阅读说明：本技术 一种可温控分离的具有表面活性的纳米材料的制备方法 (Preparation method of temperature-controllable separated nano material with surface activity ) 是由 王玥 黄亥珊 莫俏媚 韦丽珊 陈桂芬 陈丽娜 于 2021-01-13 设计创作，主要内容包括：本发明一种可温控分离的具有表面活性的纳米材料的制备方法,将多壁碳纳米管羧基化、酰氯化和羟基化,然后在羟基化的碳纳米管表面固载引发剂2-溴异丁酰溴,最后通过原子转移自由基聚合反应将适当数量的聚乙二醇甲基丙烯酸酯-475接枝于碳纳米管表面,制备得到的表面接枝碳纳米管具有表面活性作用,可以实现疏水性离子液体1-乙基-3-甲基咪唑双三氟甲烷磺酰亚胺和水在室温下的乳化,形成乳液,升高温度至80℃,可以使乳液自发分为两层,具有表面活性的纳米材料位于离子液体相,只需改变温度即可实现疏水性离子液体1-乙基-3-甲基咪唑双三氟甲烷磺酰亚胺、水的分层和乳化,此过程是可逆的,便于分离出表面接枝碳纳米管,使表面接枝碳纳米管可以重复利用。(The invention relates to a preparation method of a nanometer material with surface activity and capable of being separated by temperature control, which comprises the steps of carboxylating, acylating, chlorinating and hydroxylating a multi-wall carbon nanotube, then immobilizing an initiator 2-bromoisobutyryl bromide on the surface of the hydroxylated carbon nanotube, and finally grafting a proper amount of polyethylene glycol methacrylate-475 on the surface of the carbon nanotube through atom transfer radical polymerization reaction to obtain a surface-grafted carbon nanotube with the surface activity effect, wherein the surface-grafted carbon nanotube can realize the emulsification of 1-ethyl-3-methylimidazole bistrifluoromethanesulfonimide as a hydrophobic ionic liquid and water at room temperature to form emulsion, the temperature is increased to 80 ℃, the emulsion can be spontaneously divided into two layers, the nanometer material with the surface activity is positioned in an ionic liquid phase, and the preparation method can realize the self-separation of the 1-ethyl-3-methylimidazole bistrifluoromethanesulfonimide, the imidazole bistrifluor, The process of water layering and emulsification is reversible, so that the surface grafted carbon nano tube can be conveniently separated, and the surface grafted carbon nano tube can be repeatedly utilized.)

1. A preparation method of a nanometer material with surface activity and capable of being separated by temperature control is characterized by comprising the following steps:

(1) carboxylating the multi-wall carbon nano tube to obtain a carboxylated carbon nano tube;

(2) acylating and chlorinating the carbon nano tube with the carboxylated surface to obtain an acyl chlorinated carbon nano tube;

(3) hydroxylating the carbon nano tube with surface acyl chloride to obtain a hydroxylated carbon nano tube;

(4) immobilizing an initiator 2-bromoisobutyryl bromide to the carbon nano tube with the hydroxylated surface to obtain the carbon nano tube immobilized with the initiator;

(5) adding a polyethylene glycol methacrylate-475 monomer into a reaction system, and carrying out graft copolymerization reaction with a carbon nano tube of a surface immobilized initiator to obtain a surface grafted carbon nano tube of which the surface is grafted with poly PEGMMA-475, wherein the surface grafted carbon nano tube is a nano material which can be separated by temperature control and has surface activity; the structural formula of the surface grafting carbon nanotube is as follows:。

2. the method for preparing the temperature-controllable separated nano-material with surface activity according to claim 1, wherein the step (1) of carboxylating the multi-wall carbon nano-tube comprises the following steps: 1) putting the multi-walled carbon nano tube into mixed acid with the volume ratio of sulfuric acid to nitric acid being 3:1, and putting the mixed acid into an ultrasonic water bath with the power of 100-150W for ultrasonic treatment for 1-10 hours; 2) filtering to obtain black solid powder, repeatedly washing the black solid powder with water until the washing liquid is neutral, and performing vacuum drying at 70-80 ℃ to obtain a carboxylated carbon nanotube; the structural formula of the carboxylated carbon nanotube is as follows:。

3. the method for preparing the temperature-controllable separated nano material with surface activity according to claim 2, wherein the mass fraction of sulfuric acid in the mixed acid in the step (1) is 98%, and the mass fraction of nitric acid is 70%; the addition amount of the mixed acid in each gram of multi-walled carbon nano-tube is 40-160 mL.

4. The method for preparing the temperature-controllable separated nano-material with surface activity according to claim 1, wherein the method for acylating and chlorinating the surface-carboxylated carbon nanotube in the step (2) comprises: 1) putting the carbon nano tube with the carboxylated surface into thionyl chloride, and stirring for 2-24 hours at the temperature of 20-65 ℃; 2) for treatingFiltering, taking filter residue, and drying in vacuum to obtain the carbon nanotube of acyl chloride; the structural formula of the acyl chloride carbon nano tube is as follows:。

5. the method for preparing the temperature-controllable separable nano-material with surface activity according to claim 4, wherein the addition amount of the carbon nano-tubes subjected to surface carboxylation in each milliliter of thionyl chloride in the step (2) is 0.05-0.1 g.

6. The method for preparing the temperature-controllable separated nano-material with surface activity according to claim 1, wherein the hydroxylating the surface acyl-chlorinated carbon nanotubes in the step (3) is as follows: 1) adding the acyl chloride carbon nano tube into ethylene glycol, and stirring for 46-50 h at the temperature of 20-120 ℃; 2) filtering, taking filter residue, washing the filter residue with tetrahydrofuran, and drying in vacuum at 70-80 ℃ to obtain a hydroxylated carbon nanotube; the structural formula of the hydroxylated carbon nanotube is as follows:。

7. the method for preparing the temperature-controllable separable surface-active nanomaterial according to claim 1, wherein the method for immobilizing the initiator 2-bromoisobutyryl bromide to the surface-hydroxylated carbon nanotube in the step (4) comprises the following steps: 1) dispersing the hydroxylated carbon nanotube into chloroform, respectively adding 4-dimethylaminopyridine, triethylamine and 2-bromoisobutyryl bromide, reacting for 2.5-3.5 h at 0 ℃ in a nitrogen atmosphere, and reacting for 46-50 h at room temperature; 2) filtering to obtain filter residues, washing the filter residues with chloroform, and drying in vacuum at 38-42 ℃ to obtain the carbon nano tube of the immobilized initiator; the structural formula of the carbon nano tube of the immobilized initiator is as follows:。

8. the method for preparing the temperature-controllable separable nano-material with surface activity according to claim 1, wherein the method for preparing the surface-grafted carbon nanotube in the step (5) comprises: 1) adding carbon nano tubes of immobilized initiators, cuprous bromide and N, N, N' -pentamethyldiethylenetriamine into N, N-dimethylformamide, sealing a reaction system, removing air, refilling nitrogen, adding polyethylene glycol methacrylate-475 monomer into the reaction system, and stirring for 23-25 h at the temperature of 68-72 ℃; 2) filtering, taking filter residue, washing the filter residue with chloroform, tetrahydrofuran and water respectively until the washing liquid is colorless and transparent; 3) and (3) drying for 9-11 hours in vacuum at 78-82 ℃ to obtain the surface grafted carbon nano tube.

9. Use of the temperature-controllable separated nano-material with surface activity as claimed in claim 1 in the preparation of a surfactant.

10. Use of a temperature-controllable separable nanomaterial with surface activity of claim 1 in the preparation of an emulsifier.

Technical Field

The invention relates to the technical field of preparation of nano materials with surface activity, in particular to a preparation method of a nano material with surface activity, which can be separated by temperature control.

Background

Any material added in small amounts to significantly reduce the surface tension of the liquid is collectively referred to as a surfactant. Their surface activity is for a particular liquid, usually water. One end of the surfactant is a nonpolar hydrocarbon chain (alkyl group), has extremely low affinity with water and is often called as a hydrophobic group; the other end being a polar group (e.g. -OH, -COOH, -NH)₂、—SO₃H, etc.), which have a large affinity for water, are called hydrophilic groups and are collectively called "amphiphilic molecules" (lipophilic and hydrophilic molecules). To achieve stability, when the surfactant is dissolved in water, two approaches can be taken: firstly, forming a monomolecular film on the liquid surface. Leaving the hydrophilic groups in the water and the hydrophobic groups towards the air to reduce repulsion. The repulsion between the hydrophobic group and the water molecule is equivalent to the outward thrust of the water molecule on the surface, and the inward pulling force originally applied to the water molecule on the surface is offset, namely the surface tension of the water is reduced. This is the basic principle of the foaming, emulsifying and wetting action of surfactants. In an oil-water system, surfactant molecules are adsorbed at the interface of the oil-water two phases, inserting polar groups into the water, and the non-polar part enters the oil and is oriented at the interface. This creates a pulling force between the oil-water phase, which reduces the oil-water interfacial tension. This property has a significant impact on the wide range of applications of surfactants. Secondly, forming 'micelle'. The micelle can be spherical or lamellar, and the hydrophobic groups are hidden in the micelle as much as possible while the hydrophilic groups are exposed. If polar groups are represented by spheres and hydrophobic nonpolar groups are represented by columns, monomolecular films and micelles are obtained.If the solution contains oil which is not dissolved in water, the oil can enter the center of the spherical micelle and the interlayer of the lamellar micelle to be dissolved. This is called solubilization of the surfactant. The surfactant can play a plurality of roles of washing, emulsifying, foaming, wetting, soaking, dispersing and the like, has small dosage, convenient operation, no toxicity or corrosion, is an ideal chemical product, and has important application in production and scientific research. When the concentration is the same, the non-polar component in the surfactant is large, and the surfactant has strong surface activity. That is, among the homologs, the surface activity is large when the number of carbon atoms is large. However, if the carbon chain is too long, the solubility in water is too low, and thus the carbon chain is of no practical value.

The surfactant is an important chemical product and is widely applied to the fields of petroleum industry, chemical industry, agriculture, textile industry, polymer industry and the like. Meanwhile, the surfactant often flows into the environment along with the wastewater after use, which poses serious threat to human health, cannot be reused and wastes resources. Therefore, the prepared nano material with surface activity and easy separation can not only protect the environment, but also be recycled, thereby saving the resources. The prior surfactant is difficult to separate, or the separation process is complex, the treatment efficiency is low, and the actual requirements are difficult to meet.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method of a recyclable, easily separated, temperature-controllable and separable nano material with surface activity.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a preparation method of a nanometer material with surface activity and capable of being separated by temperature control comprises the following steps:

(1) carboxylating the multi-wall carbon nano tube to obtain a carboxylated carbon nano tube;

(2) acylating and chlorinating the carbon nano tube with the carboxylated surface to obtain an acyl chlorinated carbon nano tube;

(3) hydroxylating the carbon nano tube with surface acyl chloride to obtain a hydroxylated carbon nano tube;

(4) immobilizing an initiator 2-bromoisobutyryl bromide to the carbon nano tube with the hydroxylated surface to obtain the carbon nano tube immobilized with the initiator;

(5) adding a polyethylene glycol methacrylate-475 monomer into a reaction system, and carrying out graft copolymerization reaction with a carbon nano tube of a surface immobilized initiator to obtain a surface grafted carbon nano tube of which the surface is grafted with poly PEGMMA-475, wherein the surface grafted carbon nano tube is a nano material which can be separated by temperature control and has surface activity; the structural formula of the surface grafting carbon nanotube is as follows:。

further, the method for carboxylating the multi-wall carbon nano-tube in the step (1) is as follows: 1) putting the multi-walled carbon nano tube into mixed acid with the volume ratio of sulfuric acid to nitric acid being 3:1, and putting the mixed acid into an ultrasonic water bath with the power of 100-150W for ultrasonic treatment for 1-10 hours; 2) filtering to obtain black solid powder, repeatedly washing the black solid powder with water until the washing liquid is neutral, and performing vacuum drying at 70-80 ℃ to obtain a carboxylated carbon nanotube; the structural formula of the carboxylated carbon nanotube is as follows:。

further, in the step (1), the mass fraction of sulfuric acid in the mixed acid is 98%, and the mass fraction of nitric acid is 70%; the addition amount of the mixed acid in each gram of multi-walled carbon nano-tube is 40-160 mL.

Further, the method for acyl-chlorinating the carbon nano tube with the carboxylated surface in the step (2) comprises the following steps: 1) putting the carbon nano tube with the carboxylated surface into thionyl chloride, and stirring for 2-24 hours at the temperature of 20-65 ℃; 2) filtering, taking filter residue, and drying in vacuum to obtain the carbon nanotube of acyl chloride; the structural formula of the acyl chloride carbon nano tube is as follows:。

furthermore, the addition amount of the carbon nano tube with the surface carboxylated carbon nano tube in each milliliter of thionyl chloride in the step (2) is 0.05-0.1 g.

Further, the method for hydroxylating the carbon nanotube with surface acyl chloride in the step (3) is as follows: 1) adding the acyl chloride carbon nano tube into ethylene glycol, and stirring for 46-50 h at the temperature of 20-120 ℃; 2) filtering, taking filter residue, washing the filter residue with tetrahydrofuran, and drying in vacuum at 70-80 ℃ to obtain a hydroxylated carbon nanotube; the structural formula of the hydroxylated carbon nanotube is as follows:。

further, the method for immobilizing the initiator 2-bromoisobutyryl bromide to the surface-hydroxylated carbon nanotube in the step (4) comprises the following steps: 1) dispersing the hydroxylated carbon nanotube into chloroform, respectively adding 4-dimethylaminopyridine, triethylamine and 2-bromoisobutyryl bromide, reacting for 2.5-3.5 h at 0 ℃ in a nitrogen atmosphere, and reacting for 46-50 h at room temperature; 2) filtering to obtain filter residues, washing the filter residues with chloroform, and drying in vacuum at 38-42 ℃ to obtain the carbon nano tube of the immobilized initiator; the structural formula of the carbon nano tube of the immobilized initiator is as follows:。

further, the preparation method of the surface-grafted carbon nanotube in the step (5) comprises the following steps: 1) adding carbon nano tubes of immobilized initiators, cuprous bromide and N, N, N' -pentamethyldiethylenetriamine into N, N-dimethylformamide, sealing a reaction system, removing air, refilling nitrogen, adding polyethylene glycol methacrylate-475 monomer into the reaction system, and stirring for 23-25 h at the temperature of 68-72 ℃; 2) filtering, taking filter residue, washing the filter residue with chloroform, tetrahydrofuran and water respectively until the washing liquid is colorless and transparent; 3) and (3) drying for 9-11 hours in vacuum at 78-82 ℃ to obtain the surface grafted carbon nano tube.

The invention also provides application of the temperature-controllable separated nano material with surface activity in preparing a surfactant.

The invention also provides application of the temperature-controllable separated nano material with surface activity in preparing an emulsifier.

The invention has the beneficial effects that: the invention relates to a preparation method of a nanometer material with surface activity and capable of being separated by temperature control, which comprises the steps of carboxylating, acylating, chlorinating and hydroxylating a multi-wall carbon nanotube, then immobilizing an initiator 2-bromoisobutyryl bromide on the surface of the hydroxylated carbon nanotube, and finally grafting a proper amount of polyethylene glycol methacrylate-475 on the surface of the carbon nanotube through atom transfer radical polymerization reaction to obtain a surface grafted carbon nanotube with the surface activity effect, wherein the surface grafted carbon nanotube can realize the emulsification of 1-ethyl-3-methylimidazole bistrifluoromethanesulfonylimide and water at room temperature to form emulsion, the temperature is increased to 80 ℃, the emulsion can be spontaneously divided into two layers, the upper layer is a water phase, the lower layer is an ionic liquid phase, the nanometer material with the surface activity is positioned in the ionic liquid phase, and the hydrophobic ionic liquid 1-ethyl-3-methylimidazole bistrifluoromethanesulfonyl imide can be realized only by changing the temperature The process is reversible, so that the surface grafted carbon nanotube can be separated conveniently, and the surface grafted carbon nanotube can be reused.

Drawings

FIG. 1 is an infrared spectrum obtained by sampling the products of steps (1) to (5) in example 1 of the present invention.

Fig. 2 is a diagram illustrating the effect of emulsifying hydrophobic ionic liquid 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonimide and water and separating the surface-grafted carbon nanotubes, which is prepared in example 2 of the present invention.

Detailed Description

The following examples may help one skilled in the art to more fully understand the present invention, but are not intended to limit the invention in any way.

Example 1

A preparation method of a nanometer material with surface activity and capable of being separated by temperature control comprises the following steps:

(1) carboxylating the multi-wall carbon nano tube to obtain a carboxylated carbon nano tube; the method specifically comprises the following steps: 1) weighing 1.0g of multi-walled carbon nano-tube, and putting the multi-walled carbon nano-tube into mixed acid with the volume ratio of sulfuric acid to nitric acid of 3:1The addition amount of the mixed acid in the gram multi-wall carbon nano tube is 40 mL; putting the mixture into an ultrasonic water bath with the power of 100-150W for ultrasonic treatment for 1 hour; 2) filtering to obtain black solid powder, repeatedly washing the black solid powder with water until the washing liquid is neutral, and vacuum drying at 70 ℃ to obtain carboxylated carbon nanotubes; the reaction formula is as follows:(ii) a The mass fraction of sulfuric acid in the mixed acid is 98 percent, and the mass fraction of nitric acid is 70 percent;

(2) acylating and chlorinating the carbon nano tube with the carboxylated surface to obtain an acyl chlorinated carbon nano tube; the method specifically comprises the following steps: 1) putting 1.0g of carbon nano-tubes with carboxylated surfaces into thionyl chloride, wherein the adding amount of the carbon nano-tubes with carboxylated surfaces in each milliliter of the thionyl chloride is 0.05 g; stirring for 2h at 20 ℃; 2) filtering, taking filter residue, and drying in vacuum for 1.8h to obtain the carbon nanotube of acyl chloride; the reaction formula is as follows:；

(3) hydroxylating the carbon nano tube with surface acyl chloride to obtain a hydroxylated carbon nano tube; the method specifically comprises the following steps: 1) adding the acyl chloride carbon nano tube into ethylene glycol, and stirring for 46h at the temperature of 20 ℃; the addition amount of the ethylene glycol in each gram of the acyl chloride carbon nano tube is 10 mL; 2) filtering, taking filter residue, washing the filter residue with tetrahydrofuran for more than 5 times, and vacuum drying at 70 ℃ for 9h to obtain a hydroxylated carbon nanotube; the reaction formula is as follows:；

(4) immobilizing an initiator 2-bromoisobutyryl bromide to the carbon nano tube with the hydroxylated surface to obtain the carbon nano tube immobilized with the initiator; the method specifically comprises the following steps: 1) dispersing 1.0g of hydroxylated carbon nanotube into 20mL of chloroform, adding 0.01g of 4-dimethylaminopyridine, 0.1g of triethylamine and 0.01g of 2-bromoisobutyryl bromide respectively, reacting for 2.5h at 0 ℃ in a nitrogen atmosphere, and reacting for 46h at room temperature; 2) filtering to obtain residue, washing the residue with large amount of chloroform, and vacuum drying at 38 deg.C7h, obtaining the carbon nano tube of the immobilized initiator; the reaction formula is as follows:；

(5) adding a polyethylene glycol methacrylate-475 monomer into a reaction system, and carrying out graft copolymerization reaction with a carbon nano tube of a surface immobilized initiator to obtain a surface grafted carbon nano tube of which the surface is grafted with poly PEGMMA-475, wherein the surface grafted carbon nano tube is a nano material which can be separated by temperature control and has surface activity; the method specifically comprises the following steps: 1) adding 1.0g of carbon nano tube of an immobilized initiator, 0.1g of cuprous bromide and 0.1g of N, N, N' -pentamethyldiethylenetriamine into 10mL of N, N-dimethylformamide, sealing a reaction system, removing air, back-filling nitrogen, adding polyethylene glycol methacrylate-475 monomer into the reaction system, and stirring for 23h at 68 ℃; 2) filtering, taking filter residue, washing the filter residue with chloroform, tetrahydrofuran and water respectively until the washing liquid is colorless and transparent; 3) vacuum drying at 78 deg.c for 9 hr to obtain surface grafted carbon nanotube; the reaction formula is as follows:。

example 2

A preparation method of a nanometer material with surface activity and capable of being separated by temperature control comprises the following steps:

(1) carboxylating the multi-wall carbon nano tube to obtain a carboxylated carbon nano tube; the method specifically comprises the following steps: 1) weighing 1.0g of multi-walled carbon nano-tube, and putting the multi-walled carbon nano-tube into mixed acid with the volume ratio of sulfuric acid to nitric acid being 3:1, wherein the addition amount of the mixed acid in each gram of the multi-walled carbon nano-tube is 160 mL; putting the mixture into an ultrasonic water bath with the power of 100-150W for ultrasonic treatment for 10 hours; 2) filtering to obtain black solid powder, repeatedly washing the black solid powder with water until the washing liquid is neutral, and vacuum drying at 80 ℃ to obtain carboxylated carbon nanotubes; the reaction formula is as follows:(ii) a The mass fraction of sulfuric acid in the mixed acid is 98 percent, and the mass fraction of nitric acid in the mixed acid isThe mass fraction is 70%;

(2) acylating and chlorinating the carbon nano tube with the carboxylated surface to obtain an acyl chlorinated carbon nano tube; the method specifically comprises the following steps: 1) putting 1.0g of carbon nano-tubes with carboxylated surfaces into thionyl chloride, wherein the adding amount of the carbon nano-tubes with carboxylated surfaces in each milliliter of the thionyl chloride is 0.1 g; stirring for 24h at 65 ℃; 2) filtering, taking filter residue, and drying in vacuum for 2.2h to obtain the carbon nanotube of acyl chloride; the reaction formula is as follows:；

(3) hydroxylating the carbon nano tube with surface acyl chloride to obtain a hydroxylated carbon nano tube; the method specifically comprises the following steps: 1) adding the acyl chloride carbon nano tube into ethylene glycol, and stirring for 46-50 h at 120 ℃; the addition amount of the ethylene glycol in each gram of the acyl chloride carbon nano tube is 80 mL; 2) filtering, taking filter residue, washing the filter residue with tetrahydrofuran for more than 5 times, and drying in vacuum at 80 ℃ for 11h to obtain a hydroxylated carbon nanotube; the reaction formula is as follows:；

(4) immobilizing an initiator 2-bromoisobutyryl bromide to the carbon nano tube with the hydroxylated surface to obtain the carbon nano tube immobilized with the initiator; the method specifically comprises the following steps: 1) dispersing 1.0g of hydroxylated carbon nanotube into 80mL of chloroform, adding 0.05g of 4-dimethylaminopyridine, 0.5g of triethylamine and 0.5g of 2-bromoisobutyryl bromide respectively, reacting for 3.5h at 0 ℃ in a nitrogen atmosphere, and reacting for 50h at room temperature; 2) filtering to obtain filter residue, washing the filter residue with a large amount of chloroform, and vacuum drying at 42 ℃ for 9h to obtain the initiator-immobilized carbon nanotube; the reaction formula is as follows:；

(5) adding polyethylene glycol methacrylate-475 monomer into a reaction system, and carrying out graft copolymerization reaction with the carbon nano tube of the surface immobilized initiator to obtain the surface grafted carbon nano tube of which the surface is grafted with the PEGMMA-475, wherein the surface grafted carbon nano tube is a temperature-controllable componentAn isolated surface-active nanomaterial; the method specifically comprises the following steps: 1) adding 4.0g of carbon nano tube of an immobilized initiator, 0.5g of cuprous bromide and 0.5g of N, N, N' -pentamethyldiethylenetriamine into 100mL of N, N-dimethylformamide, sealing a reaction system, removing air, back-filling nitrogen, adding polyethylene glycol methacrylate-475 monomer into the reaction system, and stirring for 25 hours at 72 ℃; 2) filtering, taking filter residue, washing the filter residue with chloroform, tetrahydrofuran and water respectively until the washing liquid is colorless and transparent; 3) vacuum drying at 82 deg.c for 11 hr to obtain surface grafted carbon nanotube; the reaction formula is as follows:。

example 3

A preparation method of a nanometer material with surface activity and capable of being separated by temperature control comprises the following steps:

(1) carboxylating the multi-wall carbon nano tube to obtain a carboxylated carbon nano tube; the method specifically comprises the following steps: 1) weighing 1.0g of multi-walled carbon nano-tube, and putting the multi-walled carbon nano-tube into mixed acid with the volume ratio of sulfuric acid to nitric acid being 3:1, wherein the addition amount of the mixed acid in each gram of the multi-walled carbon nano-tube is 60 mL; putting the mixture into an ultrasonic water bath with the power of 100-150W for ultrasonic treatment for 5 hours; 2) filtering to obtain black solid powder, repeatedly washing the black solid powder with water until the washing liquid is neutral, and vacuum drying at 75 ℃ to obtain carboxylated carbon nanotubes; the reaction formula is as follows:(ii) a The mass fraction of sulfuric acid in the mixed acid is 98 percent, and the mass fraction of nitric acid is 70 percent;

(2) acylating and chlorinating the carbon nano tube with the carboxylated surface to obtain an acyl chlorinated carbon nano tube; the method specifically comprises the following steps: 1) putting 1.0g of carbon nano-tube with carboxylated surface into thionyl chloride, wherein the adding amount of the carbon nano-tube with carboxylated surface in each milliliter of the thionyl chloride is 0.07 g; stirring for 7h at 35 ℃; 2) filtering, taking filter residue, and drying in vacuum for 2h to obtain the carbon nanotube of acyl chloride; the reaction formula is as follows:；

(3) hydroxylating the carbon nano tube with surface acyl chloride to obtain a hydroxylated carbon nano tube; the method specifically comprises the following steps: 1) adding the acyl chloride carbon nano tube into ethylene glycol, and stirring for 48 hours at the temperature of 60 ℃; the adding amount of the glycol in each gram of the acyl chloride carbon nano tube is 40 mL; 2) filtering, taking filter residue, washing the filter residue with tetrahydrofuran for more than 5 times, and vacuum drying at 75 ℃ for 10h to obtain a hydroxylated carbon nanotube; the reaction formula is as follows:；

(4) immobilizing an initiator 2-bromoisobutyryl bromide to the carbon nano tube with the hydroxylated surface to obtain the carbon nano tube immobilized with the initiator; the method specifically comprises the following steps: 1) dispersing 1.0g of hydroxylated carbon nanotube into 50mL of chloroform, adding 0.03g of 4-dimethylaminopyridine, 0.2g of triethylamine and 0.25 g of 2-bromoisobutyryl bromide respectively, reacting for 2.8h at 0 ℃ in a nitrogen atmosphere, and reacting for 48h at room temperature; 2) filtering to obtain filter residue, washing the filter residue with a large amount of chloroform, and drying in vacuum at 40 ℃ for 8h to obtain the initiator-immobilized carbon nanotube; the reaction formula is as follows:；

(5) adding a polyethylene glycol methacrylate-475 monomer into a reaction system, and carrying out graft copolymerization reaction with a carbon nano tube of a surface immobilized initiator to obtain a surface grafted carbon nano tube of which the surface is grafted with poly PEGMMA-475, wherein the surface grafted carbon nano tube is a nano material which can be separated by temperature control and has surface activity; the method specifically comprises the following steps: 1) adding 3.0g of carbon nano tube of an immobilized initiator, 0.3g of cuprous bromide and 0.2g of N, N, N' -pentamethyldiethylenetriamine into 70mL of N, N-dimethylformamide, sealing a reaction system, removing air, back-filling nitrogen, adding polyethylene glycol methacrylate-475 monomer into the reaction system, and stirring for 24 hours at 69 ℃; 2) filtering, taking filter residue, washing the filter residue with chloroform, tetrahydrofuran and water respectively until the washing liquid is colorless and transparent; 3) at 80 deg.CVacuum drying for 10 hours under the condition to obtain the surface grafted carbon nano tube; the reaction formula is as follows:。

example 4

A preparation method of a nanometer material with surface activity and capable of being separated by temperature control comprises the following steps:

(1) carboxylating the multi-wall carbon nano tube to obtain a carboxylated carbon nano tube; the method specifically comprises the following steps: 1) weighing 1.0g of multi-walled carbon nano-tube, and putting the multi-walled carbon nano-tube into mixed acid with the volume ratio of sulfuric acid to nitric acid being 3:1, wherein the addition amount of the mixed acid in each gram of the multi-walled carbon nano-tube is 70 mL; putting the mixture into an ultrasonic water bath with the power of 100-150W for ultrasonic treatment for 7 hours; 2) filtering to obtain black solid powder, repeatedly washing the black solid powder with water until the washing liquid is neutral, and vacuum drying at 75 ℃ to obtain carboxylated carbon nanotubes; the reaction formula is as follows:(ii) a The mass fraction of sulfuric acid in the mixed acid is 98 percent, and the mass fraction of nitric acid is 70 percent;

(2) acylating and chlorinating the carbon nano tube with the carboxylated surface to obtain an acyl chlorinated carbon nano tube; the method specifically comprises the following steps: 1) putting 1.0g of carbon nano-tube with carboxylated surface into thionyl chloride, wherein the adding amount of the carbon nano-tube with carboxylated surface in each milliliter of the thionyl chloride is 0.085 g; stirring for 12h at the temperature of 55 ℃; 2) filtering, taking filter residue, and drying in vacuum for 2h to obtain the carbon nanotube of acyl chloride; the reaction formula is as follows:；

(3) hydroxylating the carbon nano tube with surface acyl chloride to obtain a hydroxylated carbon nano tube; the method specifically comprises the following steps: 1) adding the acyl chloride carbon nano tube into ethylene glycol, and stirring for 47 hours at the temperature of 90 ℃; the adding amount of the glycol in each gram of the acyl chloride carbon nano tube is 60 mL; 2) filtering, taking filter residue, washing the filter residue with tetrahydrofuran for more than 5 times, and vacuum drying at 75 ℃ for 9.5h to obtain the hydroxylated carbon nanotube; reaction formula is：；

(4) Immobilizing an initiator 2-bromoisobutyryl bromide to the carbon nano tube with the hydroxylated surface to obtain the carbon nano tube immobilized with the initiator; the method specifically comprises the following steps: 1) dispersing 1.0g of hydroxylated carbon nanotube into 55mL of chloroform, respectively adding 0.035g of 4-dimethylaminopyridine, 0.35 g of triethylamine and 0.26 g of 2-bromoisobutyryl bromide, reacting for 3h at 0 ℃ in a nitrogen atmosphere, and reacting for 48h at room temperature; 2) filtering to obtain filter residue, washing the filter residue with a large amount of chloroform, and vacuum drying at 41 ℃ for 8h to obtain the initiator-immobilized carbon nanotube; the reaction formula is as follows:；

(5) adding a polyethylene glycol methacrylate-475 monomer into a reaction system, and carrying out graft copolymerization reaction with a carbon nano tube of a surface immobilized initiator to obtain a surface grafted carbon nano tube of which the surface is grafted with poly PEGMMA-475, wherein the surface grafted carbon nano tube is a nano material which can be separated by temperature control and has surface activity; the method specifically comprises the following steps: 1) adding 3.0g of carbon nano tube of an immobilized initiator, 0.4g of cuprous bromide and 0.3g of N, N, N' -pentamethyldiethylenetriamine into 50mL of N, N-dimethylformamide, sealing a reaction system, removing air, back-filling nitrogen, adding polyethylene glycol methacrylate-475 monomer into the reaction system, and stirring for 24 hours at 70 ℃; 2) filtering, taking filter residue, washing the filter residue with chloroform, tetrahydrofuran and water respectively until the washing liquid is colorless and transparent; 3) vacuum drying at 80 deg.c for 10 hr to obtain surface grafted carbon nanotube; the reaction formula is as follows:。

the products of steps (1) to (5) in example 1 were sampled to obtain an infrared spectrum, as shown in FIG. 1, in which CN-COOH represents the product of step (1), CN-COCL represents the product of step (2), CN-OH represents the product of step (3), CN-Br represents the product of step (4), and CN-475 represents the product of step (5), from which it can be seen that the products prepared in steps (1) to (5) in example 1 all have a strong absorption peak at a wave number of 1724cm-1, which is a typical C = O stretching vibration peak of carbonyl group; a weak absorption peak at a wave number of 1638cm < -1 >, which is an absorption peak of a C = C conjugated bond of the carbon nanotube; the absorption peak at a wave number of 1571cm-1 is a carbon nanotube skeleton plane vibration absorption peak. In addition, the strong absorption peak of the sample CN-475 at the wave number of 2871cm < -1 > is the C-H stretching vibration peak of saturated aliphatic hydrocarbon, and the strong absorption peak at the wave number of 1104cm < -1 > is the stretching vibration peak of C-O bond, thereby confirming that the surface of the carbon nano tube is successfully grafted with the polyethylene glycol methacrylate-475.

An experiment for emulsifying hydrophobic ionic liquid 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonimide and water with the surface grafted carbon nanotube prepared in example 1 and separating the surface grafted carbon nanotube was performed:

putting 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonimide (1-3 mL) and deionized water (1-3 mL) into a small plastic bottle, adding the prepared nano material with surface activity (0.01-0.1 g) into the small plastic bottle, and slightly stirring to obtain the emulsion without obvious layering. The emulsion was heated to 80 ℃ and spontaneously separated into two layers, the upper layer being the aqueous phase and the lower layer being the ionic liquid phase, the surface active nanomaterial being in the ionic liquid phase, as shown in figure 2, this process being reversible.

From an infrared spectrogram and an experiment for separating the surface-grafted carbon nanotube emulsified hydrophobic ionic liquid 1-ethyl-3-methylimidazole bistrifluoromethane sulfimide from water prepared in example 1, it can be known that the preparation method of the surface-active nanomaterial capable of being separated by temperature control, disclosed by the invention, comprises the steps of carboxylating, acylating and hydroxylating a multi-wall carbon nanotube, then immobilizing an initiator 2-bromoisobutyryl bromide on the surface of the hydroxylated carbon nanotube, finally grafting a proper amount of polyethylene glycol methacrylate-475 on the surface of the carbon nanotube through atom transfer radical polymerization reaction, wherein the prepared surface-grafted carbon nanotube has a surface activity effect, and can realize the emulsification of the hydrophobic ionic liquid 1-ethyl-3-methylimidazole bistrifluoromethane sulfimide and water at room temperature, forming an emulsion, raising the temperature to 80 ℃, so that the emulsion can be spontaneously divided into two layers, wherein the upper layer is a water phase, the lower layer is an ionic liquid phase, the nano material with surface activity is positioned in the ionic liquid phase, the layering and emulsification of the hydrophobic ionic liquid 1-ethyl-3-methylimidazole bistrifluoromethanesulfonylimide and water can be realized only by changing the temperature, the process is reversible, the surface grafted carbon nano tube can be conveniently separated, and the surface grafted carbon nano tube can be repeatedly utilized; the invention relates to a preparation method of a nanometer material with surface activity and temperature control separation, the prepared surface grafting carbon nanometer tube has certain surface activity, and has certain application prospect in the aspect of preparing a surfactant; the preparation method of the nanometer material with surface activity capable of being separated by temperature control has certain emulsification effect and has certain application prospect in the aspect of preparing the emulsifier.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.