CN110484232B - A kind of preparation method of thermoreversible color-changing composite material based on PDA and CoZn-ZIF - Google Patents

Abstract

The invention provides a thermally reversible discoloration composite material based on PDA and CoZn-ZIF, wherein diacetylene monomer and bimetallic zeolite imidazolate skeleton structure compound are dissolved in dimethyl sulfoxide-deionized water mixed solvent A mixed solution was formed; then the mixed solution was sonicated at 50-80 °C for 30-60 min, cooled to room temperature, and then self-assembled at low temperature. Finally, it was placed under ultraviolet light with a wavelength of 254 nm for polymerization for 2-20 min to obtain blue heat. The reversible color-changing composite PDA/CoZn-ZIF appears blue at room temperature. With the continuous increase of temperature, the color of the composite material gradually transitioned from blue to purple and then to red; after the heating was stopped, the composite material returned to the original blue color within 1-2 min. The composite material has excellent thermal sensitivity and can be thermally reversible discoloration after repeated cycles, and can be used as a temperature sensor in many fields.

Description

Preparation of a Thermoreversible Color-changing Composite Based on PDA and CoZn-ZIF method

technical field

The invention relates to a preparation method of a thermo-reversible color-changing material, in particular to a thermo-reversible color-changing composite material based on polydiacetylene (PDA) and bimetallic zeolite imidazolate framework compound (CoZn-ZIF). The preparation method belongs to the field of intelligent sensing.

technical background

Materials are an indispensable part of human life, and are mainly divided into two parts: functional materials and structural materials. Smart materials combine structural materials with functional materials, and have three basic elements: perception, response, and feedback. It can make judgments according to changes in the perception of the external environment, and adjust its own situation in time to adapt to the changes after issuing instructions. At present, smart materials have a wide range of applications in aerospace, industry, military, medical and many other fields.

Polydiacetylene (PDA) exhibits sensitive optical response characteristics when it is stimulated by the external environment, and its own color exhibits a blue-to-red transition, which can be used as a temperature-sensitive sensor. However, the PDA still appears red after the stimulus is withdrawn, which limits the recycling of the PDA sensor. The study found that in order to obtain a recyclable PDA sensor, it is necessary to chemically modify the DA monomer or prepare a composite material.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of a thermoreversible color-changing composite material based on PDA and CoZn-ZIF.

1. Preparation of PDA/ZIF composites

Diacetylene monomer (DA) was dissolved in dimethyl sulfoxide-deionized water mixed solvent; bimetallic zeolite imidazolate framework compound (CoZn-ZIF) was dispersed in deionized water; the above two solutions were mixed in Ultrasound at 50-80 °C for 30-60 min, cool to room temperature for low-temperature self-assembly for 8-16 h, and obtain a white suspension; then place the white suspension under ultraviolet light with a wavelength of 254 nm to irradiate and polymerize for 2-20 min to obtain The uniform blue suspension of is a thermoreversibly color-changing composite, labeled as PDA/CoZn-ZIF.

The diacetylene monomer (DA) is 10,12-pentacosadiynoic acid (PCDA) or 10,12-docosadiynoic acid (TCDA);

The bimetallic zeolite imidazolate framework structure compound is CoZn-ZIF. The mass ratio of diacetylene monomer to bimetallic zeolite imidazolate framework compound (CoZn-ZIF) was 1:1~5:1.

In the dimethyl sulfoxide-deionized water mixed solvent, the volume ratio of dimethyl sulfoxide to deionized water is 1:5 to 1:9.

In the mixed solution, the total amount of the diacetylene monomer and the bimetallic zeolite imidazolate framework compound is 0.4-1.5 mg/mL.

2. Thermoreversible discoloration performance test of PDA/CoZn-ZIF composites

The PDA/CoZn-ZIF composite was heated gradually in a water bath at 30-95 °C, and the UV absorption spectra and the color photos of the suspension were recorded at different temperatures. It was found that at room temperature, the PDA/CoZn-ZIF composite showed blue; as the temperature continued to increase, the color of the composite gradually transitioned from blue to purple and then to red; after stopping the heating, the composite was in the range of 1~ Return to original blue color within 2 minutes. Therefore, the PDA/CoZn-ZIF composite material has the properties of rapid thermally reversible color change, has temperature sensitivity, can realize multiple reversible color transformations, and has good temperature sensor conditions.

In addition, the study also found that in CoZn-ZIF, different Co and Zn mass ratios have a certain influence on the thermochromic temperature of PDA/CoZn-ZIF composites.

The mechanism of the thermally reversible discoloration of the composite PDA/ZIF of the present invention: by introducing the interaction between ZIF, PDA and ZIF, the disordered PDA conformation after heating can be restored to the original ordered conformation arrangement after cooling, Thereby, the composite material rapidly recovers from red to blue.

Description of drawings

Figure 1 shows the UV-Vis absorption spectra of poly(PCDA)/CoZn-ZIF composites at different temperatures.

Figure 2 shows the UV-Vis absorption spectra of poly(TCDA)/CoZn-ZIF composites at different temperatures.

Detailed ways

The preparation and thermally reversible discoloration properties of the PDA/CoZn-ZIF composite material of the present invention will be further described below through specific examples.

Example 1. Preparation and reversible thermochromic properties of poly(PCDA)/CoZn-ZIF composites

(1) Preparation of CoZn-ZIF: add 0.240 g dimethylimidazole, 5 mL triethylamine, and 15 mL methanol to the beaker respectively, and after stirring the dimethyl imidazole to dissolve completely, add 0.365~0.610 g Co(NO ₃ ) After ₂ 6H ₂ O and 0.041~0.368g Zn(NO ₃ ) ₂ 6H ₂ O, stirring was continued for 12 h, and the obtained solid-liquid mixed solution was suction filtered. Seven groups of CoZn-ZIF zeolite imidazolate framework compounds with different Co and Zn mass ratios were obtained;

(2) Preparation of poly(PCDA)/CoZn-ZIF composites: Dissolve 12 mg of 10,12-pentacosadiynoic acid (PCDA) in 1 mL of dimethyl sulfoxide, add 9 mL of deionized water, PCDA solution was obtained; the solution was mixed with 10 mL of 7 groups of deionized aqueous solutions (different Co and Zn mass ratios) dispersed with 6 mg CoZn-ZIF, respectively, ultrasonicated at 50-80 °C for 30-60 min, cooled to room temperature, and then cooled to room temperature. Set aside for 8-16 h to obtain a white suspension; the white suspension was irradiated and polymerized under ultraviolet light with a wavelength of 254 nm for 5 min to obtain 7 groups of blue suspensions—poly(PCDA)/CoZn-ZIF;

(3) Test of reversible thermochromic properties of poly(PCDA)/CoZn-ZIF: 7 groups of poly(PCDA)/CoZn-ZIF composites were gradually heated in a water bath at 30~95 °C, and UV-vis absorption spectra were measured. At the same time, take pictures to record the color change. With the increase of the system temperature, the poly(PCDA)/CoZn-ZIF composites gradually changed from blue to red, completely changed to red and then cooled down naturally, and all 7 groups immediately returned from red to original blue.

Figure 1 shows the UV-Vis absorption spectra of poly(PCDA)/CoZn-ZIF composites at different temperatures. It can be seen from Figure 1 that at room temperature, the poly(PCDA)/CoZn-ZIF composite appears blue, with a maximum absorption peak at 645 nm, and a shoulder peak at 590 nm. The color gradually transitioned from blue to purple and then to red. At the same time, the absorption peak shifted to blue with the decrease of absorption intensity, the shoulder peak disappeared, the overall absorption peak broadened, and the absorption peak moved to 600 nm. After the heating was stopped, the composite material returned to the original blue color within 1-2 min.

Example 2. Preparation and reversible thermochromic properties of poly(TCDA)/CoZn-ZIF composites

(1) Preparation of CoZn-ZIF: the same as in Example 1;

(2) Preparation of poly(TCDA)/CoZn-ZIF composite material: Weigh 12 mg of purified 10,12-tcosadiynoic acid (TCDA), dissolve it in 1 mL of dimethyl sulfoxide, add 9 mL deionized water to obtain TCDA solution. The solution was mixed with 10 mL of 7 groups of deionized aqueous solutions (different Co and Zn mass ratios) dispersed with 6 mg of CoZn-ZIF, respectively, sonicated at 50-80 °C for 30-60 min, cooled to room temperature, and then allowed to stand at low temperature for 8-16 minutes. h, a white suspension was obtained; it was irradiated and polymerized under ultraviolet light with a wavelength of 254 nm for 5 min to obtain 7 groups of blue suspensions—poly(TCDA)/CoZn-ZIF;

(3) Test of reversible thermochromic properties of poly(TCDA)/CoZn-ZIF: 7 groups of poly(TCDA)/CoZn-ZIF and poly(PCDA)/CoZn-ZIF have similar thermochromic properties .

Figure 2 shows the UV-Vis absorption spectra of poly(TCDA)/CoZn-ZIF composites at different temperatures. It can be seen from Figure 2 that at room temperature, the poly(TCDA)/CoZn-ZIF composite appears blue, with a maximum absorption peak at 645 nm and a shoulder peak at 590 nm. The color gradually transitioned from blue to purple and then to red. At the same time, the absorption peak shifted to blue with the decrease of absorption intensity, the shoulder peak disappeared, the overall absorption peak broadened, and the absorption peak moved to 600 nm. After the heating was stopped, the composite material returned to the original blue color within 1-2 min.

Claims (4)

1. The preparation method of the thermoreversible color-changing composite material based on PDA and CoZn-ZIF comprises the steps of dissolving a diacetylene monomer into a dimethyl sulfoxide-deionized water mixed solvent; dispersing a compound with a bimetallic zeolite imidazole ester framework structure in deionized water, and adding the mixture into a diacetylene monomer solution to form a mixed solution; then, carrying out ultrasonic treatment on the mixed solution at 50-80 ℃ for 30-60 min, cooling to room temperature, and then carrying out low-temperature self-assembly for 8-16 h to obtain a white suspension; finally, placing the white suspension under ultraviolet light with the wavelength of 254 nm for irradiation polymerization for 2-20 min to obtain a uniform blue thermochromism composite material PDA/CoZn-ZIF; the zeolite imidazole ester framework structure compound is CoZn-ZIF, and the diacetylene monomer is 10, 12-tricosanoic diacetylene acid or 10, 12-pentacosadiynoic acid.

2. The method for preparing a PDA and CoZn-ZIF based thermoreversible color composite material as claimed in claim 1, wherein: the mass ratio of the diacetylene monomer to the bimetallic zeolite imidazole ester framework structure compound is 1: 1-5: 1.

3. The method for preparing a PDA and CoZn-ZIF based thermoreversible colour composite material according to claim 1, wherein: in the dimethyl sulfoxide-deionized water mixed solution, the volume ratio of dimethyl sulfoxide to deionized water is 1: 5-1: 9.

4. The method for preparing a PDA and CoZn-ZIF based thermoreversible color composite material as claimed in claim 1, wherein: in the mixed solution, the total amount of the diacetylene monomer and the bimetallic zeolite imidazole ester framework structure compound is 0.4-1.5 mg/mL.

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