Preparation method of multi-stimuli-response polyion liquid material based on supramolecular acting force
By introducing carboxyl groups into imidazolium-based ionic liquids via RAFT polymerization, the method addresses the complexity of existing multi-stimulus polymer synthesis, enabling efficient and sensitive polyionic liquids for environmental monitoring and sensing.
Patent Information
- Application Number
- CN202510451754.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2025-07-15
AI Technical Summary
The prior art is difficult to efficiently prepare multiple stimulus responsive polymers, and the traditional methods are cumbersome and time-consuming, making it difficult to meet the needs of complex applications.
Multiple stimulus-responsive polyion liquid materials are prepared by introducing carboxyl groups into imidazolyl ionic liquid and polymerizing using RAFT, combining supramolecular forces such as hydrogen bonds, electrostatic interactions, and hydrophobic interactions.
It realizes sensitive response to multiple stimuli such as pH, anions, and temperature, and is suitable for environmental monitoring and sensor fields, simplifying the preparation process.
Smart Images
Figure CN120309776A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of intelligent materials, and particularly relates to a preparation method of a multi-stimuli responsive polyionic liquid material based on supramolecular interactions. Background Art
[0002] In the current era of rapid technological development, the research, development and application of intelligent materials are attracting extensive global attention. Integrating bionics, nanotechnology and new material science, they are known as the fourth generation of materials after natural materials, synthetic polymer materials and artificially designed materials, and have become one of the core directions for the development of modern high-tech new materials.
[0003] As a new type of intelligent material, stimulus-responsive polymers can undergo reversible physical or chemical changes under external stimuli (such as temperature, pH, light, redox, CO2, etc.), thereby achieving intelligent responses to the environment and showing broad application prospects. With the continuous in-depth research of stimulus-responsive polymers, single stimulus responsiveness has gradually become difficult to meet the increasingly complex application requirements. Therefore, it has become particularly urgent to develop polymer materials with multiple stimulus responsiveness. Currently, the main method to achieve multi-responsive polymers is through copolymerization of different stimulus-responsive monomers, but this method has disadvantages such as cumbersome processes and long time consumption. Therefore, developing monomers with multiple stimulus responsiveness and developing new polymerization methods to achieve multiple responsiveness in a simple polymer structure have important scientific significance and application value.
[0004] Ionic liquids (ILs) are organic molten salts composed of cations and anions, which can be in a liquid state at room temperature or near room temperature, and have unique physical and chemical properties such as low vapor pressure, high electrical conductivity, wide electrochemical window and excellent thermal stability. These characteristics make them show broad application potential in the fields of chemistry, materials, energy and environment. Polyionic liquids (PILs) are a new type of material formed by polymerizing ionic liquid monomers, combining the excellent physical and chemical properties of ionic liquids and the mechanical properties and processability of polymers. Compared with traditional polymers, polyionic liquids not only inherit the low volatility, high thermal stability and chemical stability of ionic liquids, but also show higher functionalization potential through the designability of their structures. By introducing responsive groups, polyionic liquids can respond to various stimuli such as temperature, pH, light, redox, CO2, etc., showing diverse intelligent behaviors. Summary of the Invention
[0005] The purpose of the present invention is to provide a preparation method and performance study of a multi-stimuli responsive poly(ionic liquid) material based on supramolecular interactions. Carboxyl groups are introduced into imidazolium-based ionic liquids, and the molecular weight is regulated through RAFT polymerization. Multiple supramolecular interactions such as hydrogen bonds, electrostatic interactions, and hydrophobic interactions are introduced into the poly(ionic liquid) to achieve its multi-stimuli responsiveness to pH, anions, and temperature.
[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:
[0007] A preparation method of a multi-stimuli responsive poly(ionic liquid) material based on supramolecular interactions, the steps are as follows: Dissolve a carboxyl-functionalized ionic liquid monomer, a radical initiator, and a RAFT chain transfer agent in an organic solvent to form a precursor solution, carry out a polymerization reaction to prepare a poly(ionic liquid) material, and use the organic solvent for sedimentation and washing, and vacuum drying.
[0008] Preferably, in the above preparation method, the chemical structural formula of the carboxyl-functionalized ionic liquid monomer is any one of those shown in (Ⅰ), (Ⅱ), (Ⅲ), and (Ⅳ):
[0009]
[0010] Among them, X1 - , X2 - , X3 - and X4 - are all Br - , Cl - , NO3 - , SO4 2- any one of them; n represents the carbon chain length of the ionic liquid monomer, and the value range is 1-11; R1, R2, R3, and R4 are all alkyl C m H 2m+1 , and m has a value range of 1-2.
[0011] Preferably, in the above preparation method, the concentration of the carboxyl-functionalized ionic liquid monomer in the precursor solution is 10-40 wt%.
[0012] Preferably, in the above preparation method, the radical initiator is any one of azobisisobutyronitrile, azodicyanovaleric acid, ammonium persulfate, and potassium persulfate.
[0013] Preferably, in the above preparation method, the RAFT chain transfer agent is any one of 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropanoic acid, 4-cyano-4-[[(dodecylthio)thioxomethyl]thio]pentanoic acid, and S,S-dibenzyl trithiocarbonate.
[0014] Preferably, in the above preparation method, the molar ratio of the radical initiator to the carboxyl-functionalized ionic liquid monomer is 1:100 to 1:500.
[0015] Preferably, in the above preparation method, the molar ratio of the RAFT chain transfer agent to the carboxyl-functionalized ionic liquid monomer is 1:25 to 1:200.
[0016] Preferably, in the above preparation method, the polymerization reaction is carried out by placing the reaction device in an oil bath at 50 - 80 °C under a nitrogen or argon atmosphere, and the reaction time is 24 - 48 h.
[0017] Preferably, in the above preparation method, the organic solvent used to dissolve the carboxyl-functionalized ionic liquid monomer, radical initiator, and RAFT chain transfer agent is an organic solvent with a boiling point of 80 - 160 °C.
[0018] Preferably, in the above preparation method, the organic solvent used for sedimentation and washing is an organic solvent with a boiling point of 40 - 80 °C.
[0019] Preferably, in the above preparation method, the vacuum drying temperature is 40 - 80 °C.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0021] 1. The preparation method of the multi-stimuli-responsive polyionic liquid material provided by the present invention can be prepared by RAFT polymerization, effectively regulating the molecular weight of the polyionic liquid, achieving monodispersity, and facilitating the study of the relationship between the molecular weight and the response performance.
[0022] 2. The preparation method of the multi-stimuli-responsive polyionic liquid material provided by the present invention prepares a series of polyionic liquid materials with different hydrophilic and hydrophobic properties by regulating the structure of the RAFT reagent, the cation and anion structures of the ionic liquid monomer, the monomer feeding ratio, and the polymerization reaction conditions.
[0023] 3. The preparation method of the multi-stimuli-responsive polyionic liquid material provided by the present invention introduces multiple supramolecular forces such as hydrogen bonds, electrostatic interactions, and hydrophobic interactions into the polymer network by introducing carboxyl groups into imidazolium-based ionic liquids, realizing its multi-stimuli response to pH, anions, and temperature in aqueous solutions, and showing application value in the fields of environmental monitoring and sensors. Description of the Drawings
[0024] Figure 1 It is a graph showing the relationship between pH and transmittance in the PIL-6 aqueous solution system in Example 4.
[0025] Figure 2 It is a graph showing the relationship between anion concentration and transmittance in the PIL-6 aqueous solution system in Example 5.
[0026] Figure 3 It is the curve graph of the relationship between temperature and transmittance of the PIL-6 aqueous solution system in Example 6 at different concentrations of ClO4 - below. Detailed implementation manners
[0027] To further understand the present invention, the preferred experimental schemes of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention rather than limiting the claims of the present invention.
[0028] Example 1 RAFT polymerization of 1-vinyl-3-carboxypentylimidazolium bromide monomer ([VImHa][Br])
[0029] The structural formula of [VImHa][Br] is as shown in (Ⅴ). At room temperature, [VImHa][Br] monomer (2.8916 g, 10 mmol), azobisisobutyronitrile (AIBN) (0.0131 g, 0.08 mmol), and 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropanoic acid (0.0729 g, 0.2 mmol) were dissolved in 8 mL of DMF, and stirred well to obtain a precursor solution. The precursor solution was added to a 50 mL ampoule, and nitrogen was bubbled through a double-tube to remove the dissolved oxygen inside. The ampoule was placed in an oil bath at 70 °C and heated with stirring for 24 h. After the reaction, the product was precipitated with acetone and washed with acetone several times to remove the unreacted monomer, and dried in vacuo at 45 °C for 24 h to obtain P[VImHa][Br] (PIL-6).
[0030]
[0031] Example 2 RAFT polymerization of 1-vinyl-3-carboxyheptylimidazolium bromide monomer ([VImOa][Br])
[0032] The structural formula of [VImOa][Br] is as shown in (Ⅵ). At room temperature, [VImOa][Br] monomer (3.1722 g, 10 mmol), azobisisobutyronitrile (AIBN) (0.0131 g, 0.08 mmol), and 2-[dodecylthio(thiocarbonyl)thio]-2-methylpropanoic acid (0.0729 g, 0.2 mmol) were dissolved in 15 mL of DMF, and stirred well to obtain a precursor solution. The precursor solution was added to a 50 mL ampoule, and nitrogen was bubbled through a double-tube to remove the dissolved oxygen inside. The ampoule was placed in an oil bath at 70 °C and heated with stirring for 24 h. After the reaction, the product was precipitated with acetone and washed with acetone several times to remove the unreacted monomer, and dried in vacuo at 45 °C for 24 h to obtain P[VImOa][Br] (PIL-8).
[0033]
[0034] Example 3 RAFT Polymerization of 1-Vinyl-3-carboxynonylimidazolium Bromide Monomer ([VImDa][Br])
[0035] [VImDa][Br] has the structural formula as (Ⅶ). At room temperature, dissolve [VImDa][Br] monomer (3.4527 g, 10 mmol), azobisisobutyronitrile (AIBN) (0.0131 g, 0.08 mmol) and 2-(dodecylthio(thiocarbonyl)thio)-2-methylpropanoic acid (0.0729 g, 0.2 mmol) in 20 mL of DMF, stir well to obtain a precursor solution. Add the precursor solution into a 50 mL ampoule, and use nitrogen to bubble through a double-tube to remove the dissolved oxygen inside. Place the ampoule in an oil bath at 70 °C and heat with stirring for 24 h. After the reaction, precipitate the product with acetone and wash it with acetone for several times to remove the unreacted monomer, and dry it in vacuum at 45 °C for 24 h to obtain P[VImDa][Br] (PIL-10).
[0036]
[0037] Example 4 pH Responsiveness Test of PIL-6 Aqueous Solution
[0038] Dissolve the dried PIL-6 in deionized water to prepare a homogeneous aqueous solution with a concentration of 0.5 wt%. Adjust its pH to 2 - 11 with 1 M HCl and 1 M NaOH. Detect its pH with a pH meter and measure its corresponding transmittance at 520 nm with a UV spectrophotometer, and plot the pH-transmittance curve (as Figure 1 ). The PIL-6 aqueous solution exhibits sensitive pH responsiveness. In the pH range of 3.53 - 3.64, the transmittance rapidly decreases from 97% to 0, and the clear solution becomes turbid. While in the pH range of 5.26 - 5.58, the transmittance recovers from 0 to 97%, and the turbid solution becomes clear again.
[0039] Example 5 Anion Responsiveness Test of PIL-6 Aqueous Solution
[0040] Dissolve the dried PIL-6 in deionized water to prepare a homogeneous aqueous solution with a concentration of 0.5 wt%. Add a certain amount of 1 M NaI and 1 M NaClO4 aqueous solutions respectively, record the added anion concentration and measure its corresponding transmittance at 520 nm with a UV spectrophotometer, and plot the anion concentration-transmittance curve (as Figure 2)。The PIL-6 aqueous solution exhibits sensitive anion responsiveness. After adding a very small amount of anions, the transmittance drops from 97% to 0, and the clear solution becomes turbid. The minimum anion concentrations required to make the PIL-6 aqueous solution completely turbid are 8.5 mM and 4.0 mM respectively.
[0041] Example 6 Temperature Responsiveness Test of PIL-6 Aqueous Solution
[0042] Taking the temperature responsiveness of the PIL-6 aqueous solution added with NaClO4 as an example, the dried PIL-6 was dissolved in deionized water to prepare a homogeneous aqueous solution with a concentration of 0.5 wt%. Different amounts of 1 M NaClO4 were added to make it a turbid solution. The temperature was adjusted with a water bath and the corresponding transmittance at 520 nm was measured with a UV spectrophotometer to plot the temperature-transmittance curve (as Figure 3 ), and the temperature (cloud point T cp ) when the transmittance recovered to half of the maximum value was measured. The PIL-6 aqueous solution exhibits sensitive temperature responsiveness and has an anion synergistic effect. The T - of the PIL-6 aqueous solution containing 4 mM and 6 mM ClO4 cp are 35.8 °C and 52.6 °C respectively.
Claims
1. A preparation method of a multiple stimulus-responsive polyionic liquid material based on supramolecular interactions, characterized in that, The steps are as follows: Dissolve the carboxyl-functionalized ionic liquid monomer, free radical initiator, and RAFT chain transfer agent in an organic solvent to form a precursor solution, carry out a polymerization reaction to prepare a polyionic liquid material, use the organic solvent for sedimentation and washing, and vacuum dry.
2. The preparation method according to claim 1, characterized in that, The chemical structural formula of the carboxyl-functionalized ionic liquid monomer is any one of those shown in (Ⅰ), (Ⅱ), (Ⅲ), and (Ⅳ): Among them, X1 - , X2 - , X3 - and X4 - are all one of Br - , Cl - , NO3 - , SO4 2- ; n represents the carbon chain length of the ionic liquid monomer, and the value range is 1 to 11; R1, R2, R3 and R4 are all alkyl C m H 2m+1 , and the value range of m is 1 to 2.
3. The preparation method according to claim 1, wherein, The concentration of the carboxyl-functionalized ionic liquid monomer in the precursor solution is 10 - 40 wt%.
4. The preparation method according to claim 1, characterized in that, The free radical initiator is any one of azobisisobutyronitrile, azodicyanovaleric acid, ammonium persulfate, and potassium persulfate.
5. The preparation method according to claim 1, characterized in that, The RAFT chain transfer agent is any one of 2 - [dodecylthio(thiocarbonyl)thio]-2-methylpropanoic acid, 4-cyano-4-[[(dodecylthio)thioxomethyl]thio]pentanoic acid, and S,S-dibenzyl trithiocarbonate.
6. The preparation method according to claim 1, characterized in that, The molar ratio of the free radical initiator to the carboxyl-functionalized ionic liquid monomer is 1:100 - 1:
500.
7. The preparation method according to claim 1, characterized in that, The molar ratio of the RAFT chain transfer agent to the carboxyl-functionalized ionic liquid monomer is 1:25 - 1:
200.
8. The preparation method according to claim 1, characterized in that, The polymerization reaction is to place the reaction device in an oil bath at 50 - 80 °C and carry out the polymerization reaction under a nitrogen or argon atmosphere, and the reaction time is 24 - 48 h.
9. The preparation method according to claim 1, characterized in that, The organic solvent used to dissolve the carboxyl-functionalized ionic liquid monomer, free radical initiator, and RAFT chain transfer agent is an organic solvent with a boiling point of 80 - 160 °C.
10. The preparation method according to claim 1, wherein, The organic solvent used for sedimentation and washing is an organic solvent with a boiling point of 40 - 80 °C; the vacuum drying temperature is 40 - 80 °C.