CN109030478B - Liquid crystal composite gel, preparation method and application thereof, and hydrogen sulfide gas detection method - Google Patents

Liquid crystal composite gel, preparation method and application thereof, and hydrogen sulfide gas detection method Download PDF

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CN109030478B
CN109030478B CN201810825160.8A CN201810825160A CN109030478B CN 109030478 B CN109030478 B CN 109030478B CN 201810825160 A CN201810825160 A CN 201810825160A CN 109030478 B CN109030478 B CN 109030478B
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liquid crystal
hydrogen sulfide
composite gel
crystal composite
gas
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CN109030478A (en
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李皓
甘盛龙
母鑫
尼克·德·罗伊
周国富
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South China Normal University
Shenzhen Guohua Optoelectronics Co Ltd
Academy of Shenzhen Guohua Optoelectronics
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Shenzhen Guohua Optoelectronics Co Ltd
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Abstract

The invention discloses a liquid crystal composite gel, a preparation method and application thereof, and a hydrogen sulfide gas detection method. The gas sensitive material in the gel provided by the invention can contact with target gas molecules to cause the change of the physical and chemical properties of the liquid crystal composite gel, so that the detection of the gas molecules is realized.

Description

Liquid crystal composite gel, preparation method and application thereof, and hydrogen sulfide gas detection method
Technical Field
The invention relates to a high-molecular composite gel, in particular to a liquid crystal composite gel, a preparation method and application thereof, and a hydrogen sulfide gas detection method.
Background
Hydrogen sulfide (H)2S) gas molecules are composed of two hydrogen atoms and one sulfur atom, are colorless, highly toxic and acidic gases, have the odor of eggs, are called as hydrosulfuric acid, have the specific gravity 1.19 times that of air, can be dissolved in water, and the solubility is reduced along with the increase of the water temperature. Are flammable in air, emit a blue flame when burned, and produce sulfur dioxide gas which is harmful to the eyes and lungs. Hydrogen sulfide (H)2S) normally exists in a gaseous state and when mixed with air or oxygen to a certain ratio (4.3% to 46%) forms an explosive mixture which is exploded upon exposure to fire. Hydrogen sulfide (H)2S) mainly comes from chemical reactions in the nature and natural decomposition processes of organisms, and also components or impurities of certain natural substances, such as natural gas, crude oil and the like, are frequently present in multiple production processes and biological decomposition in the nature, such as mining, copper, nickel, cobalt and the like (particularly sulfide ores), low-temperature coking of coal, and extraction and refining of sulfur-containing oil; rubber, rayon, tanning, sulfur dyes, pigments, sugar beet, animal glue and other industrial production, excavation and remediation of marshland, ditches, wells, sewers and tunnels, and operation of removing garbage, dirt, excrement and the like; natural hot springs and volcanic eruptions are also common. Hydrogen sulfide (H)2S) can be rapidly absorbed by the lung through the respiratory tract, thereby affecting the health of the human body. Pathological studies have shown that hydrogen sulfide (H)2S) can directly hinder the uptake and transport of oxygen by the body. Thereby causing the inactivation of the respiratory enzyme in the cells, causing the anoxic asphyxia death of the cells, having strong toxicity of the hydrogen sulfide and the absolute lethal concentration of 1000mg/m for human3. When the concentration of hydrogen sulfide in the air is 10-15 ppm, people have poisoning symptoms, and the maximum allowable concentration of the working site environment in China is 10 ppm. The hydrogen sulfide poisoning is mainly caused by respiratory tract inhalation, but in a long-term low-concentration environment, the skin can slowly absorb hydrogen sulfide to cause poisoning. The mild poisoning generally has no sequelae, and patients with several mild poisoning have intractable sequelae, such as severe neurasthenia, severe and intractable headache, severe insomnia, memory dysfunction, and even intelligence dysfunction. Thus, for hydrogen sulfide (H) in air2S) foulingDetection of contaminants for prevention of hydrogen sulfide (H)2S), the maintenance of safe production and the harmonious development of human and environment.
Second, hydrogen sulfide (H)2S) is a third endogenous gas signaling molecule that has been identified following nitric oxide and carbon monoxide, and plays an important role in many physiological processes, including angiogenesis, vasodilation, neuromodulation, apoptosis, inflammation, and the like. Studies have shown that H is present in respiratory gases2S content has obvious correlation with many respiratory diseases (such as lung cancer). The traditional gas detection and analysis methods, such as gas chromatography-mass spectrometry, spectroscopy (fluorescence, ultraviolet, laser, Raman, and the like), have the advantages of high accuracy, low detection limit, and the like, but have high requirements on chemical analysis instruments, complex detection steps and operation, long time consumption, and difficulty in achieving the effect of rapid diagnosis and treatment in clinical medicine. In clinical medicine, time is often the key point for diagnosing and treating diseases, so how to effectively detect the exhaled gas of a human body is the key point of research.
Modern breath analysis began in the 70's of the 20 th century and American scientist Linus Pauling et al analyzed exhaled gas by gas chromatography to quantitatively determine about 250 gas components, including mainly nitrogen, oxygen, carbon dioxide, water vapor and common gases such as inert gases, as well as a small portion of endogenous volatile organic compounds, ethane, pentane, acetone, isoprene, and the like. With the development of modern medicine, through the research on the biochemical processes of human metabolism and pathogenic mechanisms of diseases, it is strongly stated that certain gas components exhaled by patients are related to diseases of some aspects of the body. In 2016, Morad K.Nakhleh et al studied the exhaled air of 17 patients with lung cancer, colon cancer and other diseases, and found that each disease has a unique "breathing fingerprint", which makes the diagnosis of diseases by analyzing the exhaled air components of people a feasible method for assisting traditional clinical diagnosis and treatment. At present, for hydrogen sulfide (H)2S) the microsensor mainly comprises a semiconductor metal oxide sensor, an electrochemical sensor, an optical sensor, a conductive polymer sensor and a differential quartz antennaFlat and surface ultrasonic wave streak analysis sensors, and the like. These gas sensors based on metal oxide, electrode and semiconductor have the characteristics of small volume, portability, low energy consumption, short detection time and low detection lower limit, but due to the limitation of the properties of the materials, especially inorganic materials, the gas sensors still have many disadvantages, such as low flexibility, high printing difficulty, high processing price, low sensitivity and specificity to gas response, and are easily influenced by the environment.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide the liquid crystal composite gel, the preparation method and the application thereof and the hydrogen sulfide gas detection method.
The technical scheme adopted by the invention is as follows:
the invention provides a liquid crystal composite gel, which comprises a smectic phase liquid crystal polymer network and a hydrogen sulfide sensitive material, wherein the smectic phase liquid crystal polymer network is formed by curing reactant raw materials under ultraviolet light, and the reactant raw materials comprise a smectic phase liquid crystal monomer, a cross-linking agent, a photoinitiator and a polymerization inhibitor.
Preferably, the hydrogen sulfide device further comprises a hydrogen sulfide molecular channel which is used for circulating hydrogen sulfide gas molecules. The size of the internal cavity of the hydrogen sulfide molecular channel is slightly larger than that of a specific solute (hydrogen sulfide gas molecules detected by a target), and selective permeation of the gas molecules can be realized by selecting hydrogen sulfide molecular channels with different internal cavity sizes. The size of the internal cavity of the hydrogen sulfide molecular channel is larger than that of water molecules, so that the water molecules can pass through the internal cavity, and specific solutes (hydrogen sulfide gas molecules for target detection) can be selected by using diffusion of an aqueous solution.
Further, the hydrogen sulfide molecular channel is a nano structure with an intramolecular water channel.
Still further, the hydrogen sulfide molecular channel includes, but is not limited to, at least one of pillar arene, carbon nanotube, calixarene.
Preferably, the hydrogen sulfide molecular channels are dispersed within the smectic liquid crystal polymer network.
Preferably, the hydrogen sulfide sensitive material includes, but is not limited to, at least one of methylene blue, cystamine, cysteamine. The hydrogen sulfide sensitive material is preferably a biomedical agent.
Preferably, the ratio of smectic phase liquid crystal monomer: a crosslinking agent: photoinitiator (2): the mass ratio of the polymerization inhibitor is (80-90): (10-15): (1.5-2): (0.005-0.01).
In some preferred embodiments, the smectic liquid crystal monomer is 4- (6- (acryloyloxy) hexyloxy) benzoic acid, the crosslinker is 1, 4-phenylene-bis (4- (6- (acryloyloxy) hexyloxy) benzoic acid), the photoinitiator is phenyl bis (2,4, 6-trimethylbenzoyl) phosphine oxide, and the polymerization inhibitor is hydroquinone.
The invention also provides a preparation method of the liquid crystal composite gel, which comprises the following steps: s1, taking a liquid crystal box, wherein the liquid crystal box comprises a first transparent substrate and a second transparent substrate which are oppositely arranged, one surface of the first transparent substrate, which is opposite to the second transparent substrate, is subjected to silanization treatment, and one surface of the second transparent substrate, which is opposite to the first transparent substrate, is coated with an orientation layer; s2, dissolving a smectic phase liquid crystal monomer, a cross-linking agent, a photoinitiator, a polymerization inhibitor and an optional hydrogen sulfide molecular channel in an organic solvent, heating and stirring to obtain a liquid crystal mixture, and filling the liquid crystal mixture into the liquid crystal box; s3, irradiating the liquid crystal box by using ultraviolet light, and curing the liquid crystal mixture to form a smectic phase liquid crystal polymer film; and S4, deprotonating the smectic phase liquid crystal polymer film, and adsorbing the hydrogen sulfide sensitive material to obtain the liquid crystal composite gel.
The smectic phase liquid crystal polymer film formed by ultraviolet light curing is a regular layered structure, and the external dimension of the gas molecular channel is slightly larger or smaller when the thickness of the liquid crystal polymer film is the same, which is beneficial for the specific solute (hydrogen sulfide gas molecules for target detection) to directly pass through the closely arranged liquid crystal polymer film to reach the interlayer of the film.
Preferably, the liquid crystal cell in step S1 is prepared by the following steps: taking a first transparent substrate and a second transparent substrate, performing silanization treatment on the first transparent substrate, coating an orientation layer on the surface of the second transparent substrate, arranging the silanization treated surface of the first transparent substrate and the orientation layer coated surface of the second transparent substrate oppositely, and packaging to prepare the liquid crystal box.
Preferably, the thickness of the smectic phase liquid crystal polymer film formed in step S3 is 15 μm to 120 μm.
Preferably, the liquid crystal polymer film is deprotonated using an alkali solution in step S4.
Preferably, the reagent used for the silanization treatment in step S1 is dimethyldichlorosilane.
Preferably, the alignment layer in step S1 is a vertical alignment layer.
The liquid crystal composite gel is applied to the detection of hydrogen sulfide gas.
The invention provides a detection method of hydrogen sulfide gas, which comprises the following steps: introducing hydrogen sulfide gas into the liquid crystal composite gel according to any one of claims 1 to 6; and detecting the change of the physical and/or chemical characteristic parameters of the liquid crystal composite gel.
The invention has the beneficial effects that:
the liquid crystal composite gel provided by the invention is a smectic phase self-assembly lamellar structure of liquid crystal polymer network cross-linking. The structure is characterized in that a specific smectic phase lamellar liquid crystal configuration is gradually formed by combining the interaction among liquid crystal molecules, the method is simpler and more convenient than a layer-by-layer self-assembly method, and the structure has better structural stability and regularity and can move layer to layer. After ultraviolet light curing, the strength of the liquid crystal polymer gel film is further enhanced by the crosslinking of liquid crystal molecules in the layer. The interlayer liquid crystal molecules can also form hydrogen bonds, the interlayer hydrogen bonds are destroyed after deprotonation treatment to form a negative cavity structure, and the positive gas sensitive material can be adsorbed into the liquid crystal composite gel through electrostatic interaction. The layered structure is also the basis for causing the change of the photoelectric properties such as the water absorption expansion rate and the electric conductivity of the liquid crystal composite gel, and simultaneously maintains the structural stability of the liquid crystal composite gel after the change of the internal physicochemical properties.
Compared with the conventional preparation method such as multilayer coating, the preparation method for preparing the liquid crystal composite gel in the liquid crystal box can accurately control the shape, thickness and surface flatness of the film, avoids the defect that the conventional preparation method can cause unstable factors during application, and improves the detection sensitivity of the prepared liquid crystal composite gel.
In addition, the silanization treatment adopted in the invention can make the surface of the transparent substrate more inert, greatly reduce the adhesive force with the liquid crystal polymer film, effectively avoid the damage of the prepared liquid crystal polymer film when the transparent substrate is removed, and simultaneously, the preparation of the liquid crystal composite gel is not influenced.
Drawings
FIG. 1a is a Differential Scanning Calorimetry (DSC) curve prior to formation of a liquid crystalline polymer network;
FIG. 1b is a Differential Scanning Calorimetry (DSC) curve after formation of a liquid crystalline polymer network;
FIG. 2a is a photograph of a polarizing microscope (POM) before formation of a liquid crystal polymer network;
FIG. 2b is a photograph of a polarizing microscope (POM) after the formation of a liquid crystal polymer network;
FIG. 3 is a graph of infrared spectra (FT-IR) before and after formation of a liquid crystalline polymer network;
FIG. 4a shows a liquid crystal composite gel and hydrogen sulfide (H)2S) picture before gas interaction;
FIG. 4b is a photograph of the liquid crystal composite gel after interaction with hydrogen sulfide (H2S) gas;
FIG. 5 is a water absorption curve of a liquid crystal composite gel;
FIG. 6 is a picture of the color change of methylene blue-containing liquid crystal composite gel after hydrogen sulfide adsorption.
Detailed Description
The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.
Example 1
Preparing a smectic phase liquid crystal polymer network by the following steps: (1) preparing two light-transmitting substrates, wherein glass is selected as a substrate material in the embodiment; (2) respectively taking a liquid crystal monomer, a photoinitiator and a polymerization inhibitor according to the mass parts shown in the table 1, dissolving the liquid crystal monomer, the photoinitiator and the polymerization inhibitor in an organic solvent dichloromethane, and heating the mixture for one hour at 60-70 ℃ under the action of magnetic stirring to obtain a liquid crystal mixture; (3) soaking one glass substrate in 6 wt% methanol solution to perform silanization treatment on the surface of the substrate, rotationally coating 5 wt% polyvinyl alcohol aqueous solution on the surface of the other clean glass substrate, performing drying treatment in a vacuum drier, and rubbing a groove to prepare a vertical orientation layer; (4) silanization treatment is carried out on the two transparent substrates, the surfaces provided with the orientation layers are oppositely arranged, ultraviolet curing glue mixed with a liner is used for curing for 40-60 s under the action of ultraviolet light, the two transparent substrates are packaged to prepare a liquid crystal box, the space thickness in a regulating area formed by packaging between the two transparent substrates of the liquid crystal box is controlled to be uniform, the space thickness range in the regulating area is 15-120 mu m, and the thickness in the embodiment is 70 mu m; (5) filling the liquid crystal mixture into a prepared liquid crystal box on a hot bench at 90-95 ℃ by a capillary action principle, heating to 100-105 ℃ after the liquid crystal mixture is completely filled, orienting for 30-60 min, and keeping the temperature for prepolymerization for 30-60 min; (6) and carrying out photo-initiated polymerization on the filled liquid crystal box for 200-400s under ultraviolet light, and then carrying out thermal curing at the temperature of 120-140 ℃ for 10-30min to form a liquid crystal polymer network through curing, wherein the thickness of the liquid crystal polymer film is the space thickness in the adjusting area of the liquid crystal box, so as to obtain the liquid crystal polymer network.
The thermodynamic properties (DSC) and the optical Properties (POM) before and after the formation of the prepared liquid crystal polymer network are respectively characterized, the infrared spectrum (FT-IR) before and after the formation of the liquid crystal polymer network is analyzed, and the experimental results are shown in figures 1-3. The DSC result is shown in fig. 1, where fig. 1a is a DSC curve before polymerization of the liquid crystal mixture, and fig. 1b is a DSC curve of a liquid crystal polymer network formed after polymerization of the liquid crystal mixture, and the result shows that the liquid crystal monomer has a distinct phase transition endothermic peak around 87 ℃, and the peak shifts to 182.8 ℃ after polymerization crosslinking, and the result shows that the formation of a polymer network structure after polymerization crosslinking is beneficial to the stabilization of the material, and also the phase transition requires higher energy. The POM results are shown in fig. 2, wherein fig. 2a is a picture of POM before polymerization of the liquid crystal mixture, and fig. 2b is a picture of POM after polymerization of the liquid crystal mixture to form a liquid crystal polymer network, and the results show that the liquid crystal polymer network is in a smectic state at normal temperature before formation, and phase change starts to occur at 95 ℃ until the liquid crystal polymer network is completely blackened under polarization and is converted into isotropy; after polymerization and film forming, the product has wide temperature range and better stability. The FT-IR results of the liquid crystal polymer network formed before and after photopolymerization are shown in fig. 3, where the infrared characteristic peak of the carbon-carbon double bond on the liquid crystal monomer molecule disappears after polymerization crosslinking, indicating the formation of the polymer network structure.
TABLE 1 compositional starting materials for the liquid crystal mixture of example 1
Figure BDA0001742307500000091
The liquid crystal polymer network structure in the embodiment is a smectic phase layered structure, the smectic phase is a self-assembly layered structure, the structure is regular, the property is stable, but the layers can slide, molecules between the layers can flow freely, and the cross-layer permeation and transportation of target molecules are facilitated by combining molecular channels in the layers, so that the liquid crystal polymer network structure has higher selectivity and better permeability, which is difficult to realize by other layered structures, and is beneficial to forming effective gas detection sites between the layers.
Example 2
The embodiment provides a liquid crystal composite gel, which comprises the following steps: (1-6) preparing a liquid crystal polymer film according to the procedure (1-6) in example 1; (7) after completion of the step (6) described in example 1, the liquid crystal polymer film was taken out of the liquid crystal cell, cut into 1cm × 1cm, and deprotonated with 0.1M to 0.5M NaOH lye; (8) and (3) cleaning the deprotonated liquid crystal polymer film, and soaking the liquid crystal polymer film in a methylene blue solution of 10-20 mu g/mL until the liquid crystal polymer film is saturated and adsorbed to obtain the liquid crystal composite gel.
Reacting a laboratory-prepared hydrogen sulfide (H)2S) introducing gas into the liquid crystal composite gel saturated and adsorbed with methylene blue, observing and detecting the change of the gel before (shown in figure 4a) and after (shown in figure 4b) adsorbing hydrogen sulfide gas, and explaining hydrogen sulfide (H)2S) carrying out oxidation-reduction reaction on the gas and the gas sensitive molecules adsorbed by the static electricity, so that the color of the liquid crystal polymer film is lightened. The water absorption of the deprotonated liquid crystal composite gel obtained by the preparation method is characterized, and the result is shown in fig. 5, and the experimental result shows that the liquid crystal composite gel has high water absorption.
This example provides a process for the preparation of hydrogen sulfide (H)2S) the liquid crystal composite gel for specificity detection comprises a liquid crystal polymer network and a gas sensitive material sensitive to hydrogen sulfide gas, wherein the liquid crystal polymer network is in a smectic phase and is in a regular interlayer structure, interlayer liquid crystal molecules form hydrogen bonds, and the interlayer hydrogen bonds are destroyed after alkali treatment to form an electronegative cavity structure. The gas sensitive material sensitive to the hydrogen sulfide gas is an electropositive molecule, and has electrostatic adsorption with an electronegative cavity structure, so that the gas sensitive material enters a liquid crystal polymer network through electrostatic interaction. The liquid crystal polymer film is subjected to color change through the redox reaction between a gas sensitive material which is loaded in the liquid crystal polymer and is sensitive to hydrogen sulfide gas and hydrogen sulfide molecules, so that the visible detection of the hydrogen sulfide gas is realized.
Example 3
This example provides a liquid crystal composite gel, which is prepared by the same steps as example 2, except that: the composition raw materials of the liquid crystal mixture in the step (2) are shown in Table 2.
TABLE 2 starting materials for the composition of the liquid-crystal mixtures of example 3
Figure BDA0001742307500000111
The liquid crystal polymer network structure in the embodiment is added with column [5] arene which is used as a gas molecular channel material on the basis of the embodiment 1, the structure of the liquid crystal polymer network structure is still a smectic phase lamellar structure, and the liquid crystal polymer network structure also has the characteristics of regular structure and stable property. Similar to the liquid crystal film without gas molecular channels, the liquid crystal film can slide between layers, molecules between layers can flow freely, and the combination of the molecular channels in the layers is very beneficial to cross-layer permeation and transportation of target molecules, so that the liquid crystal film has higher selectivity and better permeability; and secondly, the addition of the gas molecular channel is more beneficial to forming effective gas detection sites between layers of the liquid crystal film, and the gas detection efficiency of the liquid crystal film is improved.
The hydrogen sulfide molecular channel provided by the embodiment is embedded in the liquid crystal composite gel and is used for circulating hydrogen sulfide gas molecules to be detected. On one hand, the molecules in the smectic phase liquid crystal layer are arranged compactly, no gap is left completely, other molecules are allowed to permeate across the layer, and only the molecules can slowly permeate through the interlayer gap, and the introduction of the hydrogen sulfide molecular channel undoubtedly improves the gas flux of the gas molecules in the gel, especially the vertical flux, so that the detection efficiency is improved, and the detection lower limit is reduced. On the other hand, the hydrogen sulfide molecule channel with a specific internal cavity size is selected to realize the specific passage of hydrogen sulfide gas molecules, and the hydrogen sulfide sensitive material in the gel is combined to realize the specific detection of hydrogen sulfide. The gel physicochemical property change caused by the change of the gel physicochemical property, such as the change of the photoelectric properties such as absorbance, water absorption expansion rate, conductivity and the like, can accurately mark the infiltration concentration of the gas molecules to be detected, and further realize the detection of the hydrogen sulfide molecules.
Example 4
The liquid crystal composite gel prepared in example 3 was taken, and hydrogen sulfide (H) prepared in the laboratory was added2S) introducing gas into the liquid crystal composite gel containing the gas molecular channel and saturated and adsorbed with methylene blue, observing and detecting the change process of the hydrogen sulfide gas adsorbed by the gel, as shown in figure 6, the color of the liquid crystal composite gel gradually fades from the edge to the center, and indicating hydrogen sulfide (H)2S) the gas and the gas sensitive molecules adsorbed by the static electricity gradually generate oxidation-reduction reaction, so that the color of the liquid crystal polymer film is lightened, and the realization time of the whole process is less than 10 minutes.
This example provides a method of producing hydrogen sulfide (H)2S) liquid crystal composite gel containing gas molecule channels optimized on the basis of liquid crystal composite gel for specificity detection comprises a liquid crystal polymer network, the gas molecule channels embedded in the polymer network and a gas sensitive material sensitive to hydrogen sulfide gas, wherein the liquid crystal polymer network is similar to the polymer prepared in the embodiment 1, is in a smectic phase and is in a regular interlayer structure, interlayer liquid crystal molecules form hydrogen bonds, and the interlayer hydrogen bonds are destroyed after alkali treatment to form a negative cavity structure. The gas sensitive material sensitive to the hydrogen sulfide gas is an electropositive molecule, and has electrostatic adsorption with an electronegative cavity structure, so that the gas sensitive material enters a liquid crystal polymer network through electrostatic interaction. Particularly, the gas molecular channels are embedded in the liquid crystal polymer network, so that the gas flux of the gas molecules in the gel can be further improved, the detection efficiency is further improved, and the detection lower limit is reduced.

Claims (10)

1. The liquid crystal composite gel is characterized by comprising a smectic phase liquid crystal polymer network and a hydrogen sulfide sensitive material, wherein the smectic phase liquid crystal polymer network is formed by curing reactant raw materials under ultraviolet light, and the reactant raw materials comprise a smectic phase liquid crystal monomer, a cross-linking agent, a photoinitiator and a polymerization inhibitor.
2. The liquid crystal composite gel according to claim 1, further comprising a hydrogen sulfide molecular channel for circulating hydrogen sulfide gas molecules.
3. The liquid crystal composite gel of claim 2, wherein the hydrogen sulfide molecular channel is a nanostructure having an intramolecular water channel.
4. The liquid crystal composite gel of claim 3, wherein the hydrogen sulfide molecular channel comprises at least one of a columnar arene, a carbon nanotube, and a calixarene.
5. The liquid crystal composite gel according to any one of claims 2 to 4, wherein the hydrogen sulfide molecular channels are dispersed inside the smectic liquid crystal polymer network.
6. The liquid crystal composite gel according to any one of claims 1 to 4, wherein the hydrogen sulfide sensitive material comprises at least one of methylene blue, cystamine, and cysteamine.
7. The method for preparing a liquid crystal composite gel according to any one of claims 1 to 6, comprising the steps of:
s1, taking a liquid crystal box, wherein the liquid crystal box comprises a first transparent substrate and a second transparent substrate which are oppositely arranged, one surface of the first transparent substrate, which is opposite to the second transparent substrate, is subjected to silanization treatment, and one surface of the second transparent substrate, which is opposite to the first transparent substrate, is coated with an orientation layer;
s2, dissolving a smectic phase liquid crystal monomer, a cross-linking agent, a photoinitiator, a polymerization inhibitor and an optional hydrogen sulfide molecular channel in an organic solvent, heating and stirring to obtain a liquid crystal mixture, and filling the liquid crystal mixture into the liquid crystal box;
s3, irradiating the liquid crystal box by using ultraviolet light, and curing the liquid crystal mixture to form a smectic phase liquid crystal polymer film;
and S4, deprotonating the smectic phase liquid crystal polymer film, and adsorbing the hydrogen sulfide sensitive material to obtain the liquid crystal composite gel.
8. The method for preparing a liquid crystal composite gel according to claim 7, wherein the thickness of the smectic phase liquid crystal polymer film formed in step S3 is 15 μm to 120 μm.
9. Use of the liquid crystal composite gel according to any one of claims 1 to 6 for detection of hydrogen sulfide gas.
10. A method for detecting hydrogen sulfide gas is characterized by comprising the following steps:
introducing hydrogen sulfide gas into the liquid crystal composite gel according to any one of claims 1 to 6;
and detecting the change of the physical and/or chemical characteristic parameters of the liquid crystal composite gel.
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