Stimulus-responsive hydrogel material as well as preparation method and application thereof

Abstract

The invention provides a stimuli-responsive hydrogel material as well as a preparation method and application thereof, and belongs to the technical field of novel materials. The preparation method comprises the following steps: dissolving 1-(2-hydroxyethyl)-3, 3-dimethylindoline-6 '-nitrobenzo spiropyrane in dimethyl sulfoxide, then adding carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid for reaction, and freezing and drying a reaction solution to obtain spiropyrane functionalized four-arm-polyethylene glycol carboxylate; then mixing a polyvinyl alcohol solution, spiropyrane functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N, N '-methylene bisacrylamide, and then adding potassium persulfate and tetramethylethylenediamine for reaction to obtain the hydrogel. The hydrogel material prepared by the method has a good color changing effect on various stimulus responses such as light, pH and temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of novel materials, and in particular to a stimulus-responsive hydrogel material and a preparation method and application thereof. Background Art

[0002] Hydrogel is a hydrophilic polymer material with a three-dimensional network structure formed by physical or chemical crosslinking. Water is the dispersion medium and accounts for at least 70% of the weight of the gel. Therefore, the hydrogel has a certain hardness, elasticity, water absorption and water retention. In addition, some hydrogels also have good biocompatibility, biodegradability and stimulus responsiveness. It is widely used in many fields such as biomedicine, cosmetics, textiles, chemicals, construction, agriculture and tissue engineering, and is also a hot topic of current research.

[0003] Spiropyran (SP) is a widely studied color-changing dye that can undergo structural transformation between the closed-ring colorless SP type and the open-ring colored merocyanine (MC) type. The reversible transformation is accompanied by reversible changes in physical and chemical properties. It has been widely studied and applied in light switching, ion detection, fluorescence imaging, light-controlled wettability, information storage and logic operations, and intelligent mechanical materials.

[0004] Therefore, it is very important to provide a hydrogel material with high strength and certain response to light, heat and pH stimulation. Summary of the invention

[0005] The purpose of the present invention is to provide a stimulus-responsive hydrogel material and a preparation method and application thereof, so as to solve the technical problem of poor stimulus responsiveness of hydrogel materials in the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a stimulus-responsive hydrogel material, comprising the following steps:

[0008] 1) dissolving 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran in dimethyl sulfoxide, then adding carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid to react, freezing and drying the reaction solution to obtain spiropyran functionalized four-arm-polyethylene glycol carboxylate;

[0009] 2) Mixing polyvinyl alcohol solution, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide, and then adding potassium persulfate and tetramethylethylenediamine to react to obtain a hydrogel.

[0010] Furthermore, the mass volume ratio of the 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran and dimethyl sulfoxide is 0.01-0.1 g:20 mL;

[0011] The mass ratio of the 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran, carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid is 0.01-0.1: 0.01-0.1: 0.01-0.08: 0.1-0.5.

[0012] Furthermore, in the step 1), the reaction temperature is 20 to 30° C., and the reaction time is 24 to 30 hours;

[0013] The freezing temperature is -20 to -16°C, and the freezing time is 20 to 28 hours;

[0014] The drying temperature is -50 to -30°C, and the drying time is 3 to 7 hours.

[0015] Further, the molecular weight of the four-arm-polyethylene glycol-carboxylic acid is 10,000 to 15,000;

[0016] The molecular weight of the spiropyran functionalized four-arm-polyethylene glycol carboxylate is greater than 10,000.

[0017] Furthermore, the mass concentration of the polyvinyl alcohol solution is 20 to 30 g / L;

[0018] The mass ratio of polyvinyl alcohol, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide in the polyvinyl alcohol solution is 0.5: 0.001-0.005: 2-3: 0.003-0.01.

[0019] Furthermore, in the step 2), the mixing is performed under stirring, the mixing temperature is 20 to 40° C., and the mixing time is 20 to 40 minutes.

[0020] Furthermore, the usage ratio of polyvinyl alcohol, potassium persulfate and tetramethylethylenediamine in the polyvinyl alcohol solution is 0.5 g: 3-7 mg: 3-7 μL.

[0021] Furthermore, in the step 2), the reaction temperature is 15-25° C., and the reaction time is 20-40 min.

[0022] The present application provides a stimulus-responsive hydrogel material prepared by the preparation method.

[0023] The present invention also provides an application of a stimulus-responsive hydrogel material in environmental analysis.

[0024] Beneficial effects of the present invention:

[0025] (1) The spiropyran-functionalized four-arm-polyethylene glycol carboxylate prepared by the present invention has a good color-changing effect in response to multiple stimuli such as light, pH and temperature. The spiropyran-functionalized four-arm-polyethylene glycol carboxylate with stimulus response is introduced into the multi-network hydrogel system of polyvinyl alcohol and isopropyl acrylamide to form a color-changing hydrogel with multiple stimulus responses.

[0026] (2) The hydrogel material prepared by the present invention has a novel design and a simple preparation process, which provides a new idea for constructing multi-stimulus responsive hydrogels. The hydrogel material has broad application prospects in environmental analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The schematic diagram of the synthesis of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in the present invention;

[0028] Figure 2 This is the nuclear magnetic resonance spectrum of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1;

[0029] Figure 3 The solid image and solution image of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1;

[0030] Figure 4 The appearance of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 under ultraviolet light irradiation for 0s (left picture) and 90s (right picture);

[0031] Figure 5 The appearance of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 at 10° C. (left picture) and 40° C. (right picture);

[0032] Figure 6 The appearance of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 in an acidic solution (left picture) and an alkaline solution (right picture);

[0033] Figure 7 A schematic diagram of the structure of the hydrogel prepared by the present invention;

[0034] Figure 8 Thermogravimetric diagram of the hydrogel prepared in Example 1;

[0035] Fig. 9 This is a tensile test diagram of the hydrogel prepared in Example 1;

[0036] Fig.10 The appearance of the hydrogel prepared in Example 1 at 60°C (left picture) and 90°C (right picture);

[0037] Fig.11 This is the appearance of the hydrogel prepared in Example 1 in response to stimulation of different ionic water samples. DETAILED DESCRIPTION

[0038] The present invention provides a method for preparing a stimulus-responsive hydrogel material, comprising the following steps:

[0039] 1) dissolving 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran in dimethyl sulfoxide, then adding carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid to react, freezing and drying the reaction solution to obtain spiropyran functionalized four-arm-polyethylene glycol carboxylate;

[0040] 2) Mixing polyvinyl alcohol solution, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide, and then adding potassium persulfate and tetramethylethylenediamine to react to obtain a hydrogel.

[0041] In the present invention, the mass volume ratio of 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran and dimethyl sulfoxide is 0.01-0.1 g:20 mL, preferably 0.02-0.0.08 g:20 mL, and more preferably 0.03-0.05 g:20 mL;

[0042] The mass ratio of the 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran, carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid is 0.01-0.1: 0.01-0.1: 0.01-0.08: 0.1-0.5, preferably 0.015-0.09: 0.015-0.09: 0.02-0.07: 0.15-0.45, and further preferably 0.02-0.08: 0.02-0.08: 0.03-0.06: 0.2-0.4.

[0043] In the present invention, in the step 1), the reaction temperature is 20 to 30°C, preferably 22 to 28°C, and more preferably 25°C; the reaction time is 24 to 30h, preferably 25 to 29h, and more preferably 26 to 28h;

[0044] The freezing temperature is -20 to -16°C, preferably -19 to -17°C, and more preferably -18°C; the freezing time is 20 to 28 hours, preferably 22 to 26 hours, and more preferably 24 hours;

[0045] The drying temperature is -50 to -30°C, preferably -45 to -35°C, and more preferably -40°C; the drying time is 3 to 7 hours, preferably 4 to 6 hours, and more preferably 5 hours.

[0046] In the present invention, the molecular weight of the four-arm-polyethylene glycol-carboxylic acid is 10,000 to 15,000, preferably 10,000 to 14,000, and more preferably 10,000 to 13,000.

[0047] In the present invention, the molecular weight of the spiropyran functionalized four-arm-polyethylene glycol carboxylate is greater than 10,000, preferably greater than 11,000, and more preferably greater than 12,000.

[0048] In the present invention, the mass concentration of the polyvinyl alcohol solution is 20 to 30 g / L, preferably 22 to 28 g / L, and more preferably 24 to 26 g / L;

[0049] The mass ratio of polyvinyl alcohol, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide in the polyvinyl alcohol solution is 0.5: 0.001-0.005: 2-3: 0.003-0.01, preferably 0.5: 0.002-0.004: 2.2-2.8: 0.004-0.009, and further preferably 0.5: 0.003: 2.4-2.6: 0.005-0.008.

[0050] In the present invention, in the step 2), the mixing is carried out under stirring, the mixing temperature is 20-40°C, preferably 22-35°C, more preferably 25-30°C; the mixing time is 20-40 min, preferably 25-35 min, more preferably 30 min.

[0051] In the present invention, the usage ratio of polyvinyl alcohol, potassium persulfate and tetramethylethylenediamine in the polyvinyl alcohol solution is 0.5g:3-7mg:3-7μL, preferably 0.5g:3.5-6mg:3.5-6μL, and more preferably 0.5g:4-5.5mg:4-5.5μL.

[0052] In the present invention, in the step 2), the reaction temperature is 15-25°C, preferably 18-22°C, and more preferably 20°C; the reaction time is 20-40 min, preferably 25-35 min, and more preferably 30 min.

[0053] The present application provides a stimulus-responsive hydrogel material prepared by the preparation method.

[0054] The present invention also provides an application of a stimulus-responsive hydrogel material in environmental analysis.

[0055] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0056] Example 1

[0057] 0.035 g of 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran (SPOH) was dissolved in 20 mL of dimethyl sulfoxide, and then 0.038 g of carbodiimide hydrochloride (EDC.HCl), 0.024 g of N-hydroxysuccinimide (NHS) and 0.20 g of four-arm-polyethylene glycol-carboxylic acid (the molecular weight of four-arm-polyethylene glycol-carboxylic acid is 10000) were added to react for 28 hours at a temperature of 25° C. After the reaction, the reaction solution was transferred to a dialysis bag (molecular weight cutoff 10000) and dialyzed continuously for 72 hours, followed by freezing at -18° C. for 24 hours, and then drying at -40° C. for 5 hours after the freezing to obtain spiropyran functionalized four-arm-polyethylene glycol carboxylate (the molecular weight of spiropyran functionalized four-arm-polyethylene glycol carboxylate is greater than 10000);

[0058] Dissolve 0.5 g of polyvinyl alcohol in 20 mL of water and stir at 90 °C until completely dissolved to obtain a 25 g / L polyvinyl alcohol solution. Add 3 mg of spiropyran functionalized four-arm-polyethylene glycol carboxylate, 2.6 g of acrylamide and 6 mg of N,N'-methylenebisacrylamide to the polyvinyl alcohol solution and mix at 25 °C. The mixing is carried out while stirring for 30 minutes. Finally, add 5 mg of potassium persulfate and 5 μL of tetramethylethylenediamine and react at 20 °C for 30 minutes. After the reaction is completed, pour it into a mold and let it stand to obtain a hydrogel.

[0059] Example 2

[0060] Compared with Example 1, the differences in Example 2 are that the reaction temperature is 20°C and the reaction time is 24h; the freezing temperature is -20°C and the freezing time is 22h; the drying temperature is -30°C and the drying time is 6h.

[0061] Example 3

[0062] Compared with Example 1, the difference is that in the polyvinyl alcohol solution in Example 3, the mass ratio of polyvinyl alcohol, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide is 0.5:0.004:2.7:0.007.

[0063] The spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 was tested, and the results were Figures 2-3 shown. Figure 2This is the nuclear magnetic resonance spectrum of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1; Figure 3 The solid and solution images of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 are shown in Figure 1. The response of the spiropyran functionalized four-arm-polyethylene glycol carboxylate to light, pH and temperature is tested. The test results are shown in Figure 1. Figures 4 to 6 shown. Figure 4 The appearance of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 under ultraviolet light irradiation for 0s (left picture) and 90s (right picture);

[0064] Figure 5 The appearance of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 at 10° C. (left picture) and 40° C. (right picture); Figure 6 The appearance of the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared in Example 1 in an acidic solution (left) and an alkaline solution (right). Figure 1 to Figure 6 It can be seen that the present invention successfully prepared spiropyran functionalized four-arm-polyethylene glycol carboxylate, proving that the spiropyran functionalized four-arm-polyethylene glycol carboxylate prepared by the present invention has a good color-changing effect in response to various stimuli such as light, pH and temperature.

[0065] The hydrogel prepared in Example 1 was tested, and the test results are as follows: Figures 8 to 10 shown. Figure 8 Thermogravimetric diagram of the hydrogel prepared in Example 1; Fig. 9 This is a tensile test diagram of the hydrogel prepared in Example 1; Fig.10 The appearance of the hydrogel prepared in Example 1 before stimulation response (left picture) and after stimulation response (right picture). Figures 8 to 10 It can be seen that the hydrogel has good thermal stability, will not decompose within 150°C, has certain tensile strength and temperature sensitivity, and is expected to be used as a temperature indicating material.

[0066] The hydrogel prepared in Example 1 was tested in different ion water samples. The test results are as follows: Fig.11 As shown. Fig.11 It can be seen that the hydrogel prepared by the present invention can combine with trace iron ions and copper ions in water to show different colors, and can be applied to the determination of iron ions and copper ions in water.

[0067] As can be seen from the above embodiments, the present invention provides a stimulus-responsive hydrogel material and its preparation method and application, dissolving 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran in dimethyl sulfoxide, then adding carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid to react, freezing and drying the reaction solution to obtain spiropyran functionalized four-arm-polyethylene glycol carboxylate; then mixing polyvinyl alcohol solution, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide, then adding potassium persulfate and tetramethylethylenediamine to react to obtain a hydrogel. The hydrogel material prepared by the present invention has a good color-changing effect in response to multiple stimuli such as light, pH and temperature.

[0068] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a stimulus-responsive hydrogel material, characterized in that: The following steps are involved: 1) dissolving 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran in dimethyl sulfoxide, then adding carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid to react, freezing and drying the reaction solution to obtain spiropyran functionalized four-arm-polyethylene glycol carboxylate; 2) Mixing polyvinyl alcohol solution, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide, and then adding potassium persulfate and tetramethylethylenediamine to react to obtain a hydrogel.

2. The method for preparing the stimulus-responsive hydrogel material according to claim 1, characterized in that: The mass volume ratio of the 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran and dimethyl sulfoxide is 0.01-0.1 g:20 mL; The mass ratio of the 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran, carbodiimide hydrochloride, N-hydroxysuccinimide and four-arm-polyethylene glycol-carboxylic acid is 0.01-0.1: 0.01-0.1: 0.01-0.08: 0.1-0.

5.

3. The method for preparing the stimulus-responsive hydrogel material according to claim 1 or 2, characterized in that: In the step 1), the reaction temperature is 20-30°C and the reaction time is 24-30h; The freezing temperature is -20 to -16°C, and the freezing time is 20 to 28 hours; The drying temperature is -50 to -30°C, and the drying time is 3 to 7 hours.

4. The method for preparing the stimulus-responsive hydrogel material according to claim 3, characterized in that: The molecular weight of the four-arm-polyethylene glycol-carboxylic acid is 10,000 to 15,000; The molecular weight of the spiropyran functionalized four-arm-polyethylene glycol carboxylate is greater than 10,000.

5. The method for preparing the stimulus-responsive hydrogel material according to claim 1, 2 or 4, characterized in that: The mass concentration of the polyvinyl alcohol solution is 20-30 g / L; The mass ratio of polyvinyl alcohol, spiropyran functionalized four-arm-polyethylene glycol carboxylate, isopropyl acrylamide and N,N'-methylenebisacrylamide in the polyvinyl alcohol solution is 0.5: 0.001-0.005: 2-3: 0.003-0.

01.

6. The method for preparing the stimulus-responsive hydrogel material according to claim 5, characterized in that: In the step 2), the mixing is performed while stirring, the mixing temperature is 20 to 40° C., and the mixing time is 20 to 40 minutes.

7. The method for preparing the stimulus-responsive hydrogel material according to claim 6, characterized in that: The dosage ratio of polyvinyl alcohol, potassium persulfate and tetramethylethylenediamine in the polyvinyl alcohol solution is 0.5 g: 3-7 mg: 3-7 μL.

8. The method for preparing the stimulus-responsive hydrogel material according to claim 7, characterized in that: In the step 2), the reaction temperature is 15-25° C. and the reaction time is 20-40 min.

9. A stimulus-responsive hydrogel material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the stimulus-responsive hydrogel material according to claim 9 in environmental analysis.

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