An ionic gel, a preparation method and application thereof

Abstract

The application discloses an ionic gel and a preparation method and application thereof. The ionic gel is obtained by reacting 2-(acryloyloxy)-N,N,N-trimethylethan-1-bis((trifluoromethyl)sulfonyl)amide under the action of a crosslinking agent, a photoinitiator and ultraviolet light. The one-step method is used without introducing a new solvent, the light curing time of the polymer is controlled, the solvent content in the material is regulated to be in a partially cured state by controlling the light curing time between the gelation point and the complete curing time, so that the ionic gel realizes high tensile property, low hysteresis and self-adhesion.

Description

Technical Field

[0001] This invention relates to the field of cathode material recycling technology, and more particularly to an ion gel. Background Technology

[0002] Ionic conductors, with their high transparency, high tensile strength, and low Young's modulus, are ideal conductive materials. Among them, ionogels, polymer networks containing ionic liquids, exhibit high conductivity, high transparency, and high tensile strength, and have attracted widespread attention in flexible sensors, soft robotics, and biomedicine.

[0003] As an ideal stretchable ionic conductor, ionogels need to consider both high stretchability and low hysteresis. High stretchability ensures the normal operation of stretchable ion devices under large deformation conditions. Low hysteresis ensures that there is no residual deformation of the ionogel during cyclic operation, thus preventing signal deviation or distortion in the corresponding stretchable ion devices. However, to achieve high stretchability, common methods include increasing the length of the polymer chain, introducing sliding crosslinks and dynamic bonds, such as hydrogen bonds (J. Cao, et al., Angew. Chem. Int. Ed. 2017; SR. Petersen, et al., Angew. Chem. Int. Ed. 2022;) and coordination bonds (LM. Zhang, et al., Small. 2019; SY. Zheng, et al., Macromolecules. 2019). These methods inevitably introduce mechanical dissipation, leading to high hysteresis.

[0004] Meanwhile, the self-adhesion of ionic gels to various solid surfaces is an indispensable property in applications. However, there is a conflict between self-adhesion and low hysteresis; ionic conductors with strong adhesion are often accompanied by high hysteresis. Previous studies have explored constructing microstructures on low-hysteresis elastomer surfaces to achieve strong adhesion (S. Baik, et al., Nature. 2017; S. Baik, et al., Adv. Mater. 2019; X. Liu, et al. Appl. Mater. Interfaces. 2020), but this microfabrication is complex and time-consuming. Alternatively, a two-step method is used to prepare heterogeneous polymer networks to achieve both low hysteresis and high adhesion (P. Zhang et al., Appl. Mater. Interfaces, 2022). However, these methods have all been applied to non-conductive elastomers and have not been implemented in ionic conductors.

[0005] Therefore, the existing technology still needs further improvement and enhancement. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides an ionic gel, its preparation method and application, aiming to solve the problems that existing ionic gels do not have low hysteresis and high adhesion and that the preparation methods are complicated.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] In a first aspect, there is an ion gel, wherein the ion gel is obtained by reacting 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide under the action of a crosslinking agent, a photoinitiator, and ultraviolet light.

[0009] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0010] As a preferred technical solution, the ionogel wherein the crosslinking agent is 1,6-hexanediol diacrylate.

[0011] As a preferred technical solution, in the ionic gel, the molar ratio of the crosslinking agent to the molar amount of 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide is 1 mol%, 0.5 mol%, 0.1 mol%, 0.05 mol%, and 0.01 mol%.

[0012] As a preferred technical solution, in the ion gel, the percentage of the photoinitiator relative to the molar amount of 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide is 0.1 mol%, 0.01 mol%, and 0.001 mol%.

[0013] In a second aspect, a method for preparing the aforementioned ionic gel includes: mixing 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide, a crosslinking agent, and a photoinitiator, and then polymerizing the mixture under ultraviolet light to obtain the ionic gel.

[0014] As a preferred technical solution, the method for preparing the ion gel, wherein the preparation of 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide comprises: uniformly mixing and reacting acryloyloxyethyltrimethylammonium chloride and lithium bis(trifluoromethanesulfonyl)imide, and then separating and drying the product to obtain 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide.

[0015] As a preferred technical solution, the method for preparing the ion gel includes:

[0016] 1,6-hexanediol diacrylate and a photoinitiator were added to the 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide to obtain a precursor solution;

[0017] The precursor solution was injected into a glass mold separated by a polytetrafluoroethylene gasket and irradiated with ultraviolet light to obtain the ionogel.

[0018] As a preferred technical solution, in the method for preparing the ion gel, the ultraviolet light irradiation time is between the gelation point and the complete curing time of the ion gel.

[0019] As a preferred technical solution, in the method for preparing the ion gel, the molar mass ratio of acryloyloxyethyltrimethylammonium chloride and lithium bis(trifluoromethanesulfonyl)imide is 1:1.

[0020] Thirdly, an application of the aforementioned ionogel, wherein the ionogel is used for 3D printing.

[0021] Beneficial effects: Compared with the prior art, the ionogel provided by this invention is in a partially cured state, and the uncured small molecule solution acts as a lubricating layer to reduce the interaction between polymer chains, thereby achieving high tensile strength and low hysteresis. Simultaneously, because the material is in a partially cured state, the surface of the material contains a large number of long suspended chains, thus achieving strong adhesive properties. Attached Figure Description

[0022] Figure 1 This is the hydrogen NMR spectrum of DT in this invention;

[0023] Figure 2 These are the UV curing curves of DT precursor solutions with different crosslinking densities in this invention;

[0024] Figure 3 This is a transparency test of PDT with a crosslinking density of 0.1 mol% in this invention;

[0025] Figure 4 These are the tensile stress-strain curves of PDT with different crosslinking densities in this invention;

[0026] Figure 5 These are the loading and unloading curves of PDT with different crosslinking densities under different maximum elongation rates in this invention;

[0027] Figure 6 This is an Ashby plot of the elongation and hysteresis of the ionic conductor in this invention;

[0028] Figure 7These are the 90° peel test curves of PDT with different crosslinking densities on a metal substrate in this invention;

[0029] Figure 8 This is a 90° peel test curve of PDT with a crosslinking density of 0.05 mol% on different substrates in this invention;

[0030] Figure 9 This is an Ashby plot of the hysteresis and adhesion energy of the ionic conductor in this invention;

[0031] Figure 10 This refers to the conductivity of PDTs with different crosslinking densities in this invention. Detailed Implementation

[0032] This invention provides an ionic gel, its preparation method, and its applications. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0033] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. Simultaneously, the steps or actions in the method description can be rearranged or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed. The component designations used herein, such as "first," "second," etc., are merely for distinguishing the described objects and do not have any sequential or technical meaning. All instruments used are commercially available products.

[0034] Example 1

[0035] Preparation of 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide (DT) from polymer monomers

[0036]

[0037] 1 mol of acryloyloxyethyltrimethylammonium chloride (DAC) with a water content of 20% and 1 mol of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were uniformly mixed and reacted to obtain the water-insoluble polymer monomer DT and the water-soluble LiCl. After the reaction was completed, the upper aqueous layer was removed by liquid-liquid extraction. Anhydrous sodium sulfate was then added to absorb the remaining water. After filtration, a viscous, transparent product (DT) was obtained. ¹H-NMR was as follows. Figure 1 As shown.

[0038] Example 2

[0039] 1,6-hexanediol diacrylate with molar densities of 1 mol%, 0.1 mol%, and 0.001 mol% was added as a crosslinking agent to 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide (DT), and 0.01 mol% of photoinitiator was dissolved in the mixture to form a transparent precursor solution. The UV curing curves for different crosslinking densities were measured using a rheometer, as shown below. Figure 2 As shown, the corresponding gelation points are obtained. (From...) Figure 2 It can be seen that, given a specific PDT precursor, crosslinking agent, and initiator, the gelation point can be determined. Therefore, the curing state of the ionogel can be achieved by controlling the curing time.

[0040] Example 3

[0041] 1,6-hexanediol diacrylate was added as a crosslinking agent to 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide (DT) at molar densities of 1 mol%, 0.5 mol%, 0.1 mol%, 0.05 mol%, and 0.01 mol%, and 0.01 mol% of photoinitiator was dissolved in the mixture to form a transparent precursor solution. The precursor solution was then injected into a glass mold separated by a 0.5 mm thick polytetrafluoroethylene gasket and irradiated with 365 nm UV light for approximately 15 min (between gelation point and complete curing) to obtain five ionogels with different crosslinking densities.

[0042] Transmittance was measured using a UV-Vis spectrophotometer (METASH UV-8000). The crosslinking density of PDT was 0.1 mol%, and the sample thickness was 0.5 mm. The test results are as follows: Figure 3 As shown, PDT with a crosslinking density of 0.1 mol% has high transparency.

[0043] Example 4

[0044] The five PDTs with different crosslinking densities from Example 3 were cut into dumbbell shapes using a punching machine according to JIS-K6251-7 standard. Their uniaxial tensile properties and hysteresis at different elongations were tested using a material testing machine at a loading speed of 30 mm / min. Figure 4 and Figure 5 The hysteresis of the five PDTs at different elongation rates was also compared with that of other reported ionic conductors. Figure 6 As can be seen, the PDT provided by this invention has a good elongation and low hysteresis.

[0045] Example 5

[0046] The adhesion performance of the five different crosslinking densities of PDT described in Example 3 on a metal substrate was tested using a 90° peel test, with comparison to the common VHB as an example. Figure 7 As shown. Taking PDT with a crosslinking density of 0.05 mol% as an example, its adhesion to different substrates was tested through a 90° peel test. Figure 8 As shown. Simultaneously, the adhesion energy and hysteresis Ashby plot were compared with other reported ionic conductors, for example... Figure 9 As shown in the figure. The test results show that the PDT provided by this invention has low hysteresis and good adhesion, that is, the ionogel provided by this invention achieves a good balance between hysteresis and adhesion performance.

[0047] Example 6

[0048] The five PDTs with different crosslinking densities described in Example 3 were cut into rectangular samples of 10mm × 5mm × 0.5mm. The resistance of the samples was tested using a KEYSIGHT 34465A digital multimeter. The conductivity of the elastomer was calculated using the formula, where represents 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 test results are as follows: Figure 10 As shown.

[0049] In summary, this invention provides an ionic gel, its preparation method, and its applications. The ionic gel is obtained by reacting 2-(acryloyloxy)-N,N,N-trimethylethane-1-bis((trifluoromethyl)sulfonyl)amide under the action of a crosslinking agent, a photoinitiator, and ultraviolet light. This invention uses a one-step method without introducing new solvents. By controlling the photocuring time of the polymer, which is controlled between the gelation point and the complete curing time, the solvent content in the material is adjusted to maintain a partially cured state, thereby enabling the ionic gel to achieve high tensile strength, low hysteresis, and self-adhesive properties.

[0050] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An ionogel, characterized in that, The ion gel is obtained by reacting ion monomers under the action of a crosslinking agent, a photoinitiator, and ultraviolet light. The chemical structural formula of the ionic monomer is as follows: ； The molar amount of the crosslinking agent relative to the molar amount of the ionic monomer is 0.01 mol%-1 mol%; The ultraviolet light irradiation time is between the gelation point and the complete curing time of the ionogel, and the ionogel is in a partially cured state.

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

3. The ionogel according to claim 1, characterized in that, The percentage of the molar amount of the photoinitiator relative to the molar amount of the ionic monomer is 0.001 mol%-0.1 mol.

4. A method for preparing the ionogel according to any one of claims 1-3, characterized in that, include: The ionic monomer, crosslinking agent, and photoinitiator are mixed and polymerized under ultraviolet light to obtain the ionic gel.

5. The method for preparing ionogel according to claim 4, characterized in that, The preparation of the ionic monomer includes: uniformly mixing and reacting acryloyloxyethyltrimethylammonium chloride and lithium bis(trifluoromethanesulfonyl)imide, and then separating and drying the product to obtain the ionic monomer.

6. The method for preparing ionogel according to claim 4, characterized in that, include: The crosslinking agent and photoinitiator are added to the ionic monomer to obtain a precursor solution; The precursor solution was injected into a glass mold separated by a polytetrafluoroethylene gasket and irradiated with ultraviolet light to obtain the ionogel.

7. The method for preparing ionogel according to claim 5, characterized in that, The molar ratio of acryloyloxyethyltrimethylammonium chloride to lithium bis(trifluoromethanesulfonylimide) is 1:

1.

8. An application of the ionogel as described in any one of claims 1-3, characterized in that, The ionogel is used for 3D printing.

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