A polymer membrane with hierarchical porous structure and its preparation method and application

Abstract

The invention belongs to the technical field of polymer composite materials, and in particular relates to a polymer film with hierarchical porous structure and its preparation method and application. The film can be used as a surface heat management film of a solar evaporator. The invention provides a polymer membrane, the polymer membrane has a micropore structure and a nanopore structure, the micropores are distributed throughout the polymer membrane, and the walls of the micropores contain nanopores. The polymer film obtained in the present invention has a hierarchical porous structure, and the film can be used as a polymer-based thermal management film. When used in a solar evaporator, it can limit the energy on the surface of the solar evaporator, and reduce heat through thermal radiation and heat convection. Loss.

Description

technical field

[0001] The invention belongs to the technical field of polymer composite materials, and in particular relates to a polymer film with a hierarchical porous structure, a preparation method and application thereof, and the film can be used as a surface heat management film of a solar evaporator. Background technique

[0002] In recent years, the shortage of water resources has become more and more obvious. By 2030, people's demand for fresh water will reach 6.9 trillion cubic meters per year. Although 70% of the earth's surface is covered by water, only 2.5% is freshwater, and 87% of this freshwater is located in polar ice caps and alpine glaciers, making it difficult for humans to use it. Solar energy is a clean and renewable energy source. Using solar energy to heat water to generate steam, desalinate seawater or treat sewage, clean water resources can be obtained.

[0003] The technology of solar energy conversion to heat energy is a technology that directly...

Examples

Embodiment 1

[0037] A polyvinyl alcohol hydrogel film with a hierarchical porous structure, the preparation of which is carried out according to the following steps:

[0038] Get 4g of polyvinyl alcohol powder and 1g of polyethylene glycol and add it to the mixed solution of 50ml of deionized water and glycerol (the mass ratio of water and glycerol in the mixed solution is 1:1), and then placed in React at 98 °C for 1 h; then add 5 mg of silver nitrate crystals into an aqueous solution and add it to the above solution, and place it at 70 °C to react for 12 h; then pour the solution into a mold to form a film and place it at -20 °C for gelation Treatment; the gelled products were successively placed in sodium tetraborate solution, ethanol solution, and aqueous solution for cross-linking and selective etching, and finally a polyvinyl alcohol hydrogel film (sample 1) was obtained, which showed micro and nano grades of hierarchical porous structures. The prepared micropores have an average si...

Embodiment 2

[0045] A polyvinyl alcohol hydrogel film with a hierarchical porous structure, the preparation of which is carried out according to the following steps:

[0046] Take 4g of polyvinyl alcohol powder and 1g of polyethylene oxide and add it to 50ml of mixed solution of deionized water and glycerol, the mass ratio of the mixed solution is 1:1; put it at 98 ℃ to react for 1h; put 1mg of Silver nitrate crystals were prepared as an aqueous solution and added to the above solution, and then placed at 70 °C for 12 h; then the solution was poured into a mold to form a film and placed at -20 °C for gelation treatment; the gelled products were successively Placed in sodium tetraborate solution, ethanol solution, and aqueous solution for cross-linking, selective etching, and water absorption treatment, and finally a polyvinyl alcohol hydrogel film (sample 2) was obtained, which presented a micro- and nano-scale hierarchical porous structure. The prepared micropores have an average size of ...

Embodiment 3

[0049] A polyvinyl alcohol hydrogel film with a hierarchical porous structure, the preparation of which is carried out according to the following steps:

[0050] Take 4g of polyvinyl alcohol powder and 1g of polyethylene glycol and add it to 50ml of mixed solution of deionized water and propylene glycol, the mass ratio of the mixed solution is 1:1, put it at 98 ℃ to react for 1h; add 1mg of nitric acid The silver crystal was added into the above solution as an aqueous solution, and was placed at 70 °C for 12 h; then the solution was poured into a mold to form a film and placed at -20 °C for gelation treatment; the gelled products were placed in succession In sodium tetraborate solution, ethanol solution, and aqueous solution, cross-linking, selective etching, and water absorption treatment are performed to finally obtain a polyvinyl alcohol hydrogel film (sample 3), which exhibits a micro- and nano-scale hierarchical porous structure. The prepared micropores have an average si...

technical field

[0001] The invention belongs to the technical field of polymer composite materials, and in particular relates to a polymer film with a hierarchical porous structure, a preparation method and application thereof, and the film can be used as a surface heat management film of a solar evaporator. Background technique

[0002] In recent years, the shortage of water resources has become more and more obvious. By 2030, people's demand for fresh water will reach 6.9 trillion cubic meters per year. Although 70% of the earth's surface is covered by water, only 2.5% is freshwater, and 87% of this freshwater is located in polar ice caps and alpine glaciers, making it difficult for humans to use it. Solar energy is a clean and renewable energy source. Using solar energy to heat water to generate steam, desalinate seawater or treat sewage, clean water resources can be obtained.

[0003] The technology of solar energy conversion to heat energy is a technology that directly...

Examples

Embodiment 1

[0037] A polyvinyl alcohol hydrogel film with a hierarchical porous structure, the preparation of which is carried out according to the following steps:

[0038] Get 4g of polyvinyl alcohol powder and 1g of polyethylene glycol and add it to the mixed solution of 50ml of deionized water and glycerol (the mass ratio of water and glycerol in the mixed solution is 1:1), and then placed in React at 98 °C for 1 h; then add 5 mg of silver nitrate crystals into an aqueous solution and add it to the above solution, and place it at 70 °C to react for 12 h; then pour the solution into a mold to form a film and place it at -20 °C for gelation Treatment; the gelled products were successively placed in sodium tetraborate solution, ethanol solution, and aqueous solution for cross-linking and selective etching, and finally a polyvinyl alcohol hydrogel film (sample 1) was obtained, which showed micro and nano grades of hierarchical porous structures. The prepared micropores have an average si...

Embodiment 2

[0045] A polyvinyl alcohol hydrogel film with a hierarchical porous structure, the preparation of which is carried out according to the following steps:

[0046] Take 4g of polyvinyl alcohol powder and 1g of polyethylene oxide and add it to 50ml of mixed solution of deionized water and glycerol, the mass ratio of the mixed solution is 1:1; put it at 98 ℃ to react for 1h; put 1mg of Silver nitrate crystals were prepared as an aqueous solution and added to the above solution, and then placed at 70 °C for 12 h; then the solution was poured into a mold to form a film and placed at -20 °C for gelation treatment; the gelled products were successively Placed in sodium tetraborate solution, ethanol solution, and aqueous solution for cross-linking, selective etching, and water absorption treatment, and finally a polyvinyl alcohol hydrogel film (sample 2) was obtained, which presented a micro- and nano-scale hierarchical porous structure. The prepared micropores have an average size of ...

Embodiment 3

[0049] A polyvinyl alcohol hydrogel film with a hierarchical porous structure, the preparation of which is carried out according to the following steps:

[0050] Take 4g of polyvinyl alcohol powder and 1g of polyethylene glycol and add it to 50ml of mixed solution of deionized water and propylene glycol, the mass ratio of the mixed solution is 1:1, put it at 98 ℃ to react for 1h; add 1mg of nitric acid The silver crystal was added into the above solution as an aqueous solution, and was placed at 70 °C for 12 h; then the solution was poured into a mold to form a film and placed at -20 °C for gelation treatment; the gelled products were placed in succession In sodium tetraborate solution, ethanol solution, and aqueous solution, cross-linking, selective etching, and water absorption treatment are performed to finally obtain a polyvinyl alcohol hydrogel film (sample 3), which exhibits a micro- and nano-scale hierarchical porous structure. The prepared micropores have an average si...

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