Preparation method and application of acrylic acid-based composite gel with fluorescence and shape memory

Abstract

The invention provides an innovative acrylic acid-based gel preparation method, and the composite conductive hydrogel with fluorescence and shape memory is prepared. The preparation method is a one-pot method and comprises the following steps: firstly, dissolving anhydrous betaine and chitosan in a mixed solution of acrylic acid and water, then adding a photoinitiator 1173, and carrying out ultrasonic treatment. Through ultraviolet curing, the transparent gel with special functions is obtained. The gel is suitable for the field of information encryption and sensing, has the advantages of luminescence and shape memory under specific illumination, and provides new possibility for development of related technologies.

Description

Technical Field

[0001] The invention relates to a preparation method and application of an acrylic acid-based composite gel with fluorescence and shape memory. Background Art In recent years, with the continuous development of science and technology, various new materials have emerged one after another. People's demand for new materials has also become more diversified. Since its first report by Wichterle et al. in the 1950s, hydrogels have been widely used in medical fields such as tissue engineering, drug delivery, and 3D cell culture. Due to their simple preparation, highly controllable physicochemical properties, and excellent biocompatibility, hydrogels have attracted widespread attention for their ability to develop novel materials with multiple functions.

[0002] Hydrogels are three-dimensional cross-linked polymer network systems with hydrophilic properties. Their flexible polymer network and extremely high water content endow hydrogels with excellent deformability and biocompatibility. Under external stimuli, such as temperature, humidity, light intensity, pH, and magnetic fields, hydrogels exhibit controllable swelling-deformation by altering their polymer network. Hydrogels are soft, can maintain a certain shape, can absorb large amounts of water, and possess good biocompatibility and biodegradability.

[0003] Conductive hydrogels are a novel type of composite material that organically combines a hydrophilic matrix and a conductive medium, forming a class of hydrogels with excellent processability, high flexibility, and superior electrochemical properties. This material has broad application prospects in fields such as electronic skin, biosensors, supercapacitors, and flexible wearable electronic devices. Conductive sensing hydrogels exhibit corresponding property changes in response to external changes (such as pressure, strain, and deformation), often containing salt solutions or conductive polymers within the gel polymer. When external pressure changes, the cross-sectional area and length of the gel change, resulting in a change in resistance. Stable sensing signals can be obtained through detection, making it considered one of the ideal materials for future flexible electronic devices.

[0004] Acrylic acid is an organic compound, a colorless liquid with a pungent odor, miscible with water, and also miscible with ethanol and ether. It can form hydrogen bonds with anhydrous betaine, dissolving together to form a eutectic solution. Currently, the addition of chitosan to this proportion of the eutectic solution has not been studied. This invention prepares anhydrous betaine / chitosan composite acrylic gel, enabling applications such as electrical signal sensing behavior under external stimuli and information encryption. Summary of the Invention

[0005] The present invention aims to solve the problem of single means of information storage of multi-stimulus responsive gel and the application of flexible materials in sensing, so as to achieve the purpose of multi-faceted application of hydrogel and provide a preparation method and application of acrylic acid-based gel for sensing.

[0006] A method for preparing and using an acrylic acid-based gel for sensing comprises the following steps: 1. Mix AA and deionized water in a molar ratio of 1:2 to obtain a clear, transparent, and stable solution; 2. First add anhydrous betaine to the solution and stir for 60 minutes, then add chitosan and stir for 60 minutes until it is completely dissolved. 3. Add photoinitiator 1173, stir for 10 min, sonicate for 10 min to remove air bubbles, transfer to a 2 mm template, and finally initiate polymerization in a UV curing oven for 120 s to obtain hydrogel.

[0007] In step one, acrylic acid and water are mixed in a molar ratio of 1:2.

[0008] The method for preparing the acrylic acid-based gel in step 2 is a one-pot method for preparing the gel material.

[0009] In the step 2, anhydrous betaine is added to water to prepare a transparent acrylic acid solution.

[0010] In the step 2, chitosan is added into the solution to prepare a light yellow transparent acrylic acid solution.

[0011] The photoinitiator 1173 added in step 3 needs to meet 2 μL / mL.

[0012] In step three, ultraviolet light is used for initiation for 120 seconds.

[0013] The glass mold used in the three steps described above can be replaced by a quartz mold.

[0014] The conductive sensing hydrogel prepared by the present invention is applied to information encryption and sensing signal detection.

[0015] Compared with the prior art, the present invention has the following advantages: The present invention uses acrylic acid, anhydrous betaine and chitosan as raw materials to prepare a conductive sensing hydrogel, which is irradiated for 120 seconds through a UV curing method and stored at room temperature.

[0016] This invention prepares conductive sensing hydrogels by UV curing of acrylic acid, anhydrous betaine, and chitosan.

[0017] The present invention is simple and easy to implement, has a short reaction time, and uses low-cost, widely available raw materials. It is easy to operate and exhibits excellent sensing performance: the prepared acrylic-based gel for information encryption and sensor signal detection can rapidly change resistance in response to external stimuli, and transparent information is revealed when no force is applied, while the gel becomes opaque and obscures information when force is applied. Therefore, the acrylic-based gel of the present invention can be used to obscure information and detect sensor signals. This process is reversible and reusable, achieving the purposes of sensor signal detection and information encryption. The material also exhibits a fluorescence effect, capable of emitting light at specific wavelengths. Finally, the material itself has antifreeze properties, enabling the gel to operate stably at low temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a photo of the actual preparation of acrylic acid-based composite gel in Specific Example 1; Figure 2 This is a reversible fluorescence display diagram of preparing acrylic acid-based composite gel in specific example 1 Figure 3 The shape memory of acrylic acid-based composite gel is prepared in specific example 1; Figure 4 is a UV-visible spectrum of the acrylic-based composite gel prepared in specific example 1 in its original state and after stretching; Figure 5 This is an electrochemical signal diagram of elbow bending in preparing acrylic acid-based composite gel in specific example 1. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0020] Embodiment 1: A method for preparing an acrylic acid-based composite gel for sensing and its use comprises the following steps: 1. Mix AA and deionized water in a molar ratio of 1:2 to obtain a clear, transparent, and stable solution; 2. First add anhydrous betaine to the solution and stir for 60 minutes, then add chitosan and stir for 60 minutes until it is completely dissolved. 3. Add photoinitiator 1173, stir for 10 min, sonicate for 10 min to remove air bubbles, transfer to a 2 mm template, and finally initiate polymerization in a UV curing oven for 120 s to obtain hydrogel.

[0021] Example 1 demonstrates the preparation of an anhydrous betaine / chitosan composite acrylic acid-based gel using a one-pot UV curing process. This method is simple, low-cost, and allows for controllable material size. It exhibits sensitive pressure sensing and mechanical responsiveness, and has promising applications in information encryption and electrical conductivity detection.

[0022] The actual picture of the anhydrous betaine / chitosan composite acrylic acid-based gel material prepared in Example 1 is as follows: Figure 1 As shown in the figure, cheap and readily available acrylic acid, anhydrous betaine and chitosan were used to prepare a conductive sensing hydrogel in one pot by UV curing.

[0023] The reversible fluorescence display diagram of the anhydrous betaine / chitosan composite acrylic acid-based gel material prepared in Example 1 is as follows: Figure 2 As shown, in the initial state, the gel is transparent and emits blue-green fluorescence at a specific wavelength; after being soaked in trivalent iron ions, it appears orange-red under natural light and the fluorescence disappears at a specified wavelength; then, by repeatedly changing the water and soaking in dilute hydrochloric acid, the trivalent iron ions are soaked out, and after reshaping, the fluorescence is restored, forming reversible fluorescence.

[0024] The shape memory display diagram of the anhydrous betaine / chitosan composite acrylic acid-based gel material prepared in Example 1 is as follows: Figure 3 As shown, in the initial state, the gel is pressed into a certain shape. The gel that has not been soaked in trivalent iron ions returns to its original shape and cannot remember the temporary shape. After being soaked in trivalent iron ions, the gel can remember the temporary shape and form shape memory.

[0025] The UV-visible spectra of the anhydrous betaine / chitosan composite acrylic acid-based gel prepared in Example 1 in the initial state and after stretching are as follows: Figure 4 As shown in the figure, UV-visible light testing was performed on the gel in its initial state and after stretching at room temperature. After the gel was stretched, its light transmittance was greatly reduced. Different light transmittances can effectively block information and be used in information encryption applications.

[0026] The application of the sensing test of the anhydrous betaine / chitosan composite acrylic acid-based gel material prepared in Example 1 is as follows: Figure 5 As shown in the figure, anhydrous betaine / chitosan composite acrylic gel was applied to the elbow of a human body to monitor human activities, and a stable electrical signal was transmitted. The hydrogel has good conductive properties.

Claims

1. A method for preparing and using an acrylic acid-based gel for sensing, characterized in that The method comprises the following steps: Preparation of acrylic acid-based composite gel The gel was prepared by a one-pot method. First, 1-5% (wt) anhydrous betaine was weighed and dissolved in a solution of acrylic acid and water in a molar ratio of 1:2, and stirred for 1 hour until completely dissolved; then 0.4% (wt) chitosan was weighed and stirred for 1 hour until completely dissolved, and photoinitiator 1173 (precursor solution volume × 2μL / mL) was added, stirred for 10 minutes, ultrasonicated for 10 minutes to remove bubbles, transferred to a 2mm template, and finally initiated polymerization in a UV curing box for 120 seconds to obtain a hydrogel.

2. The preparation method and use of an acrylic acid-based composite gel according to claim 1, characterized in that The solvent is prepared with acrylic acid and water in a molar ratio of 1:

2.

3. The preparation method and use of an acrylic acid-based composite gel according to claim 1, characterized in that :The acrylic acid-based composite gel preparation method is a one-pot method for preparing gel material.

4. The preparation method and use of an acrylic acid-based composite gel according to claim 1, characterized in that In the steps, anhydrous betaine is added into the solution to prepare a transparent acrylic acid solution.

5. The preparation method and use of an acrylic acid-based composite gel according to claim 1, characterized in that: Chitosan was added into the solution to prepare a light yellow, transparent acrylic acid solution.

6. The preparation method and use of an acrylic acid-based composite gel according to claim 1, characterized in that :The added photoinitiator 1173 needs to meet 2μL / mL.

7. The preparation method and use of an acrylic acid-based composite gel according to claim 1, characterized in that :UV light initiation for 120s.

8. A multi-responsive color-changing hydrogel and its preparation method and use according to claim 1, characterized in that : Used for shape memory, information encryption and sensing functions.

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