A polyelectrolyte elastomer and its preparation method and application

Abstract

The present invention provides a polyelectrolyte elastomer, its preparation method, and application. The polyelectrolyte elastomer is obtained by reacting 1-methyl-3-butylimidazole-3-sulfopropyl acrylate and / or 2-methoxyethyl acrylate in the presence of a crosslinker and a photoinitiator, followed by ultraviolet light exposure. In this polyelectrolyte elastomer, anions are fixed to the polymer chains, and cations are adsorbed around the anions due to the charge, allowing it to be used in 3D printing. The present invention primarily addresses the problem that current conductive elastomers are unstable and prone to solvent leakage or ion diffusion.

Description

Technical Field

[0001] The present invention relates to the technical field of high molecular polymer materials, and in particular to a polyelectrolyte elastomer and a preparation method and application thereof. Background Art

[0002] In recent years, soft ion devices (flexible touch screens, ion cables, ion skin) have high stretchability, good conductivity and transparency, and have attracted widespread attention in flexible sensors, soft robots and biomedicine.

[0003] As a biocompatible polymer network, hydrogels have long been used for electrophysiological measurements. Hydrogel-based ion conductors have properties that electronic conductors do not have, including stretchability, optical transparency, self-healing ability, and biocompatibility. This combination of properties makes hydrogels an ideal material for flexible electronics and soft machinery. However, due to the limitations of their inherent properties, hydrogels cannot adhere well to other materials. Hydrogel devices cannot work below 0°C, and the rapid evaporation of water in natural environmental conditions will also cause the conductive and mechanical properties of hydrogel-based devices to deteriorate. In addition, electrodes will be corroded if they are in contact with hydrogels for a long time. Therefore, due to the characteristics of the hydrogel device material itself, hydrogels cannot be exposed to the natural environment for long-term applications.

[0004] Ionic liquid-based ion gels have attracted widespread attention due to their non-volatility, excellent thermal stability and ionic conductivity. However, one problem facing ionic liquid gels is that when ionic liquids are subjected to mechanical forces (such as squeezing), they will inevitably leak.

[0005] In 2018, Ding's team reported a strategy for preparing a series of ion-conducting elastomers (ICEs) by dissolving salts in polymers. The material has good tensile properties, transparency, and ionic conductivity. In addition, ICE exhibits very high stability in air, high temperature, or high pressure, has good adhesion, and has no corrosive effect on metal electrodes because it does not contain water and does not absorb moisture from the air (the polymer matrix is hydrophobic). Based on the above advantages, ICE was considered an ideal material for engineered ionic devices at the time. However, the ions in ICE are freely mobile ions, and their free ions may penetrate into the dielectric layer, causing a short circuit and device failure. Therefore, with the development of soft ion conductor devices, there is an urgent need to study a new type of more stable polyelectrolyte elastomer. Summary of the Invention

[0006] In order to solve the above-mentioned problems, the present invention provides a polyelectrolyte elastomer, which is obtained by reacting 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and / or 2-methoxyethyl acrylate under the action of a crosslinker, a photoinitiator and ultraviolet light.

[0007] As a further improvement of the present invention, the crosslinking agent is 1,6-hexanediol diacrylate.

[0008] As a further improvement of the present invention, the photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0009] As a further improvement of the present invention, the molar ratio of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate to 2-methoxyethyl acrylate is 1:0-1:10. Poly(2-methoxyethyl acrylate) is a hydrophobic polymer. Increasing the proportion of 2-methoxyethyl acrylate improves the stability of the copolymer in the environment. However, excessive 2-methoxyethyl acrylate content can reduce the conductivity of the copolymer.

[0010] As a further improvement of the present invention, the molar ratio of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate to 2-methoxyethyl acrylate is 1:1.

[0011] As a further improvement of the present invention, the molar amount of the crosslinker accounts for 0.1-0.5 mol% of the sum of the molar amounts of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate, and the molar amount of the initiator accounts for 0.1-0.5 mol% of the sum of the molar amounts of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate.

[0012] The present invention also provides a method for preparing the polyelectrolyte elastomer, comprising mixing 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate, adding a crosslinking agent and a photoinitiator, and polymerizing the mixture under ultraviolet light to obtain the polyelectrolyte elastomer.

[0013] As a further improvement of the present invention, the preparation method is specifically as follows: 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate are mixed, 1,6-hexanediol diacrylate is added as a cross-linking agent, a photoinitiator is dissolved in the mixed liquid to form a transparent precursor liquid, and then the precursor liquid is injected into a glass mold separated by a polytetrafluoroethylene gasket and irradiated with ultraviolet light to obtain a polyelectrolyte elastomer.

[0014] As a further improvement of the present invention, the wavelength of ultraviolet light is 365 nm.

[0015] As a further improvement of the present invention, 1-methyl-3-butylimidazole 3-sulfopropyl acrylate is obtained by stirring 3-sulfopropyl acrylate potassium salt and 1-butyl-3-methylimidazole chloride in a solvent, filtering, and removing the solvent, wherein the mass ratio of 3-sulfopropyl acrylate potassium salt to 1-butyl-3-methylimidazole chloride is 1.0:1-1.5:1.

[0016] As a further improvement of the present invention, the preparation method of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate is specifically comprising adding 3-sulfopropyl acrylate potassium salt and 1-butyl-3-methylimidazole chloride to a solvent, adding a polymerization inhibitor, stirring at room temperature, filtering the mixture to remove the precipitate, collecting the filtrate, and then removing the solvent from the filtrate to obtain a viscous transparent product.

[0017] As a further improvement of the present invention, the polymerization inhibitor is 4-methoxyphenol.

[0018] The present invention also provides an application of the polyelectrolyte elastomer, wherein the polyelectrolyte elastomer is used for 3D printing. The polyelectrolyte elastomer is used as 3D printing ink to print various high-precision shapes and devices.

[0019] Compared with the prior art, the present invention provides a polyelectrolyte elastomer, its preparation method, and application. The anions of the polyelectrolyte elastomer are fixed on the polymer chain, and the cations are adsorbed around the anions due to the action of the charge. Therefore, the polyelectrolyte elastomer does not contain any solvent, and there is no problem of unstable electrical signals caused by solvent leakage or ion diffusion. It has excellent stability, can maintain signal stability in the environment for a long time, and can be used for 3D printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the H NMR spectrum of the polymer monomer 1-methyl-3-butylimidazole 3-sulfopropyl acrylate disclosed in the embodiments of the present invention;

[0021] Figure 2 Schematic diagram of the mechanical properties of six polyelectrolyte elastomers disclosed in the embodiments of the present invention;

[0022] Figure 3 Schematic diagram of transparency test results of six polyelectrolyte elastomers disclosed in embodiments of the present invention;

[0023] Figure 4 The conductivity test results of six polyelectrolyte elastomers disclosed in the embodiments of the present invention are as follows;

[0024] Figure 5 The capacitance change test results of the polyelectrolyte elastomer device disclosed in the embodiment of the present invention and the conventional device;

[0025] Figure 6 This is the 340-day capacitance continuous change test result of the polyelectrolyte elastomer device disclosed in the embodiment of the present invention. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0027] Example 1. Preparation of polymer monomer 1-methyl-3-butylimidazole 3-sulfopropyl acrylate

[0028]

[0029] 11.615 g of 3-sulfopropyl acrylate potassium salt (K[SPA]) and 8.734 g of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) were added to 35 ml of acetonitrile, and 12 mg of 4-methoxyphenol was added as a polymerization inhibitor. The mixture was stirred at room temperature for 24 hours. After the reaction was completed, the reactants were filtered to remove the precipitated potassium chloride. The filtrate was collected and the solvent was removed using a rotary evaporator to obtain a viscous, transparent product, which was the polymer monomer 1-methyl-3-butylimidazolium 3-sulfopropyl acrylate (BS). Its H NMR spectrum (solvent: D2O, power: 400 MHz) showed the following: Figure 1 shown.

[0030] Example 2: Preparation of polyelectrolyte elastomer

[0031] 0.5 mol% of 1,6-hexanediol diacrylate was added as a crosslinker to 1-methyl-3-butylimidazole 3-sulfopropyl acrylate (BS), and 0.5 mol% of a photoinitiator was dissolved in the mixture to form a transparent precursor solution. This precursor solution was then injected into a glass mold separated by a 0.5 mm thick polytetrafluoroethylene spacer and irradiated with 365 nm UV light for 2 hours to obtain polyelectrolyte elastomer A.

[0032] Example 3: Preparation of polyelectrolyte elastomer

[0033] A transparent precursor solution was formed by mixing 1-methyl-3-butylimidazole 3-sulfopropyl acrylate (BS) and 2-methoxyethyl acrylate (MEA) in a 1:1 molar ratio. 0.5 mol% of 1,6-hexanediol diacrylate was added as a crosslinker, and 0.5 mol% of a photoinitiator was dissolved in the mixture. The precursor solution was then injected into a glass mold separated by a 0.5 mm thick polytetrafluoroethylene spacer and irradiated with 365 nm UV light for 2 hours to obtain polyelectrolyte elastomer B.

[0034] Example 4: Preparation of polyelectrolyte elastomer

[0035] A transparent precursor solution was formed by mixing 1-methyl-3-butylimidazole 3-sulfopropyl acrylate (BS) and 2-methoxyethyl acrylate (MEA) in a 1:2 molar ratio. 0.5 mol% of 1,6-hexanediol diacrylate was added as a crosslinker, and 0.5 mol% of a photoinitiator was dissolved in the mixture. The precursor solution was then injected into a glass mold separated by a 0.5 mm thick polytetrafluoroethylene spacer and irradiated with 365 nm UV light for 2 hours to obtain polyelectrolyte elastomer C.

[0036] Example 5. Preparation of polyelectrolyte elastomer

[0037] A transparent precursor solution was formed by mixing 1-methyl-3-butylimidazole 3-sulfopropyl acrylate (BS) and 2-methoxyethyl acrylate (MEA) in a 1:4 molar ratio. 0.5 mol% of 1,6-hexanediol diacrylate was added as a crosslinker, and 0.5 mol% of a photoinitiator was dissolved in the mixture. The precursor solution was then injected into a glass mold separated by a 0.5 mm thick polytetrafluoroethylene spacer and irradiated with 365 nm UV light for 2 hours to obtain polyelectrolyte elastomer D.

[0038] Example 6. Preparation of polyelectrolyte elastomer

[0039] A transparent precursor solution was formed by mixing 1-methyl-3-butylimidazole 3-sulfopropyl acrylate (BS) and 2-methoxyethyl acrylate (MEA) in a molar ratio of 1:7. 0.5 mol% of 1,6-hexanediol diacrylate was added as a crosslinker, and 0.5 mol% of a photoinitiator was dissolved in the mixture. The precursor solution was then injected into a glass mold separated by a 0.5 mm thick polytetrafluoroethylene spacer and irradiated with 365 nm UV light for 2 hours to obtain polyelectrolyte elastomer E.

[0040] Example 7. Preparation of polyelectrolyte elastomer

[0041] A transparent precursor solution was formed by mixing 1-methyl-3-butylimidazole 3-sulfopropyl acrylate (BS) and 2-methoxyethyl acrylate (MEA) in a molar ratio of 1:10. 0.5 mol% of 1,6-hexanediol diacrylate was added as a crosslinker, and 0.5 mol% of a photoinitiator was dissolved in the mixture. This precursor solution was then injected into a glass mold separated by a 0.5 mm thick polytetrafluoroethylene spacer and irradiated with 365 nm UV light for 2 hours to obtain polyelectrolyte elastomer F.

[0042] Example 8 Mechanical Properties Test of Polyelectrolyte Elastomer

[0043] The polyelectrolyte elastomer AE was cut into dumbbell shapes using a punching machine according to JIS-K6251-7 standard. Its tensile properties were tested using a material testing machine with a loading speed of 50 mm / min. The mechanical properties of the six polyelectrolyte elastomers are shown in Figure 2. Figure 2 As shown, the samples of polyelectrolyte elastomer A (BS:MEA=1:0) were divided into 3 groups and measured 3 times, the samples of polyelectrolyte elastomer B (BS:MEA=1:1) were divided into 5 groups and measured 5 times, the samples of polyelectrolyte elastomer C (BS:MEA=1:2) were divided into 5 groups and measured 5 times, the samples of polyelectrolyte elastomer D (BS:MEA=1:4) were divided into 5 groups and measured 5 times, the samples of polyelectrolyte elastomer E (BS:MEA=1:7) were divided into 5 groups and measured 5 times, and the samples of polyelectrolyte elastomer F (BS:MEA=1:10) were divided into 5 groups and measured 5 times. It can be seen that the polyelectrolyte elastomer is stretchable and has good mechanical properties.

[0044] Example 9: Transparency Test of Polyelectrolyte Elastomer

[0045] The transmittance of the polyelectrolyte elastomers AE was tested on a UV-visible spectrophotometer (METASH UV-8000). The thickness of the six test samples was 0.5 mm. The transparency test results of the six polyelectrolyte elastomers are shown in Figure 2. Figure 3 As shown, the polyelectrolyte elastomer has high transparency, and its transparency in the visible light range is basically around 90%.

[0046] Example 10: Conductivity Test of Polyelectrolyte Elastomer

[0047] The polyelectrolyte elastomer AE was cut into rectangular samples of 40mm*5mm*0.5mm and the resistance of the samples was tested using a digital multimeter KEYSIGHT 34465A. The conductivity of the elastomer was calculated using the formula σ=L / AR, where σ represents the conductivity, L represents the length of the sample, A represents the cross-sectional area of the sample, and R represents the resistance of the measured sample. The conductivity test results of the above six polyelectrolyte elastomers are shown in Figure 2. Figure 4As shown, it can be seen that the polyelectrolyte elastomer has good conductive properties, and the conductivity decreases with decreasing BS content.

[0048] Example 11: Polyelectrolyte Elastomer for 3D Printing

[0049] A polyelectrolyte elastic material is prepared by mixing 1-methyl-3-butylimidazole 3-sulfopropyl acrylate (BS) and 2-methoxyethyl acrylate (MEA) in a 1:1 molar ratio. 0.5 mol% of 1,6-hexanediol diacrylate is added as a crosslinker, and 0.5 wt% of a photoinitiator, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), is added and stirred evenly. This polyelectrolyte elastic printable ink, when combined with digital light processing (DLP) 3D printing, can be used to print various 3D shapes and integrated devices.

[0050] Example 12: Experiment on capacitance change of polyelectrolyte elastomer in device

[0051] The polyelectrolyte elastomer device obtained in Example 11 and a conventional device were selected for comparative capacitance change experiments. The anions and cations in the elastomer used in the conventional device were all free ions. The capacitance changes of the polyelectrolyte elastomer device and the conventional device under external environment for 12 days were monitored. The results are as follows: Figure 5 As shown in the figure, it can be seen that the electrical signal of the conventional device is very unstable due to ion leakage, while the capacitance of the polyelectrolyte elastomer device remains stable. The capacitance of the polyelectrolyte elastomer device was continuously monitored for 340 days, and the results are shown in the figure. Figure 6 As shown, the capacitance change never exceeds 15%.

[0052] in conclusion:

[0053] The present invention provides a polyelectrolyte elastomer, a preparation method, and an application thereof. In the polyelectrolyte elastomer, anions are fixed on polymer chains, and cations are adsorbed around the anions due to the action of electric charge. Therefore, the polyelectrolyte elastomer does not suffer from unstable electrical signals caused by solvent leakage or ion diffusion. It has excellent stability, can maintain signal stability in the environment for a long time, and can be used for 3D printing.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A polyelectrolyte elastomer, characterized in that The polyelectrolyte elastomer is obtained by reacting 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate, or only 1-methyl-3-butylimidazole 3-sulfopropyl acrylate, under the action of a crosslinking agent, a photoinitiator and ultraviolet light.

2. The polyelectrolyte elastomer according to claim 1, characterized in that The crosslinking agent is 1,6-hexanediol diacrylate.

3. The polyelectrolyte elastomer according to claim 1, characterized in that The molar ratio of the 1-methyl-3-butylimidazole 3-sulfopropyl acrylate to 2-methoxyethyl acrylate is 1:0-1:

10.

4. The polyelectrolyte elastomer according to claim 1, characterized in that The molar ratio of the 1-methyl-3-butylimidazole 3-sulfopropyl acrylate to 2-methoxyethyl acrylate is 1:

1.

5. The polyelectrolyte elastomer according to claim 1, characterized in that The molar amount of the crosslinker accounts for 0.1-0.5 mol% of the total molar amount of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate, and the molar amount of the initiator accounts for 0.1-0.5 mol% of the total molar amount of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate.

6. A method for preparing a polyelectrolyte elastomer according to any one of claims 1 to 5, characterized in that: 1-Methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate are mixed, a crosslinking agent and a photoinitiator are added, and the mixture is polymerized under ultraviolet light to obtain a polyelectrolyte elastomer.

7. The preparation method according to claim 6, characterized in that Specifically, 1-methyl-3-butylimidazole 3-sulfopropyl acrylate and 2-methoxyethyl acrylate are mixed, 1,6-hexanediol diacrylate is added as a cross-linking agent, and a photoinitiator is dissolved in the mixed liquid to form a transparent precursor liquid. The precursor liquid is then injected into a glass mold separated by a polytetrafluoroethylene gasket and irradiated with ultraviolet light to obtain a polyelectrolyte elastomer.

8. The preparation method according to claim 6, characterized in that The 1-methyl-3-butylimidazole 3-sulfopropyl acrylate is obtained by stirring 3-sulfopropyl acrylate potassium salt and 1-butyl-3-methylimidazole chloride in a solvent, filtering, and removing the solvent, wherein the mass ratio of 3-sulfopropyl acrylate potassium salt to 1-butyl-3-methylimidazole chloride is 1.0:1-1.5:

1.

9. The preparation method according to claim 8, characterized in that The preparation of 1-methyl-3-butylimidazole 3-sulfopropyl acrylate is specifically as follows: 3-sulfopropyl acrylate potassium salt and 1-butyl-3-methylimidazole chloride are added to a solvent, and then a polymerization inhibitor is added, and the mixture is stirred at room temperature. The mixture is then filtered to remove the precipitate, the filtrate is collected, and then the solvent in the filtrate is removed to obtain a viscous transparent product.

10. Use of the polyelectrolyte elastomer according to any one of claims 1 to 5, characterized in that: The polyelectrolyte elastomer is used for 3D printing.

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