A polyimide super-slip surface with self-repairing properties and its preparation method and application

Abstract

The present invention belongs to the field of super-slippery surface materials and discloses a super-slip polyimide surface with self-repairing properties, its preparation method and application. First, amino-terminated polydimethylsiloxane liquid (APT-PDMS) is prepared, and then PDMS is prepared using silicone oil, APT-PDMS, isophorone diisocyanate (IPDI) and terephthalaldehyde (TPAL). m IT‑oil3. Finally, the prepared PDMS m A self-healing polyimide and its resulting super-slippery surface material were synthesized through a polycondensation reaction of IT-oil3, 2,2'-bis[4-(4-aminophenoxyphenyl)]propane (BAPP), and 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA). The resulting super-slippery surface exhibits self-healing, drag-reducing, and antibacterial properties.

Description

Technical Field

[0001] The present invention belongs to the field of super-slippery surface materials, and in particular relates to a simple preparation method of a super-slippery surface with self-repairing properties and the super-slippery surface material obtained. Background Art

[0002] In 2011, inspired by the insect-catching mechanism of pitcher plants, Joanna Aizenberg and her team at Harvard University first proposed the concept of slippery liquid-infused porous surfaces (SLIPS). Because these surfaces are liquid-liquid surfaces composed of a smooth, continuous, and uniform layer of lubricant, they exhibit properties such as anti-icing and antifreeze, antibacterial properties, drag reduction, and self-healing properties. In recent years, superslippery surfaces have become a hot topic of research. Superslippery surfaces are created by infusing various lubricating fluids into micro- and nanostructures, where the roughness of the solid substrate is crucial. However, with the increasing complexity of life, superslippery surfaces are becoming less stable, prone to lubricant removal, and susceptible to surface damage. Therefore, the development of SLIPS with self-healing properties is of great significance.

[0003] CN201811485363.3 A method for preparing a bionic super-slippery surface with self-healing properties at room temperature, using aminopropyl-terminated polydimethylsiloxane (APT-PDMS) and isophorone diisocyanate (IPDI) in the presence of lubricating oil to form a bionic super-slippery surface, which does not involve the preparation and application of polyimide super-slippery surfaces, and the average velocity and drag reduction rate in water (G) and oil (H) are not studied, while the different group reactions used have a great influence on the performance.

[0004] CN202211423884.2 is a rough substrate composed of polyimide microspheres prepared by combining inverse emulsion polymerization and drop coating method, and finally oil is poured to form a lubricating oil layer to form a super-slip surface with a sliding angle of <10°. Soaking silicone oil can only form silicone oil on the surface of the coating, rather than encapsulating silicone oil. When the silicone oil layer that does not reach the surface of the coating is damaged, the silicone oil molecules inside the coating will spontaneously migrate to the coating. Therefore, when the substrate is damaged, the performance of the lubricating layer will disappear and it will not have self-repairing ability. Secondly, a self-repairing elastomer is prepared in CN202210600757.9 and CN202310392396.8, and disulfide compounds are present in the monomer. Different monomers, different reaction orders, different reaction conditions and different performances. In addition, the presence of disulfide compounds will also affect the stability of the super-slip surface. CN201710665115.6 A highly transparent, super-lubricating, self-replenishing glass coating and its preparation method and application. The glass coated with PDMS coating is immersed in dimethyl silicone oil, so that the silicone oil molecules penetrate the internal network skeleton of the PDMS coating and the coating surface. When the surface silicone oil layer of the coating is damaged, the silicone oil molecules inside the coating will spontaneously migrate to the coating surface, showing excellent self-replenishing performance. It mainly uses external silicone oil to repair the lubricating oil layer. The repair requires the internal silicone oil molecules to spontaneously replenish to the surface. The silicone oil consumption is large, and it will lose its repair ability when it is consumed. Therefore, it cannot achieve the effect of multiple repairs, and the cracks and wounds caused by the coating cannot be repaired. Summary of the Invention

[0005] The purpose of the present invention is to provide a simple preparation method of a super-slippery surface with self-repairing properties and the super-slippery surface material obtained.

[0006] In order to achieve the purpose of the present invention, the technical solution adopted is:

[0007] A simple method for preparing a super-slip surface with self-repairing properties comprises the following steps:

[0008] (1) Preparation of APT-PDMS: Using octamethylcyclotetrasiloxane (D4) and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane as monomers and tetramethylammonium hydroxide ((Me)4NOH) as catalyst, amino-terminated polydimethylsiloxane (APT-PDMS) was prepared by ring-opening reaction. The structural formula of APT-PDMS is as follows:

[0009] ;

[0010] The mass ratio of octamethylcyclotetrasiloxane to 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is 10-50:2-3, and the obtained APT-PDMS molecular weight ranges from 1000 to 6000. As the molecular weight of APT-PDMS increases, the mechanical properties of the self-healing elastomer increase.

[0011] (2) PDMS m IT-oil n Preparation: Dissolve silicone oil in tetrahydrofuran and stir magnetically at room temperature. Add APT-PDMS and a certain amount of THF to a round-bottom flask and stir thoroughly under a nitrogen atmosphere (10 min). Slowly add a mixed solvent of IPDI and THF to the reaction system and stir at a reaction temperature of 60 °C for 12 h. Dissolve TPAL in THF and add it to the flask. Continue stirring at the reaction temperature for at least 24 h until the reaction is complete. Named PDMS m IT-oil n , where m is the molecular weight of APT-PDMS and n is the mass of silicone oil (g), specifically 3~5.

[0012] The molar ratio of APT-PDMS:IPDI:TPAL is 1~3:2.4:0.6. The amount ratio of IPDI and silicone oil is 2.4:3~5mmol / g.

[0013] (3) Preparation of super-slippery surface: PDMS m IT-oil n , 2,2'-bis[4-(4-aminophenoxyphenyl)]propane (BAPP) and 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) were subjected to polycondensation. After the reaction, the mixture was poured into a square Teflon mold. The mold and sample were degassed in a vacuum oven at 50-60°C for 12 hours to obtain a super-slip surface of the polyimide. m -IT x -oil n Indicates; where X represents PDMS m IT-oil n The mass ratio of BAPP to HPMDA is 1:1; n is the mass of silicone oil.

[0014] Furthermore, PDMS m IT-oil n The mass ratio of BAPP and HPMDA is 5~20:1:1; the preferred mass ratio is 5~10:1:1.

[0015] Further, PDMS was weighed m IT-oil nThe polyimide was dissolved in a mixture of THF and CH3OH and reacted under vacuum for 1 hour. HPMDA was then added in three portions using the starvation feeding method and reacted in an ice bath for 6 hours. After 2 hours of chemical imidization, the polyimide was poured into a square Teflon mold. The mold and sample were then degassed in a vacuum oven at 50°C for 12 hours to produce a series of polyimide superslippery surfaces.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention uses PDMS m IT-oil n , BAPP and HPMDA as raw materials, and by adding silicone oil into the reaction system, a polyimide super-slippery surface with self-healing properties was prepared. In addition, by changing the molecular weight of APT-PDMS, PDMS m IT-oil n The results of a study on the self-healing properties of SLIPS, along with the mass ratio of BAPP to HPMDA, show that the resulting superslippery surface exhibits excellent self-healing, drag-reducing, and antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the APT-PDMS reaction formula in step (1) of Example 1;

[0019] Figure 2 PDMS in step (2) of Example 1 m IT x -oil3 reaction formula;

[0020] Figure 3 PDMS prepared in Example 1 m IR spectrum of IT-oil3 (A) and IR spectrum of polyimide containing polysiloxane with self-healing properties (B);

[0021] Figure 4 Polarized microscope images of the super-slippery surface of polyimide containing polysiloxane with self-healing properties prepared with different molecular weights and the same mass ratio (A. Mn APT-PDMS =1676, APT-PDMS:BAPP:HPMDA=5:1:1; B. Mn APT-PDMS =3060, APT-PDMS:BAPP:HPMDA=5:1:1; C. Mn APT-PDMS =5162, APT-PDMS:BAPP:HPMDA=5:1:1);

[0022] Figure 5 This is the antibacterial test diagram of the super-slippery surface of polyimide containing polysiloxane with self-healing properties.

[0023] Figure 6 The photos of pure glass sheet movement (A, D), P m IT-oil0 (B, E), P m Average velocity and drag reduction of IT-oil3 (C, F) samples underwater (A−C) and on the oil surface (D−F) in water (G) and oil (H).

[0024] Figure 7 For super-slippery surface (P m IT-oil3) Water droplet sliding diagram before and after scratching and self-healing.

[0025] Figure 8 P m IT5-oil0、P m IT 10 -oil0、P m IT 15 -oil0 and P m IT 20 -oil0 Different molecular weight APT-PDMS, different BAPP and PDMS m Stress-strain curve of IT-oil0 mass ratio.

[0026] Figure 9 P 1676 IT x -oil3、P 3060 IT x -oil3、P 5162 IT x - Comparison of the healing effects of oil3 at 60°C and room temperature. DETAILED DESCRIPTION

[0027] The present invention is not limited to the following specific embodiments. Based on the disclosure of the present invention, a person skilled in the art may adopt a variety of other specific embodiments to implement the present invention. Any simple changes or modifications made to the design structure and concept of the present invention fall within the scope of protection of the present invention. It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other unless they conflict.

[0028] The present invention is further described in detail below in conjunction with the embodiments: Example 1:

[0029] (1) Preparation of APT-PDMS (Mn=5162)

[0030] 44.5 g of octamethylcyclotetrasiloxane (D4) and 2.5 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were weighed separately and added to a three-necked round-bottom flask. Then, 0.6 g of tetramethylammonium hydroxide ((Me)4NOH) was weighed as a catalyst and ring-opened at 105°C in a dry N2 atmosphere. After 18 h of reaction, the temperature was raised to 180°C to degrade the catalyst and then cooled to 160°C to remove low-boiling point small molecular impurities and other by-products to obtain a colorless viscous APT-PDMS liquid (Mn=5162).

[0031] (2) PDMS 5162 Synthesis of IT-oil3

[0032] First, 3 g of silicone oil was dissolved in 10 ml of THF and magnetically stirred at room temperature for 10 min. Then 5 g of APT-PDMS and 10 mL of THF were added to a 250 mL round-bottom flask and stirred for 10 min under a nitrogen atmosphere. 2.44 mmol of isophorone diisocyanate (IPDI) was added to 5 mL of THF and slowly dripped into the flask. The mixture was stirred at 60 °C for 12 h. 0.61 mmol of terephthalaldehyde (TPAL) was dissolved in 5 mL of THF and added to the flask. The reaction was completed after stirring at 60 °C for 24 h to obtain PDMS. 5162 IT-oil3.

[0033] (3) Preparation of super-slippery surfaces

[0034] Weigh 1.1435 g of PDMS at room temperature. 5162 IT-oil3 and 0.2287 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) were dissolved in a mixture of THF and CH3OH (mass ratio 15:85) and reacted under vacuum for 1 hour. Then, 0.2287 g of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) was added in three portions using the starvation feeding method, and the reaction was continued in an ice bath for 6 hours. After 2 hours of chemical imidization, the mixture was poured into a square Teflon mold. The mold and sample were degassed in a vacuum oven at 50°C for 12 hours. The resulting polyimide ultraslippery surface was then treated with P 5162 -IT5-oil3 indicates.

[0035] The SLIPS prepared in Example 1 had a static contact angle of 102° and a sliding angle of 4°. Example 2:

[0036] (1) Preparation of APT-PDMS (Mn=3060)

[0037] 25.4 g of D4 and 2.5 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were weighed separately and added to a three-necked round-bottom flask. Then 0.6 g of catalyst (Me)4NOH was weighed and used as a catalyst for ring opening under a dry N2 atmosphere at reaction conditions of 105°C. After 18 h of reaction, the temperature was raised to 180°C to degrade the catalyst, and then cooled to 160°C to remove low-boiling point small molecular impurities and other by-products to obtain a colorless viscous APT-PDMS liquid (Mn=3060).

[0038] (2) PDMS 3060 The preparation of IT-oil 3 was the same as in Example 1.

[0039] (3) The preparation method of the super-slippery surface is the same as that in Example 1, and P is obtained. 3060 -IT5-oil3.

[0040] The SLIPS prepared in Example 2 had a static contact angle of 102° and a sliding angle of 5°. Example 3:

[0041] (1) Preparation of APT-PDMS (Mn=1676)

[0042] 11.8 g of D4 and 2.5 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were weighed separately and added to a three-necked round-bottom flask. Then 0.6 g of catalyst (Me)4NOH was weighed and used as a catalyst for ring opening under a dry N2 atmosphere at reaction conditions of 105°C. After 18 h of reaction, the temperature was raised to 180°C to degrade the catalyst, and then cooled to 160°C to remove low-boiling point small molecular impurities and other by-products to obtain colorless viscous APT-PDMS liquids of different molecular weights.

[0043] (2) PDMS 1676 The preparation method of IT-oil3 is the same as that of Example 1.

[0044] (3) The preparation method of the super-slippery surface is the same as that in Example 1, and P is obtained. 1676 -IT5-oil3.

[0045] The SLIPS prepared in Example 3 had a static contact angle of 103.5° and a sliding angle of 6°.

[0046] Comparative Example 1:

[0047] (1) The preparation method of APT-PDMS is the same as that in Example 1;

[0048] (2) PDMS 5162 Synthesis of IT-oil3

[0049] First, 3 g of silicone oil was dissolved in 10 ml of dimethylacetamide (DMAc) under a nitrogen atmosphere and magnetically stirred at room temperature for 10 min. Then 5 g of APT-PDMS and 10 mL of DMAc were added to a 250 mL round-bottom flask and stirred for 10 min under a nitrogen atmosphere. 2.44 mmol of IPDI was added to 5 mL of DMAc and slowly dripped into the flask. The mixture was stirred at 60 °C for 12 h. 0.61 mmol of TPAL was dissolved in 5 mL of DMAc and added to the flask. The reaction was completed after stirring at 60 °C for 24 h to obtain PDMS. 5162 IT-oil3.

[0050] (3) Preparation of super-slippery surfaces

[0051] Weigh 1.1435 PDMS at room temperature 5162 IT-oil3 and 0.2287 g of BAPP were dissolved in DMAc and reacted under vacuum for 1 hour. Then, 0.2287 g of HPMDA was added in three portions using the starvation feeding method, and the reaction was continued in an ice bath for 6 hours. After 2 hours of chemical imidization, the mixture was poured into a square Teflon mold. The mold and sample were then degassed in a vacuum oven at 50°C for 12 hours.

[0052] The main difference between Comparative Example 1 and Example 1 is that the selected solvent is different. In Comparative Example 1, DMAc is used in both step (2) and step (3).

[0053] In Comparative Example 1, DMAc is not miscible with silicone oil, and the material prepared ultimately does not have the properties of SLIPS.

[0054] Comparative Example 2:

[0055] (1) The preparation method of APT-PDMS is the same as that in Example 1

[0056] (2) PDMS m Synthesis of IT-oil0

[0057] 5 g of APT-PDMS and 10 mL of THF were added to a 250 mL round-bottom flask and stirred under nitrogen for 10 min. 2.44 mmol of IPDI was added to 5 mL of THF and slowly dripped into the flask. The mixture was stirred at 60 °C for 12 h. 0.61 mmol of TPAL was dissolved in 5 mL of THF and added to the flask. The reaction was completed after stirring at 60 °C for 24 h to obtain PDMS. 5162 IT-oil3.

[0058] (3) Preparation of super-slippery surfaces

[0059] Weigh 1.1435 g of PDMS at room temperature. 5162 IT-oil3 and 0.2287 g of BAPP were dissolved in a mixture of THF and CH3OH and reacted under vacuum for 1 hour. Then, 0.2287 g of HPMDA was added in three portions using the starvation feeding method, and the reaction was continued in an ice bath for 6 hours. After 2 hours of chemical imidization, the mixture was poured into a square Teflon mold. The mold and sample were then degassed in a vacuum oven at 50°C for 12 hours.

[0060] The main difference between Comparative Example 2 and Example 1 is that: m IT-oil n Silicone oil was not added during the preparation. In Comparative Example 2, silicone oil was not added, and therefore, the resulting material did not exhibit SLIPS properties, with a WCA of 105° and a SA of 18°. Because of the absence of silicone oil, this system lacks self-healing properties.

[0061] Comparative Example 3:

[0062] Comparative Example 3 differs from Example 1 in that no phthalaldehyde is added. Other operations are the same as in Example 1. The material prepared in Comparative Example 3 does not have self-healing properties.

[0063] In addition, the following comparative tests were conducted: PDMS m Testing of self-healing superslip surfaces prepared using different mass ratios of IT-oil3, BAPP, and HPMDA. As shown in Table 1, the SLIPS with the best sliding performance was achieved when the mass ratio was 5:1:1.

[0064] Table 1: Monomer addition formula of polymer and wettability analysis of SLIPS with different ratios

[0065]

[0066] Table 2

[0067]

[0068] Figure 1 Reaction formula for synthesizing APT-PDMS; Figure 2 For the synthesis of PDMS m IT-oil3 reaction formula;

[0069] Figure 3 Curve a in (A) is PDMS m IT-oil n Curve b is APT-PDMS; curve c is the infrared image of IPDI. Curve b is at 3332 cm –1The characteristic absorption peak of -NH2- is 2962 cm –1 and 2905 cm –1 The two are the stretching vibration absorption peaks of the methyl group attached to the silicon atom of the main chain, 1093 cm –1 and 1020 cm –1 The left and right are the stretching vibration peaks of the main chain Si—O, indicating that APT-PDMS was successfully synthesized.

[0070] Figure 3 Curve a in (A) is PDMS m IT-oil n Compared with IPDI (curve c), the infrared curve of 2256 cm in curve a is -1 The significant characteristic peaks at 3337 and 1573 cm-1 caused by the asymmetric stretching vibration of the −NCO group disappeared, proving that the IPDI reaction was complete. -1 The stretching vibration and shear vibration of NH are shown at 1636 cm -1 The vibration absorption peak at is C=O, which further confirms that the imine bond and urea group exist simultaneously in PDMS. m IT-oil3.

[0071] Figure 3 (B) is the infrared spectrum of polyimide containing polysiloxane with self-healing properties. 1390 cm -1 There is a characteristic absorption peak of CN at 1780 cm –1 and 1717 cm –1 The asymmetric and symmetric stretching vibrations of C=O in the imide ring are 804 cm -1 It is the bending vibration of C=O, which proves that polyimide containing polysiloxane with self-healing properties was successfully synthesized.

[0072] Figure 4 Polarized microscope images of the super-slippery surface of polyimide containing polysiloxane with self-healing properties prepared with different molecular weights and the same mass ratio. 1676 IT5-oil3、P 3060 IT5-oil3 and P 5162 IT5-oil3 was used to study the self-healing properties of the samples. Figure 4 Polarizing microscopy was used to detect the self-healing process. Without external force, the sample began to heal after 12 hours at 60°C, and the sample was gradually repaired after 24 hours. Figure 4 Middle (A) to Figure 4In (C), it can be seen that at the same temperature and time, the self-healing efficiency of the substrate increases with the increase of APT-PDMS molecular weight. This is because the increase in molecular weight improves the fluidity and flexibility, allowing for faster repair.

[0073] Figure 5 The antibacterial test diagram of the super-slip polyimide surface with self-healing properties containing polysiloxane (coating plate method. Escherichia coli), it can be seen that compared with pure glass and porous surface (porous material P 5162 The surface of IT5-oil0) has excellent anti-bacterial adhesion properties, as the number of bacterial adhesion sites on the polyimide super-slip surface is reduced, thereby reducing the number of surface colonies.

[0074] Figure 6 The photos of pure glass sheet movement (A, D), P m IT-oil0 -X(B, E), P m IT-oil3 -X(C,F); Figure 6 Among them, A, B, and C are in water; Figure 6 D, E, and F are the tests of drag reduction performance in oil. Figure 6 It can be seen that when the liquid medium is water, pure glass, P 5162 IT5-oil0、P 5162 The average velocities of IT5-oil3 were 25, 35.3, and 40 cm·s, respectively. −1 The sailing time was measured and the average sailing speed (v) and drag reduction rate (r) were calculated as follows:

[0075]

[0076] Where v is the average speed calculated over the measured flight time, t is the flight time, R is the drag reduction rate, and V0 and V are the speeds of the pure sheet and the test sample, respectively. Each drag reduction rate was measured three times to obtain the average value.

[0077] Therefore, P 5162 IT5-oil0、P 5162 The drag reduction rates of IT5-oil3 are approximately 44.2% and 68%, respectively. 5162 The drag reduction rate of IT5-oil0 is lower than that of P 5162 The drag reduction rate of IT5-oil3 is due to the 5162 There is a solid-liquid interface between IT5-oil0 and water, and a strong adsorption force will be generated between the two interfaces, which will increase the resistance and reduce the speed. 5162 The original solid-liquid interface between IT5-oil3 and water is transformed into a liquid-liquid interface, reducing resistance and achieving a drag reduction effect. Figure 6 As shown in (A) and (B), when P5162 IT5-oil0、P 5162 When IT5-oil3 sails on the surface of low surface energy and high viscosity peanut oil, the sailing speed is reduced to a certain extent. When the liquid medium is peanut oil, P 5162 IT5-oil0、P 5162 The drag reduction rate of IT5-oil3 is reduced to 41.3% and 59%. 5162 There is a solid-liquid interface between IT5-oil0 and peanut oil, and some peanut oil will adhere to the substrate surface. 5162 The drag reduction effect of IT5-oil0 in oil is reduced. 5162 IT5-oil3 has a layer of silicone oil on its surface. Figure 6 In (B), the immiscible silicone oil and peanut oil form a liquid-liquid interface with good non-wetting properties, which enhances the P 5162 The drag reduction effect of IT5-oil3 on the oil surface. The working environment of the hull surface materials and underwater components will contain a large amount of water, oil, microorganisms, organic matter and other pollutants. Taking the above factors into consideration, the present invention P 5162 IT5-oil3 has broad application prospects in underwater anti-fouling and drag reduction materials.

[0078] Figure 7 For super-slippery surface (P m IT x -oil3) Images of a water droplet sliding down the surface before and after scratching and self-healing. When the super-slippery surface is repeatedly cut by a blade, the water droplet stops at the scratch. Once the substrate self-heals, new lubricating oil is released from within the substrate, forming a new lubricating layer. The water droplet still slides smoothly down the repaired surface, demonstrating the surface's excellent self-healing properties.

[0079] Figure 8 P m IT5-oil0、P m IT 10 -oil0、P m IT 15 -oil0 and P m IT 20 -oil0 Different molecular weight APT-PDMS, different BAPP and PDMS m Stress-strain curves of IT-oil0 mass ratio. Figure 8 E to Figure 8 H is P when the silicone oil content is the same m IT5-oil3、P m IT 10 -oil3、P m IT 15 -oil3 and Pm IT 20 Comparison of stress-strain curves of APT-PDMS with different molecular weights and different mass ratios of BAPP to PDMSmIT-oil0. [(A) a. P 1676 IT5-oil0, b. P 3060 IT5-oil0,c. P 5162 IT5-oil0. (B) a. P 1676 IT 10 -oil0, b. P 3060 IT 10 -oil0, c. P 5162 IT 10 -oil0. (C) aP 1676 IT 15 -oil0, b. P 3060 IT 15 -oil0, c. P 5162 IT 15 -oil0. (D) a. P 1676 IT 20 -oil0, bP 3060 IT 20 -oil0, c. P 5162 IT 20 -oil0. (E) a. P 1676 IT5-oil3, b. P 3060 IT5-oil3, c. P 5162 IT5-oil3. (F) a. P 1676 IT 10 -oil3, b. P 3060 IT 10 -oil3, c. P 5162 IT 10 -oil3. (G) a. P 1676 IT 15 -oil3, b. P 3060 IT 15 -oil3, c. P 5162 IT 15 -oil3. (H) a. P 1676 IT 20 -oil3, b. P 3060 IT 20 -oil3,c. P 5162 IT 20 -oil3.]

[0080] After curing at room temperature and 60 °C for 24 h, the molecular weight of APT-PDMS and PDMS m The increase of IT-oil3, P m IT x The healing rate of -oil3 gradually increased. This is because the flexibility of the elastomer molecular chain accelerates the rapid healing of the fracture surface. The self-healing efficiency is calculated by tensile strain using the following formula:

[0081]

[0082] Among them, HE original and HE healed are the average tensile strains of the original and healed specimens, respectively. Each self-healing efficiency was tested three times to obtain the average value.

[0083] The mechanical properties of the self-healing elastomers depend largely on the molecular weight of APT-PDMS and the m The content of IT-oil3. Figure 8 From (H), we can see that P 1676 IT 20 -oil3 has good mechanical properties, with a tensile strength of about 0.1009 MPa, an elongation at break of about 922.81%, and P 3060 IT 20 -oil3 tensile strength is about 0.0566 MPa, elongation at break is about 1005.03%, P 5162 IT 20 -oil3 has a tensile strength of only 0.0484 MPa, with a maximum elongation at break of approximately 1049.16%. This is due to the intermolecular hydrogen bonds formed by the urea groups acting as physical crosslinking points. Furthermore, a high TPAL content improves the flexibility of the self-healing elastomer but reduces physical crosslinking.

[0084] Figure 9 The self-healing properties of the samples after healing at room temperature and 60℃ for 24 h were compared. Figure 9 (A) P after recovery at room temperature (RT) and 60 ℃ for 24 h 1676 IT x -oil3's self-healing efficiency, Figure 9 (B) P after recovery at room temperature (RT) and 60 ℃ for 24 h 3060 IT x -Oil3's self-healing efficiency and Figure 9 (C) room temperature (RT) and 60 ℃ after 24 h recovery P 5162 IT x -oil3 self-healing efficiency. When the sample heals at 60℃, P 1676 IT x-oil3、P 3060 IT x -oil3、P 5162 IT x -oil3 healing rate compared with that at room temperature 1676 IT x -oil3、P 3060 IT x -oil3、P 5162 IT x -oil3's healing rate increased by about 15%, which shows that increasing the temperature can improve the mobility of molecular segments.

[0085] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a polyimide super-slippery surface with self-repairing properties, characterized by: The steps include: (1) Preparation of APT-PDMS: Using octamethylcyclotetrasiloxane and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane as monomers and tetramethylammonium hydroxide as catalyst, a ring-opening reaction was performed under heating conditions to obtain amino-terminated polydimethylsiloxane liquid, which was referred to as APT-PDMS. (2) PDMS m IT-oil n Synthesis: PDMS was prepared using silicone oil, APT-PDMS, isophorone diisocyanate (IPDI) and terephthalaldehyde (TPAL) as raw materials. m IT-oil n ; Wherein m is the molecular weight of APT-PDMS, the range of m is 1000~6000, and n is the mass of silicone oil; (3) Preparation of polyimide superslippery surface: PDMS m IT-oil n The polycondensation reaction was carried out with 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA). After the reaction, the sample was poured onto a substrate and degassed in a vacuum oven to obtain a polyimide superslip surface with self-healing properties, which was calculated as P m IT x -oil n ; x is PDMS m IT-oil n The mass ratio of x to BAPP is 5-20.

2. The method for preparing a polyimide super-slippery surface with self-repairing properties according to claim 1, characterized in that: The mass ratio of octamethylcyclotetrasiloxane to 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is 10~50:2~3.

3. The method for preparing a polyimide super-slippery surface with self-repairing properties according to claim 1, wherein: The specific steps of step (2) include: dissolving silicone oil in tetrahydrofuran, adding APT-PDMS tetrahydrofuran solution thereto, stirring under nitrogen atmosphere, adding isophorone diisocyanate tetrahydrofuran solution, stirring under nitrogen atmosphere, adding terephthalaldehyde tetrahydrofuran solution under heating conditions, stirring under heating conditions, and reacting to obtain PDMS m IT-oil n ; The molar ratio of APT-PDMS:IPDI:TPAL is =1~3:2.4:0.6; the usage ratio of IPDI and silicone oil is 2.4mmol:3~5g.

4. The method for preparing a polyimide super-slippery surface with self-repairing properties according to claim 1, wherein: The specific steps of step (3) include: weighing PDMS at room temperature m IT-oil n It is dissolved in a mixed solvent of THF and CH3OH with BAPP and reacted under vacuum conditions. HPMDA is then added in batches and reacted in an ice bath. After chemical imidization, it is poured onto a substrate and degassed in a vacuum oven to obtain a polyimide super-slippery surface.

5. The method for preparing a polyimide super-slippery surface with self-repairing properties according to claim 4, characterized in that: The mass ratio of THF and CH3OH is 15:

85.

6. The method for preparing a polyimide super-slippery surface with self-repairing properties according to claim 1, wherein: PDMS m IT-oil n The mass ratio of BAPP and HPMDA is 5~20:1:

1.

7. The method for preparing a polyimide super-slippery surface with self-repairing properties according to claim 6, characterized in that: PDMS m IT-oil n The mass ratio of BAPP and HPMDA is 5~10:1:

1.

8. A polyimide super-slippery surface with self-repairing properties prepared according to the method according to any one of claims 1 to 7.

9. Application of the polyimide super-slippery surface with self-repairing properties prepared by the method according to any one of claims 1 to 7 in the fields of super-slippery, self-repairing and drag reduction.

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