A 3D AIE-based bifluorophore covalent organic framework (3D-COFs) material and preparation and application thereof

Abstract

The application provides a 3D AIE-based bifluorophore covalent organic framework (3D-COF) material and preparation and application thereof. The application simultaneously introduces a metal complex and an AIE dye into a covalent organic framework, and limits the spatial configuration of the transition metal complex and the AIE dye through dynamic imine bond connection. The secondary assembly of the 3D-COF particles is induced by weak interaction, and the effective regulation of the photoluminescence spectrum of the 3D-COF nanoluminescent material is successfully realized, so that the 3D-COF nanoluminescent material has concentration dependence, a wide color gamut range and reversible stress-strain responsiveness.

Description

Technical Field

[0001] This invention belongs to the fields of photoluminescence ratiometric fluorescence sensing and detection, specifically relating to a 3D AIE-based dual-fluorophore covalent organic framework (3D-COFs) material and its preparation and application, and more specifically relating to the preparation and use of a 3D AIE-based dual-fluorophore covalent organic framework (3D-COFs) composed of a metal complex and an aggregation-induced emission dye, its secondary assembly, and the composite system dispersed in a polymer matrix. Background Technology

[0002] Photoluminescence sensing relies on the enhancement, quenching, changes in fluorescence lifetime, or wavelength shifts to measure stimulus responses. Photoluminescence sensing strategies include fluorescence resonance energy transfer, ratiometric fluorescence, and aggregated-state fluorescence emission. For traditional aggregation-induced quenching (ACQ) dyes, fluorescence sensing typically faces challenges such as nonradiative energy decay and reduced sensitivity due to increased probe concentration. Furthermore, aggregation-induced emission dyes usually require restriction of intramolecular motion to achieve fluorescence enhancement. These factors pose challenges to improving the performance of photoluminescence sensing (Yang D, Ren Y, Li J, et al. Highly sensitive AIE-based mechanoresponsive luminescent polymer coatings for surface pressure imaging[J]. Chemical Engineering Journal, 2022, 431:133449).

[0003] Covalent organic frameworks (COFs) are porous materials with strong covalent bonds connecting molecules. These covalent bonds endow them with extremely strong chemical and thermal stability. Furthermore, due to their low density, high specific surface area, ease of modification and functionalization, they have attracted widespread attention in fields such as gas storage and separation, heterogeneous catalysis, energy storage materials, optoelectronics, sensing, and drug delivery, especially showing great application potential in photoluminescence sensing (Liu Y, Ma Y, Zhao Y, et al. Weaving of organic threads into a crystalline covalent organic framework[J]. Science, 2016, 351(6271):365-369). However, the performance of luminescent materials and sensors constructed from COFs is affected by the interactions between their monomer units and adjacent layers. Aggregation-induced quenching (ACQ) caused by π-π stacking and thermal dissipation due to intramolecular rotation / vibration can also lead to nonradiative energy decay in COFs, resulting in luminescence quenching and decreased sensitivity. Therefore, how to achieve better luminescence and sensing performance through precise structural control of COFs materials is one of the current research hotspots.

[0004] Existing research has shown that utilizing the aggregation-induced emission properties of AIE molecules to restrict the rotation, vibration, and motion within AIE molecules through the rigid structure of COF materials, thereby reducing nonradiative energy decay and obtaining enhanced fluorescence emission, is a highly attractive approach. Summary of the Invention

[0005] The purpose of this invention is to provide a 3D AIE-based dual-fluorescent covalent organic framework (3D-COFs) material with dynamic strain response, as well as its preparation and application.

[0006] This invention modulates the spatial configuration of COFs materials composed of metal complexes and AIE dyes through dynamic imine, amide, or ester bonds. Then, by utilizing weak interactions to induce secondary assembly of 3D-COF particles, it achieves precise control over the photoluminescence spectrum of this AIE-based framework-structured luminescent material, making it exhibit significant concentration dependence, expanding its wide color gamut from blue to red light, and endowing it with good reversible stress and strain responsiveness. Through the composite and dispersion of 3D-COFs with polymer substrates such as polymer elastomers and fluids, the aggregate structure of COFs changes through non-covalent interactions within different concentration ranges, further enhancing the photoluminescent COFs' high-sensitivity shear response. This enables non-contact material strain and surface friction detection, as well as fluid velocity imaging measurement, and can be used for optical sensing and fluid dynamics visualization measurements.

[0007] The 3D AIE-based dual-fluorophoretic covalent organic framework (3D-COFs) material provided by the present invention comprises a metal complex and an aggregation-induced emission (AIE) dye, wherein the molar ratio of the metal complex probe to the AIE dye can be 1:3-3:1.

[0008] The metal complex is at least one of transition metal complexes with iridium, ruthenium, or cobalt as the central atom, or a mixture thereof;

[0009] The transition metal complex uses bipyridine and / or phenanthroline compounds with carboxyl and / or amino groups as ligands.

[0010] Specifically, the transition metal complex has the following structural formula:

[0011]

[0012] Where M can be Ir, Ru or Co; R can be -OH, -CHO, -COOH or -NH2, but at least one or two R are amino or carboxyl functional groups;

[0013] or:

[0014]

[0015] Where M can be Ir, Ru or Co; R can be -OH, -CHO, -COOH or -NH2, but at least one or two R are amino or carboxyl functional groups;

[0016] or:

[0017]

[0018] Where M can be Ir, Ru or Co; R can be -OH, -CHO, -COOH or -NH2, but at least one or two R are amino or carboxyl functional groups;

[0019] or:

[0020]

[0021] Where M can be Ir, Ru or Co; R can be -OH, -CHO, -COOH or -NH2, but at least one or two R are amino or carboxyl functional groups;

[0022] Or a mixture of them.

[0023] The AIE dye is at least one of tetraphenylethylene and its derivatives, triphenylamine and its derivatives, phenoxazine and its derivatives, phenothiazine and its derivatives, and carbazole and its derivatives, which have different functional groups.

[0024] Specifically, the AIE dye comprises at least one of the compounds shown in Formula I, Formula II, Formula III, Formula IV, Formula V, Formula VI and Formula VII:

[0025]

[0026] In Formulas I, II, III, IV, V, VI and VII, R1 is independently selected from at least one of H, -OH, -CHO, -COOH and -NH2, and contains at least two non-H R1 groups;

[0027] More specifically, the AIE dye is selected from at least one of the following compounds:

[0028]

[0029] The 3D-AIE-based dual-fluorescent covalent organic framework material can be prepared by a method including the following steps: linking a transition metal complex with the AIE dye to obtain a 3D-COFs system synthesized by linking the transition metal complex with the AIE dye.

[0030] The bonding between the transition metal complex and the AIE dye is achieved through Schiff base reaction, amidation reaction, esterification reaction, and activated esterification reaction.

[0031] The reaction temperature can be 30-180℃, specifically 50℃, 80℃, 120℃, or 150℃, and the time can be 2-48 hours.

[0032] The reaction is carried out in DMF, anhydrous ethanol or anhydrous methanol by hydrothermal method or reflux;

[0033] The molar ratio of the transition metal complex probe to the AIE dye can be 1:3-3:1, specifically 1:3-2:3.

[0034] The 3D AIE-based dual-fluorophore covalent organic framework (3D-COFs) material exhibits photoluminescence spectrum concentration dependence, a wide color gamut (from blue to red), and reversible strain response.

[0035] The present invention also provides a secondary assembly of the above-mentioned 3D AIE-based dual-fluorophore covalent organic framework (3D-COFs).

[0036] The secondary assembly is prepared by allowing 3D-COFs to stand in a solvent at a certain concentration for a certain period of time.

[0037] The solvent may be selected from: DMF, anhydrous ethanol or anhydrous methanol;

[0038] The concentration can be 0.00075-1.5 mg / mL;

[0039] The settling time can be 0.5-2 hours.

[0040] The present invention also provides a composite system of the above-mentioned 3D AIE-based dual-fluorophore covalent organic framework (3D-COFs) dispersed in a polymer matrix, wherein the composite system may specifically be a ratioluminescent thin film or a fluid sensor.

[0041] The composite system of 3D AIE-based dual-fluorophoretic covalent organic frameworks (3D-COFs) dispersed in a polymer matrix provided by the present invention includes the above-mentioned 3D AIE-based dual-fluorophoretic covalent organic framework (3D-COFs) material and a polymer matrix, wherein the 3D AIE-based dual-fluorophoretic covalent organic framework (3D-COFs) material is dispersed in the polymer matrix.

[0042] The polymer matrix includes polymeric elastomers and fluids.

[0043] The polymer matrix may specifically be at least one of polyethylene glycol and its derivatives, chitosan and its derivatives, dextran and its derivatives, polyvinyl alcohol and its derivatives, polylactic acid and its derivatives, cellulose and its derivatives, polyacrylate and silicone polymers; more specifically, it may be room temperature vulcanizing silicone rubber (RTV), polydimethylsiloxane, or polymethyl acrylate.

[0044] The concentration of the 3D-COFs in the polymer matrix ranges from 0.01% to 1.8% (w / w).

[0045] The applications of the aforementioned 3D-COFs materials, their secondary assemblies, and their composite systems dispersed in a polymer matrix in the detection of material strain, surface friction, and spatial visualization measurement of shear force in fluids also fall within the scope of protection of this invention.

[0046] In this application, the detection is a non-contact optical image detection.

[0047] The present invention has the following advantages:

[0048] 1. This invention introduces metal complexes and AIE dyes simultaneously into a covalent organic framework, using dynamic imine bonds to restrict the spatial configuration of the transition metal complexes and AIE dyes. By utilizing weak interactions to induce the secondary assembly of these 3D-COF particles, the photoluminescence spectrum of the 3D-COF nanomaterials is successfully controlled, exhibiting concentration dependence, a wide color gamut, and reversible stress-strain response.

[0049] 2. By restricting the intramolecular rotation and vibration of AIE dyes through the COF structure and regulating the aggregation state of transition metal complex molecules, the influence of probe aggregation-induced quenching was effectively suppressed, resulting in higher quantum yield.

[0050] 3. By combining polymer substrates with 3D-COFs, the aggregation structure of COFs changes through non-covalent interactions within different concentration ranges, enabling photoluminescent COFs to further acquire highly sensitive shear response.

[0051] This invention combines aggregation-induced quenching (AIE) metal complex dyes with AIE dyes to construct AIE-based dual-fluorophoretic COF materials. By combining oxygen responsiveness with the AIE effect, the photoluminescence spectrum of the COF materials can be effectively controlled, exhibiting concentration dependence, a wide color gamut, and reversible strain responsiveness. Finally, by introducing a polymer matrix to further adjust the aggregated structure, a non-contact optical sensor with high sensitivity to stimuli can be obtained.

[0052] This invention provides a method for synthesizing AIE-based dual-fluorophoretic 3D-COF materials constructed from metal complexes and AIE dyes. By controlling the dynamics of imine, amide, and ester bonds, and further utilizing weak interactions to induce secondary assembly of 3D-COF particles, precise control of the photoluminescence spectrum of the AIE-based framework structure luminescent material is achieved. This material exhibits significant advantages in photoluminescence properties, demonstrating a clear concentration dependence, covering a wide color gamut from blue to red light, and possessing good stress and strain responsiveness, capable of producing reversible spectral changes under external stress or strain. Furthermore, by compositing and dispersing the 3D-COF material with polymer substrates (such as polymeric elastomers, fluids, etc.), the aggregated structure of the 3D-COF can change through non-covalent interactions within different concentration ranges, further endowing the photoluminescent COF material with highly sensitive shear response. Based on this, the material can achieve non-contact strain and surface friction detection, as well as fluid velocity imaging measurement, and can be widely used in optical sensing and fluid dynamics visualization measurement, showing significant application prospects. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the structure of the 3D AIE-based dual-fluorophore COFs material prepared in Example 1 of the present invention.

[0054] Figure 2 In the figure, a represents the emission spectra of the COFs material prepared in Example 2 of this invention and the original TPE, and b represents the dependence of the COFs material spectrum on concentration.

[0055] Figure 3 TEM images of the 3D-COFs prepared in Example 3 of this invention in DMF dispersions at concentrations of 0.03 mg / mL and 0.75 mg / mL.

[0056] Figure 4The results show the detection of microcracks in the 3D AIE-based dual-fluorophore COFs thin film prepared in Example 4 of this invention.

[0057] Figure 5 The results show the surface friction force monitoring of the 3D AIE-based dual-fluorophore COFs thin film prepared in Example 5 of this invention.

[0058] Figure 6 Fluorescence images of the 3D-COFs material dispersed in a polymer solution prepared in Example 6 of this invention at different shear rates.

[0059] Figure 7 The ratio fluorescence pseudocolor image of the 3D-COFs material dispersed in a polymer solution prepared in Example 7 of the present invention under different linear velocity conditions in a liquid pipeline flow. Detailed Implementation

[0060] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0061] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0062] Example 1

[0063] First, dichlorobis(4-methylisopropylphenyl)iridium(II) and 2,2'-bipyridine-4,4'-diamine were dispersed in anhydrous methanol at a molar ratio of 1:5 and refluxed at 65°C. After stirring for 36 hours under a nitrogen atmosphere, the reaction was stopped. The insoluble matter was filtered off, the filtrate was collected, the solvent was removed by rotary evaporation, and the product was recrystallized from acetone to obtain the metallic iridium complex IrX3, with the following structural formula:

[0064]

[0065] IrX3 (0.4 mmol) and tris(4-aldehydephenyl)amine (3CHO-TPA) dye (1.2 mmol) were weighed and dissolved in anhydrous methanol at a molar ratio of 1:3. The solutions were sonicated for 20 minutes and then transferred to a Teflon-lined stainless steel high-pressure reactor, where a Schiff base reaction was carried out at 150 °C for 18 hours. After cooling to room temperature, the product was collected by centrifugation and vacuum dried at 60 °C for 24 hours to obtain the product, Ir-TPA3D fluorophore covalent organic framework material (Ir-TPA1 3D-COFs).

[0066] Figure 1 This is a schematic diagram of the structure of Ir-TPA1 3D-COFs prepared in Example 1 of the present invention.

[0067] Example 2

[0068] First, ruthenium trichloride trihydrate (0.3 mmol) and 2,2'-bipyridine-4,4'-dicarboxylic acid (dcbpy, 0.9 mmol) were dispersed in DMF at a molar ratio of 1:3 and refluxed. The reaction was carried out at 80 °C and stirred under a nitrogen atmosphere for 24 hours. The reaction was then stopped, the insoluble matter was filtered off, the filtrate was collected, the solvent was removed by rotary evaporation, and the product was recrystallized from isopropanol to obtain the ruthenium complex [Ru(dcbpy)3]Cl2.

[0069] [Ru(dcbpy)3]Cl2 (0.2 mmol) and 1-phenyl-1,2,2-tris(4-aminophenyl)ethylene (3NH2-TPE) dye (0.3 mmol) were weighed and dissolved in anhydrous ethanol at a molar ratio of 2:3. The solutions were sonicated for 25 minutes and then transferred to a Teflon-lined stainless steel high-pressure reactor, where an amidation reaction was carried out at 120 °C for 12 hours. After cooling to room temperature, the product was collected by centrifugation and vacuum dried at 55 °C for 36 hours to obtain Ru-TPE 3D fluorophore covalent organic framework materials (Ru-TPE 3D-COFs).

[0070] Two mL of uniformly dispersed 3NH2-TPE at a concentration of 0.03 mg / mL and anhydrous ethanol solutions of Ru-TPE 3D-COFs at different concentrations were respectively added to a four-way quartz cell. The fluorescence emission spectra of individual AIE molecules and 3D-COFs at different concentrations were measured using a fluorescence spectrophotometer with excitation light at a wavelength of 365 ± 10 nm.

[0071] Figure 2 In Figure a, the emission spectra of the prepared Ru-TPE 3D-COFs and the original TPE are shown, indicating that the three-dimensional framework structure of 3D-COF restricts the intramolecular rotation, vibration and motion of AIE dyes, resulting in higher AIE quantum yield. Figure 2 Figure b shows the concentration dependence of the emission spectrum of 3D-COFs and their secondary assembly behavior.

[0072] Example 3

[0073] First, cobalt dichloride hexahydrate (0.2 mmol) and 2,2'-bipyridine-4,4'-dicarboxylic acid (dcbpy, 0.6 mmol) were dispersed in an aqueous solution of NaOH (1.2 mmol) at a molar ratio of 1:3. The reaction was carried out at 45 °C under a nitrogen atmosphere and stirred for 12 hours. The reaction was then stopped, and water was removed by rotary evaporation. The resulting solid was redispersed in a supersaturated aqueous solution and recrystallized from acetone to obtain a crude product precipitate. The solid was collected by vacuum filtration and washed with ethanol and acetone. The product was then dried under vacuum to obtain the cobalt metal complex [Co(dcbpy)3]Cl2.

[0074] [Co(dcbpy)3]Cl2 (0.3 mmol) and 1,1-diphenyl-2,2-di(4-hydroxyphenyl)ethylene (2OH-TPE) dye (0.1 mmol) were weighed and dissolved in anhydrous ethanol at a molar ratio of 3:1. The solutions were sonicated for 30 minutes and then transferred to a Teflon-lined stainless steel high-pressure reactor, where an esterification reaction was carried out at 100 °C for 48 hours. After cooling to room temperature, the product was collected by centrifugation and vacuum dried at 35 °C for 24 hours to obtain the product Co-TPE 3DAIE-based dual-fluorescent covalent organic framework material (Co-TPE 3D-COFs).

[0075] The prepared Co-TPE 3D-COFs were dispersed in DMF at concentrations of 0.03 mg / mL and 0.75 mg / mL, respectively, and allowed to stand for half an hour. Figure 3 TEM images of the prepared 3D-COFs in DMF dispersions at concentrations of 0.03 mg / mL and 0.75 mg / mL show that the morphology and size of the 3D-COF units vary considerably with changes in concentration.

[0076] Example 4

[0077] First, dichlorobis(4-methylisopropylphenyl)iridium(II) and 2,2'-bipyridine-5,5'-dicarboxylic acid were dispersed in anhydrous methanol at a molar ratio of 1:6 and refluxed at 50-100℃. After stirring under a nitrogen atmosphere for 36 hours, the reaction was stopped, filtered, and the filtrate was collected. The solvent was removed by rotary evaporation, and the product was recrystallized using acetone to obtain the metallic iridium complex [Ir(dcbpy)3]. 2+ Cl2.

[0078] [Ir(dcbpy)3] 2+Cl2 (0.35 mmol), EDC (0.4 mmol), and NHS (0.8 mmol) were dissolved in 10 mL of deionized water. After stirring at room temperature for 1 h, tris(4-aminophenyl)amine (3NH2-TPA, 1.4 mmol) was added. The amide reaction was then transferred to 50 °C and stirred in the dark for 24 h. The product, Ir-TPA 3DAIE-based dual-fluorescent covalent organic framework material (Ir-TPA2 3D-COFs), was purified by thin-layer chromatography.

[0079] 0.5 mg Ir-TPA2 3D-COFs were ultrasonically dispersed in 200 μL of anhydrous methanol. Then, 2 g of polydimethylsiloxane (PDMS) and 0.2 g of curing agent were added under stirring, and the mixture was vacuum dried to remove air bubbles. The mixture was poured onto a glass slide and coated to prepare a uniform COF@PDMS film. After pre-curing at 80 °C for 30 minutes, it was then cured at 150 °C for 3 hours.

[0080] Figure 4 The results show the detection of microcracks in the 3D AIE-based dual-fluorophore COFs thin film prepared in this embodiment. After stretching the film, a gradient color change from green to blue was observed along the stretching direction, and the luminescence intensity increased, indicating that the addition of this material can be used for non-destructive detection of microcracks in the thin film.

[0081] Example 5

[0082] First, cobalt dichloride hexahydrate (0.15 mmol) and 5-amino-1,10-phenanthroline (0.45 mmol) were dissolved in 25 mL of water and stirred. After thorough mixing, the mixture was transferred to a hydrothermal reactor and reacted for 38 h at a reaction temperature of 120 °C. After filtration and freeze-drying, the product, cobalt metal complex CoY3, was obtained.

[0083] CoY3 (0.5 mmol) and N1,N1-bis(4-aldehydephenyl)aniline (2CHO-TPA) dye (0.3 mmol) were weighed and dissolved in anhydrous ethanol at a molar ratio of 5:3. The solutions were sonicated for 40 minutes and then dispersed in DMF under reflux. The Schiff base reaction was carried out at 70 °C. After stirring under a nitrogen atmosphere for 45 hours, the reaction was stopped. Insoluble matter was filtered off, the filtrate was collected, the solvent was removed by rotary evaporation, and the product was recrystallized from isopropanol to obtain Co-TPA 3DAIE-based dual-fluorescent covalent organic framework materials (Co-TPA 3D-COFs).

[0084] 0.3 mg of Co-TPA3D-COFs were ultrasonically dispersed in 300 μL of chloroform. Then, 1.5 g of room temperature vulcanized silicone rubber (RTV) was added with stirring, and the mixture was vacuum dried to remove air bubbles. The mixture was poured onto a glass slide, spread evenly, and cured in air for 30 minutes to prepare a COF@RTV film.

[0085] Figure 5 This image shows the surface friction monitoring results of the 3D AIE-based dual-fluorophore COFs thin film prepared in this embodiment. When an object moves above the film, generating friction, the film color changes significantly. The shear deformation responsiveness of the film allows for non-contact optical measurement of the surface friction distribution.

[0086] Example 6

[0087] The Co-TPE 3D-COFs prepared in Example 3 of the present invention were dispersed in PEG (MW = 350 Da) liquid at a mass fraction of 0.08% (w / w) to form a Newtonian fluid with a shear viscosity range of 0.1 Pa·s.

[0088] Figure 6 The 3D-COFs material prepared in this embodiment and dispersed in a polymer solution was subjected to shear rates of 0, 64, 128, 256, 512, and 1024 s⁻¹. -1 The fluorescence images below show the significant changes in the fluorescence intensity and distribution of 3D-COFs in PEG fluid as the shear rate gradually increases, from left to right. This phenomenon indicates that 3D-COFs possess excellent dynamic mechanical response properties in polymer fluids, capable of adjusting their aggregated structure in liquids with varying shear rates, thus exhibiting different fluorescence behaviors. This demonstrates that the material prepared in Example 6 possesses properties that enable it to have greater application possibilities in hydrodynamic environments.

[0089] Example 7

[0090] The Ir-TPA2 3D-COFs prepared in Example 4 of this invention were dispersed in PEG (MW = 600 Da) liquid at a mass fraction of 0.5% (w / w) to form a Newtonian fluid with a shear viscosity range of 0.3 Pa·s.

[0091] Figure 7The figures show ratio fluorescence pseudocolor images of the 3D-COFs material dispersed in a polymer solution prepared in this embodiment at linear velocities of 0, 2, 4, 8, and 0 cm / s in a liquid pipeline. The colors in the figures, from blue to red, represent the change in fluid velocity from low to high. As the liquid flow velocity in the pipeline increases, the fluorescence intensity of the 3D-COFs in the PEG solution also increases, exhibiting a clear flow velocity dependence. This phenomenon indicates that the 3D-COFs material can reflect changes in liquid flow velocity through changes in fluorescence signal, and that the fluorescence response of the material is more sensitive under high-speed flow conditions. The material prepared in Example 7 of the invention has significant potential application value in the fields of liquid flow velocity detection and fluid mechanics.

[0092] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A 3D AIE-based dual-fluorophoretic covalent organic framework material, comprising a metal complex and an aggregation-induced emission (AIE) dye, wherein, The molar ratio of the metal complex probe to the AIE dye is 1:3-3:

1.

2. The 3D AIE-based dual-fluorescent covalent organic framework material according to claim 1, characterized in that, The metal complex is at least one of transition metal complexes with iridium, ruthenium, or cobalt as the central atom, or a mixture thereof; The transition metal complex uses bipyridine and / or phenanthroline compounds with carboxyl and / or amino groups as ligands.

3. The 3D AIE-based dual-fluorescent covalent organic framework material according to claim 1, characterized in that, The AIE dye is at least one of tetraphenylethylene and its derivatives, triphenylamine and its derivatives, phenoxazine and its derivatives, phenothiazine and its derivatives, and carbazole and its derivatives, which have different functional groups. The functional group is selected from at least one of -OH, -CHO, -COOH and -NH2.

4. A method for preparing the 3D AIE-based dual-fluorescent covalent organic framework material according to any one of claims 1-3, comprising the following steps: bonding a transition metal complex to the AIE dye to obtain a 3D-COFs system synthesized by bonding the transition metal complex to the AIE dye; in, The bonding between the transition metal complex and the AIE dye is achieved through Schiff base reaction, amidation reaction, esterification reaction, and activated esterification reaction; The molar ratio of the transition metal complex probe to the AIE dye is 1:3-3:

1.

5. The secondary assembly of the 3D AIE-based dual-fluorophoretic covalent organic framework according to any one of claims 1-3.

6. The composite system of the 3D AIE-based dual-fluorophoretic covalent organic framework dispersed in a polymer matrix according to any one of claims 1-3.

7. The composite system according to claim 6, characterized in that, The composite system includes a 3D AIE-based dual-fluorophore covalent organic framework (3D-COFs) material and a polymer matrix, wherein the 3D AIE-based dual-fluorophore covalent organic framework (3D-COFs) material is dispersed in the polymer matrix.

8. The composite system according to claim 7, characterized in that, The polymer matrix includes polymeric elastomers and fluids; The polymer matrix may specifically be at least one of polyethylene glycol and its derivatives, chitosan and its derivatives, dextran and its derivatives, polyvinyl alcohol and its derivatives, polylactic acid and its derivatives, cellulose and its derivatives, polyacrylate and silicone polymers; The concentration of the 3D-COFs in the polymer matrix ranges from 0.01% to 1.8% (w / w).

9. The application of the 3D AIE-based dual-fluorophoretic covalent organic framework material, its secondary assembly, or its composite system dispersed in a polymer matrix as described in any one of claims 1-3 in the spatial visualization measurement of material strain, surface friction, and shear force in fluids.

10. The application according to claim 9, characterized in that, In this application, the detection is a non-contact optical image detection.

Images