light or pH adjustment, and the repair efficiency is low, making it difficult to achieve rapid and efficient self-healing at room temperature.
[0004] 2. The balance between mechanical properties and dynamic properties: The mechanical strength of supramolecular gels is often inversely proportional to their dynamic reversibility. Gels with high mechanical strength usually have poor dynamic properties and it is difficult to achieve good thixotropy and self-healing properties.
[0005] 3. Complex preparation process: Most existing methods for preparing supramolecular gels require complex synthesis steps or relatively harsh external conditions, which limits their large-scale production and practical applications.
[0006] 4. Limited solvent selection: Many supramolecular gels can only be formed in specific solvents, and the solvent selection range is narrow, which limits their applicability in different environments.
[0007] In view of the above problems, the present invention intends to provide a supramolecular gel with excellent self-healing ability and thixotropy. Summary of the Invention
[0008] The purpose of the present invention is to provide a supramolecular gel with self-healing and thixotropic properties, which can be prepared by a supramolecular assembly method. The gel not only achieves high gel strength, excellent self-healing performance and highly stable cyclic thixotropy, but can also be prepared under relatively mild conditions and is suitable for a variety of organic solvents, thereby solving the defects in the prior art.
[0009] The present invention first provides an organic molecule based on a tetraphenylethylene derivative, the structural formula of which is shown in Formula I, namely, 4-(1,2,2-triphenylvinyl)aniline and (R)-(-)-1-(1-naphthyl)ethyl isocyanate or (S)-(+)-1-(1-naphthyl)ethyl isocyanate are covalently linked through a urea bond.
[0010]
[0011] In the organic molecule shown in Formula I, the tetraphenylethylene group provides a π-π stacking site, the chiral naphthyl unit induces the formation of a helical supramolecular structure, and the urea bond not only acts as a hydrogen bond donor and acceptor, but also improves the rigidity of the conformation, thereby significantly maintaining the thermal stability of the gel.
[0012] The organic molecules based on tetraphenylethylene derivatives of the present invention are prepared according to the following method:
[0013] (S)-(+)-1-(1-naphthyl)ethyl isocyanate and 4-(1,2,2-triphenylvinyl)aniline are refluxed in an organic solvent I to obtain the organic molecule.
[0014] The organic solvent I may be at least one of dichloromethane, tetrahydrofuran, N,N-dimethylformamide, ethanol, chloroform, ethyl acetate, 1,4-dioxane and dimethyl sulfoxide;
[0015] The reaction temperature may be 20-100°C and the reaction time may be 4 to 24 hours.
[0016] Preferably, after the reaction is completed, the reaction solution is concentrated under reduced pressure and purified by column chromatography in a mixed solvent system of dichloromethane and methanol.
[0017] The organic molecules represented by formula I of the present invention can form supramolecular gels with self-repairing ability and thixotropy through supramolecular self-assembly in an organic solvent. Specifically:
[0018] A) dissolving the organic molecule represented by formula I in an organic solvent II and completely dissolving it by heating or ultrasonication;
[0019] B) applying ultrasonic stimulation to the solution obtained in step A) for 0.2-10 minutes to induce supramolecular assembly;
[0020] C) standing at -10°C to 40°C for 5 minutes to 10 hours to form a nanofiber gel with an interpenetrating network structure.
[0021] In the solution obtained in step A), the concentration of the organic molecule represented by formula I is 0.1 mM-100 mM.
[0022] In step A), when ultrasonic treatment is used, after the molecules are fully dispersed by ultrasound, they only need to be allowed to stand in an environment below 40°C to complete self-assembly to form a gel; when heating is used for dissolution, after the solution is cooled to room temperature, it needs to be supplemented with 1 minute of ultrasonic stimulation, and then allowed to stand in the range of -10-40°C to induce gel formation. It should be noted that lower ambient temperature can significantly accelerate the process of molecular self-assembly, which is mainly attributed to the enhancement of intermolecular hydrogen bonds and π-π stacking under low temperature conditions. Specifically, when the temperature is controlled at 5-15°C, the gelation time can be shortened to 10-30 minutes, and the formed gel network structure is uniform and dense.
[0023] In addition, the gelation behavior of the supramolecular gel of the present invention exhibits significant solvent dependence, which is specifically manifested in three typical solvent-concentration relationships: the first type of solvent includes polar solvents such as exo-tetrahydrodicyclopentadiene, methanol, ethanol, propanol, isopropanol, acetonitrile, n-butanol, and n-pentanol. This type of solvent only requires a single component to achieve efficient gelation, and the required concentration range of the organic molecule represented by Formula I is relatively narrow (5-30mM), exhibiting excellent solvation ability; the second type uses dichloromethane and tetrahydrofuran as solvents, requiring the concentration of the molecule represented by Formula I to be increased to 30-100mM to form a gel; the third type is non-polar solvents such as n-hexane or kerosene, which need to be used in combination with the first two types of solvent systems and have a wide gelation concentration window (0.1-30mM). Gels formed at higher concentrations are strong and less prone to collapse, while gels formed at lower concentrations are weaker and more prone to collapse. The gelation effects of different solvents vary.
[0024] The self-repairing ability of the supramolecular gel of the present invention is manifested as follows: after being damaged by shear force, the supramolecular gel can spontaneously recover its mechanical strength within 24 hours when placed in an environment of -10-40°C. Lower ambient temperature is conducive to the self-repair process and is conducive to completing self-repair in a shorter time. At 5-15°C, the self-repair time of the gel is significantly shortened to 10 minutes to 2 hours.
[0025] The thixotropic properties of the supramolecular gel of the present invention are characterized by a transition from a gel to a sol state under varying degrees of shear stress, and a return to the gel state upon removal of the shear stress. When mechanical shear of varying intensities is applied, the gel's three-dimensional network temporarily dissociates, forming a fluid sol state. However, upon removal of the force, the system rapidly reconstructs the network structure and returns to the gel state. This dynamic reversible behavior was quantitatively characterized using a TADHR-1 rheometer using 12 continuous cycles in time-sweep mode, each consisting of alternating periods of low strain (0.1%) and high strain (400%) for 100 seconds each. The test results showed that after multiple cycles, the gel's storage modulus (G') and loss modulus (G") rapidly recovered, and the phase transition response time remained essentially unchanged, demonstrating the highly stable thixotropic recovery properties of the supramolecular gel of the present invention. This excellent cyclic stability stems from the dynamic non-covalent bond network incorporated into the molecular design, which maintains structural integrity despite repeated mechanical stimulation, ensuring the material's long-term use in practical applications.
[0026] The supramolecular gel of the present invention has a microscopic appearance of nanofibers with a dense interpenetrating network structure under a scanning electron microscope.
[0027] The supramolecular gel of the present invention has self-repairing and thixotropic properties and can be used to prepare self-repairing materials, flexible electronic devices, biomedical materials or optical switches. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 This is the UV-visible absorption spectrum of the organic molecule represented by Formula I in acetonitrile solvent with an organic molecule concentration of 0.25 mM.
[0029] Figure 2 This is a strain scan diagram of the organic molecule represented by formula I forming a gel with a concentration of 10 mM in acetonitrile solvent.
[0030] Figure 3 This is a scanning electron micrograph of a gel formed by an organic molecule of formula I in acetonitrile solvent at a concentration of 10 mM.
[0031] Figure 4 This is a time scan diagram of the organic molecule of formula I forming a gel with a concentration of 10 mM in acetonitrile solvent.
[0032] Figure 5 This is a self-repair demonstration diagram of the organic molecule of Formula I forming a gel with a concentration of 10mM in acetonitrile solvent.
[0033] Figure 6 This is a diagram showing the states of the comparative compound and the organic molecule of Formula I of the present invention in acetonitrile solvent at a concentration of 10 mM. DETAILED DESCRIPTION
[0034] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods.
[0035] Unless otherwise specified, the materials, reagents, etc. used in the following examples are all commercially available.
[0036] The present invention first provides an organic molecule with a specific structure, which includes:
[0037] Tetraphenylethylene group: providing π-π stacking interaction and enhancing intermolecular assembly ability;
[0038] Chiral naphthyl unit: inducing a helical supramolecular structure and endowing dynamic reversibility;
[0039] Urea bond: serving as a hydrogen bond donor-acceptor and enhancing the network rigidity and thermal stability.
[0040] The present invention further forms an interpenetrating nanofiber network through the self-assembly of the shown organic molecule in an organic solvent, and further achieves the following technical effects:
[0041] Dynamic self-healing property: After the gel is shear-damaged, it can spontaneously recover its mechanical strength within 1-24 hours at -10 - 40 °C (preferably 5 °C) without external stimulation, and the repair efficiency is over 90%.
[0042] Intelligent thixotropy: Verified by rheology, the gel reversibly transforms into a sol state under an external shear force (G' < G" when the strain > 100%), and quickly returns to the gel state after removing the external force (G' reaches 10 4 Pa at a strain of 0.1%), and the modulus recovery rate remains stable after 12 cycles.
[0043] Efficient gelation at low temperature: The gelation time is shortened to 30 minutes at 5 °C, which is suitable for preparation under mild conditions.
[0044] Solvent universality: Compatible with polar and non-polar solvents (such as acetonitrile, kerosene), with a wide concentration window (0.1 - 100 mM), and suitable for diverse application scenarios.
[0045] The present invention breaks through the balance problem between the strength and dynamic performance of supramolecular gels, and achieves low-temperature rapid self-repair, high-stability thixotropic response and strong mechanical properties, which are suitable for frontier fields such as flexible electronics and biomedicine.
[0046] Example 1. Preparation of the tetraphenylethylene derivative molecule of Formula I
[0047] The synthetic route of the S configuration is as follows:
[0048]
[0049] (S)-(+)-1-(1-naphthyl)ethyl isocyanate (1.5 mmol, 295.86 mg) and 4-(1,2,2-triphenylvinyl)aniline (1 mmol, 347.45 mg) were added to a 50 mL round-bottom flask, and 15 mL of dichloromethane was added to dissolve the product. The mixture was stirred and refluxed at 60°C for 24 hours. The reaction solution was separated by column chromatography using dichloromethane as the eluent to obtain 370 mg of the S-configuration product with a yield of 67.93%.
[0050] The synthetic route of the R configuration is as follows:
[0051]
[0052] (R)-(+)-1-(1-naphthyl)ethyl isocyanate (1.5 mmol, 295.86 mg) and 4-(1,2,2-triphenylvinyl)aniline (1 mmol, 347.45 mg) were added to a 50 mL round-bottom flask, and 15 mL of dichloromethane was added to dissolve the product. The mixture was stirred and refluxed at 60°C for 24 hours. The reaction solution was separated by column chromatography using dichloromethane as the eluent to obtain 380 mg of the R-configuration product with a yield of 69.76%.
[0053] The structural verification data of the target product are as follows:
[0054] S-configuration product:
[0055] 1H NMR (400MHz, DMSO) δ8.34(s,1H),8.13(d,J=8.4Hz,1H),7.95(d,J=8.0Hz,1H),7.83(d,J=7.9Hz,1H),7.54(tt,J=15.9,7.3Hz,4H),7 .19–7.04(m,11H),6.95(q,J=7.7Hz,6H),6.78(d,J=8.2Hz,2H),6.72(d,J=7.8Hz,1H),5.58(p,J=6.9Hz,1H),1.51(d,J=6.8Hz,3H).
[0056] R-configuration product:
[0057] 1H NMR (400MHz, DMSO) δ8.35(s,1H),8.14(d,J=8.1Hz,1H),7.95(d,J=7.5,1H),7.84(d,J=7.9,1 H),7.63(tt,J=16.2,7.5Hz,4H),7.16-7.05(m,11H),6.96(q,J=7.2Hz,6H),6.76(d,J=8.0Hz 2H), 6.74 (d, J = 7.8Hz, 1H), 5.59 (p, J = 6.9Hz, 1H), 1.52 (d, J = 6.8Hz, 3H).
[0058] Example 2: Preparation of supramolecular gel
[0059] A 0.25 mM acetonitrile solution of the organic molecule prepared in Example 1 was prepared and tested using a UV-visible absorption spectrometer. The test results are as follows: Figure 1 As shown in the figure, it can be seen that there are absorption peaks at 220nm and 275nm, which can be attributed to the π→π * The absorption peaks at 296 nm and 330 nm are mainly attributed to the π→π transition of the benzene ring. * Transition and extended conjugated structure induced π→π * jump.
[0060] 5.45 mg of the organic molecule was weighed and placed in a 4 mL sample vial. 1 mL of acetonitrile was added to prepare a 10 mM solution. Ultrasound was used to promote the dissolution of the molecule. After dissolution, the solution was placed in a constant temperature box at 5°C to form a slightly transparent white gel.
[0061] By observing the dry gel sample under a scanning electron microscope, it can be seen that nanofibers with an interpenetrating network structure are formed, such as Figure 3 shown.
[0062] The rheological test of fresh gel samples was carried out by TA DHR-1 rheometer. In the strain sweep mode, the storage modulus G' and loss modulus G" of the gel were measured in the strain range of 0.1% to 1000%. The results are shown in Figure 2. Figure 3 shown.
[0063] Depend on Figure 3It can be seen that in the low strain region (about 0.1%-1%), G' is always higher than G", and the two remain constant, indicating that the gel maintains a stable three-dimensional network structure in this range and no irreversible damage occurs. The G' value is significantly higher than G", indicating that the material mainly responds elastically, which is consistent with the typical gel characteristics. As the strain increases, G' begins to decrease in the range of 1%-10%, and G" reaches a peak. This phenomenon indicates that local damage to the gel network has begun. When the strain exceeds 100%, the two modulus curves drop sharply, indicating that the material has completely transformed into a sol state. This strain-dependent phase change behavior shows that the gel material of the present invention has thixotropy.
[0064] In the time scan mode, 12 continuous cycle tests were set, each cycle including alternating processes of low strain (0.1%) and high strain (400%) for 100 seconds each. Figure 4 shown.
[0065] Figure 4 Test results show that after multiple cycles, the gel's G' and G" can recover rapidly, and the phase change response time remains essentially unchanged, fully demonstrating the highly stable thixotropic recovery properties of the supramolecular gel. This excellent cyclic stability stems from the dynamic non-covalent bond network introduced in the molecular design, which enables it to maintain structural integrity under repeated mechanical stimulation, providing a guarantee for the long-term use of the material in practical applications.
[0066] The self-healing properties of the gel were verified by performing a shear damage experiment on the gel sample using a syringe. When the gel was repeatedly pumped with a syringe, the shear force applied completely destroyed the three-dimensional network structure of the gel, causing it to transform from a solid gel to a sol state with good fluidity. After the destroyed sol sample was placed in a constant temperature environment of 5°C and left to stand for 20 minutes, it was observed that the sol was transformed back into a gel with a complete structure, such as Figure 5 This repair process occurs completely spontaneously, without any external energy input. A low ambient temperature (5°C) significantly promotes the self-repair process, reducing the repair time to less than 20 minutes.
[0067] Comparative Example 1: Comparative Compounds' Gel-forming Effects
[0068] The comparative compounds were purchased from TCI.
[0069]
[0070] From a structural point of view, both compounds (1) and (2) contain naphthalene groups, while compound (3) contains a benzene ring. The presence of these aromatic groups is conducive to the occurrence of π-π stacking in solution. At the same time, the isocyanate or amino groups in the comparative compounds can form intermolecular hydrogen bonds in acetonitrile solvent. Based on the above molecular design, acetonitrile solutions with a concentration of 10mM were prepared using the comparative compounds. The solution preparation process was supplemented with ultrasonic stimulation, and the solution was then placed in a 5°C thermostat for 20 minutes. The gelation of the solution was detected by inverting the sample.
[0071] like Figure 6 As shown, the results show that the solutions of the three comparative compounds, although prepared in the same process as the present invention, did not undergo a transition from solution to gel, indicating that relying solely on the π-π stacking and simple hydrogen bonding of aromatic groups is insufficient to drive macroscopic phase transitions. The above experimental results further demonstrate that the organic molecules of the present invention have unique structural advantages—by introducing urea bonds and aromatic groups, multiple non-covalent interaction patterns are constructed to achieve organic molecular gelation. The organic molecule construction concept involved in the present invention provides a new strategy for the rational design of intelligent responsive gel materials.
Claims
1. An organic molecule based on a tetraphenylethylene derivative, the structural formula of which is shown in Formula I:
2. A method for preparing the organic molecule represented by formula I, comprising the following steps: (S)-(+)-1-(1-naphthyl)ethyl isocyanate and 4-(1,2,2-triphenylvinyl)aniline are refluxed in an organic solvent I to obtain the organic molecule.
3. The preparation method according to claim 2, wherein: The organic solvent I is at least one of dichloromethane, tetrahydrofuran, N,N-dimethylformamide, ethanol, chloroform, ethyl acetate, 1,4-dioxane and dimethyl sulfoxide; The reaction temperature is 20-100° C. and the reaction time is 4-24 hours.
4. The preparation method according to claim 2 or 3, characterized in that: After the reaction was completed, the reaction solution was concentrated under reduced pressure and purified by column chromatography in a mixed solvent system of dichloromethane and methanol.
5. Use of the organic molecule represented by formula I in claim 1 in the preparation of supramolecular gels with self-repairing ability and thixotropy.
6. A supramolecular gel with self-repairing ability and thixotropy, formed by supramolecular self-assembly of the organic molecules represented by formula I in claim 1 in an organic solvent II.
7. The use according to claim 5 or the supramolecular gel according to claim 6, characterized in that: The self-repairing ability is manifested as follows: after the supramolecular gel is damaged by shear force, it can spontaneously recover its mechanical strength within 24 hours when placed in an environment of -10-40°C; The thixotropy is manifested as: under the action of shear forces of different degrees, the supramolecular gel changes from a gel state to a sol state, and returns to the gel state after the shear force is removed.
8. The method for preparing the supramolecular gel according to claim 6 or 7, comprising the following steps: A) dissolving the organic molecule represented by formula I in the organic solvent II and completely dissolving it by heating or ultrasonication; B) applying ultrasonic stimulation to the solution obtained in step A) for 0.2-10 minutes to induce supramolecular assembly; C) standing at -10°C to 40°C for 5 minutes to 10 hours to form a nanofiber gel with an interpenetrating network structure.
9. The preparation method according to claim 8, characterized in that: The organic solvent II is selected from at least one of the following: dichloromethane, n-hexane, tetrahydrofuran, kerosene, exo-tetrahydrodicyclopentadiene, methanol, ethanol, propanol, isopropanol, acetonitrile, n-butanol, and n-pentanol; In the solution obtained in step A), the concentration of the organic molecule represented by formula I is 0.1 mM-100 mM.
10. Use of the supramolecular gel according to claim 6 or 7 in the preparation of self-repairing materials, flexible electronic devices, biomedicine or optical switches.