Reversible thermochromic polydiacetylene material and application thereof in medium-high temperature overheating monitoring

Abstract

The invention discloses a reversible thermochromic polydiacetylene material and application thereof in medium-high temperature overheat monitoring, the material is an amide functionalized conjugated polymer containing polydiacetylene on both sides, and the preparation method comprises the following steps: a) reacting 10, 12-pentacosadiynoic acid with an amine compound to synthesize an amidated conjugated diacetylene monomer; and b) carrying out in-situ topological chemical polymerization on the diacetylene monomer under the irradiation of ultraviolet light to obtain the polydiacetylene material. The polydiacetylene material shows a remarkable thermochromic characteristic under thermal stimulation, the color of the polydiacetylene material changes in multiple steps at different temperature critical points, after the polydiacetylene material is cooled to the room temperature, the color of a polymer is rapidly restored, and the color change of the material is stable through multiple heating and cooling cycle experiments. The material can repeatedly monitor the real-time temperature of various electric appliances or equipment, and overheating after long-time use is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermochromic sensing materials, and particularly relates to a reversible thermochromic polydiacetylene material, a preparation method thereof, and an application thereof in medium and high temperature overheat monitoring. Background Art

[0002] With the rapid development of electrification and intelligence, overheating problems often occur in power devices, production lines, and intelligent equipment, which may lead to various accidents. To address these problems, various temperature sensing devices or technical solutions have been developed and put into use. Among them, infrared imagers and various online electronic sensors are widely used for daily monitoring. However, most of these devices require complex experimental setups, continuous power supply, and high maintenance costs. Therefore, there is an urgent need to develop sensitive and energy-saving temperature monitoring solutions to meet the monitoring requirements in unattended or harsh environments. Thermochromic materials are a class of materials that can respond to temperature changes and change their own colors accordingly, providing a portable and intuitive way of temperature monitoring. Among them, polydiacetylene has attracted wide attention in the field of temperature monitoring due to its unique optical properties with a π-conjugated backbone structure.

[0003] Chinese Patent CN 117085603A provides a method for real-time monitoring of the failure of a kinematic pair. In this method, high-temperature irreversible thermochromic microcapsules are arranged on the surface of the kinematic pair. When the surface temperature of the kinematic pair changes to the color-changing temperature of the high-temperature irreversible thermochromic microcapsules, the high-temperature irreversible thermochromic microcapsules change color to realize real-time monitoring of whether the kinematic pair fails. Chinese Patent CN 112326058A discloses a system and method capable of sensing temperature. The method includes four temperature-changing layers, and when the temperature reaches or exceeds a preset temperature, the four color-changing layers change color to remind the user. The temperature-sensing wire is connected to a temperature controller to monitor the temperature of the wire in real time. When the temperature of the wire exceeds the preset safe range, the temperature controller reminds the user. The system designed by this invention solves the problem that the temperature rise of the wire cannot be detected and is easy to be mass-produced in industry. However, the color of the irreversible thermochromic material cannot be restored when the environmental temperature decreases, and this characteristic makes it impossible to be reused in the temperature monitoring of electrical appliances or equipment, thus increasing the cost.

[0004] In contrast, reversible thermochromic materials not only have simple operations but also can maintain stable color-changing performance in multiple cycles, significantly reducing production and use costs, improving the use efficiency, and showing obvious application advantages. Therefore, it is of great significance to develop polydiacetylene materials with reversible thermochromic properties. Summary of the Invention

[0005] The object of the present invention is to provide a reversible thermochromic polydiacetylene material, a preparation method thereof and an application in medium and high temperature overheat monitoring. The reversible thermochromic polydiacetylene material is formed by in-situ topochemical polymerization of monomers. The material preparation process is simple, the product purity is high, the temperature range of its monitoring application is 80 - 110 °C, it has high sensitivity, excellent thermal stability and reusability in temperature monitoring applications, and the high-contrast color change enhances the visual recognition ability.

[0006] The technical solution of the present invention is as follows:

[0007] In the first aspect, the present invention provides a reversible thermochromic polydiacetylene material, and the structural general formula of the polydiacetylene material is:

[0008]

[0009] Among them, is a repeating unit;

[0010] R is any one of the following groups

[0011] One of them.

[0012] Furthermore, the polydiacetylene material has reversible thermochromic properties.

[0013] In the second aspect, the present invention provides a synthesis method of the reversible thermochromic polydiacetylene material described in the first aspect, including:

[0014] Step a), adding pure 10,12-pentacosadiynoic acid and dichloromethane into a container, then adding a condensing reagent and an amine compound, stirring overnight at room temperature to obtain a crude product of bis-10,12-pentacosadiynamide compound, and obtaining the bis-10,12-pentacosadiynamide compound after extraction and column chromatography purification;

[0015] Step b), using the bis-10,12-pentacosadiynamide compound as a monomer and irradiating it with an ultraviolet lamp to polymerize to obtain the reversible thermochromic polydiacetylene material.

[0016] Furthermore, the condensing reagent is one of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC), diisopropylcarbodiimide (DIC) and dicyclohexylcarbodiimide (DCC); the molar ratio of 10,12-pentacosadiynoic acid to the condensing reagent is 1:1.5 - 3.

[0017] Furthermore, the amine compound is selected from compounds with the following structures:

[0018]

[0019] Furthermore, the molar ratio of the amine compound to 10,12-pentacosadiynoic acid is 1:2 - 2.5.

[0020] Furthermore, the eluent for column chromatography is ethyl acetate: petroleum ether at a ratio of 1:1 - 3, and silica gel or basic alumina is used for column chromatography.

[0021] Furthermore, the irradiation wavelength of the ultraviolet lamp is 254 - 325 nm, and the irradiation time is 3 - 10 min.

[0022] In a third aspect, the present invention provides the application of the reversible thermochromic polydiacetylene material described in the first aspect in medium and high temperature overheat monitoring.

[0023] Furthermore, the polydiacetylene material has reversible thermochromic properties, and its thermochromic temperature range is 80 - 110 °C.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) The polydiacetylene material exhibits significant reversible thermochromic characteristics. In the range of 80 - 110 °C, the color of the material undergoes multiple-step changes. When cooled to room temperature, the color of the polymer returns to the initial state. The high-contrast color changes under thermal stimulation enhance its visual recognition ability in temperature monitoring applications.

[0026] (2) The polydiacetylene material has high sensitivity. Under thermal stimulation, an obvious color change will occur within 1 second. After removing the heat source, the color of the pattern immediately returns.

[0027] (3) The polydiacetylene material has excellent thermal stability and reusability. After multiple heating and cooling cycle experiments, it still has reversible thermochromic characteristics, and the color changes are stable, with good durability. Description of the Drawings

[0028] Figure 1 1H NMR spectrum of N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene obtained in Example 1.

[0029] Figure 2 13C NMR spectrum of poly(N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene) obtained in Example 1.

[0030] Figure 3 1H NMR spectrum of 4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl obtained in Example 2.

[0031] Figure 4Solid-state NMR carbon spectrum of poly(4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl) obtained in Example 2.

[0032] Figure 5 Liquid-state NMR hydrogen spectrum of 5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine obtained in Example 3.

[0033] Figure 6 Solid-state NMR carbon spectrum of poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) obtained in Example 3.

[0034] Figure 7 Infrared spectra of poly(N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene) (Bis-PDA-1), poly(4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl) (Bis-PDA-2), and poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) (Bis-PDA-3) obtained in Examples 1, 2, and 3.

[0035] Figure 8 Raman spectra of poly(N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene) (Bis-PDA-1), poly(4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl) (Bis-PDA-2), and poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) (Bis-PDA-3) obtained in Examples 1, 2, and 3.

[0036] Figure 9 Thermochromic behavior images of poly(N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene) (Bis-PDA-1), poly(4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl) (Bis-PDA-2), and poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) (Bis-PDA-3) obtained in Examples 1, 2, and 3. Detailed implementation mode

[0037] The reversible thermochromic polydiacetylene materials of the present invention will be further described below through specific examples and drawings. However, these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0040] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement, or value. One of ordinary skill in the art can readily determine the degree of flexibility for a particular variable.

[0041] As used herein, the term "at least one of..." is intended to be synonymous with "one or more of...". For example, "at least one of A, B, and C" clearly includes only A, only B, only C, and their respective combinations.

[0042] Concentrations, amounts, and other numerical data may be presented herein in a range format. It should be understood that such range formats are used merely for convenience and brevity and should be interpreted flexibly as including not only the numerical values explicitly recited as the limits of the range, but also all individual numerical values or sub-ranges subsumed within the stated range as if each numerical value and sub-range were explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted as including not only the explicitly recited limit values of 1 to about 4.5, but also the individual numbers (such as 2, 3, 4) and sub-ranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges that recite only one numerical value, such as "less than about 4.5", which should be interpreted as including all of the above values and ranges. In addition, this interpretation should apply regardless of the breadth of the range or feature described.

[0043] The present invention provides a route for monomers to polymerize to form polymers:

[0044]

[0045] Example 1

[0046] R is When, that is, the preparation method of the target product poly(N,N'-bis(N-(10,12-pentacosadiynoyl)amino)-benzene) includes:

[0047] The purchased 10,12-pentacosadiynoic acid was dissolved in dichloromethane. The polymerized part of the raw materials was removed using a syringe filter, and then the solvent was concentrated under vacuum to obtain pure 10,12-pentacosadiynoic acid. The pretreated pure 10,12-pentacosadiynoic acid (2.7 g, 7.2 mmol) was added to a two-necked round-bottom flask. The flask was evacuated with a vacuum pump and then filled with argon, and this cycle was repeated 3 times. Subsequently, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (1.68 g, 10.8 mmol) and dichloromethane (120 ml) were added to the flask, and then p-phenylenediamine (0.36 g, 3.3 mmol) was injected into the reactor. The reaction mixture was stirred overnight at room temperature, and the reaction progress was monitored by thin-layer chromatography. After the reaction was completed, the product was extracted with dichloromethane and sodium chloride solution. The organic phase was dried over anhydrous sodium sulfate, and the anhydrous sodium sulfate was removed by filtration. The filtrate was concentrated under reduced pressure to obtain a crude product. Finally, the crude product was purified by silica gel column chromatography using petroleum ether:ethyl acetate = 1:3 as the eluent to obtain pure white monomeric powder N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene. The liquid nuclear magnetic resonance hydrogen spectrum of N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene is as Figure 1 shown, 1 HNMR(500MHz,Chloroform-d), δ=6.93(s,2H),6.65(s,4H),2.27(d,J=33.1Hz,12H),1.71(s,4H),1.63-1.17(m,60H),0.88(s,6H).

[0048] 100 mg of the white monomer N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene was weighed, and the loose-packed monomer thin layer was irradiated with a portable ultraviolet analyzer at a wavelength of 254 nm for 3 minutes for polymerization at room temperature to obtain blue poly-N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene. The solid nuclear magnetic resonance carbon spectrum of poly-N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene is as Figure 2 shown, and the infrared spectrum is as Figure 7 shown, FTIR:ν(cm -1 )=3285,2920,2847,2165,1655,1537,1171. Figure 8 The Raman spectrum of poly-N,N'-bis(N-(10,12-pentacosadiynyl)amido)-benzene is shown, ν(C≡C):2191cm -1 ,ν(C=C):1451cm -1 .

[0049] Figure 9Thermochromic property test of poly(N,N'-bis(N-(10,12-pentacosadiynoyl)amino)-benzene). When heated to 110 °C, poly(N,N'-bis(N-(10,12-pentacosadiynoyl)amino)-benzene) changes from blue to red, and the color change effect is obvious. After the temperature is cooled to 25 °C, the material becomes black-purple.

[0050] Example 2

[0051] R is That is, the preparation method of the target product, poly(4,4'-bis(N-(10,12-pentacosadiynoyl)amino)-biphenyl), includes:

[0052] Transfer pure 10,12-pentacosadiynoic acid (2.7 g, 7.2 mmol) to a two-necked round-bottom flask. First, evacuate it with a vacuum pump and then introduce argon, repeating the cycle 3 times. Then, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (1.68 g, 10.8 mmol) and dichloromethane (180 ml) into the flask through a syringe, and then add 4,4'-diaminobiphenyl (0.61 g, 3.3 mmol). Stir the reaction mixture at room temperature for 24 hours and monitor the reaction progress by thin-layer chromatography. After the reaction is completed, remove the solvent under reduced pressure, and then extract with dichloromethane and brine. Dry the organic phase with anhydrous sodium sulfate, filter to remove sodium sulfate, and then concentrate under vacuum to obtain the crude product. Finally, purify the crude product by silica gel column chromatography using petroleum ether:ethyl acetate = 1:1 as the eluent to obtain pure light pink monomer powder 4,4'-bis(N-(10,12-pentacosadiynoyl)amino)-biphenyl. The liquid nuclear magnetic resonance hydrogen spectrum of 4,4'-bis(N-(10,12-pentacosadiynoyl)amino)-biphenyl is as Figure 3 shown as 1 HNMR(500MHz,Chloroform-d), δ = 7.51(d,J = 18.4Hz,9H),7.12(s,2H),2.30(d,J = 61.6Hz,12H),1.74(s,4H),1.41(d,J = 158.5Hz,62H),0.88(s,6H).

[0053] Weigh 100 mg of the monomer 4,4'-bis(N-(10,12-pentacosadiynoyl)amino)-biphenyl, and irradiate the loose-packed monomer thin layer with a hand-held ultraviolet analyzer at a wavelength of 254 nm for 3 minutes to carry out polymerization at room temperature to obtain purple powder poly(4,4'-bis(N-(10,12-pentacosadiynoyl)amino)-biphenyl). The solid nuclear magnetic resonance carbon spectrum of poly(4,4'-bis(N-(10,12-pentacosadiynoyl)amino)-biphenyl) is as Figure 4 shown, and the infrared spectrum is asFigure 7 As shown, FTIR: ν(cm -1 ) = 3300, 2921, 2847, 2163, 1656, 1502, 1178. Figure 8 The Raman spectrum of poly(4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl) is shown, ν(C≡C): 2072 cm -1 , ν(C=C): 1485 cm -1 .

[0054] Figure 9 The color-changing performance test of poly(4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl) was carried out. When heated to 80 °C, poly(4,4'-bis(N-(10,12-pentacosadiynyl)amido)-biphenyl) changed from purple to orange, and as the temperature gradually increased, the material changed to yellow, showing a multi-step color change with high contrast. When the temperature was cooled to 25 °C, the material returned to the initial purple state.

[0055] Example 3

[0056] R is That is, the preparation method of the target product poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) includes:

[0057] Transfer pure 10,12-pentacosadiynoic acid (2.7 g, 7.2 mmol) to a two-necked round-bottom flask. First, evacuate it with a vacuum pump, and then introduce argon, repeating three times for atmosphere replacement, which helps to remove moisture in the reactor and oxygen in the air, preventing side reactions during the reaction. Subsequently, use a syringe to add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (1.68 g, 10.8 mmol) and dichloromethane (180 ml) to the flask, and then add 5,5'-diamino-2,2'-bipyridine (0.615 g, 3.3 mmol). Stir the reaction mixture at room temperature for 24 hours, and monitor the reaction progress by thin-layer chromatography for a quick check of whether the reaction is complete. After the reaction is completed, remove the solvent by reduced pressure, and then extract with dichloromethane and brine. Dry the organic phase with anhydrous sodium sulfate, filter to remove sodium sulfate, and then concentrate in vacuo to obtain the crude product. Finally, purify the crude product by column chromatography on basic alumina using petroleum ether:ethyl acetate = 1:1 as the eluent to obtain pure white monomeric powder 5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine. The liquid nuclear magnetic resonance hydrogen spectrum of 5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine is as Figure 5 shown, 1HNMR (500 MHz, Chloroform-d), δ = 8.60 (s, 2H), 8.17 (d, J = 34.1 Hz, 6H), 2.32 (d, J = 80.0 Hz, 12H), 1.74 (s, 4H), 1.74 - 0.91 (m, 61H), 0.88 (s, 6H).

[0058] Weigh 50 mg of the white monomer 5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine, and irradiate it with a portable ultraviolet lamp at 254 nm for 5 minutes at room temperature to polymerize it, obtaining the blue powder poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine). The solid-state nuclear magnetic resonance carbon spectrum of poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) is as Figure 6 shown, and the infrared spectrum is as Figure 7 shown, FTIR: ν (cm -1 ) = 3273, 2918, 2846, 2164, 1658, 1522, 1179. Figure 8 The Raman spectrum of poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) is shown, ν(C≡C): 2089 cm -1 , ν(C=C): 1456 cm -1 .

[0059] Figure 9 This is the color-changing performance test of poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine). When heated to 80 °C, poly(5,5'-bis(N-(10,12-pentacosadiynyl)amido)-2,2'-bipyridine) changes from blue to purple. When heated to 95 °C, the material turns pink, and at 110 °C, the color changes to pinkish-red, indicating that as the temperature gradually increases, the color of the polymer undergoes multiple-step changes, and the color-changing effect is obvious. After the temperature is cooled to 25 °C, the material returns to its initial blue color.

[0060] The above embodiments are only the preferred embodiments in the present invention, but the implementation manners of the present invention are not limited by the above embodiments. For example, various forms of combinations of the solutions in the embodiments, any other changes, modifications, substitutions, and combinations made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all within the protection scope of the present invention.

Claims

1. A reversible thermochromic polydiacetylene material, characterized in that: The general structural formula of the polydiacetylene material is: in, is a repeating unit; R is any of the following groups One of them.

2. The reversible thermochromic polydiacetylene material according to claim 1, characterized in that: It has reversible thermochromic properties.

3. A method for synthesizing a reversible thermochromic polydiacetylene material as claimed in claim 1 or 2, characterized in that: include: Step a), reacting 10,12-pentacosadiynoic acid with dichloromethane, a condensation reagent and an amine compound at room temperature to obtain a crude product of a bis-10,12-pentacosadiynamide compound, and extracting and purifying by column chromatography to obtain a bis-10,12-pentacosadiynamide compound; Step b), using a bis-10,12-pentacosadiynylamide compound as a monomer and irradiating it with an ultraviolet lamp to polymerize it to obtain the reversible thermochromic polydiacetylene material.

4. The method according to claim 3, characterized in that The condensation reagent is one of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, diisopropylcarbodiimide and dicyclohexylcarbodiimide; the molar ratio of 10,12-pentacosadiynoic acid to the condensation reagent is 1:1.5-3.

5. The method according to claim 3, characterized in that The amine compound is selected from the compounds of the following structures:

6. The method according to claim 3, characterized in that The molar ratio of the amine compound to the 10,12-pentacosadiynoic acid is 1:2-2.

5.

7. The method according to claim 3, characterized in that The eluent for column chromatography is ethyl acetate:petroleum ether in a ratio of 1:1-3, and silica gel or basic alumina is used for column chromatography.

8. The method according to claim 3, characterized in that The wavelength of ultraviolet lamp irradiation is 254-325nm, and the irradiation time is 3-10min.

9. Use of the reversible thermochromic polydiacetylene material as claimed in claim 1 or 2 in medium and high temperature overheating monitoring.

10. The use according to claim 9, characterized in that The polydiacetylene material has a reversible thermochromic property, and the thermochromic temperature range is 80-110°C.

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