A method for preparing ion gel spheres using Pickering emulsion as template

Abstract

The present invention relates to a method for preparing an ion gel sphere using a Pickering emulsion as a template, comprising the following steps: (1) mixing a hydrophobic vinyl ionic liquid and a hydrophobic alkyl ionic liquid in a certain molar ratio, and ultrasonically dispersing until a uniform solution A is formed; (2) dissolving a particle emulsifier and a photoinitiator in water, and ultrasonically dispersing until a uniform solution B is formed; (3) mixing solution A and solution B in a certain volume ratio, vortex mixing for a period of time, and obtaining a stable Pickering emulsion; (4) irradiating the Pickering emulsion under an ultraviolet lamp for a period of time, centrifuging, and drying to form an ion liquid gel sphere using the Pickering emulsion as a template. The ion liquid gel sphere contains an ion liquid gel and a functionally modified particle emulsifier, and can simultaneously have the properties and performances of both, and can be applied to the fields of extraction and catalysis.

Description

Technical Field

[0001] The invention belongs to the technical field of ion gel synthesis, and in particular relates to a method for preparing ion gel balls using Pickering emulsion as a template. Background Art

[0002] In daily life, emulsions are widely used in many fields, such as food, skin care products, medicine, petroleum industry, etc. Emulsion is a typical liquid / liquid dispersion system that can remain dynamically stable for a period of time. In an emulsion, one fluid is dispersed in another fluid in the form of droplets. At this time, an emulsifier is needed to reduce the interfacial tension and prevent agglomeration between droplets to ensure dynamic stability. Pickering emulsions have the advantages of low cost, low toxicity, strong stability, and the emulsifier in the particle state itself can be modified and functionalized.

[0003] In recent years, the research on Pickering emulsions using room temperature ILs as the internal phase has become more and more extensive. Pickering emulsions use solid particles to replace surfactants or some amphiphilic polymers to stabilize the oil-water interface. Pickering emulsions prepared by particle dispersion can effectively solve the problems of high viscosity of ILs systems, increase the specific surface area of ​​ILs, and improve their utilization rate.

[0004] Ionic liquid gel is made by fixing ILs in a solid spatial network matrix. The interstices of the spatial network structure are filled with anions and cations as dispersion media. It is a new type of hybrid material with confined polymer networks. Ionic liquid gel contains not only free ionic liquid units, but also ionic liquid pairs and ionic liquid clusters. Therefore, it retains the original properties of ionic liquids, while keeping ILs stably confined in the polymer network without leakage. For ionic liquids with double bonds in the structural formula, polyionic liquid microgels can be prepared by bulk polymerization. Summary of the invention

[0005] To achieve the above object, the present invention provides a method for preparing ion gel spheres using Pickering emulsion as a template.

[0006] The technical solution adopted by the present invention is:

[0007] A method for preparing ion gel spheres using Pickering emulsion as a template comprises the following steps:

[0008] 1) mixing a hydrophobic vinyl ionic liquid and a hydrophobic alkyl ionic liquid, and dispersing them by ultrasonication until a uniform liquid solution A is formed;

[0009] 2) dissolving the particulate emulsifier and the photoinitiator in water and dispersing them by ultrasonication until a uniform solution B is formed;

[0010] 3) Mix solution A and solution B, vortex mix, and obtain a stable Pickering emulsion;

[0011] 4) The Pickering emulsion is placed under ultraviolet light for irradiation, and then shaken after the irradiation is stopped to form ionic liquid gel balls, which are centrifuged and freeze-dried to obtain ionic gel balls using the Pickering emulsion as a template, because freeze-drying can well preserve the structure of the ionic gel balls.

[0012] Furthermore, in the above preparation method, in step 1), the anions of the hydrophobic vinyl ionic liquid and the hydrophobic alkyl ionic liquid are bistrifluoromethanesulfonyl iminium anions or hexafluorophosphate anions.

[0013] Furthermore, in the above-mentioned preparation method, in step 1), the molar ratio of the hydrophobic vinyl ionic liquid to the hydrophobic alkyl ionic liquid is 2:3 to 3:2. If the amount of the hydrophobic vinyl ionic liquid is too much, it cannot be completely dissolved in the hydrophobic alkyl ionic liquid; if the amount of the hydrophobic vinyl ionic liquid is too little, the gel network is too little, and the ion gel spheres are unstable or cannot be formed.

[0014] Furthermore, in the above preparation method, in step 2), the particle emulsifier and the photoinitiator are silica nanoparticles and Irgacure-2959, respectively.

[0015] Furthermore, in the above preparation method, in step 2), the concentration of the particulate emulsifier is 2 g / L to 9 g / L.

[0016] Furthermore, in the above preparation method, in step 2), the concentration of the photoinitiator is 5 g / L.

[0017] Furthermore, in the above preparation method, in step 3), the volume ratio of solution A to solution B is 1:4, 1:3 or 1:2.

[0018] Furthermore, in the above preparation method, in step 4), the power of the ultraviolet lamp is greater than or equal to 30W.

[0019] Furthermore, in the above-mentioned preparation method, in step 4), the irradiation method under ultraviolet light adopts intermittent irradiation, the time is irradiation for 30 seconds every 1 minute, and it is repeated 6 times.

[0020] Furthermore, in the above preparation method, in step 4), the shaking is to shake the Pickering emulsion within 1 minute after the UV lamp stops irradiating, because this can help the monodispersity of the ion gel spheres.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention is an ion gel sphere prepared by using a polymerizable vinyl ionic liquid as a gel network, a non-polymerizable ionic liquid as a mobile phase in the gel, and a Pickering emulsion as a template. The ion gel sphere can fix the liquid ionic liquid inside the formed ion liquid gel sphere, and the size of the ion gel sphere can be controlled by adjusting the amount of the Pickering emulsifier.

[0023] 2. In the present invention, a mixed ionic liquid containing a polymerizable ionic liquid is emulsified by a particulate emulsifier to form a Pickering emulsion, which is then polymerized to form ion gel spheres. The performance of the ion gel is adjusted by controlling the ratio of the various substances in the mixed ionic liquid; the surface properties and size of the ion gel spheres are adjusted by controlling the type and amount of the particulate emulsifier. The combination of the Pickering emulsion and the ion gel can effectively solve the problem of high viscosity of the ionic liquid system.

[0024] 3. The ion gel spheres of the present invention using Pickering emulsion as a template contain ionic liquid gel and functionally modified particle emulsifiers, and can have the properties and performances of both, and can be applied to the fields of extraction and catalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The following are the physical picture and microscope picture of the Pickering emulsion formed in Example 1.

[0026] Figure 2 This is a microscope image of the ion gel spheres obtained after centrifugation in Example 1.

[0027] Figure 3 This is a microscope image of the ion gel sphere prepared in Example 1 using the Pickering emulsion as a template.

[0028] Figure 4 This is a SEM image of the surface of the ion gel sphere prepared in Example 1 using the Pickering emulsion as a template.

[0029] Figure 5 The infrared spectra of 1-vinyl-3-ethylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate and ion gel spheres with Pickering emulsion as template.

[0030] Figure 6 Schematic diagram of ion gel spheres templated with Pickering emulsion. DETAILED DESCRIPTION

[0031] In order to better explain the present invention, the present invention is further described below through examples. It should be understood that the purpose of the following implementation is to better explain the content of the present invention, rather than to impose any limitation on the protection scope of the present invention.

[0032] Example 1 Preparation of ion gel spheres using Pickering emulsion as template

[0033] 1) accurately weighing 2.56 g of 1-vinyl-3-ethylimidazolium hexafluorophosphate and 2.84 g of 1-butyl-3-methylimidazolium hexafluorophosphate (molar ratio of 1:1), mixing, and ultrasonically dispersing until a uniform liquid solution A is formed;

[0034] 2) Dissolve 0.4 g SiO2 nanoparticles and 0.5 g Irgacure-2959 in 100 mL water and disperse by ultrasonic until a uniform solution B is formed;

[0035] 3) 0.5 mL of solution A and 2 mL of solution B (volume ratio of 1:4) were mixed and vortexed for 1 min to obtain a stable Pickering emulsion;

[0036] 4) Place the Pickering emulsion in a petri dish covered with aluminum foil, irradiate with an ultraviolet lamp (365 nm, 30 W) at a distance of 5 cm from the sample for 30 s, let stand for 1 min, repeat the above operation six times, shake the Pickering emulsion within 1 min after the ultraviolet lamp stops irradiating, then transfer the sample to a centrifuge tube for centrifugation, take out the upper water layer, and freeze-dry to obtain ion gel spheres using the Pickering emulsion as a template.

[0037] The reaction formula is as follows:

[0038]

[0039] Figure 1 The actual picture and microscope picture of the formed Pickering emulsion show that a stable Pickering emulsion can be formed and the diameter of the emulsion is about 100-200 μm.

[0040] Figure 2 This is a microscope image of the ion gel spheres obtained after centrifugation, indicating that the ion gel spheres have been formed. Due to the gel formed inside, the light transmittance is poor.

[0041] Figure 3 This is a microscope image of ion gel spheres using Pickering emulsion as a template, indicating that the ionic liquid gel spheres have no adhesion and are monodisperse.

[0042] Figure 4 is the SEM image of ion gel spheres templated with Pickering emulsion.

[0043] Figure 5 The infrared spectra of 1-vinyl-3-ethylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate and ion gel spheres with Pickering emulsion as template are shown in Figure 1. Figure 5 It can be seen that 3100cm -1 The CH stretching vibration absorption peak on the imidazole ring is 1465 cm -1 It is the vibration peak of the imidazole aromatic skeleton. In the infrared spectrum of [BMIm][PF6], the stretching vibration absorption peak of saturated CH is at 2877 cm -1 In the infrared spectrum of [VEIm][PF6], the stretching vibration peak of C=C is at 1660 cm -1 In the infrared spectrum of the ion gel sphere, there is a saturated CH stretching vibration absorption peak, but no C=C stretching vibration peak, which proves the successful synthesis of the ion gel sphere.

[0044] Figure 6 Schematic diagram of ion gel spheres templated with Pickering emulsion.

Claims

1. A method for preparing ion gel spheres using Pickering emulsion as a template, characterized in that: The steps include: 1) mixing a hydrophobic vinyl ionic liquid and a hydrophobic alkyl ionic liquid, and ultrasonically dispersing the mixture until a uniform liquid solution A is formed; 2) dissolving the particulate emulsifier and the photoinitiator in water and dispersing them by ultrasonication until a uniform solution B is formed; 3) Mix solution A and solution B, vortex mix, and obtain a stable Pickering emulsion; 4) placing the Pickering emulsion under ultraviolet light for irradiation, shaking after stopping the irradiation to form ionic liquid gel spheres, centrifuging, and freeze-drying to obtain ionic gel spheres with the Pickering emulsion as a template; The anions of the hydrophobic vinyl ionic liquid and the hydrophobic alkyl ionic liquid are bistrifluoromethanesulfonyl iminium anions or hexafluorophosphate anions.

2. The preparation method according to claim 1, characterized in that: In step 1), the molar ratio of the hydrophobic vinyl ionic liquid to the hydrophobic alkyl ionic liquid is 2:3 to 3:

2.

3. The preparation method according to claim 1, characterized in that: In step 2), the particle emulsifier and the photoinitiator are silica nanoparticles and Irgacure-2959, respectively.

4. The preparation method according to claim 1, characterized in that: In step 2), the concentration of the particulate emulsifier is 2 g / L to 9 g / L.

5. The preparation method according to claim 1, characterized in that: In step 2), the concentration of the photoinitiator is 5 g / L.

6. The preparation method according to claim 1, characterized in that: In step 3), the volume ratio of solution A to solution B is 1:4, 1:3 or 1:

2.

7. The preparation method according to claim 1, characterized in that: In step 4), the power of the ultraviolet lamp is greater than or equal to 30W.

8. The preparation method according to claim 1, characterized in that: In step 4), the irradiation method under the ultraviolet lamp adopts interval irradiation, the time is irradiation for 30 seconds every 1 minute, and it is repeated 6 times.

9. The preparation method according to claim 1, characterized in that: In step 4), the shaking is to shake the Pickering emulsion within 1 minute after the UV lamp stops irradiating.

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