Supramolecular polymer composite film and preparation method thereof

Abstract

The application belongs to the field of polymer composite membranes and preparation thereof, and relates to a preparation method of a supramolecular polymer composite membrane. The supramolecular polymer composite membrane is prepared by the following steps: forming a supramolecular film at a water-oil liquid-liquid interface in an interfacial polymerization manner through a supramolecular crosslinking agent in a water phase and an amino polymer in an oil phase, and transferring the supramolecular film to a porous support membrane to prepare the supramolecular polymer composite membrane by the method of immersing the porous support membrane in the bottom water phase in advance. The obtained supramolecular polymer composite membrane has good mechanical properties, a complete structure without defects, a thickness of about 300 nm and a certain roughness, and exhibits excellent separation performance in the field of dye molecule separation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polymer composite membranes and their preparation, and relates to a preparation method of a supramolecular polymer composite membrane. BACKGROUND

[0002] Supramolecular interfacial polymerization refers to a polymerization method for preparing supramolecular polymers with controllable structures through covalent bond connection at a liquid-liquid interface. This method can convert non-covalent polymerization, which is difficult to control, into controllable covalent polymerization, which can effectively control the properties of supramolecular polymers.

[0003] Supramolecular interfacial polymerization provides a feasible polymerization method for immiscible monomers. The two-phase monomers are enriched at the interface, and a high molecular weight supramolecular polymer is formed at the interface. At present, the research on supramolecular interfacial polymerization is limited to the construction of supramolecular polymers based on host-guest interactions and multiple hydrogen bonds mediated by cucurbituril (CB[8]). The manufacture of supramolecular polymers with adjustable structures and specific functions needs to be developed.

[0004] Using a composite membrane to separate dye molecules in the industrial field (such as wastewater treatment, textile industry, etc.) is a green, environmentally friendly and cost-effective method. Exploring a composite membrane with good retention efficiency for high molecular weight dyes has very high application value. At the same time, the simple preparation process, structural stability and solvent resistance of the composite membrane are the prerequisites to ensure its application. SUMMARY

[0005] One of the purposes of the present application is to prepare a supramolecular polymer by the method of supramolecular interfacial polymerization; the second purpose is to prepare a defect-free, centimeter-scale supramolecular polymer film using a water-oil liquid-liquid interface as a template, and to transfer it to a polymer support film to prepare a supramolecular polymer composite membrane with nanofiltration performance.

[0006] To achieve the above purposes, the present application adopts the following technical solutions:

[0007] A preparation method of a supramolecular polymer composite membrane, comprising the following steps:

[0008] S1) Dissolving a water-soluble supramolecular crosslinking agent in an aqueous phase to obtain an aqueous phase mixed solution;

[0009] S2) Dissolving an amino-functionalized polymer ligand in a non-polar or polar organic phase to obtain an organic phase mixed solution;

[0010] S3) Immerse a support membrane with a pore size of 2 micrometers into an aqueous mixed solution. Slowly add an organic mixed solution containing polymer to the surface of the aqueous mixed solution. The supramolecular crosslinking agent in the aqueous mixed solution and the aminated polymer ligand in the organic mixed solution undergo interfacial polymerization at the interface between the aqueous and oil phases. After interfacial polymerization for 3-6 hours, slowly lift the support membrane so that the supramolecular film generated during interfacial polymerization adheres to the support membrane. Allow it to stand and dry at room temperature to obtain a supramolecular polymer composite membrane.

[0011] The above-mentioned method for preparing supramolecular polymer composite membranes includes supramolecular crosslinking agents comprising catechol derivative-metal ion coordination compounds, wherein the catechol derivatives include, but are not limited to, catechol compounds containing acyl chloride groups or amino groups.

[0012] The above-mentioned method for preparing supramolecular polymer composite membranes uses metal ions including, but not limited to, trivalent or divalent metal cations such as ferric ions, ferrous ions, copper ions, and cobalt ions.

[0013] In the above-mentioned method for preparing supramolecular polymer composite membranes, the mass of the supramolecular crosslinking agent is 0.3 to 1.0% of the mass of the aqueous mixed solution.

[0014] In the above-mentioned method for preparing supramolecular polymer composite membranes, the aminated polymer is one or more of the following: aminated cage-type polysilsesquioxane, aminated polystyrene, mono-amino-terminated polydimethylsiloxane, and bi-amino-terminated polydimethylsiloxane.

[0015] In the above-mentioned method for preparing supramolecular polymer composite membranes, the mass of the aminated polymer is 1-10% of the mass of the organic phase mixed solution.

[0016] In the above-mentioned method for preparing supramolecular polymer composite membranes, the supporting membrane is one or both of polytetrafluoroethylene supporting membrane and polyacrylonitrile supporting membrane.

[0017] In the above-mentioned method for preparing supramolecular polymer composite membranes, the non-polar organic phase in step S2) is one or more of silicone oil, carbon tetrachloride, n-hexane, octane, dodecane, and petroleum ether, and the polar organic phase is one or more of toluene, chloroform, and dichloromethane.

[0018] The above-mentioned method for preparing supramolecular polymer composite films has a supramolecular film thickness of 280–320 nanometers and a roughness of 5–24 nanometers.

[0019] A supramolecular polymer composite membrane, wherein the supramolecular polymer composite membrane is prepared by the above-described method for preparing supramolecular polymer composite membranes.

[0020] The present invention has the following advantages and beneficial effects:

[0021] (1) This invention develops a method for preparing supramolecular polymers and supramolecular polymer composite films based on the water-oil liquid-liquid interface. The method has a simple synthesis route and preparation technology, requires no additives or catalysts, and compared with linear supramolecular polymers, supramolecular polymers with network structures have good mechanical properties.

[0022] (2) A centimeter-diameter, defect-free supramolecular polymer composite membrane was prepared in situ at the water-oil liquid-liquid interface, which showed good separation performance in the field of dye molecule separation. Attached Figure Description

[0023] Figure 1 shows the static water contact angle test results of the supramolecular polymer films in Examples 1, 4 and 5;

[0024] Figure 2 shows atomic force microscopy results of the supramolecular polymer films in Examples 1, 4 and 5;

[0025] Figure 3 shows atomic force microscopy results of the supramolecular polymer films in Examples 1, 4 and 5;

[0026] Figure 4 This is a comparison chart of the dye molecule retention properties of the supramolecular polymer composite membranes in Examples 1, 4, and 5. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. The described embodiments are only some preferred embodiments of the present invention, and the present invention is not limited to these embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels.

[0028] Example 1

[0029] In an aqueous sodium hydroxide solution at 80℃ and pH=10.0, protocatechuic aldehyde and ferric chloride were added at a molar ratio of 3:1, with a protocatechuic aldehyde concentration of 0.5 mol / L. The mixture was stirred for 3 hours, the reaction was stopped, and the product was freeze-dried to obtain a brownish-red solid powder of protocatechuic aldehyde-iron ion coordination compound (PA3 / Fe(III)).

[0030] PA3 / Fe(III) was dissolved in deionized water to obtain an aqueous mixed solution with a PA3 / Fe(III) mass fraction of 0.5%. Diamino-terminated polydimethylsiloxane (NH2-PDMS-NH2) was dissolved in toluene to obtain an organic mixed solution with a NH2-PDMS-NH2 mass fraction of 2%. A polytetrafluoroethylene (PTFE) supporting membrane was immersed in the aqueous mixed solution, and the organic mixed solution was slowly added to the top layer. After 3 hours, a complete supramolecular film was formed at the water-oil liquid-liquid interface. The pre-immersed PTFE supporting membrane was then slowly lifted, and the supramolecular film adhered completely to the supporting membrane, forming a supramolecular polymer composite membrane. After the supramolecular polymer composite membrane dried, its dye molecule separation performance was tested.

[0031] Example 2

[0032] The specific experimental steps are the same as in Example 1, except that the interface aggregation time is 4 hours.

[0033] Example 3

[0034] The specific experimental steps are the same as in Example 1, except that the interface aggregation time is 6 hours.

[0035] Example 4

[0036] PA3 / Fe(III) was dissolved in deionized water to obtain an aqueous mixed solution with a PA3 / Fe(III) mass fraction of 0.5%. Diamino-terminated polydimethylsiloxane (NH2-PDMS-NH2) was dissolved in toluene to obtain an organic mixed solution with a NH2-PDMS-NH2 mass fraction of 5%. A polytetrafluoroethylene (PTFE) supporting membrane was immersed in the aqueous mixed solution, and the organic mixed solution was slowly added to the top layer. After 3 hours, a complete supramolecular film was formed at the water-oil liquid-liquid interface. The pre-immersed PTFE supporting membrane was then slowly lifted, and the supramolecular film adhered completely to the supporting membrane, forming a supramolecular polymer composite membrane. After the supramolecular polymer composite membrane dried, its nanofiltration performance was tested.

[0037] Example 5

[0038] PA3 / Fe(III) was dissolved in deionized water to obtain an aqueous mixed solution with a PA3 / Fe(III) mass fraction of 0.5%. Diamino-terminated polydimethylsiloxane (NH2-PDMS-NH2) was dissolved in toluene to obtain an organic mixed solution with a NH2-PDMS-NH2 mass fraction of 10%. A polytetrafluoroethylene (PTFE) supporting membrane was immersed in the aqueous mixed solution. A toluene solution containing 10% NH2-PDMS-NH2 mass fraction was slowly added to the upper layer of the aqueous mixed solution. After 3 hours, a complete supramolecular film was formed at the water-oil liquid-liquid interface. The pre-immersed PTFE supporting membrane was then slowly lifted, and the supramolecular film adhered completely to the supporting membrane to form a supramolecular polymer composite membrane. After the supramolecular polymer composite membrane dried, its nanofiltration performance was tested.

[0039] Performance testing

[0040] (1) Water Contact Angle Test (WCA)

[0041] Using a multi-functional tension meter ( The water contact angle of the supramolecular polymer films prepared in Examples 1, 4, and 5 was tested using the sessile drop module of the DSA30. The test results are shown in Figure 1. Figure 1-a This is the water contact angle of Example 1. Figure 1-b and Figure 1-c These are the water contact angles of Examples 4 and 5, respectively.

[0042] (2) Atomic force microscopy test

[0043] The supramolecular polymer films prepared in Examples 1, 4, and 5 were tested for film thickness and surface roughness using an atomic force microscope (Bruker, DMFASTSCAN2-SYS). The test results are shown in Figures 2 and 3. Figure 2-a For the characterization of film thickness in Example 1, Figure 2-b and Figure 2-c The film thickness characterization of Examples 4 and 5 are respectively; Figure 3-a For the characterization of membrane surface roughness in Example 1, Figure 3-b and Figure 3-c The surface roughness of the membranes in Examples 4 and 5 are characterized respectively.

[0044] (3) Nanofiltration performance test

[0045] The nanofiltration performance test of the supramolecular polymer composite membrane was conducted at a pressure of 0.8 bar, and the effective usable area of ​​the membrane was 1.77 cm². 2 (Diameter 1.5cm), the dye molecules are methyl orange (MO, Mw = 327.33g·mol⁻¹).-1 Rhodamine B (Rh B, Mw = 479.01 g·mol⁻¹) -1 Congo Red (CR, Mw = 696.66 g·mol⁻¹) -1 ) and Evans Blue (EB, Mw = 960.81 g·mol⁻¹) -1 The test results are as follows: Figure 4 As shown, the dye rejection rate of the supramolecular polymer composite membrane increases with the increase of the NH2-PDMS-NH2 concentration in the organic phase mixed solution.

[0046] The above descriptions and illustrations are merely preferred experimental examples. The present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely disclosures of principles and are not intended to limit the present invention. Any modifications or alterations that do not depart from the technical solution of the present invention do not depart from the scope of the technical solution of the present invention. Any equivalent substitutions or transformations that do not depart from the essential content of the present invention are also within the protection scope of the present invention.

Claims

1. A method for preparing a supramolecular polymer composite film, characterized by, The method comprises the following steps: S1) dissolving a water-soluble supramolecular crosslinking agent in an aqueous phase to obtain an aqueous phase mixed solution; wherein the supramolecular crosslinking agent is a protocatechuic aldehyde-iron ion coordination compound; S2) dissolving an aminated polymer ligand in a non-polar or polar organic phase to obtain an organic phase mixed solution; wherein the aminated polymer is one or more of an aminated cage polysilsesquioxane, an aminated polystyrene, a mono-terminated aminated polydimethylsiloxane, and a double-terminated aminated polydimethylsiloxane; S3) immersing a support membrane with a pore size of 2 microns in the aqueous phase mixed solution, slowly adding the organic phase mixed solution containing the polymer on the surface of the aqueous phase mixed solution, and allowing the supramolecular crosslinking agent in the aqueous phase mixed solution and the aminated polymer ligand in the organic phase mixed solution to undergo interfacial polymerization at the interface of the aqueous phase and the oil phase; after 3-6 hours of interfacial polymerization, slowly lifting the support membrane to allow the supramolecular film generated in the interfacial polymerization to adhere to the support membrane, and then allowing the supramolecular film to dry at room temperature, thereby obtaining a supramolecular polymer composite film; wherein the thickness of the supramolecular film is 280-320 nanometers, and the roughness is 5-24 nanometers.

2. The method for preparing a supramolecular polymer composite film according to claim 1, characterized by, The mass of the supramolecular crosslinking agent is 0.3-1.0% of the mass of the aqueous phase mixed solution.

3. The method for preparing a supramolecular polymer composite film according to claim 1, characterized by, The mass of the aminated polymer is 1-10% of the mass of the organic phase mixed solution.

4. The method for preparing a supramolecular polymer composite film according to claim 1, characterized by, The support membrane is one or both of a polytetrafluoroethylene support membrane and a polyacrylonitrile support membrane.

5. The method for preparing a supramolecular polymer composite film according to claim 1, characterized by, In step S2), the non-polar organic phase is one or a combination of silicone oil, carbon tetrachloride, n-hexane, octane, dodecane, and petroleum ether, and the polar organic phase is one or a combination of toluene, trichloromethane, and dichloromethane.

6. A supramolecular polymer composite film, characterized by, The supramolecular polymer composite film is prepared by the method of any one of claims 1-5.

Images