Green and efficient ionic conductive hydrogel, preparation method and application thereof
By using a simple preparation method with sodium alginate, lithium chloride, and deionized water, the problems of complex preparation and uneven performance of existing ionic conductive hydrogels are solved. A transparent hydrogel with high mechanical strength and excellent conductivity is prepared, which is suitable for multi-part motion monitoring in flexible wearable devices.
Patent Information
- Application Number
- CN202310278683.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-21
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2043-03-21
AI Technical Summary
Existing methods for preparing ionic conductive hydrogels are complex, cannot simultaneously achieve both mechanical and electrical properties, and involve significant raw material pollution and high costs, making it difficult to meet the application requirements of flexible wearable devices.
Using sodium alginate, lithium chloride, and deionized water as raw materials, and by controlling their mass ratio and stirring conditions, a transparent, mechanically strong, and highly conductive ionic hydrogel was prepared. Lithium chloride was used as a solvent and conductive medium, which simplified the preparation process and reduced the cost.
A green and efficient ionic conductive hydrogel was prepared, which has excellent mechanical properties, electrical conductivity and freeze resistance, and is suitable for multi-part motion monitoring in flexible wearable devices, showing good application prospects.
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Figure CN116396539B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of natural polymers, and particularly relates to a green and efficient ionic conductive hydrogel, a preparation method and application thereof. BACKGROUND
[0002] In recent years, wearable devices play an important role in the biomedical field such as personalized healthcare, physical activity monitoring and clinical diagnosis, and have attracted widespread attention. Compared with sensor devices based on rigid components, flexible wearable devices have great potential for development in real-time monitoring of individual physiological states due to their inherent flexibility and flexibility. Traditional flexible sensor networks assemble metal circuits on flexible substrates, thereby endowing the sensor with higher extensibility. However, the compatibility between the metal circuit and the flexible substrate is limited and the sensitivity is low, which will seriously affect the signal transmission of the wearable device. In addition, poor biocompatibility is also an important factor affecting its application.
[0003] As a new type of conductive material with excellent mechanical properties and conductivity, ionic conductive hydrogel has attracted extensive attention from researchers in recent years. Ionic conductive hydrogel is a kind of material which takes hydrogel polymer as matrix material and metal ion salt as conductive medium. The unique three-dimensional network structure and hydrophilicity of hydrogel provide a guarantee for the free migration of metal ions in hydrogel. At the same time, the rich cross-linking system ensures the stability of the hydrogel itself, effectively solving the shortcomings of traditional conductive materials. Based on the outstanding performance of ionic conductive hydrogel, it has achieved certain research results in the fields of stress-strain sensor, temperature sensor, electronic skin, flexible supercapacitor, soft robot and bionic electronic skin.
[0004] Currently, the preparation of ionic conductive hydrogel mainly falls into two categories: one is chemical synthesis of ionic conductive hydrogel. Metal ion salt solution is added during the preparation of hydrogel to endow the hydrogel with conductivity. However, the content of metal ions added by this method is limited, and the conductivity of the finished product is poor, which cannot meet the use demand. Excessive metal ions will seriously affect the cross-linking density of hydrogel material and greatly reduce the mechanical properties of hydrogel itself; the other is physical mixing of ionic conductive hydrogel. The prepared hydrogel is soaked in metal ion salt solution, and metal ions are introduced into the hydrogel through adsorption. However, the content of metal ions adsorbed by this method is limited. At the same time, the metal ions are mostly enriched on the surface of the hydrogel, and the internal content is small, which leads to poor uniformity of metal ion distribution and unstable conductivity of the hydrogel. Therefore, it is necessary to develop a simple and rapid preparation method of ionic conductive hydrogel to solve the problem of imbalance between mechanical properties and electrochemical properties in the existing preparation method, which is of great significance for the application of ionic conductive hydrogel in the field of flexible wearable electronic devices. SUMMARY
[0005] The present application aims to provide a green and efficient ionic conductive hydrogel, a preparation method and application thereof, so as to solve the problems of complex preparation process, and the mechanical properties and conductivity of the existing conductive hydrogel cannot be considered.
[0006] In order to solve the above technical problems, the present application adopts the following technical solutions:
[0007] According to the first aspect of the present application, a green and efficient ionic conductive hydrogel is provided, and the preparation raw materials include sodium alginate, lithium chloride and deionized water, and the mass ratio of sodium alginate, lithium chloride and deionized water in the sodium alginate conductive hydrogel is (2.0-6.0):(1.0-8.0):100.
[0008] According to a preferred embodiment of the present application, the mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is (3.0-6.0):(6.0-8.0):100.
[0009] According to the second aspect of the present application, a preparation method of a green and efficient ionic conductive hydrogel is provided, which comprises the following steps: S1: a certain amount of lithium chloride is dissolved in deionized water to obtain a lithium chloride salt solution; S2: a certain amount of sodium alginate is slowly added to the lithium chloride salt solution, heated to 20-90℃, and stirred at a speed of 200-1500rpm for 1.0-6.0h to obtain a sodium alginate salt solution; S3: the sodium alginate salt solution is poured into a mold and left to stand for 3.0-12.0h to obtain a colorless and transparent ionic conductive hydrogel; wherein the mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is (2.0-6.0):(1.0-8.0):100.
[0010] According to a preferred embodiment of the present application, the mass ratio of sodium alginate, lithium chloride and deionized water in the prepared ionic conductive hydrogel is (3.0-6.0):(6.0-8.0):100.
[0011] According to another preferred embodiment of the present application, the mass ratio of sodium alginate, lithium chloride and deionized water in the prepared ionic conductive hydrogel is 3:6:100.
[0012] According to still another preferred embodiment of the present application, the mass ratio of sodium alginate, lithium chloride and deionized water in the prepared ionic conductive hydrogel is 6:8:100.
[0013] According to still another preferred embodiment of the present application, the mass ratio of sodium alginate, lithium chloride and deionized water in the prepared ionic conductive hydrogel is 2:6:100.
[0014] Preferably, the mold is a polytetrafluoroethylene mold.
[0015] The viscosity of the sodium alginate is 200-1000 mPa·s. It should be known that the viscosity of a high molecular material generally represents the size of the molecular weight, and the larger the viscosity represents the larger the molecular weight and the more difficult to dissolve and form.
[0016] The application point of the present application is that a salt solution solvent prepared from lithium chloride and deionized water is used to dissolve sodium alginate, so that a stable high-concentration sodium alginate solution can be obtained. At the same time, lithium chloride can also act as a metal ion electrolyte to impart the hydrogel with conductivity. The raw materials for preparation are simple and easy to obtain, low in price, green and pollution-free, the preparation process is simple and fast, the obtained conductive hydrogel has high transparency, good mechanical strength, excellent conductivity and excellent frost resistance. Although there are many methods for preparing conductive hydrogels using sodium alginate as raw materials, some of the hydrogels also have certain conductivity and mechanical properties, but there is no method of using lithium chloride alone as a solute and a conductive medium, and most of the existing preparation methods require a variety of polymers and are expensive. The method of the present application solves the problems of complex preparation method, high preparation cost and large raw material pollution of the existing conductive hydrogel preparation method.
[0017] In summary, the green and efficient ionic conductive hydrogel provided by the present application and its preparation and application have the following advantages over the prior art:
[0018] 1) The ionic conductive hydrogel provided by the present application has the advantages of green and pollution-free raw materials, low price, easy recycling, etc.
[0019] 2) The preparation process of the ionic conductive hydrogel provided by the present application is simple, the preparation rate is fast, the preparation process is green and pollution-free, the preparation system is neutral, and it is suitable for large-scale production.
[0020] 3) The ionic conductive hydrogel provided by the present application has excellent mechanical properties, ionic conductivity and frost resistance.
[0021] 4) The ionic conductive hydrogel prepared by the present application is used as a flexible sensor for human motion detection, which can accurately monitor the motion amplitude, frequency, speed, time, etc. of multiple parts of the human body (fingers, wrists, elbows, necks, knees, ankles, etc.), therefore, the green and efficient ionic conductive hydrogel prepared by the present application has good application prospect in the field of flexible wearable electronic devices. BRIEF DESCRIPTION OF DRAWINGS
[0022] Figure 1 The infrared spectra of the sodium alginate raw material and the sodium alginate conductive hydrogel obtained in Example 1;
[0023] Figure 2 NMR spectra of sodium alginate raw material and sodium alginate conductive hydrogel obtained in Example 1;
[0024] Figure 3 Mechanical property display of sodium alginate conductive hydrogel sample performed in Example 6;
[0025] Figure 4 Conductive property display of sodium alginate conductive hydrogel sample performed in Example 7;
[0026] Figure 5 Anti-freezing property display of sodium alginate conductive hydrogel sample performed in Example 8;
[0027] Figure 6 Experimental results of sodium alginate conductive hydrogel sample as wearable flexible sensor for monitoring limb movement (taking finger movement as an example) performed in Example 9;
[0028] Figure 7 Experimental results of sodium alginate conductive hydrogel sample as wearable flexible sensor for monitoring limb movement (taking elbow movement as an example) performed in Example 9. DETAILED DESCRIPTION
[0029] The present application will be further explained and described with reference to specific embodiments. It should be understood that the embodiments given are only illustrative and do not in any way limit the scope of the present application.
[0030] Example 1
[0031] An ionic conductive hydrogel, the preparation raw material includes sodium alginate, lithium chloride and deionized water, the mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is 3:6:100.
[0032] Step 1: Dissolve 1.2 g of lithium chloride in 20.0 g of deionized water to form a hydrated salt solution;
[0033] Step 2: Slowly add 0.6 g of sodium alginate to the hydrated salt solution, stir at 20℃ and 200 rpm for 1.0 h to obtain a sodium alginate solution;
[0034] Step 3: Pour the sodium alginate solution obtained in step 2 into a polytetrafluoroethylene mold, and stand in air for 12.0 h to obtain a sodium alginate ionic conductive hydrogel.
[0035] By structural characterization of sodium alginate raw material and sodium alginate conductive hydrogel, the infrared spectrum is as shown in Figure 1 , and the nuclear magnetic resonance spectrum is as shown in Figure 2 .
[0036] The breaking elongation of the hydrogel prepared under this scheme is 200%, and the conductivity is 1.42 S / m.
[0037] Example 2
[0038] An ionic conductive hydrogel, the preparation raw materials include sodium alginate, lithium chloride and deionized water, the mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is 6:8:100.
[0039] Step 1: Dissolve 1.6 g of lithium chloride in 20.0 g of deionized water to form a hydrated salt solution;
[0040] Step 2: Slowly add 1.2 g of sodium alginate to the hydrated salt solution, stir at 90°C and 1500 rpm for 6.0 h to obtain a sodium alginate solution;
[0041] Step 3: Pour the sodium alginate solution obtained in step 2 into a polytetrafluoroethylene mold, and stand in the air for 3.0 h to obtain a sodium alginate ionic conductive hydrogel.
[0042] Example 3
[0043] An ionic conductive hydrogel, the preparation raw materials include sodium alginate, lithium chloride and deionized water, the mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is 2:6:100.
[0044] Step 1: Dissolve 1.2 g of lithium chloride in 20.0 g of deionized water to form a hydrated salt solution;
[0045] Step 2: Slowly add 0.4 g of sodium alginate to the hydrated salt solution, stir at 40°C and 500 rpm for 2.0 h to obtain a sodium alginate solution;
[0046] Step 3: Pour the sodium alginate solution obtained in step 2 into a polytetrafluoroethylene mold, and stand in the air for 6.0 h to obtain a sodium alginate ionic conductive hydrogel.
[0047] The breaking elongation of the hydrogel prepared under this scheme is 170%, and the conductivity is 1.63 S / m.
[0048] Example 4
[0049] An ionic conductive hydrogel, the preparation raw materials include sodium alginate, lithium chloride and deionized water, the mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is 3:1:100.
[0050] Step 1: Dissolve 0.2 g of lithium chloride in 20.0 g of deionized water to form a hydrated salt solution;
[0051] Step 2: 0.6 g of sodium alginate was slowly added into the hydrated salt solution, and stirred at 60℃ and 800 rpm for 3.0 h to obtain a sodium alginate solution;
[0052] Step 3: The sodium alginate solution obtained in Step 2 was poured into a polytetrafluoroethylene mold, and left to stand in air for 9.0 h to obtain a sodium alginate ionic conductive hydrogel.
[0053] Example 5
[0054] An ionic conductive hydrogel, raw materials for preparation including sodium alginate, lithium chloride and deionized water, the mass ratio of sodium alginate, lithium chloride and deionized water in the ionic hydrogel is 3:8:100.
[0055] Step 1: 1.6 g of lithium chloride was dissolved in 20.0 g of deionized water to form a hydrated salt solution;
[0056] Step 2: 0.6 g of sodium alginate was slowly added into the hydrated salt solution, and stirred at 80℃ and 1000 rpm for 4.0 h to obtain a sodium alginate solution;
[0057] Step 3: The sodium alginate solution obtained in Step 2 was poured into a polytetrafluoroethylene mold, and left to stand in air for 12.0 h to obtain a sodium alginate ionic conductive hydrogel.
[0058] Example 6
[0059] The mechanical properties of the sodium alginate ionic conductive hydrogel obtained in Examples 1-5 of the present application were exhibited.
[0060] The sodium alginate hydrogel sample was subjected to continuous bending action, and the hydrogel deformed when external force was applied. After the mechanical properties were removed, the hydrogel could quickly recover to the initial state without damage or breakage, indicating that the sodium alginate hydrogel exhibited excellent mechanical properties, as shown in Figure 3 .
[0061] Example 7
[0062] The conductive properties of the sodium alginate ionic conductive hydrogel obtained in Examples 1-5 of the present application were exhibited.
[0063] The sodium alginate hydrogel sample was subjected to current measurement, and the hydrogel as a conductor could make the small bulb in the circuit normally light, indicating that the sodium alginate hydrogel exhibited excellent conductive properties, as shown in Figure 4 .
[0064] Example 8
[0065] The anti-freezing properties of the sodium alginate ionic conductive hydrogel obtained in Examples 1-5 of the present application were exhibited.
[0066] The anti-freezing test was carried out on the sodium alginate hydrogel sample. The sample was frozen in a refrigerator at -20°C for 24 hours, then the sample was immediately taken out and connected in the circuit. It can be seen that the frozen hydrogel did not freeze and still had excellent conductivity. The small bulb normally glowed, and the brightness was basically the same as that at 25°C, indicating that the sodium alginate hydrogel showed excellent anti-freezing performance, as shown in Figure 5 The sodium alginate ionic conductive hydrogel obtained in Example 5 has the best anti-freezing property.
[0067] Example 9
[0068] The sodium alginate ionic conductive hydrogel obtained in Example 1 was used as a sensor for monitoring the motion amplitude, frequency, speed and time of multiple parts of the human body (fingers, wrists, elbows, necks, knees, ankles, etc.).
[0069] The sodium alginate ionic conductive hydrogel sample was used as a wearable flexible sensor. Taking finger motion Figure 6 ) and wrist motion Figure 7 ) as examples, the limb motion was monitored. When the action response caused the hydrogel to deform, the resistance of the hydrogel changed accordingly. The resistance value change can be used to detect the motion amplitude, frequency, speed and time of the fingers and wrists in real time, indicating that the sodium alginate hydrogel shows excellent conductivity and action response.
[0070] Comparative Example 1
[0071] An ionic conductive hydrogel, the preparation raw materials include sodium alginate, lithium chloride and deionized water, the mass ratio of sodium alginate, lithium chloride and deionized water in the sodium alginate hydrogel is 3:0.5:100.
[0072] Step 1: Dissolve 0.1 g of lithium chloride in 20.0 g of deionized water to form a hydrated salt solution;
[0073] Step 2: Slowly add 0.6 g of sodium alginate to the hydrated salt solution, and stir at a speed of 300 rpm for 1 h to obtain a transparent solution;
[0074] Step 3: Pour the sodium alginate solution obtained in step 2 into a polytetrafluoroethylene mold, and stand still for 12 h. The sodium alginate hydrogel cannot be obtained.
[0075] Comparative Example 2
[0076] An ionic conductive hydrogel, the preparation raw materials include sodium alginate, lithium chloride and deionized water, the mass ratio of sodium alginate, lithium chloride and deionized water in the sodium alginate hydrogel is 3:0.5:100.
[0077] Step 1: Dissolve 1.8g of lithium chloride in 20.0g of deionized water to form a hydrated salt solution;
[0078] Step 2: Slowly add 0.6g of sodium alginate to the hydrated salt solution and stir at 20℃ and 800rpm for 1 hour. Sodium alginate cannot be completely dissolved in the solution.
[0079] Comparative Example 3
[0080] An ionic conductive hydrogel is prepared from sodium alginate, lithium chloride, and deionized water, wherein the mass ratio of sodium alginate, lithium chloride, and deionized water in the sodium alginate hydrogel is 1:6:100.
[0081] Step 1: Dissolve 1.2g of lithium chloride in 20.0g of deionized water to form a hydrated salt solution;
[0082] Step 2: Slowly add 0.2g of sodium alginate to the hydrated salt solution and stir at 50℃ and 1200rpm for 1.0h to obtain sodium alginate solution;
[0083] Step 3: Pour the sodium alginate solution obtained in Step 2 into a polytetrafluoroethylene mold and let it stand for 12.0 h. The sodium alginate hydrogel will not form.
[0084] Comparative Example 4
[0085] An ionic conductive hydrogel is prepared from sodium alginate, lithium chloride, and deionized water, wherein the mass ratio of sodium alginate, lithium chloride, and deionized water in the sodium alginate hydrogel is 7:6:100.
[0086] Step 1: Dissolve 1.2g of lithium chloride in 20.0g of deionized water to form a hydrated salt solution;
[0087] Step 2: Slowly add 1.4g of sodium alginate to the hydrated salt solution and stir at 90℃ and 200rpm for 1.0h. Sodium alginate cannot be completely dissolved in the solution.
[0088] Experimental measurements showed that Example 1 had the best overall performance, Example 3 had the best ionic conductivity, and Example 5 had the best antifreeze properties.
[0089] In summary, this invention proposes a simple, efficient, and green method for dissolving sodium alginate in hydrated salt solutions, and successfully prepares sodium alginate hydrogels with high transparency, good mechanical strength, and excellent conductivity, which are suitable for promotion in the field of flexible wearable devices and have broad development prospects.
[0090] The above merely describes the preferred embodiments of the present application, and is not intended to limit the scope of the present application. The above-described embodiments of the present application can be variously changed. Any simple, equivalent changes and modifications made according to the content of the claims and the specification of the present application are intended to fall within the scope of the present application. The present application is not described in detail, and is conventional technical content.
Claims
1. A green and efficient ionic conductive hydrogel, characterized in that, The raw materials for preparing the ionic conductive hydrogel only include sodium alginate, lithium chloride and deionized water, wherein the mass ratio of sodium alginate, lithium chloride and deionized water is (3.0-6.0) : (6.0-8.0) : 100 or 2:6:100; The ionic conductive hydrogel is prepared by the following preparation method, comprising the following steps: S1: a certain amount of lithium chloride is dissolved in deionized water to obtain a lithium chloride salt solution; S2: a certain amount of sodium alginate is slowly added to the lithium chloride salt solution, heated to 20-90 ℃, and stirred at a speed of 200-1500 rpm for 1.0-6.0 h to obtain a sodium alginate salt solution; S3: the sodium alginate salt solution is poured into a mold and left to stand for 3.0-12.0 h to obtain a colorless and transparent ionic conductive hydrogel.
2. The green and efficient ionically conductive hydrogel according to claim 1, wherein, The mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is 3:6:
100.
3. The green and efficient ionically conductive hydrogel according to claim 1, wherein, The mass ratio of sodium alginate, lithium chloride and deionized water in the ionic conductive hydrogel is 6:8:
100.
4. The green and efficient ionically conductive hydrogel according to claim 1, wherein, The mold is a polytetrafluoroethylene mold.
5. The green and efficient ionically conductive hydrogel according to claim 1, wherein The viscosity of the sodium alginate is 200-1000 mPa·s.
6. The green and efficient ionic conductive hydrogel according to any one of claims 1-5 is applied in the field of sensors.
7. The green and efficient ionic conductive hydrogel according to any one of claims 1-5 is applied in the field of flexible wearable electronic devices.