Ion conductive elastomer and preparation method thereof
By introducing specific monomers and polymers into flexible ion conductive materials, and using dithiothreitol and 3,6-dioxa-1,8-octanedithiol as chain extenders and crosslinkers, the problem of difficulty in existing materials being able to have high conductivity and stretchability at the same time is solved, and the combination of high conductivity and good mechanical properties is achieved, and it is suitable for wearable devices and other fields.
Patent Information
- Application Number
- CN202211444599.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-18
- Publication Date
- 2025-05-23
- Estimated Expiration
- 2042-11-18
AI Technical Summary
It is difficult for existing flexible ion conductive materials to have high conductivity and stretchability at the same time, and are not stable enough for environmental changes.
By introducing monomer 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene and polyethylene glycol dimethacrylate, dithiothreitol and 3,6-dioxa-1,8-octanedithiol are used as chain extenders and crosslinkers, the coordination reaction of lithium ions with polyethylene glycol dimethacrylate is improved, and conductivity and mechanical properties are improved.
It has achieved significant improvement in conductivity without sacrificing mechanical properties, and has good conductivity, tensileness, transparency and cycle stability. It is suitable for wearable devices and other fields.
Smart Images
Figure CN115716894B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a conductive material, in particular to an ion conductive elastomer and a preparation method thereof. Background Art
[0002] Flexible conductive materials have attracted the attention of researchers because of their potential for wide application in wearable devices, human health monitoring, and soft robots. Flexible conductive materials can generally be divided into flexible electronic conductive materials using electrons as carriers and flexible ion conductive materials using ions as carriers according to their conductive mechanism. Due to the properties of electronic conductive materials, it is difficult for flexible electronic conductive elastomers to have both stretchability and high transparency.
[0003] Water / organic gel is a polymer material with a three-dimensional network structure, which can be used as a carrier for ion conduction to prepare ion conductive elastomers. However, water / organic gel is sensitive to changes in the external environment during use. It will freeze when used at low temperatures, and will lose solvent at higher temperatures, affecting its performance. Ion gel is a polymer material with a three-dimensional network structure using ionic liquid as a dispersion medium. Due to the high temperature stability of ionic liquids, ion gels effectively solve the problem of poor environmental tolerance of water / organic gels. However, during the use of ion gels, ionic liquids may leak, which has a certain impact on the conductivity and mechanical properties of ion gels. Therefore, the shortcomings of these materials limit their application in wearable devices and other fields.
[0004] In order to meet the material performance requirements of wearable devices, more and more researchers have turned their attention to ion conductive elastomers. Ion conductive elastomers are mainly prepared by doping ionic salts into polymer networks through cross-linking. Ion conductive elastomers have attracted extensive attention from researchers in recent years due to their good thermal stability, resilience and other properties. However, it is difficult for current ion conductive elastomers to simultaneously exhibit high conductivity and stretchability. Summary of the invention
[0005] Objective of the invention: The first objective of the present invention is to provide an ion conductive elastomer having both excellent conductivity and stretchability; the second objective of the present invention is to provide a method for preparing the ion conductive elastomer.
[0006] Technical solution: The ion conductive elastomer described in the present invention comprises raw materials including monomers 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene and polyethylene glycol dimethacrylate, chain extenders dithiothreitol and 3,6-dioxa-1,8-octanedithiol, and cross-linking agents tetrakis(3-mercaptopropionic acid)pentaerythritol ester and lithium bis(trifluoromethylsulfonyl imide).
[0007] The structural formula of the 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene (RM257) is: The structural formula of polyethylene glycol dimethacrylate is: The structural formula of dithiothreitol is: The structural formula of 3,6-dioxa-1,8-octanedithiol is: The structural formula of pentaerythritol tetrakis(3-mercaptopropionic acid) ester is: The structural formula of lithium bis(trifluoromethanesulfonyl)imide is: The total number of double bonds in the monomers in the raw material is the same as the total number of thiol groups in the chain extender and the crosslinking agent.
[0008] At the same time, polyethylene glycol dimethacrylate and dithiothreitol are introduced, wherein the coordination of lithium ions with the alkoxy chains in polyethylene glycol dimethacrylate effectively increases the migration rate of lithium ions and thus increases the conductivity, and the hydroxyl groups in dithiothreitol can form hydrogen bonds with the alkoxy chains of polyethylene glycol dimethacrylate, thereby improving the mechanical properties of the conductive elastomer. The introduction of these two substances effectively increases the conductivity of the conductive elastomer without sacrificing the mechanical properties.
[0009] Preferably, the molar ratio of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene to polyethylene glycol dimethacrylate is (3:1) to (3:3).
[0010] As the amount of ester added increases, the elongation at break of the conductive elastomer increases (the stretching multiple is longer), and the modulus decreases (the force required for the same stretching multiple becomes smaller).
[0011] Preferably, the molar ratio of dithiothreitol to 3,6-dioxa-1,8-octanedithiol is (3:1) to (3:9).
[0012] Preferably, the molar ratio of the lithium bis(trifluoromethylsulfonyl)imide to 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene is (1:1) to (1:2).
[0013] The method for preparing the ion conductive elastomer of the present invention comprises the following steps:
[0014] (1) adding 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, polyethylene glycol dimethacrylate, dithiothreitol, 3,6-dioxa-1,8-octanedithiol, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and lithium bis(trifluoromethylsulfonyl imide) into a sample bottle, adding an organic solvent, and performing ultrasonic dispersion to obtain a homogeneous solution;
[0015] (2) Adding a catalyst to the solution obtained in step (1) to carry out a polymerization and cross-linking reaction to obtain an ion conductive elastomer.
[0016] Preferably, in step (2), the catalyst is di-n-propylamine, whose structural formula is
[0017] Preferably, in step (2), the polymerization reaction temperature is 25° C. and the reaction time is not less than 3 hours.
[0018] Preferably, the solvent in step (1) is acetone.
[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) This technical solution simultaneously introduces polyethylene glycol dimethacrylate and dithiothreitol, thereby effectively increasing the conductivity of the conductive elastomer without sacrificing mechanical properties; (2) The conductive elastomer has good conductivity, stretchability, transparency and cycle stability; (3) The preparation method is simple and easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The stress-strain curves of the ion-conductive elastomers prepared in Examples 1 to 3;
[0021] Figure 2 The stress-strain curves of the ion-conductive elastomers prepared in Examples 1, 4 and 5;
[0022] Figure 3 The stress-strain curves of the ion-conductive elastomers prepared in Example 1 and Comparative Examples 1, 3, and 4;
[0023] Figure 4 A bar graph showing the resistance comparison of the ion conductive elastomers prepared in Examples 1 to 5 and Comparative Examples 1, 3, and 4;
[0024] Figure 5 This is the UV projection spectrum of the ion conductive elastomer prepared in Example 1;
[0025] Figure 6 The electrical signal sensitivity diagram of the strain sensor assembled with the ion conductive elastomer prepared in Example 1;
[0026] Figure 7 The electrical signal curves of the strain sensor assembled with the ion conductive elastomer prepared in Example 1 under different strain conditions. DETAILED DESCRIPTION
[0027] The technical solution of the present invention is further described below in conjunction with embodiments.
[0028] Example 1
[0029] The ion conductive elastomer of the present invention is prepared by a method comprising the following steps:
[0030] (1) 200.1 mg (0.34 mmol) of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 18.9 mg of dithiothreitol (0.1125 mmol), 120 mg (0.16 mmol, molecular weight 750) of polyethylene glycol dimethacrylate, 61.5 mg (0.337 mmol) of 3,6-dioxa-1,8-octanedithiol, 12.2 mg (0.025 mmol) of pentaerythritol tetrakis(3-mercaptopropionic acid), and 57.4 mg (0.2 mmol) of lithium bis(trifluoromethylsulfonyl imide) were dissolved in 1 mL of acetone and ultrasonically dispersed for 1 min to obtain a homogeneous solution;
[0031] (2) Add 3uL of catalyst di-n-propylamine to the solution obtained in step (1), pour it into a polytetrafluoroethylene mold, and perform polymerization and cross-linking reaction at 30°C for 3 hours; after the reaction is completed, remove the film from the polytetrafluoroethylene mold to obtain the ion conductive elastomer.
[0032] Example 2
[0033] The ion conductive elastomer of the present invention is prepared by a method comprising the following steps:
[0034] (1) 223.6 mg (0.38 mmol) of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 18.9 mg of dithiothreitol (0.1125 mmol), 90 mg (0.12 mmol, molecular weight 750) of polyethylene glycol dimethacrylate, 61.5 mg (0.3375 mmol) of 3,6-dioxa-1,8-octanedithiol, 12.2 mg (0.025 mmol) of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and 57.4 mg (0.2 mmol) of lithium bis(trifluoromethylsulfonyl imide) were dissolved in 1 mL of acetone and ultrasonically dispersed for 1 min to obtain a homogeneous solution;
[0035] (2) Add 3uL of catalyst di-n-propylamine to the solution obtained in step (1), pour it into a polytetrafluoroethylene mold and perform polymerization and cross-linking reaction at 30°C for 3h; after the reaction is completed, remove the film from the polytetrafluoroethylene mold to obtain the ion conductive elastomer.
[0036] Example 3
[0037] The ion conductive elastomer of the present invention is prepared by a method comprising the following steps:
[0038] (1) 176.6 mg (0.3 mmol) of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 18.9 mg of dithiothreitol (0.1125 mmol), 150 mg (0.2 mmol, molecular weight 750) of polyethylene glycol dimethacrylate, 61.5 mg (0.3375 mmol) of 3,6-dioxa-1,8-octanedithiol, 12.2 mg (0.025 mmol) of pentaerythritol tetrakis(3-mercaptopropionic acid), and 57.4 mg (0.2 mmol) of lithium bis(trifluoromethylsulfonyl imide) were dissolved in 1 mL of acetone and ultrasonically dispersed for 1 min to obtain a homogeneous solution;
[0039] (2) Add 3uL of catalyst di-n-propylamine to the solution obtained in step (1), pour it into a polytetrafluoroethylene mold and perform polymerization and cross-linking reaction at 30°C for 3h; after the reaction is completed, remove the film from the polytetrafluoroethylene mold to obtain the ion conductive elastomer.
[0040] Example 4
[0041] The ion conductive elastomer of the present invention is prepared by a method comprising the following steps:
[0042] (1) 200.1 mg (0.34 mmol) of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 37.8 mg of dithiothreitol (0.225 mmol), 120 mg (0.16 mmol, molecular weight 750) of polyethylene glycol dimethacrylate, 41.0 mg (0.225 mmol) of 3,6-dioxa-1,8-octanedithiol, 12.2 mg (0.025 mmol) of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and 57.4 mg (0.2 mmol) of lithium bis(trifluoromethylsulfonyl imide) were dissolved in 1 mL of acetone and ultrasonically dispersed for 1 min to obtain a homogeneous solution;
[0043] (2) Add 3uL of catalyst di-n-propylamine to the solution obtained in step (1), pour it into a polytetrafluoroethylene mold, and perform polymerization and cross-linking reaction at 30°C for 3 hours; after the reaction is completed, remove the film from the polytetrafluoroethylene mold to obtain the ion conductive elastomer.
[0044] Example 5
[0045] The ion conductive elastomer of the present invention is prepared by a method comprising the following steps:
[0046] (1) 200.1 mg (0.34 mmol) of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 56.7 mg of dithiothreitol (0.3375 mmol), 120 mg (0.16 mmol, molecular weight 750) of polyethylene glycol dimethacrylate, 20.5 mg (0.1125 mmol) of 3,6-dioxa-1,8-octanedithiol, 12.2 mg (0.025 mmol) of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and 57.4 mg (0.2 mmol) of lithium bis(trifluoromethylsulfonyl imide) were dissolved in 1 mL of acetone and ultrasonically dispersed for 1 min to obtain a homogeneous solution;
[0047] (2) Add 3uL of catalyst di-n-propylamine to the solution obtained in step (1), pour it into a polytetrafluoroethylene mold, and perform polymerization and cross-linking reaction at 30°C for 3 hours; after the reaction is completed, remove the film from the polytetrafluoroethylene mold to obtain the ion conductive elastomer.
[0048] Example 6
[0049] The ion conductive elastomer of the present invention is prepared by a method comprising the following steps:
[0050] (1) 200.1 mg (0.34 mmol) of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 18.9 mg of dithiothreitol (0.1125 mmol), 120 mg (0.16 mmol, molecular weight 750) of polyethylene glycol dimethacrylate, 61.5 mg (0.3375 mmol) of 3,6-dioxa-1,8-octanedithiol, 12.2 mg (0.025 mmol) of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and 48.8 mg (0.17 mmol) of lithium bis(trifluoromethylsulfonyl imide) were dissolved in 1 mL of acetone and ultrasonically dispersed for 1 min to obtain a homogeneous solution;
[0051] (2) Add 3uL of catalyst di-n-propylamine to the solution obtained in step (1), pour it into a polytetrafluoroethylene mold and perform polymerization and cross-linking reaction at 30°C for 3h; after the reaction is completed, remove the film from the polytetrafluoroethylene mold to obtain the ion conductive elastomer.
[0052] Example 7
[0053] The ion conductive elastomer of the present invention is prepared by a method comprising the following steps:
[0054] (1) 200.1 mg (0.34 mmol) of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 18.9 mg of dithiothreitol (0.1125 mmol), 120 mg (0.16 mmol, molecular weight 750) of polyethylene glycol dimethacrylate, 61.5 mg (0.3375 mmol) of 3,6-dioxa-1,8-octanedithiol, 12.2 mg (0.025 mmol) of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and 97.6 mg (0.34 mmol) of lithium bis(trifluoromethylsulfonyl imide) were dissolved in 1 mL of acetone and ultrasonically dispersed for 1 min to obtain a homogeneous solution;
[0055] (2) Add 3uL of catalyst di-n-propylamine to the solution obtained in step (1), pour it into a polytetrafluoroethylene mold and perform polymerization and cross-linking reaction at 30°C for 3h; after the reaction is completed, remove the film from the polytetrafluoroethylene mold to obtain the ion conductive elastomer.
[0056] Comparative Example 1
[0057] On the basis of Example 1, polyethylene glycol dimethacrylate was not added, and other conditions remained unchanged.
[0058] Comparative Example 2
[0059] On the basis of Example 1, 0.45 mmol of polyethylene glycol dimethacrylate was added, and the other conditions remained unchanged.
[0060] Comparative Example 3
[0061] On the basis of Example 1, dithiothreitol was not added, and other conditions remained unchanged.
[0062] Comparative Example 4
[0063] On the basis of Example 1, 3,6-dioxa-1,8-octanedithiol was not added, and other conditions remained unchanged.
[0064] Performance Characterization
[0065] The tensile properties and electrical conductivity of the ion conductive elastomers prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were tested. Figures 1 to 4 shown.
[0066] Depend on Figure 1 It can be seen that the elongation at break of the ion conductive elastomer prepared in Examples 1 to 3 increases and the modulus decreases as the content of polyethylene glycol dimethacrylate increases. Figure 4 It can be seen that the conductivity of the ion conductive elastomer does not change much with the increase of the polyethylene glycol dimethacrylate content.
[0067] Depend on Figure 2 It can be seen that in Examples 1, 4 and 5, as the dithiothreitol content increases, the fracture strength is almost unchanged, and the modulus increases; the conductivity of the ion conductive elastomer does not change much.
[0068] Depend on Figure 4 It can be seen that in Comparative Example 1, since polyethylene glycol dimethacrylate is not added, the resistance of the ion conductive elastomer is significantly increased, indicating that the coupling of the alkoxy chain and the lithium ion improves the conductivity of the ion conductive elastomer.
[0069] Comparative Example 2 did not form a film due to the addition of excessive polyethylene glycol dimethacrylate.
[0070] In Comparative Example 3, since only 3,6-dioxa-1,8-octanedithiol was added as the chain extender and dithiothreitol was not added, the elongation at break and the modulus were relatively low.
[0071] In comparative example 4, since only dithiothreitol was added as the chain extender without 3,6-dioxa-1,8-octanedithiol, the elastic modulus was too high and it was not easy to stretch, which limited its application in the fields of strain sensors.
[0072] Figure 5 The transmittance of Example 1 in the visible light wavelength range is about 80% in the wavelength range of 400-800nm.
[0073] The strain sensor is assembled using the ion conductive elastomer prepared in Example 1. The assembly method mainly includes the following two steps:
[0074] (1) Cutting the transparent stretchable ion conductive elastomer into a film of 2 cm*4 cm*0.1 cm;
[0075] (2) Copper wires are bonded to both sides of the film obtained in step (1) to obtain a strain sensor.
[0076] Figure 6 The sensitivity of the strain sensor assembled in Example 1 is shown in that the resistance of the device increases linearly under external stretching conditions, indicating that the ionic salt is uniformly dispersed in the polymer network.
[0077] Figure 7 The electrical signal curves under different strains of the strain sensor assembled in Example 1 are shown. The strain sensor can maintain a cyclically stable electrical signal curve under a strain of 20% to 100%, indicating that the device has a certain stability during use.
Claims
1. An ion-conductive elastomer, It is characterized in that The raw materials include monomers 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene and polyethylene glycol dimethacrylate, chain extenders dithiothreitol and 3,6-dioxa-1,8-octanedithiol, crosslinking agents tetrakis(3-mercaptopropionic acid)pentaerythritol ester and bis(trifluoromethylsulfonyl imide) lithium; the molar ratio of the 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene to the polyethylene glycol dimethacrylate is (3:1) to (3:3); the molar ratio of the dithiothreitol and 3,6-dioxa-1,8-octanedithiol is (3:1) to (3:9); and the molar ratio of the bis(trifluoromethylsulfonyl imide) lithium to the 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene is (1:1) to (1:2).
2. A method for preparing the ion conductive elastomer according to claim 1, It is characterized in that The following steps are involved: (1) Add 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, polyethylene glycol dimethacrylate, dithiothreitol, 3,6-dioxa-1,8-octanedithiol, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, and lithium bis(trifluoromethylsulfonyl imide) into a sample bottle, add an organic solvent, and perform ultrasonic dispersion to obtain a homogeneous solution; (2) Adding a catalyst to the solution obtained in step (1) to carry out a polymerization and cross-linking reaction to obtain an ion conductive elastomer.
3. The method for preparing the ion conductive elastomer according to claim 2, It is characterized in that In step (2), the catalyst is di-n-propylamine.
4. The method for preparing an ion conductive elastomer according to claim 2, It is characterized in that In step (2), the polymerization reaction temperature is 25° C. and the reaction time is not less than 3 hours.
5. The method for preparing the ion conductive elastomer according to claim 2, It is characterized in that The solvent described in step (1) is acetone.