阅读说明：本技术 一种采用旋涂法在疏水介孔有机硅表面制备无缺陷微孔有机硅膜的方法 (Method for preparing defect-free microporous organic silicon film on hydrophobic mesoporous organic silicon surface by spin coating method ) 是由 任秀秀 张佳佳 钟璟 徐荣 左士祥 丘童越 张凌波 于 2020-04-24 设计创作，主要内容包括：本发明提供了一种采用旋涂法在疏水介孔有机硅表面制备无缺陷微孔有机硅膜的方法,主要在于解决微孔有机硅纳米溶胶难以旋涂于介孔表面形成连续膜的问题。本发明的主要特征在于先在大孔载体上负载疏水介孔有机硅层,然后采用常温低压水蒸汽等离子体流进行改性,仅在其表面形成亲水薄层,介孔内结构依然保持疏水性,且表面形貌未被等离子体破坏,最后再旋涂有机硅纳米溶胶,制备出无缺陷微孔膜。该微孔有机硅膜在含有水蒸气条件下的气体分离应用中,表现了良好的渗透选择性能。(The invention provides a method for preparing a defect-free microporous organic silicon film on the surface of hydrophobic mesoporous organic silicon by adopting a spin-coating method, and mainly aims to solve the problem that microporous organic silicon nano sol is difficult to spin on the surface of mesoporous to form a continuous film. The method is mainly characterized in that a hydrophobic mesoporous organic silicon layer is loaded on a macroporous carrier, then a normal-temperature low-pressure water vapor plasma flow is adopted for modification, only a hydrophilic thin layer is formed on the surface of the mesoporous organic silicon layer, the mesoporous structure still keeps hydrophobic, the surface appearance is not damaged by the plasma, and finally the organic silicon nano sol is coated in a spinning mode to prepare the defect-free microporous membrane. The microporous silicone membrane exhibits good permselectivity in gas separation applications under water vapor-containing conditions.)

1. A method for preparing a defect-free microporous organic silicon film on the surface of hydrophobic mesoporous organic silicon by adopting a spin-coating method comprises the following specific steps:

(1) mixing two kinds of alkoxy silane to prepare organic silica sol, spin-coating the organic silica sol on a ceramic chip, and roasting to form a hydrophobic mesoporous layer;

(2) putting the obtained ceramic wafer loaded with the hydrophobic mesoporous layer into a plasma instrument, and carrying out hydrophilic surface modification by using water vapor plasma;

(3) and after hydrophilic surface modification, taking out the ceramic wafer, spin-coating the ceramic wafer after plasma treatment with the organic silicon nano sol, and calcining to prepare the microporous organic silicon film for gas separation.

2. The method for preparing a defect-free microporous organosilicon film on the surface of hydrophobic mesoporous organosilicon by spin coating according to claim 1, wherein the ceramic sheet in step (1) is α -Al₂O₃The material has a pore diameter of 100-200nm and a porosity of 35%.

3. The method of claim 1 for preparing a defect-free microporous silicone film on a hydrophobic mesoporous organosilicon surface by spin coating, wherein the method comprises the following steps: in the step (1), the two alkoxysilanes are organic silica sol Me-SiO prepared by mixing methyltrimethoxysilane or methyltriethoxy and ethyl orthosilicate₂The particle size of the formed sol is 10-30 nm.

4. The method of claim 1 for preparing a defect-free microporous silicone film on a hydrophobic mesoporous organosilicon surface by spin coating, wherein the method comprises the following steps: the concentration of the organic silica sol spun in the step (1) is 2-5 wt%, the rotating speed of a spin coater is 1000r/min, the time is 1-10min, and the step is repeated for 3-5 times.

5. The method of claim 1 for preparing a defect-free microporous silicone film on a hydrophobic mesoporous organosilicon surface by spin coating, wherein the method comprises the following steps: the ceramic wafer with the organic silicon layer coated in the step (1) is roasted for 0.5 to 3 hours at the temperature of 300 ℃, and finally Me-SiO is formed₂The ceramic sheet membrane has a surface contact angle of between 110 DEG and 130 DEG, and is a hydrophobic surface.

6. The method of claim 1 for preparing a defect-free microporous silicone film on a hydrophobic mesoporous organosilicon surface by spin coating, wherein the method comprises the following steps: in the step (2), the power of the plasma is 10-50W, the pressure is 10-100Pa, and the treatment time is 5-90 seconds.

7. The method of claim 1 for preparing a defect-free microporous silicone film on a hydrophobic mesoporous organosilicon surface by spin coating, wherein the method comprises the following steps: the organic silicon nano sol in the step (3) is prepared from one or more of bis (triethoxysilyl) methane (BTESM), 1, 2-bis (triethoxysilyl) ethane (BTESE) and 1, 3-bis (triethoxysilyl) propane (BTESP).

8. The method of claim 1 for preparing a defect-free microporous silicone film on a hydrophobic mesoporous organosilicon surface by spin coating, wherein the method comprises the following steps: the spin coating in the step (3) refers to spin coating the organosilicon nano sol with the concentration of 0.5-1 wt% on the plasma treated Me-SiO₂Setting the rotating speed of a spin coating instrument to be 2000r/min for 1-10min on the ceramic wafer, and repeating the step for 2-3 times.

9. The method of claim 1 for preparing a defect-free microporous silicone film on a hydrophobic mesoporous organosilicon surface by spin coating, wherein the method comprises the following steps: the calcining temperature in the step (3) is 300 ℃, and the calcining time is 0.5-3 h.

10. A defect free microporous silicone membrane prepared by the method of any one of claims 1-9 for gas separation under high water vapor conditions.

Technical Field

The invention belongs to the technical field of membrane material preparation, and particularly relates to a method for preparing a continuous microporous organic silicon membrane by spin coating after hydrophilic modification of steam plasma flow on the surface of hydrophobic mesoporous organic silicon.

Background

The hydrophobic mesoporous film has good water vapor condensation resistance. The hydrophobic mesoporous membrane is used as a matrix to prepare a microporous organic silicon membrane which can be used for gas separation under water vapor. At present, methods for coating an organic silica sol on a support to form a membrane include wiping, dip coating, spin coating and spraying, wherein the spin coating method has a simple process, and the obtained membrane is uniform and thin, so that the method is a membrane preparation method which is beneficial to industrial amplification. Pre-coating large-particle-size mixed sol on a ceramic wafer containing rich-OH, performing roasting heat treatment, bonding-OH among particle sizes and-OH of the ceramic wafer to dewater to form Me-SiO₂And (3) coating organic silicon sol on the hydrophobic mesoporous transition layer, calcining to form a microporous organic silicon separation membrane, and finally obtaining the organic silicon composite membrane for gas separation.

In the method for preparing the organic silicon composite membrane on the hydrophobic transition layer of CN201910986165.3 and the application of gas separation under the condition of water vapor, hydrophobic mixed silica sol is prepared, the hydrophobic transition layer is formed on a carrier, and then the microporous organic silicon separation layer is prepared on the hydrophobic transition layer by adopting a wiping method. With the continuous research and the deepening of the technology, the discovery is made on the Me-SiO₂If the microporous organic silica sol is prepared on the mesoporous hydrophobic membrane layer by adopting a spin-coating method, the organic silica sol contains a large amount of silicon hydroxyl groups, and discontinuous defects occur due to the extremely high centrifugal force and the repulsion action of hydrophobic groups during spin-coating. The defective organic silicon film is applied to gas separation under the condition of water vapor, and the performance is difficult to keep stable. But if on Me-SiO₂Hydrophilic modification of mesoporous hydrophobic membraneAnd then spin-coating the small-particle-size microporous organic silica sol to improve the defect problem of microporous membranes and ensure the separation of gas in a dry state, but the capillary condensation phenomenon occurs in hydrophilic mesoporous membranes during gas separation under the condition of water vapor, so that the gas permeation is greatly hindered.

Therefore, how to not only ensure that the gas separation under the condition of water vapor has good gas separation effect, but also prepare a defect-free microporous separation layer under the spin coating method and ensure the stability of the gas separation performance is a technical problem which needs to be solved urgently. There has been no current research in the art regarding proposals and solutions for gas separation membranes under water vapor to have this problem.

Disclosure of Invention

Aiming at the problem that a microporous organic silicon film prepared by a spin-coating method on a hydrophobic mesoporous layer has defects, the invention provides a method for preparing the microporous organic silicon film by modifying hydrophobic mesoporous organic silicon, wherein a hydrophobic surface is treated by a steam plasma flow formed after introducing nitrogen into steam, only a surface thin layer is hydrophilized, but the pore diameter is still hydrophobic, then, an organic silicon sol containing silicon hydroxyl groups is spin-coated and roasted, so that the silicon hydroxyl groups are mutually bonded and dehydrated to form a compact defect-free organic silicon film, and the prepared separation film has a good gas separation effect when performing gas separation under the steam condition, and the defect-free microporous separation layer also ensures the stability of the gas separation performance.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

(1) two kinds of alkoxy silane are mixed to prepare organic silica sol Me-SiO with the particle size of 10-30nm₂；

The two alkoxysilanes are organic silica sol Me-SiO prepared by mixing methyltrimethoxysilane or methyltriethoxy and ethyl orthosilicate₂The particle size of the formed sol is 10-30 nm.

(2) Mixing the sol with ethanol solvent to obtain 2-5 wt% of organic silica sol, spin-coating on ceramic wafer (ceramic wafer aperture of 100-Roasting for 5 times in a muffle furnace at 300 ℃ for 0.5 to 3 hours to form hydrophobic mesoporous Me-SiO₂The ceramic sheet membrane has a surface contact angle of between 110 DEG and 130 DEG, and is a hydrophobic surface.

(3) The obtained hydrophobic mesoporous Me-SiO₂Putting the ceramic wafer into the center of the plasma cavity, and then vacuumizing to keep the vacuum degree at 10-100 Pa.

(4) Opening N₂And a steam valve, wherein the flow rate ratio of the steam valve to the steam valve is adjusted to be 1-5: 1, turning on a plasma power supply, setting the power at 10-50W, treating for 5-90 seconds, introducing helium (He) gas to pressurize to atmospheric pressure (based on local atmospheric pressure), and taking out the substrate.

According to the invention, water vapor is used as plasma, nitrogen plays a role in carrying out water vapor, transitional wetting of the water vapor to the mesoporous layer is weakened, and the hydrophobic mesoporous surface is hydrophilic through plasma treatment, so that the subsequent spin coating effect is facilitated.

(5) One or more of bis (triethoxysilyl) methane (BTESM), 1, 2-bis (triethoxysilyl) ethane (BTESE) or 1, 3-bis (triethoxysilyl) propane (BTESP) are adopted to prepare the sol with the particle size of the organic silicon of 1-2nm by a conventional method.

(6) Me-SiO treated in a stream of water vapor plasma₂The organic silicon nano sol prepared in the step (5) is immediately spin-coated on the ceramic wafer for 2-3 times at a rotating speed of 2000r/min for 1-10min, and then the ceramic wafer is put into a muffle furnace, the roasting temperature is 300 ℃, and the roasting time is 0.5-3 hours, so that the defect-free microporous organic silicon film is obtained.

The invention has the beneficial effects that: the method for preparing the microporous organic silicon film by modifying the hydrophobic mesoporous organic silicon through the hydrophilic modification of the hydrophobic mesoporous organic silicon film comprises the steps of modifying the surface of a hydrophobic mesoporous matrix through normal-temperature low-pressure steam plasma flow, controlling condition parameters, and enabling the treated hydrophobic mesoporous organic silicon film to only change the hydrophobic property of the outer surface, not change the hydrophobicity inside the mesoporous, be hydrophobic in the pore diameter, not be damaged by the plasma, and not block the pore diameter and damage the structure, so that the subsequent hydrophilic layer is spin-coated with the organic silicon film containing the hydroxyl groups, a continuous and flawless film layer can be formed, and the gas separation effect and the separation stability are ensured when the organic silicon film is applied to gas separation under steam.

Drawings

FIG. 1 is a schematic representation of the invention of Me-SiO untreated and water vapor plasma stream treated₂Layer atomic force microscopy images.

FIG. 2 shows the nano-permeameter test N of the present invention₂The permeability is reduced by the degree of water vapor conditions of the untreated and water vapor plasma stream treated membranes.

FIG. 3 is a BTESE/Me-SiO solid phase of the invention untreated and treated with a steam plasma stream₂Scanning electron microscope image of ceramic film surface.

FIG. 4 depicts untreated and water vapor plasma flow treated spin-on bodies of the invention BTESE/Me-SiO₂Silicon wafer surface pattern.

Detailed Description