Mechanical interlocking polymer network with photoresponsiveness as well as preparation method and application thereof

Abstract

The invention discloses a mechanical interlocking polymer network with photoresponsiveness, a preparation method of the mechanical interlocking polymer network and application of the mechanical interlocking polymer network in a photosensitive material. The mechanical interlocking polymer network with photoresponsiveness is obtained by reaction of raw materials including an azo monomer, polytetrahydrofuran, isophorone diisocyanate and a pseudo rotaxane monomer. The structure of azo monomer is shown in the specification: # imgabs 0 # pseudo rotaxane monomer has the specific structure shown in the specification: # imgabs 1 #

Description

Technical Field

[0001] The present invention relates to the field of intelligent responsive optical materials, and in particular to a mechanically interlocked polymer network with light responsiveness, a preparation method thereof and an application thereof. Background Art

[0002] Mechanically interlocked polymer networks are the product of the fusion of polymer science and mechanically interlocked structures, and are one of the latest research directions in polymer materials. Mechanically interlocked polymers have both the dynamic properties of supramolecular polymers and the stability of covalent polymers. At the same time, the molecular-scale microscopic motion of mechanically interlocked units, such as the sliding and rotation of rotaxanes, can accumulate and amplify on the polymer, giving the polymer material unique macroscopic properties. Although there are extensive reports on mechanically interlocked polymer networks, there are few reports on photoresponsive mechanically interlocked polymer networks, and the existing synthesis methods are also relatively complicated.

[0003] The patent specification with publication number CN115403797A discloses a sliding-ring supramolecular gel film with fast light response performance and a preparation method. The preparation method uses acrylamide functionalized with azobenzene and benzyl isocyanate and acrylamide functionalized with β-cyclodextrin as reaction monomers, forms a sliding host-guest cross-linked structure through pre-inclusion of azobenzene and cyclodextrin, and uses potassium persulfate to initiate free radical polymerization to form a supramolecular polymer. Finally, the obtained polymer is precipitated and washed with acetone and fully swelled, spread and dried in water to obtain a gel film. The gel film has fast light response performance. Under 365nm light, it can quickly bend 40° in the direction of the light source within 0.5s, and can achieve film flipping and other movements under ultraviolet light; at the same time, it has a high tensile strength of 15MPa, an elongation at break of 150% and a Young's modulus of 0.34MPa. The patent specification with publication number CN118063716A discloses an anti-fatigue mechanically interlocked photoresponsive supramolecular hydrogel and a preparation method. The preparation method uses (E')-N-(4-(4-(4-hydroxyazobenzene)butoxy)benzyl)acrylamide-functionalized cyclodextrin as a reaction monomer, forms a mechanically interlocked cross-linked structure by pre-inclusion of azobenzene and cyclodextrin, and then uses potassium persulfate to initiate free radical polymerization, and copolymerizes with acrylamide to form a mechanically interlocked supramolecular hydrogel. The hydrogel has rapid photoresponsiveness and can bend rapidly by 15° in the direction of the light source within 2 seconds under irradiation of 365nm; it also has a tensile strength of 722kPa and an elongation at break of 544%; under a tensile strain of 400%, after 30 cycles of stretching, its cyclic tensile stress remains stable.

[0004] Although these studies have introduced the effect of the introduction of azobenzene on the mechanical properties of mechanically interlocked polymers, they have not deeply explained the effect of the cis-trans isomerization of azobenzene on the mechanical properties of the mechanically interlocked polymer network. Due to the highly reversible nature of the cis / trans photo-switch, azobenzene-based photoresponsive materials have applications in toughening agents, energy storage systems, switchable catalysis, controlled release, and photopharmacology.

[0005] The applicant previously disclosed a photoresponsive polymer network based on azo motifs and mechanical interlocking structures, and its preparation method and application (see patent specification with publication number CN119161553A), which is obtained by reacting raw materials including azo motifs, polytetrahydrofuran, hexamethylene diisocyanate and mechanical interlocking units. This patented technology combines the azo motifs with photoregulated steric changes with the slip ring system, and uses the cis-trans isomers of the azo motifs to regulate the sliding ability of the macrocycle in the mechanical interlocking unit, that is, the trans conformation slip ring can pass, while the cis conformation slip ring cannot pass, thereby achieving the effect of regulating the mechanical properties of the material (such as tensile properties, etc.) by light stimulation. Summary of the invention

[0006] The present invention provides a mechanically interlocked polymer network with photoresponsiveness, a preparation method thereof, and an application thereof in photosensitive materials. The present invention introduces azo moieties that undergo cis-trans isomerization under light into a mechanically interlocked polymer network to prepare a polymer network with photoresponsiveness, and studies the influence of the network mechanical properties before and after light irradiation, which has application potential in the fields of energy storage systems, switchable catalysis, controlled release and photopharmacology, toughening agents, etc.

[0007] [1] A photoresponsive mechanically interlocked polymer network obtained by reacting raw materials including an azo monomer, polytetrahydrofuran, isophorone diisocyanate and a pseudorotaxane monomer;

[0008] The structure of the azo monomer is shown below:

[0009]

[0010] The pseudorotaxane monomer is formed by the host-guest interaction between benzo-21-crown-7 containing an olefin group at the end and a secondary ammonium salt with hydroxyl groups at both ends. The specific structure is shown below:

[0011]

[0012] The present invention provides a method for preparing the azo monomer, comprising the steps of:

[0013] (1) mixing 4,4'-dihydroxyazobenzene, monomer I, potassium carbonate and a first solvent for reaction, removing the first solvent after the reaction, extracting and purifying, and separating by column chromatography to obtain an azo monomer precursor;

[0014] The structure of the monomer I is shown below:

[0015]

[0016] (2) Under nitrogen protection, an azo monomer precursor, azobisisobutyronitrile, 1,3-propanedithiol and a second solvent are mixed for reaction, and after the reaction, the second solvent is removed, and the mixture is extracted and purified, and separated by column chromatography to obtain the azo monomer.

[0017] In step (1), optionally, the usage ratio of 4,4'-dihydroxyazobenzene, monomer I, potassium carbonate and the first solvent is 1 mmol:2.4-3.0 mmol:2-4 mmol:4-8 mL.

[0018] In step (1), optionally, the first solvent includes at least one of N,N-dimethylformamide and N,N-dimethylacetamide.

[0019] In step (1), optionally, the temperature of the mixed reaction is room temperature.

[0020] In step (1), optionally, the mixing reaction time is 12 to 24 hours.

[0021] In step (1), optionally, the extraction solvent used for the extraction purification includes dichloromethane.

[0022] In step (1), optionally, the eluent used in the column chromatography separation is dichloromethane and petroleum ether. Further optionally, in the eluent, the volume ratio of the dichloromethane to the petroleum ether is 3:1.

[0023] In step (2), optionally, the amount ratio of the azo monomer precursor, azobisisobutyronitrile, 1,3-propanedithiol and the second solvent is 1 mmol: 3-4 mmol: 15-20 mmol: 10-20 mL.

[0024] In step (2), optionally, the second solvent includes at least one of dichloromethane and N,N-dimethylacetamide.

[0025] In step (2), optionally, the temperature of the mixed reaction is 50 to 80°C.

[0026] In step (2), optionally, the mixing reaction time is 12 to 24 hours.

[0027] In step (2), optionally, the extraction solvent used for the extraction purification includes dichloromethane.

[0028] In step (2), optionally, the eluent used in the column chromatography separation is dichloromethane and petroleum ether. Further optionally, in the eluent, the volume ratio of the dichloromethane to the petroleum ether is 5:1.

[0029] Optionally, the number average molecular weight of the polytetrahydrofuran is 1000 to 2000 g / mol;

[0030] Optionally, in the raw materials, the total molar number of hydroxyl groups of polytetrahydrofuran and pseudorotaxane monomers is equal to the total molar number of NCO groups of isophorone diisocyanate.

[0031] Optionally, in the raw material, the total molar number of thiol groups in the azo monomer is equal to the total molar number of olefin groups in the pseudorotaxane monomer.

[0032] The present invention provides a method for preparing the pseudorotaxane monomer, comprising:

[0033] At 40-50° C., reactant 3 and reactant 4 are mixed in dichloromethane for reaction, and dichloromethane is removed after the reaction is completed to obtain the pseudorotaxane monomer;

[0034] The reactant 3 has the structure shown below:

[0035]

[0036] The reactant 4 has the structure shown below:

[0037]

[0038] [2] The method for preparing a photoresponsive mechanically interlocked polymer network according to [1], comprising:

[0039] Under an inert atmosphere, polytetrahydrofuran, isophorone diisocyanate and pseudorotaxane monomers, a reaction solvent and an optionally added catalyst are mixed and reacted, and then an azo monomer is added. After it is completely dissolved, a photoinitiator is added and mixed evenly. The resulting mixed solution is irradiated with ultraviolet light to cause an olefin-thiol click reaction to obtain a molded sample; the molded sample is further cured and excess reaction solvent is removed to obtain the photoresponsive mechanical interlocking polymer network.

[0040] Optionally, the inert atmosphere is a nitrogen atmosphere.

[0041] Optionally, the reaction solvent is an organic solvent. Further optionally, the organic solvent includes at least one of dichloromethane, tetrahydrofuran, acetonitrile and acetone.

[0042] Optionally, the catalyst comprises dibutyltin dilaurate.

[0043] Optionally, the photoinitiator includes benzoin dimethyl ether.

[0044] Optionally, the wavelength of the ultraviolet light is 360-370 nm, for example, 365 nm.

[0045] Optionally, the intensity of the ultraviolet light is 15 to 25 mW / cm 2 , for example 20mW / cm 2 wait.

[0046] Optionally, the temperature of the olefin-thiol click reaction is 30-50°C.

[0047] Optionally, the olefin-thiol click reaction is carried out for 1 to 1.5 hours.

[0048] The method for preparing the photoresponsive mechanically interlocked polymer network can place the molded sample in a vacuum oven for further curing and removal of excess reaction solvent.

[0049] Optionally, the curing temperature is 55-65°C, such as 60°C.

[0050] Optionally, the curing time is 24 to 30 hours.

[0051] [3] Application of the photoresponsive mechanically interlocked polymer network according to [1] in photosensitive materials. The photoresponsive mechanically interlocked polymer network utilizes the cis-trans isomerization of azo to regulate the mechanical properties of the polymer, and is expected to be applied in the fields of toughening agents, energy storage systems, switchable catalysis, controlled release and photopharmacology.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] 1. The mechanically interlocked polymer network of the present invention has outstanding properties such as energy dissipation capacity and toughness, and creatively adds azobenzene units into the mechanically interlocked polymer network, making the network photoresponsive, and illustrating the changes in the mechanical properties of the network before and after illumination.

[0054] 2. The photoresponsive mechanical interlocking polymer network provided by the present invention has the added azo moieties, which change its mechanical properties under light irradiation, and is expected to exert new functions and broaden the application scenarios.

[0055] 3. The method for preparing the photoresponsive mechanical interlocking polymer network provided by the present invention is simple to operate, has a reliable route and is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the NMR comparison result of compound 3, compound 4 and pseudorotaxane monomer 2.

[0057] Figure 2 Schematic diagram of the synthesis of a photoresponsive mechanically interlocked polymer network of the present invention.

[0058] Figure 3 This is the infrared comparison result of azo monomer 1 (monomer 1), pseudorotaxane monomer 2 (monomer 2) and the photoresponsive mechanically interlocked polymer network AC.

[0059] Figure 4 This is a diagram showing the swelling results of the polymer network AC of the present invention in Example 4.

[0060] Figure 5 Graph showing the thermogravimetric analysis results of the polymer networks AC of the present invention in Examples 1-3.

[0061] Figure 6 This is a diagram of the light response color change of the polymer network C of the present invention in Example 3, (A) left is the polymer network C without illumination, (A) right is the color of the polymer network C after illumination for 1 hour, (B) left is the polymer network C without illumination, (B) right is the color of the polymer network C after illumination for 1 hour and standing for 1 hour, (C) left is the polymer network C without illumination, (C) right is the color of the polymer network C after illumination for 1 hour and standing for 3 hours.

[0062] Figure 7 Graph showing stress-strain test results of the polymer network AC (AC) of the present invention before and after irradiation at a stretching rate of 100 mm / min in Examples 1-3.

[0063] Figure 8 This is a graph showing the toughness results of the polymer network of Examples 1-3 before and after AC irradiation.

[0064] Fig. 9 Graphs showing the results of cyclic stress-strain testing of polymer network C of Example 3 before (A) and after (B) irradiation over a wide range of maximum applied strains from 100% to 500%.

[0065] Fig.10 Comparison of the energy dissipation value (A) and the damping energy (B) of the polymer network C of Example 3 before and after illumination. DETAILED DESCRIPTION

[0066] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0067] In the present invention, the stress-strain curves are all measured at room temperature at a constant tensile rate of 100 mm / min. Young's modulus is determined by the initial slope of the stress-strain curve. Toughness is a parameter that characterizes the work required for fracture of each unit sample, and is calculated based on the area of ​​the region below the stress-strain curve (until fracture). Energy dissipation is calculated by integrating the area contained in the cyclic tensile curve. Damping capacity is defined as the ratio of dissipated energy (area enclosed by the loading and unloading curves) to the loading energy (area enclosed by the loading curve).

[0068] The number average molecular weight of the polytetrahydrofuran used in the following examples is 1000 g / mol.

[0069] Embodiment 1:

[0070] Synthesis of azo monomer 1:

[0071]

[0072] (1) 4,4'-dihydroxyazobenzene (23.4mmol, 5g) was added to a 500mL round-bottom flask, 100mL N,N-dimethylformamide (DMF) was added to dissolve, and then potassium carbonate (72.3mmol, 10.0g) aqueous solution was added, and finally 10-bromo-1-decene (56.8mmol, 12.43g) was added, and the reaction was carried out at room temperature for 24h. Thin layer chromatography TLC detection, if the reaction is complete, the reaction system is distilled under reduced pressure to remove the solvent, and then dichloromethane (60mL×3) is added to the system for extraction, and the combined organic phase is dried over anhydrous sodium sulfate, filtered and distilled under reduced pressure, and separated by column chromatography, the eluent is dichloromethane / petroleum ether (volume ratio 3 / 1), to obtain an azo unit precursor (4.92g, 43%).

[0073] (2) Azo unit precursor

[0074]

[0075] Under nitrogen protection, the azo unit precursor (1.0mmol, 492.0mg) and azobisisobutyronitrile (AIBN) (3.0mmol, 492.0mg) were dissolved in 15mL of dichloromethane. Subsequently, 1,3-propanedithiol (20mmol, 2.160g) was added to the reaction mixture using a syringe and reacted at 80°C for 24h. Thin layer chromatography TLC detection, if the reaction is complete, the reaction system is distilled under reduced pressure to remove the solvent, and dichloromethane (60mL×3) is added to the system for extraction. The combined organic phase is dried over anhydrous sodium sulfate, filtered and distilled under reduced pressure, and separated by column chromatography. The eluent is dichloromethane / petroleum ether (volume ratio 5 / 1), and azo unit 1 (4.24g, 60%) is obtained.

[0076] The hydrogen nuclear magnetic resonance results of the azo unit 1 in this example are as follows:

[0077] 1 H NMR (600MHz, CDCl3) δ (ppm): 7.86 (d, J = 8.7Hz, 4H), 6.98 (d, J = 8.7Hz, 4H), 4.03 (t, J = 6.5Hz, 4H), 2.70 -2.57(m,8H),2.50(t,J=7.4Hz,4H),1.93-1.84(m,4H),1.84-1.78(m,4H),1.60-1.54(m,8H),1.47(d,J=7.8Hz,4H),1.41-1.32(m,16H).

[0078] Synthesis of pseudorotaxane monomer 2:

[0079]

[0080] Reactant 3 (1.0 mmol, 455.0 mg) and reactant 4 (1.0 mmol, 582.0 mg) were added to a 25 mL round-bottom flask, 10 mL of dichloromethane (DCM) was added to dissolve, and refluxed at 45° C. for 6 h. The reaction was stopped, and the solvent was dried to obtain pseudorotaxane monomer 2.

[0081] The NMR comparison results of pseudorotaxane monomer 2 and reactants 3 and 4 are as follows Figure 1 shown.

[0082] Synthesis of photoresponsive mechanically interlocked polymer network A (PPN-A):

[0083] Under nitrogen, polytetrahydrofuran (0.20 mmol), pseudorotaxane monomer 2 (0.20 mmol) of Example 1, isophorone diisocyanate (0.40 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred for 1 day; then the azo monomer 1 (0.10 mmol) of Example 1 was added, and after it was completely dissolved, the photoinitiator benzoin dimethyl ether was added; the stirred mixed solution was poured into a mold, and an ultraviolet lamp (365 nm, 20 mW / cm 2 ) for 1 hour to cause olefin-thiol click reaction; then the formed sample was placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent, and the sample was taken out and cooled to room temperature to obtain a photoresponsive mechanical interlocking polymer network A (PPN-A). After obtaining the mechanical interlocking polymer network A (PPN-A), the mechanical properties were tested before and after irradiation with a 365nm light source for 1 hour.

[0084] Example 2

[0085] Synthesis of photoresponsive mechanically interlocked polymer network B (PPN-B):

[0086] Under nitrogen, polytetrahydrofuran (0.10 mmol), pseudorotaxane monomer 2 (0.20 mmol) of Example 1, isophorone diisocyanate (0.30 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred for 1 day; then the azo monomer 1 (0.10 mmol) of Example 1 was added, and after it was completely dissolved, the photoinitiator benzoin dimethyl ether was added; the stirred mixed solution was poured into a mold, and an ultraviolet lamp (365 nm, 20 mW / cm 2 ) for 1 hour to cause olefin-thiol click reaction; then the formed sample was placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent, and the sample was taken out and cooled to room temperature to obtain a photoresponsive mechanical interlocking polymer network B (PPN-B). After obtaining the mechanical interlocking polymer network B (PPN-B), the mechanical properties were tested before and after irradiation with a 365nm light source for 1 hour.

[0087] Example 3

[0088] Synthesis of photoresponsive mechanically interlocked polymer networks C (PPN-C):

[0089] Under nitrogen, polytetrahydrofuran (0.10 mmol), pseudorotaxane monomer 2 (0.30 mmol) of Example 1, isophorone diisocyanate (0.40 mmol) and reaction solvent DCM (2 mL) were added to the reaction bottle, and a drop of dibutyltin dilaurate was used as a catalyst. The system was stirred for 1 day; then the azo monomer 1 (0.15 mmol) of Example 1 was added, and after it was completely dissolved, the photoinitiator benzoin dimethyl ether was added; the stirred mixed solution was poured into a mold, and an ultraviolet lamp (365 nm, 20 mW / cm 2 ) for 1 hour to cause olefin-thiol click reaction; then the formed sample was placed in a vacuum oven at 60°C for 24 hours to further solidify the sample and remove excess solvent, and the sample was taken out and cooled to room temperature to obtain a photoresponsive mechanical interlocking polymer network C (PPN-C). After obtaining the mechanical interlocking polymer network C (PPN-C), the mechanical properties were tested before and after irradiation with a 365nm light source for 1 hour.

[0090] Figure 2This is a schematic diagram of the synthesis of a photoresponsive mechanical interlocking polymer network of the present invention. First, the hydroxyl groups in the pseudorotaxane monomer, the hydroxyl groups in polytetrahydrofuran and isophorone diisocyanate are reacted to obtain a linear polymer. Then, the double bonds in the pseudorotaxane monomer and the thiol groups on the azo monomer react to generate a cross-linked photoresponsive mechanical interlocking polymer network.

[0091] Sample Analysis:

[0092] The polymer networks prepared in Examples 1-3 were subjected to performance tests. Figure 3 The infrared spectra of the photoresponsive mechanical interlocking polymer network obtained in Examples 1-3, the azo monomer 1, and the pseudorotaxane monomer 2 show that the double bonds in the pseudorotaxane monomer 2 are basically completely reacted. Figure 4 The swelling experiment showed that the polymer network only swelled but did not dissolve. These results further demonstrated that the double bond in the pseudorotaxane monomer 2 and the thiol group in the azo monomer 1 reacted completely, and a photoresponsive mechanically interlocked polymer network was successfully prepared. Figure 5 The thermogravimetric diagram of the polymer network obtained in Examples 1-3 shows that the polymer has good thermal stability and the temperature of 5% mass loss is above 200°C; Figure 6 This is the photoresponsiveness diagram of the polymer network. It can be seen from the figure that the azo units in the polymer network can recover the trans conformation after being irradiated for 1 hour and then left to stand for 3 hours; Figure 7 The stress-strain curves of different polymer networks AC show that the maximum strain and maximum stress of the polymer network after illumination are both greater than those before illumination. Figure 8 This is a graph showing the toughness changes of different polymer networks before and after illumination. It can be seen from the graph that the toughness of the polymer network increases after illumination; Fig. 9 AB are the cyclic tensile curves of the polymer network C before and after illumination, respectively. It can be seen from the figure that the hysteresis loop of the polymer network becomes larger with the increase of strain, whether before or after illumination, indicating that the sliding of the sliding loop plays a dissipative role under the condition of large strain, thereby enhancing the toughness of the polymer network. Fig.10 AB are the energy dissipation value and damping energy of the polymer network C before and after illumination, respectively. It can be seen from the figure that the energy dissipation value and damping energy after illumination are greater than those before illumination.

[0093] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A photoresponsive mechanically interlocked polymer network, characterized in that: It is obtained by reacting raw materials including azo monomer, polytetrahydrofuran, isophorone diisocyanate and pseudorotaxane monomer; The structure of the azo monomer is shown below: The specific structure of the pseudorotaxane monomer is shown below:

2. The photoresponsive mechanically interlocked polymer network according to claim 1, characterized in that The preparation method of the azo monomer comprises the steps of: (1) mixing 4,4'-dihydroxyazobenzene, monomer I, potassium carbonate and a first solvent for reaction, removing the first solvent after the reaction, extracting and purifying, and separating by column chromatography to obtain an azo monomer precursor; The structure of the monomer I is shown below: (2) Under nitrogen protection, an azo monomer precursor, azobisisobutyronitrile, 1,3-propanedithiol and a second solvent are mixed for reaction, and after the reaction, the second solvent is removed, and the mixture is extracted and purified, and separated by column chromatography to obtain the azo monomer.

3. The photoresponsive mechanically interlocked polymer network according to claim 2, characterized in that In step (1): The usage ratio of 4,4'-dihydroxyazobenzene, monomer I, potassium carbonate and the first solvent is 1 mmol: 2.4-3.0 mmol: 2-4 mmol: 4-8 mL; The first solvent includes at least one of N,N-dimethylformamide and N,N-dimethylacetamide; The temperature of the mixed reaction is room temperature; The mixing reaction time is 12 to 24 hours; The extraction solvent used in the extraction purification includes dichloromethane; The eluents used in the column chromatography separation are dichloromethane and petroleum ether; in the eluent, the volume ratio of the dichloromethane to the petroleum ether is 3:

1.

4. The photoresponsive mechanically interlocked polymer network according to claim 2, characterized in that In step (2): The amount ratio of the azo monomer precursor, azobisisobutyronitrile, 1,3-propanedithiol and the second solvent is 1mmol:3-4mmol:15-20mmol:10-20mL; The second solvent includes at least one of dichloromethane and N,N-dimethylacetamide; The temperature of the mixed reaction is 50-80°C; The mixing reaction time is 12 to 24 hours; The extraction solvent used in the extraction purification includes dichloromethane; The eluents used in the column chromatography separation are dichloromethane and petroleum ether; in the eluent, the volume ratio of the dichloromethane to the petroleum ether is 5:

1.

5. The photoresponsive mechanically interlocked polymer network according to claim 1, characterized in that The number average molecular weight of the polytetrahydrofuran is 1000 to 2000 g / mol; In the raw materials, the total molar number of hydroxyl groups of polytetrahydrofuran and pseudorotaxane monomers is equal to the total molar number of NCO groups of isophorone diisocyanate; In the raw material, the total molar number of the mercapto groups in the azo monomer is equal to the total molar number of the olefin groups in the pseudorotaxane monomer.

6. The photoresponsive mechanically interlocked polymer network according to claim 1, characterized in that The preparation method of the pseudorotaxane monomer comprises: At 40-50° C., reactant 3 and reactant 4 are mixed in dichloromethane for reaction, and dichloromethane is removed after the reaction is completed to obtain the pseudorotaxane monomer; The reactant 3 has the structure shown below: The reactant 4 has the structure shown below:

7. The method for preparing a photoresponsive mechanically interlocked polymer network according to any one of claims 1 to 6, characterized in that: include: Under an inert atmosphere, polytetrahydrofuran, isophorone diisocyanate and pseudorotaxane monomers, a reaction solvent and an optionally added catalyst are mixed and reacted, and then an azo monomer is added. After it is completely dissolved, a photoinitiator is added and mixed evenly. The resulting mixed solution is irradiated with ultraviolet light to cause an olefin-thiol click reaction to obtain a molded sample; the molded sample is further cured and excess reaction solvent is removed to obtain the photoresponsive mechanical interlocking polymer network.

8. The method for preparing a photoresponsive mechanically interlocked polymer network according to claim 7, characterized in that: The inert atmosphere is a nitrogen atmosphere; The reaction solvent is an organic solvent; the organic solvent includes at least one of dichloromethane, tetrahydrofuran, acetonitrile and acetone; The catalyst includes dibutyltin dilaurate; The photoinitiator includes benzoin dimethyl ether; The wavelength of the ultraviolet light is 360-370nm; The illumination intensity of the ultraviolet light is 15-25 mW / cm 2 ; The temperature of the olefin-thiol click reaction is 30 to 50° C.; The time of the olefin-thiol click reaction is 1 to 1.5 hours; The molded samples were placed in a vacuum oven for further curing and removal of excess reaction solvent; The curing temperature is 55-65°C; The curing time is 24 to 30 hours.

9. Use of the photoresponsive mechanically interlocked polymer network according to any one of claims 1 to 6 in photosensitive materials.

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