CN112876835A

CN112876835A - Multicolor fluorescent polymer film with environment humidity response and preparation method and application thereof

Info

Publication number: CN112876835A
Application number: CN202110089878.7A
Authority: CN
Inventors: 赵强; 马云; 魏娟; 刘淑娟
Original assignee: Nanjing University of Posts and Telecommunications
Current assignee: Nanjing University of Posts and Telecommunications
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2021-06-01
Anticipated expiration: 2041-01-22
Also published as: CN112876835B

Abstract

The invention provides a multicolor fluorescent polymer film with environment humidity response, a preparation method and application thereof, wherein triphenylamine is taken as a raw material, and a BPPA ligand is obtained through three-step reaction; ligand BPPA is coordinated with zinc, and the complex is added into a polyethylene glycol (PEG) matrix to construct a luminous Relative Humidity (RH) ratio type sensor. The obtained polymer film can convert the invisible information of RH into obviously different fluorescent colors from blue to yellow (450 nm-547 nm); the multicolor fluorescent polymer film with the environmental humidity response has the excellent performances of high identification degree, high sensitivity, good reversibility, quick response time and the like.

Description

Multicolor fluorescent polymer film with environment humidity response and preparation method and application thereof

Technical Field

The invention relates to a preparation method and application of a multicolor fluorescent polymer with environment humidity response, belonging to the field of organic photoelectric functional materials.

Background

Humidity detection is of great significance in various fields such as environmental monitoring, chemical engineering processes, agricultural production, cargo storage, biomedical analysis and the like. Semiconductor sensors with fast response and good readability are widely used in everyday applications for measuring relative humidity, and most sensors convert humidity response into electrical signals. High performance semiconductor RH sensors have limited their wider application due to the need for complex operating procedures and external power supply systems. Compared with semiconductor humidity sensors, luminescence sensors have received much attention because of their low cost, simple structure, fast response speed, and high visibility to the naked eye. Humidity sensitive luminescent materials, whose luminescence intensity varies with the RHs, however, this type of RH sensor is sensitive to electromagnetic power and detector sensitivity, making it difficult to accurately measure RH in complex environments. In order to improve the detection performance of the RH sensor, a luminescence ratio type sensor has been developed. However, the emission wavelength variation of these luminescent RH sensors at different RHs is usually relatively narrow, with the maximum range being within 50nm, which is not conducive to direct visual observation. Therefore, one current challenge is how to fabricate high performance RH sensors with a wide response emission wavelength range under different RHs conditions.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a multicolor fluorescent polymer film with environment humidity response, which can be used as a high-performance RH sensor and solves the problem of narrow response emission wavelength range of the RH sensor under different RHs conditions in the prior art.

The technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides a multicolor fluorescent polymer film with environmental humidity response, which is a film formed by mixing and doping Zn-BPPA and polyethylene glycol (PEG) and coating the mixture on the surface of a transparent weighing body, and is hereinafter referred to as a Zn-BPPA/PEG polymer film, wherein the doping ratio of Zn-BPPA to PEG is 0.1 wt%.

In a second aspect, the present invention provides a method for preparing a multicolor fluorescent polymer film with an environmental humidity response, comprising the following steps: and (3) sucking a proper amount of the 0.1 wt% Zn-BPPA/PEG polymer doping solution, placing the solution on a transparent glass sheet cleaned by ultrasound and microwave, spin-coating for 30s at the rotating speed of 3000r/min, and airing to obtain the Zn-BPPA/PEG polymer film with humidity response.

In a third aspect, the invention provides an application of a multicolor fluorescent polymer film with an environmental humidity response, wherein the multicolor fluorescent polymer film with the environmental humidity response is irradiated by 365 ultraviolet light, so that multicolor fluorescence under different humidity environments can be realized, further environment humidity visualization is realized, and the multicolor fluorescent polymer film can be applied as a luminous RH ratio type sensor.

The invention principle is as follows: according to the invention, the metal zinc complex is added into the polyethylene glycol (PEG) substrate, so that the prepared luminescent polymer can convert invisible information of environmental RH into visible multicolor fluorescence information, a water bridge is utilized to form a coordination bond between zinc ions and a bipyridine ligand, further the luminescent color change of the film is regulated and controlled, and the visualization of humidity is realized, as shown in figure 5, when 0.1 wt% of low mass ratio is doped, the BPPA and Zn are matched²⁺The ion interaction is very weak, when the relative humidity of the environment is lower than 50%, the thin-film fluorescence light is close to the blue fluorescence light of the ligand, when the relative humidity of the environment is increased to exceed 50%, hydrogen bonds are formed between the water molecules in the environment and the BPPA ligand, and oxygen atoms in the water molecules and Zn²⁺The ions combine to form Zn-O bonds, so that the color of the film is gradually changed. The more pronounced the color change of the film as the humidity increases.

Has the advantages that: the multicolor fluorescent polymer film with the environmental humidity response provided by the invention has simple synthesis and preparation steps and mild conditions; the Zn-BPPA/PEG polymer film with the weight percent of 0.1 obtained by changing the doping ratio of different masses has the best application effect and can be applied to RH ratio type sensors; the invention provides a multicolor fluorescent polymer film with environmental humidity response.

Under different humidity responses, the macroscopic multicolor fluorescence with wide range of fluorescence from blue to yellow (450nm to 547nm) can be realized, and the defect that the prior emission wavelength has narrow change (the maximum change range is not more than 50nm) and is not beneficial to direct observation by naked eyes is overcome;

the 0.1 wt% Zn-BPPA/PEG polymer with humidity response has excellent performances of high sensitivity, good reversibility, quick response time and the like;

the film can show multi-color fluorescence from blue-cyan-yellow green-yellow under the irradiation of white light when placed in different humidity environments (RH is low-high), the discrimination is high, and further the application of environment humidity visualization is realized.

Drawings

FIG. 1 illustrates a process for preparing a Zn-BPPA/PEG polymer film according to an embodiment;

FIG. 2 is a BPPA nuclear magnetic structure characterization spectrum according to an embodiment;

FIG. 3a is a fluorescence emission spectrum of humidity response of the 0.1 wt% Zn-BPPA/PEG polymer film according to an embodiment;

FIG. 3b is a fluorescence emission spectrum of humidity response of the 0.05 wt% Zn-BPPA/PEG polymer film according to an embodiment;

FIG. 3c is a fluorescence emission spectrum of humidity response of the 0.4 wt% Zn-BPPA/PEG polymer film according to an embodiment;

FIG. 4 is a graph showing the results of monitoring the ambient humidity during a 365nm LED small bulb test experiment in accordance with an exemplary embodiment;

fig. 5 is a schematic diagram of the visualization of the humidity of the polymer film according to the disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.

Example 1 preparation of BPPA

The chemical structural formula of the BPPA selected in this example is as follows:

the synthesis of BPPA in this example is divided into three steps:

the first step is as follows: reacting triphenylamine(3g) Dissolved in chloroform (50mL) and stirred in an ice-water bath at 0 ℃ and N-bromosuccinimide (NBS) (2.2g) was slowly added to dissolve it completely, and then warmed to room temperature and stirred for 8-12 hours. After the reaction, the reaction solution was dried by distillation under reduced pressure, and then water and CH were added₂Cl₂Extracting for three times, collecting organic phase and using anhydrous Na₂SO₄Drying, distilling under reduced pressure, removing solvent, and using CH₂Cl₂EtOH recrystallization afforded Compound 1 as a white powder, yield: 96 percent

The second step is that: in N₂Compound 1(2g) was dissolved with ultra dry tetrahydrofuran (30mL) under protection and placed in a dry ice/acetone bath at-78 ℃; after 10min, n-butyllithium (3.4mL) was added dropwise and stirred for 1h, followed by addition of trimethyl borate (0.6mL), warming to room temperature, and stirring for 8-12 h. After the reaction is finished, adding deionized water (10mL) to quench unreacted n-butyllithium, then adding a small amount of dilute hydrochloric acid to adjust the pH value to acidity, stirring for a little time, and then spin-drying the reaction solution under vacuum; followed by extraction with ethyl acetate and aqueous sodium chloride solution three times to remove inorganic salts formed by the reaction, collecting the organic phase and reacting with anhydrous Na₂SO₄Drying, and finally removing the solvent by distillation under reduced pressure to obtain the white powder compound 2, wherein the yield is as follows: 78 percent.

The third step: in N₂Compound 2(1g) was dissolved with 4, 4-dibromo-2, 2-bipyridine (434mg), tetrakistriphenylphosphine palladium (80.7mg), and potassium carbonate (2.713mg) in 50mL of a mixed solvent of toluene, ethanol, and ultrapure water (V) which had been deoxygenated under protection_TolueneV B_Alcohol(s):V_{Water (W)}3:1:1) and refluxed at 65 ℃ for 40 h. After the reaction is finished, the reaction solution is dried in vacuum, and the product is treated by CH₂Cl₂/H₂Extracting with O for three times, removing excessive inorganic salt, collecting organic phase, and adding anhydrous Na₂SO₄Drying, then removal of the solvent by distillation under reduced pressure, and finally purification by column chromatography, gave BBPA as a yellow powder, yield: and 55 percent.¹H NMR(400MHz)¹H NMR(400MHz,CD3Cl)δ(ppm):9.16(s,2H),8.80(d,J＝4.0Hz,2H),7.9(d,J＝8.0Hz,4H),7.81(d,J＝4.0Hz,2H),7.7(m,2H),7.58(m,2H),7.49(m,2H),7.35(t,J＝16.0Hz,6H),7.21(m,12H).[m/z]:(calculated,642.79,found,642.29).

Example 2: preparation method of Zn-BPPA/PEG polymer film

As shown in figure 1, certain amount of ligands BPPA and Zn (ClO) are weighed according to the molar ratio of 1:1₄)₂·6H₂CH with O dissolved in a little methanol₂Cl₂In the mixed solution, 10mL of 1X 10 solution was prepared^-3moL/L Zn-BPPA solution. 2.0g of PEG8000 was weighed to prepare 20mL of 100mg/mL PEG8000 solution. 0.1 wt% Zn-BPPA/PEG doping solution is prepared. Sucking 45 μ L of the doping solution, placing on a transparent glass sheet of 1.5cm × 1.5cm cleaned by ultrasound and microwave, spin-coating at 3000r/min for 30s, and air drying to obtain the Zn-BPPA/PEG polymer film with humidity response. In addition, by changing the doping ratio of Zn-BPPA to PEG, 0.05 wt% and 0.4 wt% Zn-BPPA/PEG polymer films can be prepared as comparative test examples.

Test example 1: characterization of ligand Zn-BPPA and photophysical property testing of Zn-BPPA/PEG polymer films:

ligand BPPA (5-10mg) was dissolved in 0.5mL of deuterated reagent and the structure of the compound was characterized using a 400Hz NMR spectrometer, which is shown in FIG. 2.

Measuring the emission spectrum of the Zn-BPPA/PEG polymer film responding to humidity, as shown in FIG. 3a, it can be seen that 0.1 wt% of the Zn-BPPA/PEG polymer film emits fluorescence from 450nm to 547nm, and the color of the film is from blue to yellow; as shown in FIG. 3b, it can be seen that 0.05 wt% Zn-BPPA/PEG polymer film fluorescence emission is from 450nm to 480nm, the film changes from dark blue to light blue, and the change is not obvious; as shown in FIG. 3c, it can be seen that 0.4 wt% Zn-BPPA/PEG polymer film fluorescence emission is from 553nm to 558nm, and the film remains almost unchanged in yellow.

Test example 2: bulb test of Zn-BPPA/PEG polymer films

The Zn-BPPA/PEG polymer film is uniformly coated on a 365nm LED small bulb, the bulb is dried and placed in different humidity environments, the relative humidity is changed from low to high, after the bulb is electrified, multicolor fluorescence from blue-cyan-yellow green-yellow appears in the small bulb, and as shown in figure 4, the application of environment humidity visualization is realized.

Claims

1. The multicolor fluorescent polymer film with the environmental humidity response is characterized in that the polymer film is formed by mixing Zn-BPPA and polyethylene glycol (PEG) according to a doping ratio of 0.1 wt% to form 0.1 wt% of Zn-BPPA/PEG polymer doping liquid and coating the Zn-BPPA/PEG polymer doping liquid on the surface of a transparent weighing body.

2. A method for preparing a multicolor fluorescent polymer film with environmental humidity response, which is characterized by comprising the following steps: and (3) sucking a proper amount of the 0.1 wt% Zn-BPPA/PEG polymer doping solution, spin-coating on a transparent glass sheet, and then airing to obtain the polymer film.

3. The method for preparing a multicolor fluorescent polymer film with environmental humidity response according to claim 2, wherein the spin coating comprises the following steps: the Zn-BPPA/PEG polymer doping solution is dripped on a transparent glass sheet at the rotating speed of 3000r/min and is kept for 30 s.

4. The method of claim 2, wherein the transparent glass sheet is an ultrasonically and microwave cleaned transparent glass sheet.

5. The method of claim 2, wherein the 0.1 wt% Zn-BPPA/PEG polymer doping solution is prepared by a method comprising: weighing a certain amount of ligands BPPA and Zn (ClO) according to the molar ratio of 1:1₄)²·6H₂O is dissolved in a little CH₃CH of OH₂Cl₂In the mixed solution, the preparation concentration is 1 × 10^-3moL/L Zn-BPPA solution; preparing PEG8000 solution with the concentration of 100 mg/mL; Zn-BPPA/PEG doping solution is prepared according to the mass ratio of 0.1 wt% between Zn-BPPA and PEG.

6. The application of the multicolor fluorescent polymer film with the environment humidity response is characterized in that the polymer film is irradiated by 365nm ultraviolet light, so that multicolor fluorescence under different humidity environments can be realized, and further, the environment humidity visualization is realized.

7. The use of a multicolor fluorescent polymer film with ambient humidity response according to claim 6, wherein said polymer film is used as a luminous RH ratio sensor.

8. The use of the multicolor fluorescent polymer film with environmental humidity response according to claim 6, wherein 0.1 wt% of Zn-BPPA/PEG polymer doping solution is dipped by a brush and uniformly coated on the 365nm LED small bulb, the 365nm LED small bulb is dried and placed in bottles with different humidity, and after power is turned on, multicolor fluorescence from blue-green-yellow green appears in the small bulb immediately, so that the application of environmental humidity visualization is realized.