An activated atomic layer deposition super-hydrophilic polymer separation membrane and a preparation method thereof

Abstract

In order to solve the problem that the surface active site of a nonpolar inert polymer separation membrane material is less and cannot be subjected to efficient atomic layer deposition, the present application provides an activated atomic layer deposition super-hydrophilic polymer separation membrane and a preparation method thereof, and specifically comprises the following steps: soaking a porous polymer separation membrane in alcohol and water respectively to obtain a wetted membrane; dissolving a water-soluble protein in water to obtain solution A, and soaking the wetted membrane in solution A, cleaning after coating, and air-drying for standby; transferring the protein-modified membrane obtained in step two into a cavity of an atomic layer deposition device for atomic layer deposition, and respectively introducing a metal organic precursor A, inert gas purging, introducing a precursor B, and inert gas purging; repeating step three for a required number of times to obtain a final modified membrane. The present application not only effectively gives the modified membrane super-hydrophilicity, but also gives the modified membrane a unique microstructure, and can be widely applied in the fields of hydrophilic modification, catalysis, oil-water separation, thin film deposition and the like.

Description

Technical Field

[0001] This invention belongs to the field of polymer separation membranes, specifically relating to an activated atomic layer deposition superhydrophilic polymer separation membrane and its preparation method. Background Technology

[0002] Atomic layer deposition (ALD) allows for precise control of surface properties through sequential gas-phase reactions to fabricate sub-nanometer functional thin films. Its simplicity, reproducibility, tunability, and conformality provide an extremely diverse chemical library for surface and interface functionalization. However, polymer separation membranes, such as polyvinylidene fluoride, polypropylene, and polytetrafluoroethylene, which dominate water treatment and related applications, cannot achieve efficient ALD due to a lack of active nucleation sites. Traditional methods for activating ALD, primarily based on plasma, ozone, or concentrated acid treatments, have significant limitations and can easily damage the base membrane material. Therefore, preparing high-performance, multifunctional separation membranes through simple and mild methods for activating ALD remains a significant challenge. Summary of the Invention

[0003] The purpose of this invention is to solve the problem that existing non-polar inert polymer separation membrane materials have few surface active sites, making efficient atomic layer deposition impossible, and to provide an activated atomic layer deposition superhydrophilic polymer separation membrane and its preparation method.

[0004] A method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane includes the following steps:

[0005] 1. The porous polymer separation membrane was soaked in alcohol and water respectively to obtain a wetted membrane;

[0006] 2. Dissolve the water-soluble protein in water to obtain solution A. Immerse the wet film from step 1 in solution A, coat it, wash it, and let it dry for later use.

[0007] 3. Transfer the protein-modified membrane obtained in step 2 into the cavity of the atomic layer deposition apparatus for atomic layer deposition. Then, introduce the metal-organic precursor A and purge with inert gas, then introduce the precursor B and purge with inert gas.

[0008] 4. Repeat step 3 as many times as required to obtain the final modified membrane.

[0009] The polymer separation membrane mentioned in step one is a polyvinylidene fluoride membrane, a polypropylene membrane, or a polytetrafluoroethylene membrane, etc.

[0010] The water-soluble protein mentioned in step two is bovine serum albumin, ovalbumin, lysozyme, or whey protein, etc.

[0011] The concentration of protein in solution A described in step two is 0.5–3 mg / mL.

[0012] The organometallic precursor A mentioned in step three is TiCl4, Ti(OC3H7)4, or SnCl4.

[0013] The precursor B mentioned in step three is H2O.

[0014] The coating time in solution A described in step two is 3 to 48 hours.

[0015] The alcohol mentioned in step one is methanol, ethanol or isopropanol, and the inert gas mentioned in step three is nitrogen.

[0016] The number of repetitions in step four is greater than 100.

[0017] Based on the above method, an activated atomic layer deposition superhydrophilic polymer separation membrane was obtained.

[0018] This invention utilizes protein dip-coating to activate the surface of an inert polymer membrane for efficient atomic layer deposition (ALD) preparation of a superhydrophilic polymer separation membrane. First, protein is coated onto the polymer membrane using dip-coating modification, imparting an active intermediate layer. Then, efficient ALD deposition is initiated to prepare the superhydrophilic polymer separation membrane. This effectively endows the modified membrane with superhydrophilicity and a unique microstructure. The ALD technique of this invention for preparing functional modified membranes can be widely applied in fields such as hydrophilic modification, catalysis, oil-water separation, and thin film deposition. Attached Figure Description

[0019] Figure 1 The graph shows the change in the contact angle between the polyvinylidene fluoride membrane base and various modified membranes and water over the test time in Example 1.

[0020] Figure 2 This is a scanning electron microscope image of the polyvinylidene fluoride membrane base in Example 1;

[0021] Figure 3 This is a scanning electron microscope image of the protein-coated modified membrane in Example 1;

[0022] Figure 4 This is a scanning electron microscope image of the modified film prepared by protein activation atomic layer deposition in Example 1;

[0023] Figure 5 A scanning electron microscope image of the modified film prepared by atomic layer deposition without protein activation in Example 1;

[0024] Figure 6 This is an underwater oleophobic effect diagram of the activated atomic layer deposition superhydrophilic polymer film in Example 1;

[0025] Figure 7The graph shows the evolution of permeation flux over time when the modified membranes prepared by and without protein-activated atomic layer deposition in Example 1, and their control group, are used for cyclic separation of oil-in-water emulsions. Detailed Implementation

[0026] The technical solution of this invention is not limited to the specific embodiments listed below. The beneficial effects of this invention are verified by the following examples:

[0027] A method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane includes the following steps:

[0028] 1. Soak the porous polymer separation membrane in alcohol and water respectively to obtain a wetted membrane. The polymer separation membrane is a polyvinylidene fluoride membrane, polypropylene membrane or polytetrafluoroethylene membrane, etc., and the alcohol is methanol, ethanol or isopropanol.

[0029] 2. Dissolve the water-soluble protein in water to obtain solution A. Immerse the wet film from step 1 in solution A, coat it, wash it, and dry it for later use. The water-soluble protein is bovine serum albumin, ovalbumin, lysozyme, or whey protein, etc. The concentration of protein in solution A is 0.5-3 mg / mL, and the coating time is 3-48 h.

[0030] 3. Transfer the protein-modified membrane obtained in step 2 into the cavity of the atomic layer deposition apparatus for atomic layer deposition. Introduce metal-organic precursor A and purge with inert gas, then introduce precursor B and purge with inert gas. Metal-organic precursor A is TiCl4, Ti(OC3H7)4 or SnCl4, precursor B is H2O, and inert gas is nitrogen.

[0031] 4. Repeat step 3 as many times as required to obtain the final modified membrane. The number of repetitions should be greater than 100.

[0032] Example 1:

[0033] The method for preparing a superhydrophilic polymer separation membrane by activated atomic layer deposition in this embodiment is specifically prepared according to the following steps:

[0034] 1. Soak the porous polyvinylidene fluoride separation membrane in ethanol and water respectively to obtain a wetted membrane;

[0035] 2. Dissolve bovine serum albumin in water to obtain solution A. Immerse the wet membrane from step 1 in solution A and coat it for 24 hours. Then wash it with deionized water, air dry it, and set it aside. The concentration of bovine serum albumin is 1 g / L.

[0036] 3. In the chamber of the protein-modified membrane transfer atomic layer deposition device obtained in step 2, TiO2 atomic layer deposition is carried out. The metal-organic precursor TiCl4 is introduced for 4 seconds, then nitrogen is purged for 35 seconds, then the precursor H2O is introduced for 4 seconds, and then nitrogen is purged for 35 seconds.

[0037] Fourth, control the number of atomic layer deposition cycles until 200 depositions are completed to obtain the final modified superhydrophilic polymer separation membrane.

[0038] The change in the contact angle between the polyvinylidene fluoride (PVDF) membrane base and various modified membranes and water over the test time in this embodiment is shown in the figure below. Figure 1 As shown, by Figure 1 It can be seen that the contact angle between the polyvinylidene fluoride (PVDF) base membrane and water is 125°, exhibiting hydrophobicity; the protein-coated membrane has a contact angle of 123°; the modified membrane prepared by protein-activated atomic layer deposition has a contact angle of 0°, exhibiting superhydrophilicity; and the modified membrane prepared without protein-activated atomic layer deposition has a contact angle of 110°, still exhibiting hydrophobicity. The comparison shows that the protein coating in step two can effectively activate the subsequent atomic layer deposition, endowing the modified membrane with superhydrophilicity.

[0039] Scanning electron microscope images of commercially available polyvinylidene fluoride (PVDF) membrane-based films in this embodiment are as follows: Figure 2 As shown, the scanning electron microscope image of the protein-coated modified membrane in this embodiment is as follows: Figure 3 As shown. By Figure 2 and Figure 3 As can be seen, the surface morphology of the protein-coated modified film is similar to that of the polymer-based film, and is relatively smooth. Scanning electron microscope images of the superhydrophilic modified film prepared by protein-activated atomic layer deposition in this embodiment are shown below. Figure 4 As shown, the scanning electron microscope image of the modified film prepared by atomic layer deposition without protein activation in this embodiment is as follows. Figure 5 As shown. By Figure 4 It can be seen that the modified film prepared by protein-activated atomic layer deposition exhibits obvious synaptic structures on its surface, due to... Figure 5 It can be seen that the surface of the modified membrane prepared without protein activation atomic layer deposition is similar to that of the base membrane and is relatively smooth. In contrast, the protein coating in step two can effectively activate the subsequent atomic layer deposition, giving the modified membrane a unique microstructure.

[0040] The underwater oleophobic effect of the superhydrophilic polymer film prepared by protein-activated atomic layer deposition in this embodiment is shown in the figure below. Figure 6 As shown, the modified membrane exhibits underwater superoleophobic properties.

[0041] The evolution of permeation flux over time during the cyclic separation of oil-in-water emulsions using modified membranes prepared by atomic layer deposition (ALD) and those prepared without protein activation, as well as a control group, is shown in the figure below. Figure 7 As shown, cleaning and regeneration refers to thoroughly cleaning the membrane with deionized water. While the membrane flux of the control group could not be restored through cleaning, the permeation flux of the modified membrane prepared by protein-activated atomic layer deposition could be effectively restored through cleaning with deionized water.

[0042] Example 2:

[0043] The method for preparing a superhydrophilic polymer separation membrane by activated atomic layer deposition in this embodiment is specifically prepared according to the following steps:

[0044] 1. Soak the porous polyvinylidene fluoride separation membrane in ethanol and water respectively to obtain a wetted membrane;

[0045] 2. Dissolve ovalbumin in water to obtain solution A. Immerse the wet membrane from step 1 in solution A and coat it for 12 hours. Then wash it with deionized water, air dry it, and set it aside. The concentration of ovalbumin is 0.5 g / L.

[0046] 3. In the chamber of the protein-modified membrane transfer atomic layer deposition device obtained in step 2, TiO2 atomic layer deposition is carried out. The metal-organic precursor TiCl4 is introduced for 4 seconds, then nitrogen is purged for 35 seconds, then the precursor H2O is introduced for 4 seconds, and then nitrogen is purged for 35 seconds.

[0047] Fourth, control the number of atomic layer deposition cycles until 200 depositions are completed to obtain the final modified superhydrophilic polymer separation membrane.

[0048] The protein-activated atomic layer deposition superhydrophilic modified membrane prepared in this embodiment has a contact angle of approximately 0° with water, while the control group's unactivated atomic layer deposition modified membrane has a contact angle of approximately 115° with water. The results indicate that this embodiment can achieve the preparation of superhydrophilic polymer separation membranes through activated atomic layer deposition.

[0049] Example 3:

[0050] The method for preparing a superhydrophilic polymer separation membrane by activated atomic layer deposition in this embodiment is specifically prepared according to the following steps:

[0051] 1. Soak the porous polyvinylidene fluoride separation membrane in ethanol and water respectively to obtain a wetted membrane;

[0052] 2. Dissolve lysozyme in water to obtain solution A. Immerse the wet film from step 1 in solution A and coat it for 48 hours. Then wash it with deionized water, air dry it, and set it aside. The concentration of bovine serum albumin is 0.5 g / L.

[0053] 3. In the chamber of the protein-modified membrane transfer atomic layer deposition device obtained in step 2, TiO2 atomic layer deposition is carried out. The metal-organic precursor TiCl4 is introduced for 5s, then nitrogen is purged for 50s, then the precursor H2O is introduced for 5s, and then nitrogen is purged for 50s.

[0054] Fourth, control the number of atomic layer deposition cycles until 200 depositions are completed to obtain the final modified superhydrophilic polymer separation membrane.

[0055] The protein-activated atomic layer deposition superhydrophilic modified membrane prepared in this embodiment has a contact angle of approximately 0° with water, while the control group without protein activation has a contact angle of approximately 110° with water. The results indicate that this embodiment can achieve the preparation of superhydrophilic polymer separation membranes through activated atomic layer deposition.

[0056] Example 4:

[0057] The method for preparing a superhydrophilic polymer separation membrane by activated atomic layer deposition in this embodiment is specifically prepared according to the following steps:

[0058] 1. Soak the porous polypropylene separation membrane in ethanol and water respectively to obtain a wetted membrane;

[0059] 2. Dissolve bovine serum albumin in water to obtain solution A. Immerse the wet membrane from step 1 in solution A and coat it for 3 hours. Then wash it with deionized water, air dry it, and set it aside. The concentration of bovine serum albumin is 3 g / L.

[0060] 3. The protein-modified membrane transfer atomic layer deposition device obtained in step 2 is subjected to SnO2 atomic layer deposition. The metal-organic precursor SnCl4 is introduced for 4 seconds, then nitrogen is purged for 35 seconds, then the precursor H2O is introduced for 4 seconds, and then nitrogen is purged for 35 seconds.

[0061] Fourth, control the number of atomic layer deposition cycles until 150 depositions are completed to obtain the final modified superhydrophilic polymer separation membrane.

[0062] The protein-activated atomic layer deposition superhydrophilic modified membrane prepared in this embodiment has a contact angle of approximately 0° with water, while the control group's unactivated atomic layer deposition modified membrane has a contact angle of approximately 120° with water. The results indicate that this embodiment can achieve the preparation of superhydrophilic polymer separation membranes through activated atomic layer deposition.

[0063] Example 5:

[0064] The method for preparing a superhydrophilic polymer separation membrane by activated atomic layer deposition in this embodiment is specifically prepared according to the following steps:

[0065] 1. Soak the porous polypropylene separation membrane in ethanol and water respectively to obtain a wetted membrane;

[0066] 2. Dissolve lysozyme in water to obtain solution A. Immerse the wet film from step 1 in solution A and coat it for 48 hours. Then wash it with deionized water, air dry it, and set it aside. The concentration of bovine serum albumin is 0.5 g / L.

[0067] 3. In the chamber of the protein-modified membrane transfer atomic layer deposition device obtained in step 2, TiO2 atomic layer deposition is carried out. The metal-organic precursor Ti(OC3H7)4 is introduced for 5s, then nitrogen is purged for 50s, then the precursor H2O is introduced for 5s, and then nitrogen is purged for 50s.

[0068] Fourth, control the number of atomic layer deposition cycles until 200 depositions are completed to obtain the final modified superhydrophilic polymer separation membrane.

[0069] The protein-activated atomic layer deposition superhydrophilic modified membrane prepared in this embodiment has a contact angle of approximately 0° with water, while the control group without protein activation has a contact angle of approximately 125° with water. The results indicate that this embodiment can achieve the preparation of superhydrophilic polymer separation membranes through activated atomic layer deposition.

[0070] Example 6:

[0071] The method for preparing a superhydrophilic polymer separation membrane by activated atomic layer deposition in this embodiment is specifically prepared according to the following steps:

[0072] 1. Soak the porous polytetrafluoroethylene separation membrane in ethanol and water respectively to obtain a wetted membrane;

[0073] 2. Dissolve whey protein in water to obtain solution A. Immerse the wet film from step 1 in solution A and coat it for 12 hours. Then wash it with deionized water, air dry it, and set it aside. The concentration of bovine serum albumin is 2 g / L.

[0074] 3. The protein-modified membrane transfer atomic layer deposition device obtained in step 2 is subjected to SnO2 atomic layer deposition. The metal-organic precursor SnCl4 is introduced for 5 seconds, then nitrogen is purged for 50 seconds, then the precursor H2O is introduced for 5 seconds, and then nitrogen is purged for 50 seconds.

[0075] Fourth, control the number of atomic layer deposition cycles until 150 depositions are completed to obtain the final modified superhydrophilic polymer separation membrane.

[0076] The protein-activated atomic layer deposition superhydrophilic modified membrane prepared in this embodiment has a contact angle of approximately 0° with water, while the control group's unactivated atomic layer deposition modified membrane has a contact angle of approximately 120° with water. The results indicate that this embodiment can achieve the preparation of superhydrophilic polymer separation membranes through activated atomic layer deposition.

[0077] Example 7:

[0078] The method for preparing a superhydrophilic polymer separation membrane by activated atomic layer deposition in this embodiment is specifically prepared according to the following steps:

[0079] 1. Soak the porous polytetrafluoroethylene separation membrane in ethanol and water respectively to obtain a wetted membrane;

[0080] 2. Dissolve ovalbumin in water to obtain solution A. Immerse the wet membrane from step 1 in solution A and coat it for 24 hours. Then wash it with deionized water, air dry it, and set it aside. The concentration of bovine serum albumin is 3 g / L.

[0081] 3. The protein-modified membrane transfer atomic layer deposition device obtained in step 2 is subjected to SnO2 atomic layer deposition. The metal-organic precursor SnCl4 is introduced for 4 seconds, then nitrogen is purged for 35 seconds, then the precursor H2O is introduced for 4 seconds, and then nitrogen is purged for 35 seconds.

[0082] Fourth, control the number of atomic layer deposition cycles until 100 depositions are completed to obtain the final modified superhydrophilic polymer separation membrane.

[0083] The protein-activated atomic layer deposition superhydrophilic modified membrane prepared in this embodiment has a contact angle of approximately 0° with water, while the control group's unactivated atomic layer deposition modified membrane has a contact angle of approximately 120° with water. The results indicate that this embodiment can achieve the preparation of superhydrophilic polymer separation membranes through activated atomic layer deposition.

Claims

1. A method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane, comprising the following steps:

1. The porous polymer separation membrane was soaked in alcohol and water respectively to obtain a wetted membrane; 2. Dissolve the water-soluble protein in water to obtain solution A. Immerse the wet membrane from step 1 in solution A, coat it, wash it, and dry it for later use to give the separation membrane an active intermediate layer.

3. Transfer the protein-modified membrane obtained in step 2 into the cavity of the atomic layer deposition apparatus for atomic layer deposition. Then, introduce the metal-organic precursor A and purge with inert gas, then introduce the precursor B and purge with inert gas.

4. Repeat step 3 as many times as required to obtain the final modified membrane.

2. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The polymer separation membrane mentioned in step one is a polyvinylidene fluoride membrane, a polypropylene membrane, or a polytetrafluoroethylene membrane.

3. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The water-soluble protein mentioned in step two is bovine serum albumin, ovalbumin, lysozyme, or whey protein.

4. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The concentration of protein in solution A described in step two is 0.5~3 mg / mL.

5. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The organometallic precursor A mentioned in step three is TiCl4, Ti(OC3H7)4, or SnCl4.

6. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The precursor B mentioned in step three is H2O.

7. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The coating time in solution A described in step two is 3 to 48 hours.

8. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The alcohol mentioned in step one is methanol, ethanol or isopropanol.

9. The method for preparing an activated atomic layer deposition superhydrophilic polymer separation membrane according to claim 1, characterized in that, The number of repetitions in step four is greater than 100.

10. An activated atomic layer deposition superhydrophilic polymer separation membrane prepared by any one of claims 1 to 9.

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