CN114481450A

CN114481450A - Piezochromic nanofiber membrane and preparation method thereof

Info

Publication number: CN114481450A
Application number: CN202210393840.3A
Authority: CN
Inventors: 赵润
Original assignee: Jiangsu New Vision Advanced Functional Fiber Innovation Center Co ltd
Current assignee: Jiangsu New Vision Advanced Functional Fiber Innovation Center Co ltd
Priority date: 2022-04-15
Filing date: 2022-04-15
Publication date: 2022-05-13
Anticipated expiration: 2042-04-15
Also published as: CN114481450B

Abstract

The invention relates to a piezochromic nanofiber membrane and a preparation method thereof, wherein the preparation method comprises the following steps: preparing electrostatic spinning solution containing PAIE-1, high polymer material and solvent, and then carrying out electrostatic spinning to prepare the piezochromic nanofiber membrane, wherein the structural formula of PAIE-1 is as follows:

(ii) a The product of the invention consists of a fibrous body and PAIE-1 doped therein. The piezochromic nano-fiber membrane has piezochromic aggregation-induced emission performance by doping piezochromic aggregation-induced emission molecules containing halogen bonds, can generate near infrared light under the action of external pressure, and has the effects of antibiosis and health care.

Description

Piezochromic nanofiber membrane and preparation method thereof

Technical Field

The invention belongs to the technical field of piezochromic aggregation-induced luminescent materials, and relates to a piezochromic nanofiber membrane and a preparation method thereof.

Background

The fibrous intelligent material, namely the intelligent fiber, is characterized by large length-diameter ratio, strong processability and the like, and is frequently seen in garment development in recent years. Meanwhile, the development of the advanced technologies such as the bionic technology, the nanotechnology, the microcapsule technology, the electronic information technology and the like also provides more support for the research and development of the intelligent fiber. The intelligent fiber is a fiber which can sense the change of the external environment or the internal state and can react.

The piezoluminescence color-changing material is an intelligent material whose luminescence color is obviously changed under the action of external force. The piezochromic fibers and the fabric can make full use of energy generated in the motion process of a human body, have the advantages of environmental protection, safety and practicability, and have great potential application value in the fields of mechanochemical sensors, intelligent fabrics, health monitoring, fashion entertainment and the like. The color of the fiber material can change along with some external mechanical forces such as grinding, friction, extrusion and the like, and the reason is that the fiber material can generate structural form transformation under the action of external force to cause charge transfer, so that the fluorescence property of the fiber material is changed accordingly.

Although the adjustment of the luminescent color by the change of the chemical structure is the easiest to achieve and theoretically the most effective method, in the solid state, the chemical reaction at the molecular level achieved by the external stimulation is difficult to predict, and the chemical reaction is often difficult to perform due to the low conversion rate of the solid state reaction. Furthermore, in the solid state, the chemical reaction is often irreversible, so that such compounds are difficult to use as smart materials operating in a switching manner. Some introduce the piezochromic luminophor into the main chain or cross-linked network of the fiber polymer macromolecule, under the traction of external force, the piezochromic luminophor on the macromolecule chain generates ring-opening reaction, for example, the spiropyran piezochromic luminophor is changed into a merocyanine structure under the action of external force, the conjugated structure of the spiropyran piezochromic luminophor is obviously changed, so that the fluorescence luminescent color moves to the direction of light with longer wavelength, but the method destroys the chemical structure of the luminophor, and the color change property is irreversible.

Most of prior art piezochromic fibers are prepared by dyeing and finishing piezochromic materials as Dyes, and document 1 (Meng Sun, Lu Zhai, Jingbo Sun, fushu Zhang, Wenhua Mi, jipen Ding, Ran Lu. Switching in visible-light emission of card base-modified pyridine derivatives induced by b y mechanical processing and solution-organic transmission. dye management, 2019, 162, 67-74.) designs a pyrazole derivative modified by a fluorescent dye butyl carbazole, and changes in molecular configuration or conformation under an external mechanical force, thereby expressing a piezochromic property, but the problems of low dyeing rate and low dyeing fastness exist, resulting in poor durability of the piezochromic property.

Therefore, it is very important to research a new piezochromic material to directly dope it into the fiber to solve the above problems.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a piezochromic nanofiber membrane and a preparation method thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation method of a piezochromic nanofiber membrane comprises the steps of preparing an electrostatic spinning solution containing PAIE-1, a high polymer material and a solvent, and then carrying out electrostatic spinning to obtain the piezochromic nanofiber membrane, wherein the structural formula of the PAIE-1 is as follows:

。

as a preferred technical scheme:

in the preparation method of the piezochromic nanofiber membrane, the PAIE-1 is prepared by the following steps: firstly, 3, 6-dimethylcarbazole reacts with p-iodobenzoyl chloride in a solvent to obtain an intermediate product, and then the intermediate product reacts with terephthalonitrile to obtain PAIE-1; PAIE-1 has a special propeller-shaped twisted conformation structure, so that the PAIE-1 is difficult to be tightly stacked in a crystalline state, and the crystalline structure of the PAIE-1 is easy to change under the action of external pressure, so that the molecular energy level and the luminescence spectrum of the PAIE-1 are changed, and the piezoluminescence discoloration phenomenon is generated; meanwhile, nitrogen atoms and halogen atoms of the cyano groups can form hydrogen bonds and halogen bonds with hydrogen atoms on a benzene ring, and the hydrogen bonds and the halogen bonds are deformed when the hydrogen bonds and the halogen bonds are subjected to external pressure, so that the color of molecules is changed; the fluorescent change of the two factors, namely the change of molecular aggregation mode in the crystal and the pressure-induced discoloration caused by the deformation of weak interaction (halogen bond and hydrogen bond), can generate near infrared light which has the functions of medical care and antibiosis; PAIE-1 is used as a piezochromic aggregation-induced emission molecule containing halogen bonds, has rigid structure, high-efficiency luminous efficiency, high stability, excellent uniformity and no reversible loss;

the preparation method of the piezochromic nanofiber membrane is characterized in that the high polymer material is PLA (polylactic acid), PBAT (polybutylene terephthalate-adipate) or PVA (polyvinyl alcohol), and the high polymer material is preferred in the invention because the high polymer material can prepare the corresponding nanofiber material by the prior art, and because the compatibility of the high polymer material and PAIE-1 is higher because of the affinity of the high polymer material and the interaction of surface functional groups.

According to the preparation method of the piezochromic nanofiber membrane, the solvent is a mixed solution of tetrahydrofuran and A, A is DMF (dimethylformamide), DEF (diethylformamide), DMSO (dimethyl sulfoxide) or DMI (1, 3-dimethyl-2-imidazolidinone), and the volume ratio of tetrahydrofuran to A is 1: 9-13.

According to the preparation method of the piezochromic nanofiber membrane, in the electrostatic spinning solution, the mass ratio of PAIE-1 to the high polymer material is 1: 15-25, and the mass volume ratio of the high polymer material to the solvent is 6-10 mg:100 mL.

According to the preparation method of the piezochromic nanofiber membrane, the preparation process of the electrostatic spinning solution comprises the following steps: firstly adding PAIE-1 into a solvent, stirring for 30-60 min at 15-25 ℃ to form a dispersion liquid, then adding a high molecular material into the dispersion liquid, and stirring for 5-10 h at 15-25 ℃ until the high molecular material is completely dissolved to obtain an electrostatic spinning liquid.

According to the preparation method of the piezochromic nanofiber membrane, the process parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1-1.5 mL/h, the receiving distance is 10-15 cm, the ambient temperature is 20-28 ℃, and the ambient relative humidity is 15-25%; the specific process of electrostatic spinning comprises the following steps: firstly, putting electrostatic spinning liquid into a syringe with the volume of 10mL and a metal needle (the inner diameter of the metal needle is 0.55mm, the outer diameter of the metal needle is 0.8 mm), horizontally fixing the syringe on an injection pump (KD Scientific, 101 type), clamping an electrode of a high-voltage power supply (Matsusada Precision, AU series) on a metal needle point, taking an aluminum foil as a fixed cylindrical receiver, keeping the distance from the needle point to the receiver at 10-15 cm, conveying the electrostatic spinning liquid at the injection speed of 1-1.5 mL/h by using a flow rate pump, applying the voltage of +15kV on the metal needle point to deposit nano fibers on the receiver, and finally putting the collected nano fibers in a vacuum drying box for pumping at normal temperature for 24 hours to remove residual solvent; the whole electrostatic spinning equipment is placed in a sealed organic glass box, and electrostatic spinning is carried out under the conditions that the temperature is 20-28 ℃ and the relative humidity is 15-25%.

The invention also provides a piezochromic nanofiber membrane prepared by the preparation method of the piezochromic nanofiber membrane, which consists of the fiber body and PAIE-1 doped in the fiber body.

As a preferred technical scheme:

the piezochromic nanofiber membrane has the advantages that the maximum tensile strength of the piezochromic nanofiber membrane is 50-100 MPa, and the elastic modulus is 1800-3000 MPa; when the applied pressure is 1-10 GPa, the maximum fluorescence emission peak position of the nanofiber membrane is 700-750 nm.

The principle of the invention is as follows:

the piezochromic material in the prior art is difficult to be directly doped into the fiber, because the phenomenon of piezochromic discoloration is difficult to observe in a solid state by a general luminescent material due to aggregation or concentration quenching effect, the piezochromic aggregation-induced luminescent molecule, namely PAIE-1, can be doped into the fiber due to the chemical structure stability (after doping, the property is not influenced) and the aggregation-induced luminescence (the luminescence can be realized in a solid state), so that the nanofiber material is endowed with the piezochromic luminescent performance; in addition, the existence of halogen bonds and hydrogen bonds can enhance intermolecular force and improve the stability of the material. In addition, the infrared-ray lamp also has the characteristic of releasing near infrared light under the action of pressure.

Drawings

FIG. 1 is a hydrogen spectrum of PAIE-1 obtained in example 1;

FIG. 2 is a piezochromic fluorescence spectrum of the piezochromic nanofiber membrane prepared in example 1;

FIG. 3 is a piezochromic fluorescence spectrum of the piezochromic nanofiber membrane prepared in example 2;

FIG. 4 is a piezochromic fluorescence spectrum of the piezochromic nanofiber membrane prepared in example 3;

FIG. 5 is a piezochromic fluorescence spectrum of the piezochromic nanofiber membrane prepared in example 4;

FIG. 6 is a piezochromic fluorescence spectrum of the piezochromic nanofiber membrane prepared in example 5;

FIG. 7 is a piezochromic fluorescence spectrum of the piezochromic nanofiber membrane prepared in example 6.

Advantageous effects

The piezochromic nano-fiber membrane has piezochromic aggregation-induced emission performance by doping piezochromic aggregation-induced emission molecules containing halogen bonds, can generate near infrared light under the action of external pressure, and has the effects of antibiosis and health care.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

A preparation method of a piezochromic nanofiber membrane comprises the following specific steps:

(1) preparation of PAIE-1;

(1.1) adding 3, 6-dimethylcarbazole, p-iodobenzoyl chloride, potassium carbonate, 18-crown-6, cuprous iodide and o-dichlorobenzene into a round-bottom flask, vacuumizing at-25 ℃ under a refrigeration condition, introducing nitrogen for 4 times, and stirring and refluxing at 180 ℃ for 60 hours; after the reaction is finished, repeatedly washing the reaction system by using acid liquor with the mass concentration of 5%, extracting for 3 times by using dichloromethane, drying by using a drying agent, then carrying out rotary evaporation to remove the solvent, and carrying out column chromatography separation to obtain an intermediate product;

wherein the mass ratio of the 3, 6-dimethylcarbazole, the p-iodobenzoyl chloride, the potassium carbonate, the 18-crown-6, the cuprous iodide and the desiccant is 1:1.2:20:0.2:0.2: 30; the volume ratio of the o-dichlorobenzene to the acid solution to the dichloromethane is 1:12: 12; the acid solution is hydrochloric acid; the drying agent is anhydrous magnesium sulfate;

(1.2) adding the intermediate product obtained in the step (1.1) and terephthalonitrile into a round-bottom flask, vacuumizing and introducing nitrogen for 4 times, adding 2-propanol and a tetrahydrofuran solution with the water content of 0.004%, stirring and heating to 46 ℃, injecting a tetrahydrofuran solution of potassium 2-propoxide with the concentration of 1mmol/L, and reacting with tetrabutylammonium hydroxide for 2 hours; pouring the system into acetic acid acidified methanol after the reaction is finished, and performing suction filtration and column chromatography separation to obtain a final piezochromic aggregation-induced emission molecule containing a halogen bond, namely PAIE-1;

wherein the mass ratio of the intermediate product, the terephthalonitrile and the potassium 2-propoxide is 2.1:1: 6; the volume ratio of 2-propanol, tetrahydrofuran solution with water content of 0.004%, tetrabutylammonium hydroxide and acetic acid acidified methanol is 1:0.6:0.04: 5;

the hydrogen spectrum of the PAIE-1 is shown in figure 1, and the structural formula is as follows:

；

the PAIE-1 has the characteristic of generating near infrared light under the pressure effect of 8-15 GPa; PAIE-1 has no fluorescence emission in tetrahydrofuran, and has fluorescence emission in mixed solution of tetrahydrofuran and water with the volume ratio of 9-99: 1; when the applied pressure is 15GPa, the maximum emission peak position of PAIE-1 is 705nm, the emission intensity is reduced along with the action time of the pressure, and the change of the pressure and the maximum emission peak position is in a linear relation; after the external pressure is removed, the maximum emission peak position and the emission intensity of the PAIE-1 are restored to the initial state; when the applied pressure is 20MPa, the crystal structure of PAIE-1 is changed; after the external pressure is removed, the crystal structure of PAIE-1 is restored to the initial state after 60 min; the luminous efficiency of PAIE-1 is 50%, and the luminous efficiency is still 40% after more than 20 times of cyclic tests;

(2) adding PAIE-1 into a solvent, stirring for 60min at 15 ℃ to form a dispersion liquid, adding PLA into the dispersion liquid, stirring for 10h at 15 ℃ until the PLA is completely dissolved to obtain an electrostatic spinning solution, and then performing electrostatic spinning to obtain a piezochromic nanofiber membrane;

wherein the solvent is a mixed solution of tetrahydrofuran and DMF with a volume ratio of 1:9, the mass ratio of PAIE-1 to PLA in the electrostatic spinning solution is 1:15, and the mass volume ratio of PLA to the solvent is 6mg to 100 mL;

the technological parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1mL/h, the receiving distance is 10cm, the ambient temperature is 20 ℃, and the ambient relative humidity is 15%.

The prepared piezochromic nanofiber membrane consists of a fiber body and PAIE-1 doped in the fiber body; the maximum tensile strength and the elastic modulus of the piezochromic nanofiber membrane are respectively 50MPa and 1800 MPa; as shown in FIG. 2, when the applied pressure was 1GPa, the maximum fluorescence emission peak of the nanofiber membrane was 700 nm.

Example 2

(1) preparation of PAIE-1;

(1.2) adding the intermediate product obtained in the step (1.1) and terephthalonitrile into a round-bottom flask, vacuumizing and introducing nitrogen for 4 times, adding 2-propanol and a tetrahydrofuran solution with the water content of 0.004%, stirring and heating to 46 ℃, injecting a tetrahydrofuran solution of potassium 2-propoxide with the concentration of 1mmol/L, and reacting with tetrabutylammonium hydroxide for 2 hours; pouring the system into methanol acidified by acetic acid after the reaction is finished, and performing suction filtration and column chromatography separation to obtain the final piezochromic aggregation-induced emission molecule containing the halogen bond, namely PAIE-1;

the PAIE-1 obtained has the following structural formula:

(ii) a The PAIE-1 has the characteristic of generating near infrared light under the pressure effect of 8-15 GPa; PAIE-1 has no fluorescence emission in tetrahydrofuran, and has fluorescence emission in mixed solution of tetrahydrofuran and water in a volume ratio of 9-99: 1; when the applied pressure is 15GPa, the maximum emission peak position of the PAIE-1 is 705nm, the emission intensity is decreased with the action time of the pressure, and the pressure and the change of the maximum emission peak position are in a linear relation; after the external pressure is removed, the maximum emission peak position and the emission intensity of the PAIE-1 are restored to the initial state; when the applied pressure is 20MPa, the crystal structure of PAIE-1 is changed; after the external pressure is removed, the crystal structure of PAIE-1 is restored to the initial state after 60 min; the luminous efficiency of PAIE-1 is 50%, and the luminous efficiency is still 40% after more than 20 times of cyclic tests;

(2) adding PAIE-1 into a solvent, stirring for 55min at 20 ℃ to form a dispersion liquid, adding PLA into the dispersion liquid, stirring for 9h at 17 ℃ until the PLA is completely dissolved to obtain an electrostatic spinning solution, and then performing electrostatic spinning to obtain a piezochromic nanofiber membrane;

wherein the solvent is a mixed solution of tetrahydrofuran and DMF with a volume ratio of 1:10, the mass ratio of PAIE-1 to PLA in the electrostatic spinning solution is 1:16, and the mass volume ratio of PLA to the solvent is 6.5mg to 100 mL;

the technological parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1.1mL/h, the receiving distance is 11cm, the ambient temperature is 22 ℃, and the ambient relative humidity is 17%.

The prepared piezochromic nanofiber membrane consists of a fiber body and PAIE-1 doped in the fiber body; the maximum tensile strength of the piezochromic nanofiber membrane is 62MPa, and the elastic modulus is 2045 MPa; as shown in FIG. 3, when the applied pressure was 2GPa, the maximum fluorescence emission peak of the nanofiber membrane was 708 nm.

Example 3

(1) preparation of PAIE-1;

(1.1) adding 3, 6-dimethylcarbazole, p-iodobenzoyl chloride, potassium carbonate, 18-crown-6, cuprous iodide and p-dichlorobenzene into a round-bottom flask, vacuumizing at-25 ℃ under a refrigeration condition, introducing nitrogen for 4 times, and stirring and refluxing at 180 ℃ for 60 hours; after the reaction is finished, repeatedly washing the reaction system by using acid liquor with the mass concentration of 5%, extracting for 3 times by using dichloromethane, drying by using a drying agent, then carrying out rotary evaporation to remove the solvent, and carrying out column chromatography separation to obtain an intermediate product;

the PAIE-1 obtained has the following structural formula:

；

(2) adding PAIE-1 into a solvent, stirring for 50min at 25 ℃ to form a dispersion liquid, adding PBAT into the dispersion liquid, stirring for 8h at 20 ℃ until PBAT is completely dissolved to obtain an electrostatic spinning liquid, and then performing electrostatic spinning to obtain a piezochromic nanofiber membrane;

wherein the solvent is a mixed solution of tetrahydrofuran and DEF with a volume ratio of 1:11, the mass ratio of PAIE-1 to PBAT in the electrostatic spinning solution is 1:17, and the mass volume ratio of PBAT to the solvent is 7mg:100 mL;

the technological parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1.2mL/h, the receiving distance is 12cm, the ambient temperature is 24 ℃, and the ambient relative humidity is 19%.

The prepared piezochromic nanofiber membrane consists of a fiber body and PAIE-1 doped in the fiber body; the maximum tensile strength of the piezochromic nanofiber membrane is 75MPa, and the elastic modulus is 2310 MPa; as shown in FIG. 4, when the applied pressure was 4GPa, the maximum fluorescence emission peak of the nanofiber membrane was 720 nm.

Example 4

(1) preparation of PAIE-1;

the PAIE-1 obtained has the following structural formula:

(ii) a The PAIE-1 has the characteristic of generating near infrared light under the pressure effect of 8-15 GPa; PAIE-1 has no fluorescence emission in tetrahydrofuran, and has fluorescence emission in mixed solution of tetrahydrofuran and water with the volume ratio of 9-99: 1; when the applied pressure is 15GPa, the maximum emission peak position of PAIE-1 is 705nm, the emission intensity is reduced along with the action time of the pressure, and the change of the pressure and the maximum emission peak position is in a linear relation;after the external pressure is removed, the maximum emission peak position and the emission intensity of the PAIE-1 are restored to the initial state; when the applied pressure is 20MPa, the crystal structure of PAIE-1 is changed; after the external pressure is removed, the crystal structure of PAIE-1 is restored to the initial state after 60 min; the luminous efficiency of PAIE-1 is 50%, and the luminous efficiency is still 40% after more than 20 times of cyclic tests;

(2) adding PAIE-1 into a solvent, stirring for 40min at 18 ℃ to form a dispersion liquid, adding PBAT into the dispersion liquid, stirring for 7h at 22 ℃ until PBAT is completely dissolved to obtain an electrostatic spinning liquid, and then performing electrostatic spinning to obtain a piezochromic nanofiber membrane;

wherein the solvent is a mixed solution of tetrahydrofuran and DMSO with a volume ratio of 1:12, the mass ratio of PAIE-1 to PBAT in the electrostatic spinning solution is 1:19, and the mass volume ratio of PBAT to the solvent is 8mg:100 mL;

the technological parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1.3mL/h, the receiving distance is 13cm, the ambient temperature is 25 ℃, and the ambient relative humidity is 21%.

The prepared piezochromic nanofiber membrane consists of a fiber body and PAIE-1 doped in the fiber body; the maximum tensile strength of the piezochromic nanofiber membrane is 83MPa, and the elastic modulus is 2550 MPa; as shown in FIG. 5, when the applied pressure is 5GPa, the maximum fluorescence emission peak position of the nanofiber membrane is 728 nm.

Example 5

(1) preparation of PAIE-1;

the PAIE-1 obtained has the following structural formula:

(ii) a The PAIE-1 has the characteristic of generating near infrared light under the pressure effect of 8-15 GPa; PAIE-1 has no fluorescence emission in tetrahydrofuran, and has fluorescence emission in mixed solution of tetrahydrofuran and water with the volume ratio of 9-99: 1; when the applied pressure is 15GPa, the maximum emission peak position of PAIE-1 is 705nm, the emission intensity is reduced along with the action time of the pressure, and the change of the pressure and the maximum emission peak position is in a linear relation; after the external pressure is removed, the maximum emission peak position and the emission intensity of the PAIE-1 are restored to the initial state; when the applied pressure is 20MPa, the crystal structure of PAIE-1 is changed; after the external pressure is removed, the crystal structure of PAIE-1 is restored to the initial state after 60 min; the luminous efficiency of PAIE-1 is 50%, and the luminous efficiency is still 40% after more than 20 times of cyclic tests;

(2) adding PAIE-1 into a solvent, stirring for 35min at 22 ℃ to form a dispersion liquid, adding PVA into the dispersion liquid, stirring for 6h at 24 ℃ until the PVA is completely dissolved to obtain an electrostatic spinning solution, and then performing electrostatic spinning to obtain a piezochromic nanofiber membrane;

wherein the solvent is a mixed solution of tetrahydrofuran and DMI with a volume ratio of 1:12, the mass ratio of PAIE-1 to PVA in the electrostatic spinning solution is 1:22, and the mass volume ratio of PVA to the solvent is 9mg:100 mL;

the technological parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1.4mL/h, the receiving distance is 14cm, the ambient temperature is 27 ℃, and the ambient relative humidity is 22%.

The prepared piezochromic nanofiber membrane consists of a fiber body and PAIE-1 doped in the fiber body; the maximum tensile strength of the piezochromic nanofiber membrane is 90MPa, and the elastic modulus is 2800 MPa; as shown in FIG. 6, when the applied pressure was 8GPa, the maximum fluorescence emission peak of the nanofiber membrane was 744 nm.

Example 6

(1) preparation of PAIE-1;

wherein the mass ratio of the 3, 6-dimethylcarbazole, the p-iodobenzoyl chloride, the potassium carbonate, the 18-crown-6, the cuprous iodide and the drying agent is 1:1.2:20:0.2:0.2: 30; the volume ratio of the o-dichlorobenzene to the acid solution to the dichloromethane is 1:12: 12; the acid solution is hydrochloric acid; the drying agent is anhydrous magnesium sulfate;

the PAIE-1 obtained has the following structural formula:

(2) adding PAIE-1 into a solvent, stirring for 30min at 25 ℃ to form a dispersion liquid, adding PVA into the dispersion liquid, stirring for 5h at 25 ℃ until the PVA is completely dissolved to obtain an electrostatic spinning solution, and then performing electrostatic spinning to obtain a piezochromic nanofiber membrane;

wherein the solvent is a mixed solution of tetrahydrofuran and DMI with a volume ratio of 1:13, the mass ratio of PAIE-1 to PVA in the electrostatic spinning solution is 1:25, and the mass volume ratio of PVA to the solvent is 10mg:100 mL;

the technological parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1.5mL/h, the receiving distance is 15cm, the ambient temperature is 28 ℃, and the ambient relative humidity is 25%.

The prepared piezochromic nanofiber membrane consists of a fiber body and PAIE-1 doped in the fiber body; the maximum tensile strength of the piezochromic nanofiber membrane is 100MPa, and the elastic modulus is 3000 MPa; as shown in FIG. 7, when the applied pressure was 10GPa, the maximum fluorescence emission peak of the nanofiber membrane was 750 nm.

Claims

1. The preparation method of the piezochromic nanofiber membrane is characterized in that an electrostatic spinning solution containing PAIE-1, a high polymer material and a solvent is prepared and then is subjected to electrostatic spinning to prepare the piezochromic nanofiber membrane, wherein the PAIE-1 has the following structural formula:

。

2. the method for preparing the piezochromic nanofiber membrane according to claim 1, wherein PAIE-1 is prepared by the following steps: firstly, 3, 6-dimethylcarbazole reacts with p-iodobenzoyl chloride in a solvent to obtain an intermediate product, and then the intermediate product reacts with terephthalonitrile to obtain PAIE-1.

3. The preparation method of the piezochromic nanofiber membrane according to claim 1, wherein the polymer material is PLA, PBAT or PVA.

4. The preparation method of the piezochromic nanofiber membrane according to claim 1, wherein the solvent is a mixed solution of tetrahydrofuran and A, A is DMF, DEF, DMSO or DMI, and the volume ratio of tetrahydrofuran to A is 1: 9-13.

5. The preparation method of the piezochromic nanofiber membrane according to any one of claims 1 to 4, wherein the mass ratio of PAIE-1 to the high polymer material in the electrospinning solution is 1: 15-25, and the mass volume ratio of the high polymer material to the solvent is 6-10 mg:100 mL.

6. The preparation method of the piezochromic nanofiber membrane according to claim 5, wherein the preparation process of the electrospinning solution is as follows: firstly adding PAIE-1 into a solvent, stirring for 30-60 min at 15-25 ℃ to form a dispersion liquid, then adding a high molecular material into the dispersion liquid, and stirring for 5-10 h at 15-25 ℃ until the high molecular material is completely dissolved to obtain an electrostatic spinning liquid.

7. The method for preparing the piezochromic nanofiber membrane according to claim 6, wherein the process parameters of electrostatic spinning comprise: the voltage is +15kV, the injection speed is 1-1.5 mL/h, the receiving distance is 10-15 cm, the ambient temperature is 20-28 ℃, and the ambient relative humidity is 15-25%.

8. The piezochromic nanofiber membrane prepared by the preparation method of the piezochromic nanofiber membrane as claimed in any one of claims 1 to 7, characterized in that the piezochromic nanofiber membrane consists of a fiber body and PAIE-1 doped therein.

9. The piezochromic nanofiber membrane according to claim 8, wherein the piezochromic nanofiber membrane has a maximum tensile strength of 50 to 100MPa and an elastic modulus of 1800 to 3000 MPa; when the applied pressure is 1-10 GPa, the maximum fluorescence emission peak position of the nanofiber membrane is 700-750 nm.