Multifunctional organic ionogel, sensor and preparation method thereof

Abstract

The present application relates to a kind of multifunctional organic ionic gel, sensor and preparation method thereof.Preparation process includes mixing ionic liquid and ethylene glycol, adding polyvinyl alcohol, then forming polyvinyl alcohol organic ionic gel by freezing.The organic ionic gel shows excellent mechanical properties, flexibility and energy absorption characteristics, overcomes the restriction of traditional hydrogel in mechanical properties, provides strong and innovative strategy for the development of future wearable technology and intelligent protective equipment.

Description

Technical Field

[0001] This invention belongs to the field of multifunctional polymer materials technology, specifically relating to a multifunctional organic ion gel, a sensor, and a method for preparing the same. The ion gel is a multifunctional organic ion gel with impact resistance, sensing properties, and human motion monitoring capabilities. Background Technology

[0002] In recent years, with the rapid development of soft robotics and flexible wearable electronic devices, sensor research has entered an unprecedented critical stage. However, with continuous societal progress, the demand for sensor performance has been steadily increasing. This is particularly evident in the field of wearable technology.

[0003] Hydrogels, as promising ion-conductive elastic materials, have attracted much attention due to their transparency and stretchability. However, traditional hydrogels face limitations due to their mechanical properties, structural stability, and sensitivity to low temperatures and dry environments. Chinese patent CN114719733A discloses a flexible hydrogel sensor with self-adhesion and self-healing properties; however, this hydrogel sensor is mechanically too fragile and lacks impact resistance, which is detrimental to the complex working conditions that may exist in practical applications.

[0004] Furthermore, most current flexible sensors lack the ability to detect minute strains. Chinese patent CN114044920A discloses a conductive polymer hydrogel sensing material with high elongation and strain sensitivity; however, its ability to detect minute strains is clearly insufficient. Therefore, there is an urgent need for multifunctional flexible sensors that integrate impact resistance and high sensing performance. Unfortunately, the development of multifunctional integrated flexible sensors capable of impact resistance and minute strain detection remains a significant challenge and a key factor limiting their application.

[0005] Based on currently available patents, there is still a lack of research on flexible sensors that possess both excellent sensing performance and mechanical protection. Developing wearable flexible sensor devices with force-electric coupling characteristics is essential and is expected to be further applied to the fields of daily human movement and impact protection. Summary of the Invention

[0006] To address the shortcomings of existing traditional hydrogel sensors, such as poor strength and micro-strain sensing performance, this invention improves upon conventional technologies by providing a multifunctional organic ion gel, a sensor, and its preparation method. The sensor is an organic ion gel sensor with impact resistance and excellent sensing performance.

[0007] Specifically, the present invention is achieved through the following technical solution:

[0008] A multifunctional organic ionic gel, wherein the multifunctional organic ionic gel is a product obtained by polymerizing ionic liquid, ethylene glycol and polyvinyl alcohol at 70 to 160 degrees Celsius, and then freezing and crystallizing at -80 to -20 degrees Celsius.

[0009] Furthermore, the multifunctional organic ionic gel is a product obtained by polymerizing ionic liquid, ethylene glycol, and polyvinyl alcohol at 70–160 degrees Celsius (e.g., 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, or 160 degrees Celsius), followed by freeze-crystallization at -80–-20 degrees Celsius (e.g., -80, -75, -70, -60, -50, -40, -30, or -20 degrees Celsius).

[0010] Furthermore, the solvent of the multifunctional organic ionic gel is a binary solvent formed by mixing an ionic liquid and ethylene glycol at 70–160 degrees Celsius (e.g., 70, 75, 80, 8, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155 or 160 degrees Celsius).

[0011] Furthermore, the conductive medium of the multifunctional organic ionic gel is the positive and negative ion charges in the ionic liquid.

[0012] A method for preparing any of the above-described multifunctional organic ionic gels, the method comprising the following steps:

[0013] a) Stir the ionic liquid and ethylene glycol at 70–160 degrees Celsius until homogeneous to obtain a mixed solution;

[0014] b) Subsequently, polyvinyl alcohol is introduced into the mixed solution obtained in step a) above, and stirred at 70-160 degrees Celsius for 1-6 hours to obtain a mixture;

[0015] c) Pour the mixture obtained in step b) into a mold and freeze it at -80 to -20 degrees Celsius for 1 to 72 hours to obtain a multifunctional organic ionic gel.

[0016] Further, in step a), the volume ratio of ethylene glycol to the ionic liquid is 2 to 50:1. For example, the volume ratio of ethylene glycol to the ionic liquid is 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, 31:1, 32:1, 33:1, 34:1, 36:1, 38:1, 40:1, 42:1, 44:1, 46:1, 48:1, or 50:1.

[0017] Furthermore, the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate.

[0018] Further, in step b), the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 2 to 20:1. For example, the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1.

[0019] A multifunctional organic ion gel sensor is disclosed, wherein the ion gel sensor has shock resistance, sensing and human motion monitoring performance, and the sensor is prepared by means of the following method: attaching wires to both ends of the organic ion gel as described above or the organic ion gel prepared by the method described above to obtain the multifunctional organic ion gel sensor.

[0020] In one embodiment of the invention, the feature is that it has excellent mechanical properties, including a strength of 3.01 MPa and a ductility of 820%.

[0021] In one embodiment of the present invention, the multifunctional organic ionic gel can significantly attenuate the external impact force (72.6%) when impacted by a drop hammer from a height of 50 cm.

[0022] In one embodiment of the present invention, the multifunctional organic ionic gel exhibits five times the energy dissipation capacity compared to commercial polyethylene foam under high-speed ballistic impact at 140 meters per second.

[0023] In one embodiment of the present invention, the multifunctional organic ionic gel is a product obtained by polymerizing ionic liquid, ethylene glycol and polyvinyl alcohol at 70 to 160 degrees Celsius, and then freezing and crystallizing at -20 to -80 degrees Celsius.

[0024] In one embodiment of the present invention, the multifunctional organic ionic gel has a stable, uniform and highly ordered internal conductive network, wherein the conductive medium is the positive and negative ion charges in the ionic liquid.

[0025] In one embodiment of the present invention, the multifunctional organic ionic gel requires the addition of an ionic liquid to ethylene glycol and mixing at 70–160 degrees Celsius for five minutes to form a homogeneous binary solvent.

[0026] In one embodiment of the present invention, a multifunctional sensor specifically refers to a multifunctional organic ion gel with shock resistance, sensing performance, and human motion monitoring performance, and its preparation method includes the following steps:

[0027] (1) Add a certain amount of ionic liquid to ethylene glycol and stir at 70-160 degrees Celsius for 1-60 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0028] (2) Subsequently, a certain amount of polyvinyl alcohol is introduced into the above binary solvent and stirred at 70 to 160 degrees Celsius for 1 to 6 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0029] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -20 to -80 degrees Celsius for 1 to 72 hours to obtain a multifunctional organic ionic gel.

[0030] In one embodiment of the present invention, the multifunctional organic ionic gel has a volume ratio of ethylene glycol to ionic liquid of 2 to 50:1; preferably, the volume ratio of ethylene glycol to ionic liquid is 25:1; more preferably, the volume ratio of ethylene glycol to ionic liquid is 10:1; and even more preferably, the volume ratio of ethylene glycol to ionic liquid is 25:2.

[0031] 8. In one embodiment of the present invention, in the multifunctional organic ionic gel, the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 4 to 20:1; preferably, the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 20:1; more preferably, the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 10:1; even more preferably, the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 20:3; more preferably, the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 5:1; even more preferably, the mass ratio of the binary solvent composed of ethylene glycol and the ionic liquid to the polyvinyl alcohol is 4:1.

[0032] The present invention has the following beneficial effects: the prepared multifunctional organic ionic gel has excellent mechanical properties, including a strength of 3.01 MPa and an elongation of 820%; it can significantly attenuate the external impact force (72.6%) when impacted by a drop hammer from a height of 50 cm; and it has five times the energy dissipation capacity compared to commercial polyethylene foam when subjected to high-speed ballistic impact at 140 m / s; the multifunctional organic ionic gel has a stable, uniform and highly ordered internal conductive network, wherein the conductive medium is the positive and negative ion charges in the ionic liquid. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the stretching of a multifunctional organic ionic gel.

[0034] Figure 2 Tensile stress-strain curves of multifunctional organic ionic gels with different polyvinyl alcohol contents.

[0035] Figure 3 This is a graph showing the sensing performance of a multifunctional organic ion gel.

[0036] Figure 4 The attenuation diagram of the impact force of a multifunctional organic ionic gel dropped hammer.

[0037] Figure 5 The image shows the impact resistance of a multifunctional organic ionic gel after multiple drop hammer tests at a height of 50 cm.

[0038] Figure 6 To detect the bending deformation of different parts of the human body; where a, b, c, and d represent the bending of the fingers, the bending of the wrist, the bending of the elbow, and the fluctuation of the pulse, respectively. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0040] A. The specific method for measuring the tensile properties of organic ionomer gels is as follows:

[0041] Tensile and compression tests were performed at the same rate of 5 mm / min on the MTS (MTS Standard 43). For the tensile test, the shape of the tested ionomer gel was 60 × 10 × 4 mm. During the test, the tensile rate was set to one-thousandth of the effective length of the sample. Figure 2 )

[0042] B. The specific method for measuring the sensing performance of organic ion gels is as follows:

[0043] Electrical signals under external stimuli were recorded using a Dynamic Mechanical Analyzer (DMA, Triton Technology Ltd, UK, model Tritec2000B). Electrical performance was measured using a ModuLab testing system (Solartron Analytical, AMETEKA Advanced Measurement Technology, Inc.) with a supply voltage of 2.5 volts. Figure 3 , Figure 6 )

[0044] C. The specific method for measuring the impact resistance of organic ionic gels is as follows:

[0045] A drop hammer test setup with force and acceleration sensors was used to study the energy dissipation characteristics of the samples. The drop hammer impact test system included an electrically driven drop hammer (Meters Industrial, ZCJ1302-A), a force sensor (Yangzhou Kedong, KD3005C), a digital oscilloscope (Tektronix DPO 2014B), and a charge amplifier (Donghua Testing, YE5853). During testing, the samples were cut into 25×25×4 mm pieces and dropped from a specified height by the drop hammer. The thickness of the PVA organic ionogel was measured using a digital micrometer (Sanliang Company, 0-25 mm). Figure 4 , Figure 5 )

[0046] In this embodiment and its comparative example, polyvinyl alcohol was used as the matrix. This polyvinyl alcohol was produced by Aladdin and had a molecular weight of 205,000.

[0047] Example 1:

[0048] (1) Add 8 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0049] (2) Subsequently, 5 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0050] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm. Then, characterize and test its tensile properties.

[0051] Example 2:

[0052] (1) Add 8 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0053] (2) Subsequently, 10 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution;

[0054] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm. Then, characterize and test its tensile properties.

[0055] Example 3:

[0056] (1) Add 8 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0057] (2) Subsequently, 15 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0058] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm. Then, characterize and test its tensile properties.

[0059] Example 4:

[0060] (1) Add 8 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0061] (2) Subsequently, 20 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution;

[0062] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm. Then, characterize and test its tensile properties.

[0063] Example 5:

[0064] (1) Add 8 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0065] (2) Subsequently, 25 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0066] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm. Then, characterize and test its tensile properties.

[0067] (4) The stress-strain curve of the obtained organic ion gel is as follows: Figure 2 As shown.

[0068] Example 6:

[0069] (1) Add 2 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent;

[0070] (2) Subsequently, 25 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0071] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm.

[0072] Example 7:

[0073] (1) Add 4 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0074] (2) Subsequently, 25 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0075] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm.

[0076] Example 8:

[0077] (1) Add 6 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0078] (2) Subsequently, 25 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0079] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm.

[0080] Example 9:

[0081] (1) Add 10 mL of 1-butyl-3-methylimidazolium tetrafluoroborate to 100 mL of ethylene glycol and stir at 130°C for 5 minutes to mix evenly to form an ionic liquid / ethylene glycol binary solvent.

[0082] (2) Subsequently, 25 g of polyvinyl alcohol was introduced into the above binary solvent and stirred at 130 degrees Celsius for 3 hours to obtain a polyvinyl alcohol / ionic liquid / ethylene glycol mixed solution.

[0083] (3) Pour the mixture obtained in step (2) into a custom polytetrafluoroethylene mold and freeze it at -25 degrees Celsius for 12 hours to obtain a multifunctional organic ion gel with a thickness of 4 mm.

[0084] Example 10:

[0085] (1) The multifunctional organic ion gel prepared in Example 5 is used to attach conductive copper sheets to both ends with silver paste to obtain a multifunctional organic ion gel sensor.

[0086] Figure 1 This is a stretched image of the multifunctional organic ionic gel prepared in Example 5. We demonstrate the high ductility of the organic ionic gel by stretching, torsional stretching, and knotting stretching.

[0087] Figure 2Tensile stress-strain curves for multifunctional organic ionic gels with different polyvinyl alcohol contents are shown. The organic ionic gel with polyvinyl alcohol content in Example 5 exhibits the best mechanical properties, showing a high tensile strength of 3.01 MPa, a fracture strain of 820%, and a modulus of 0.50 MPa similar to human skin.

[0088] Figure 3 The image shows the sensing performance of the multifunctional organic ion gel sensor prepared in Example 5. The polyvinyl alcohol organic ion gel exhibits high repeatability in both (a) a small strain range (0.2% to 1%) and (b) a large strain range (10% to 50%), and is able to detect ultra-low deformation of 0.2% strain.

[0089] Figure 4 The drop hammer impact force attenuation diagram of the multifunctional organic ionic gel prepared in Example 5 shows good energy dissipation characteristics. Under the impact of a drop hammer from a height of 50 cm, the impact force attenuation effect can reach 72.6%.

[0090] Figure 5 The image shows the performance of the multifunctional organic ionic gel prepared in Example 5 under repeated drop impacts from a height of 50 cm. Typical force-time curves were recorded for 20 cycles of drop impacts from a height of 50 cm. Clearly, the maximum impact force remained almost unchanged throughout the 20 consecutive impacts, indicating that the multifunctional organic ionic gel possesses significant protective capabilities under repeated impact loads.

[0091] Figure 6 The multifunctional organic ion gel sensor prepared in Example 5 detects bending deformations of different parts of the human body; where a, b, c, and d represent finger bending, wrist bending, elbow bending, and pulse fluctuations, respectively. The multifunctional organic ion gel can detect relative resistance changes caused by larger human movements such as finger bending (30°, 60°, 90°), wrist bending, and elbow bending. Furthermore, the multifunctional organic ion gel can also accurately detect weak human movements and monitor human pulse signals in real time.

[0092] In summary, the preparation method of the multifunctional organic ionic gel of the present invention not only overcomes the limitations of traditional hydrogels, but also paves the way for advancements in wearable electronic devices, protective equipment, and other fields.

[0093] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a multifunctional organic ionogel, characterized by, The method comprises the following steps: a) stirring and mixing the ionic liquid and ethylene glycol at 70-160 degrees Celsius to obtain a binary solvent, wherein the binary solvent is free of water; the volume ratio of the ethylene glycol to the ionic liquid is 2-48:1; the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate; b) subsequently, introducing polyvinyl alcohol into the binary solvent obtained in step a) and stirring at 70-160 degrees Celsius for 1-6 hours to obtain a mixture; the mass ratio of the binary solvent to the polyvinyl alcohol is 4-20:1; c) pouring the mixture obtained in step b) into a mold and freezing at -80--20 degrees Celsius for 1-72 hours to obtain a multifunctional organic ionic gel.

2. The method of claim 1, wherein: The conductive medium of the multifunctional organic ionic gel is the positive and negative ion charges in the ionic liquid.

3. The method of claim 1, wherein: The volume ratio of the ethylene glycol to the ionic liquid is 25:

1.

4. The method of claim 1, wherein: In step b), the mass ratio of the binary solvent to the polyvinyl alcohol is 10:

1.

5. A multifunctional organic ionic gel sensor, characterized by, The ionic gel sensor has the properties of impact resistance, sensing and human motion monitoring, and the preparation method of the sensor is as follows: installing wires at both ends of the organic ionic gel prepared by the preparation method of any one of claims 1-4 to obtain the multifunctional organic ionic gel sensor.

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