Bionic confinement ionic liquid membrane material and preparation method thereof

Abstract

The invention discloses a bionic confinement ionic liquid membrane material and a preparation method thereof. The membrane material is formed by stacking chemically modified graphene oxide nanosheets, and ionic liquid is confined between nanosheet layers, provides gas recognition sites and serves as a signal transmission carrier. By changing the stacking form of the graphene oxide film, a nano confinement channel is converted into a fluffy tremella-shaped structure from a compact layered structure, a gas transmission channel is optimized, and the mass transfer efficiency is improved. The membrane material provided by the invention has good organic gas recognition capability.

Description

Technical Field

[0001] The present invention belongs to the field of bionic technology. Specifically, it relates to a bionic confined ionic liquid membrane material and a preparation method thereof. The membrane material can efficiently identify and transmit volatile organic compound (VOCs) signals, has high-sensitivity and high-selectivity gas sensing performance at room temperature, and is applicable to fields such as environmental monitoring, health detection, and food quality assessment. Background Art

[0002] Ion channels are the core mechanism for efficient signal transmission in living organisms, featuring low energy consumption, high selectivity, and rapid response. However, traditional gas sensors rely on an electronic conduction mechanism, with poor sensitivity and selectivity at room temperature, making it difficult to meet complex detection requirements.

[0003] Ionic liquids (ILs) are considered ideal media for gas sensing due to their high ionic conductivity, tunable properties, and unique interactions with volatile organic compounds (VOCs). However, liquid ILs are easily restricted by problems such as encapsulation and leakage. Confining ILs in two-dimensional materials such as graphene oxide (GO) can form stable ion channels, significantly enhancing conductivity and selectivity. However, how to construct a bionic ion sensor to achieve high sensitivity, selectivity, and efficient detection at room temperature remains a challenge to be urgently solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a bionic confined ionic liquid membrane material, which has good stability, ionic selectivity, and can achieve high-sensitivity and high-selectivity detection of volatile organic compounds (VOCs).

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A bionic confined ionic liquid membrane material, which is stacked by chemically modified graphene oxide nanosheets, and the ionic liquid is confined between the nanosheets, providing gas recognition sites and acting as a signal transmission carrier. By changing the stacking morphology of the graphene oxide membrane, the nano-confined channels change from a dense layered structure to a fluffy tremella-like structure, optimizing the gas transmission channels and achieving an improvement in mass transfer efficiency.

[0007] In the present invention, the obtained confined ionic liquid membrane material is a thin sheet with a diameter of 3 - 6 cm and a thickness of 10 - 50 μm.

[0008] The present invention also provides a preparation method of a bionic confined ionic liquid membrane material, and the method includes the following steps:

[0009] 1) Adding GO nanosheets to a mixed solvent and ultrasonicating to obtain a dispersion

[0010] 2) Add a silane coupling agent to the dispersion for chemical modification and freeze-dry to obtain NH2-GO

[0011] 3) Ultrasonically mix NH2-GO nanosheets and ILs in an organic solvent to obtain a dispersion

[0012] 4) Obtain the biomimetic confined ionic liquid membrane material by vacuum filtration

[0013] Preferably, the mixed solution in step 1) is a mixed solvent of water and ethanol (1:1).

[0014] Preferably, the silane coupling agent is 3-aminopropyltriethoxysilane.

[0015] Preferably, the freeze-drying time in step 2) is 24 - 48 h.

[0016] Preferably, the organic solvent in step 3) is ethanol.

[0017] Preferably, the filtration time in step 4) is 1 - 10 h.

[0018] The present invention provides a biomimetic ion-confined membrane material based on graphene oxide (GO) and ionic liquids (ILs) for highly sensitive and selective detection of volatile organic compounds (VOCs). Through the structural design and functional optimization of two-dimensional materials and ionic liquids, the present invention overcomes the problems of low sensitivity, poor selectivity of traditional electronic sensors, and difficulty in encapsulating liquid ILs, providing a new path for the development of new ionic sensors.

[0019] The present invention uses amino-modified graphene oxide nanosheets as two-dimensional confinement materials. By regulating the stacking morphology of the nanosheets, the dense layered structure is transformed into a fluffy tremella-like structure, significantly increasing the number and efficiency of ion transport channels. The ionic liquid confined between the GO layers enhances ion conductivity through electrostatic interaction, and at the same time selectively interacts with target gas molecules to achieve efficient signal transmission.

[0020] By reasonably designing the functional modification and stacking morphology of two-dimensional materials, this membrane material not only improves the ion conduction performance, but also optimizes the transmission path of gas molecules, significantly enhancing the recognition ability of VOCs and the detection sensitivity at room temperature, and having good organic gas recognition ability. Description of the Drawings

[0021] Figure 1 It is the electron micrograph of the membrane material prepared in Example 1 of the present invention;

[0022] Figure 2 It is the enlarged electron micrograph of the membrane material prepared in Example 1 of the present invention;

[0023] Figure 3 Elemental analysis diagram of the membrane material prepared in Example 1 of the present invention;

[0024] Figure 4 Organic gas detection result diagram of the membrane material prepared in Example 1 of the present invention. Specific implementation method

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0027] Example 1

[0028] A preparation method of a bionic confined ionic liquid membrane material, the method comprising the following steps:

[0029] (1) Disperse GO powder in a mixed solvent of water and ethanol, and use a cell crusher to ultrasonically obtain a GO nanosheet dispersion of 1-10 mg / mL. Add APTMS accounting for 10 wt%-100 wt% of the mass of GO to the above dispersion, and condense and reflux the mixture in a N2 atmosphere at 50-150 °C for 12-48 h. The reaction product is washed several times with ethanol and water respectively. After being frozen with liquid nitrogen and freeze-dried, NH2-GO nanosheets are obtained, and the freeze-drying time is 24-48 h.

[0030] (2) Ultrasonically disperse the prepared NH2-GO nanosheets in ethanol. Weigh 2-10 g of ILs,

[0031] Add it to the above dispersion and ultrasonically disperse. Vacuum filter the dispersion on a filter membrane substrate for 1-10 h to obtain a NH2-GO / ILs membrane, the membrane thickness is 10-50 μm, and the membrane diameter is 3-8 cm.

[0032] The prepared membrane material is subjected to electron microscopy detection, and the results are as Figure 1 shown. From Figure 1 it can be seen that the surface of the functionalized ion channel membrane presents a uniform fluffy structure. From the enlarged SEM image ( Figure 2 ), it is observed that after introducing ILs, the boundaries of the NH2-GO nanosheets become round, and the wrinkles become wider, similar to the expanded Tremella fuciformis after soaking in water. In addition, energy dispersive X-ray spectroscopy (EDS) surface scanning is performed on the cross-section SEM of NH2-GO / ILs ( Figure 3 ), and the characteristic elements (C, O, S, N, F) contained are uniformly distributed with the characteristic elements (C, O, Si, N) contained in APTMS, proving the successful modification of the amino functional group and the uniform filling of ILs in the membrane.

[0033] As Figure 4, To verify the detection ability of the bionic confined ionic liquid membrane material for VOC gases, the membrane material was exposed to 500 ppm ethanol, and the response time τ res (the time required to reach 90% of the maximum current) and the recovery time τ res (the time required to recover 90% of the maximum current) were 35.59 s and 45.66 s respectively, and the response value was 1132.06%.

Claims

1. A bionic confined ionic liquid membrane material, characterized in that: The membrane material is stacked by chemically modified graphene oxide nanosheets, and the ionic liquid is confined between the nanosheet layers, providing gas recognition sites and acting as a signal transmission carrier. By changing the stacking morphology of the graphene oxide membrane, the nano-confined channel is transformed from a dense layered structure to a fluffy tremella-like structure, optimizing the gas transmission channel and achieving an improvement in mass transfer efficiency. The membrane material of the present invention has good organic gas recognition ability.

2. A method for preparing a biomimetic confined ionic liquid membrane material according to claim 1, the method comprising the following steps: 1) GO powder is added to the mixed solution and ultrasonicated to obtain a dispersion 2) Add silane coupling agent to the dispersion for chemical modification and freeze-drying to obtain NH2-GO nanosheets 3) NH2-GO nanosheets and ILs were ultrasonically dispersed in organic solvents to obtain a dispersion 4) Vacuum filtration to obtain bionic confined ionic liquid membrane material.

3. The method for preparing a biomimetic confined ionic liquid membrane material according to claim 2, characterized in that: The mixed solvent in step 1) is a mixed solvent of water and ethanol (1:1).

4. The method for preparing a biomimetic confined ionic liquid membrane material according to claim 2, characterized in that: The silane coupling agent is 3-aminopropyltriethoxysilane (APTMS).

5. The method for preparing a biomimetic confined ionic liquid membrane material according to claim 2, characterized in that: The freeze-drying time in step 2) is 24-48 hours.

6. The method for preparing a biomimetic confined ionic liquid membrane material according to claim 2, characterized in that: The organic solvent in step 3) is ethanol.

7. The method for preparing a biomimetic confined ionic liquid membrane material according to claim 2, characterized in that: The filtration time in step 4) is 1-10 hours.

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