Porous polystyrene template with adjustable pore diameter, preparation method of porous polystyrene template and application of porous polystyrene template in porous spherical shell
By adding a sulfonic acid group modification layer to the surface of a polystyrene template and etching it to form a porous structure, the problem of small pore size in the prior art is solved, and the preparation of porous polystyrene templates with adjustable pore size is realized. When applied to porous spherical shells, it improves the mass transfer rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIV OF SCI & TECH
- Filing Date
- 2025-12-18
- Publication Date
- 2026-04-21
AI Technical Summary
The pore size of nanomaterials prepared by existing polystyrene templates is less than 10 nm, which is insufficient to meet the high mass transfer rate requirements in fields such as catalytic reactions and gas/water separation.
By adding a sulfonic acid group modification layer to the surface of a polystyrene template, a porous structure is formed by etching with an organic solvent, and a porous polystyrene template with adjustable pore size is achieved by adjusting the template pore size structure design.
A porous polystyrene template with adjustable pore size was prepared and applied to porous spherical shells, achieving a higher mass transfer rate.
Smart Images
Figure CN121895618A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanostructure materials technology, specifically relating to a porous polystyrene template with adjustable pore size, its preparation method, and its application in porous spherical shells. Background Technology
[0002] Template-based methods are one of the most important techniques for synthesizing nanostructured materials. These methods utilize templates with desired micro / nano structural features to guide the growth of nanomaterials, enabling the synthesis of morphologies that are difficult to obtain through other methods.
[0003] Polystyrene (PS) is one of the most commonly used polymer templates, offering advantages such as low cost, simple synthesis, and easy removal. The polystyrene template is typically a smooth sphere (the sphere has the lowest free energy). Nanomaterials are deposited on the PS surface to form a spherical shell, and the PS template is finally removed through pyrolysis, organic solvent dissolution, or other methods to synthesize the spherical shell nanomaterials. Typically, the pore size of the spherical shell nanomaterials synthesized by this method is usually less than 10 nm. In applications such as catalysis and gas / water separation, the small pore size is insufficient to meet the requirements of high mass transfer rates. Summary of the Invention
[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.
[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.
[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a porous polystyrene template with adjustable pore size, its preparation method, and its application in porous spherical shells.
[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a porous polystyrene template with adjustable pore size, comprising, Use the PS microsphere as the basic PS template; Using PS microspheres as the core, they were dissolved with PVP, styrene, and sodium styrene sulfonate in a mixed solvent of anhydrous ethanol and deionized water. After ultrasonic dispersion, the mixture was purged with argon gas, AIBN was added, and the mixture was heated and stirred in an oil bath. After centrifugation and washing with anhydrous ethanol, a sulfonic acid-modified bilayer PS template was obtained. Sulfonic acid-modified bilayer PS template, along with AIBN and PVP, was dissolved in a mixed solvent of anhydrous ethanol and deionized water. After ultrasonic dispersion, isooctyl methacrylate and n-decane were added. The mixture was then purged with argon gas, heated in a water bath, centrifuged, and washed with anhydrous ethanol to obtain the final product.
[0008] As a preferred embodiment of the preparation method described in this invention, the method for preparing the PS microspheres includes dissolving polyvinylpyrrolidone and azobisisobutyronitrile in a mixed solvent of anhydrous ethanol and deionized water, purging with argon gas, adding styrene oil bath for heating and stirring, centrifuging, and washing with anhydrous ethanol to obtain the microspheres.
[0009] In a preferred embodiment of the preparation method described in this invention, the mass fraction of n-decane relative to the mixed solvent of anhydrous ethanol and deionized water is 3-5%.
[0010] In a preferred embodiment of the preparation method described in this invention, the water bath heating time is 1-2 hours and the temperature is 65-70°C.
[0011] Another objective of this invention is to overcome the shortcomings of the prior art and provide a porous polystyrene template with adjustable pore size prepared by a method thereof.
[0012] As a preferred embodiment of the porous polystyrene template of the present invention, the core of the porous polystyrene template is PS microspheres, the outer shell is a sulfonic acid modified polystyrene layer, and the surface has a porous structure.
[0013] As a preferred embodiment of the porous polystyrene template of the present invention, the porous polystyrene template has a pore size of 200nm~400nm.
[0014] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of porous polystyrene templates in porous spherical shells.
[0015] In a preferred embodiment of the application described in this invention, a porous polystyrene template with adjustable pore size is added to an aqueous solution containing polyacrylamide hydrochloride and sodium chloride, ultrasonically dispersed and stirred, and then filtered. The modified porous PS template is dispersed in a mixed solvent of anhydrous ethanol and deionized water, ammonia and tetraethyl orthosilicate are added, ultrasonically dried at room temperature, and the PS template is removed using dichloromethane.
[0016] As a preferred embodiment of the application described in this invention, the porous spherical shell has a pore size of 100nm~300nm, a diameter of 1.3μm, and a wall thickness of 100nm.
[0017] Beneficial effects of this invention: This invention adds a sulfonic acid group modification layer to the surface of a polystyrene template, induces organic solvent etching, and forms a porous structure on the template surface. By adjusting the pore size structure of the template, different pore size structures of nanomaterials can be designed. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This invention relates to a porous polystyrene template and its synthesis pathway for porous spherical shell materials.
[0019] Figure 2 This is a scanning electron microscope image of the PS template in Embodiment 1 of the present invention.
[0020] Figure 3 This is a scanning electron microscope image of microporous polystyrene on the surface of Example 1 of the present invention.
[0021] Figure 4 This is a scanning electron microscope image of mH-SiO2 with surface pore size in Embodiment 1 of the present invention.
[0022] Figure 5 This is a scanning electron microscope image of the porous PS template in Embodiment 2 of the present invention.
[0023] Figure 6 This is a scanning electron microscope image of porous shell-like SiO2 in Embodiment 2 of the present invention. Figure 7 This is a scanning electron microscope image of the porous PS template in Embodiment 3 of the present invention.
[0024] Figure 8 This is a scanning electron microscope image of porous shell-shaped SiO2 in Embodiment 3 of the present invention.
[0025] Figure 9 This is a scanning electron microscope image of the porous PS template used in Comparative Example 1 of the present invention.
[0026] Figure 10 This is a scanning electron microscope image of the porous shell-like SiO2 in Comparative Example 1 of the present invention.
[0027] Figure 11 This is a scanning electron microscope image of the porous PS template used in Comparative Example 2 of this invention.
[0028] Figure 12 This is a scanning electron microscope image of the porous shell-like SiO2 in Comparative Example 2 of the present invention.
[0029] Figure 13This is a scanning electron microscope image of the porous shell-like SiO2 in Comparative Example 3 of the present invention.
[0030] Figure 14 The image shown is a PS template SEM image, which is a comparative example of this invention.
[0031] Figure 15 Example 5 is a PS template SEM image of the present invention. Detailed Implementation
[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.
[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0034] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0035] Unless otherwise specified, all raw materials used in the embodiments of this invention are commercially available. See Table 1 for details.
[0036] Table 1
[0037] Example 1 (1) Preparation of PS template core: Using a 250 mL three-necked flask as the container, 1.5 g PVP K30 and 0.15 g AIBN were dissolved in a solvent containing 80 mL anhydrous ethanol and 20 mL deionized water. The solvent was purged with argon (Ar) for 30 min to remove residual air from the solvent and the container. 10 mL of styrene was added to the three-necked flask, and purging with Ar was continued for 20 min. After purging, the three-necked flask was sealed and heated and stirred in an oil bath for 24 h at 70 °C and 60 rpm. After the reaction was completed, the obtained PS microspheres were separated by centrifugation. The microspheres were washed three times with anhydrous ethanol to remove surface residues.
[0038] Figure 2 The image shows a scanning electron microscope image of the prepared PS microspheres. As can be seen from the image, the microspheres are uniform in size and have good dispersibility.
[0039] (2) Preparation of sulfonic acid modified outer shell: To prepare porous PS microspheres, the PS surface needs to be modified. Using the PS microspheres prepared in step (1) as the core, a polystyrene shell modified with sulfonic acid is grown on the core surface. The preparation steps are as follows: Using a 250 mL three-necked flask as a container, 200 mg of the prepared PS microspheres, 1.5 g PVP K30, 2 mL of styrene and 0.04 g of NaSS are dissolved in a solvent containing 80 mL of anhydrous ethanol and 20 mL of deionized water. The three-necked flask is then placed in an ultrasonic cleaner and sonicated for 30 min to uniformly disperse the PS spheres in the solvent. Ar is used to purge for 30 min to remove residual air from the solvent and container. 0.03 g of AIBN is added to the three-necked flask, and Ar purging is continued for 20 min. After purging, the three-necked flask is sealed and placed in an oil bath for stirring and heating for 24 h. The temperature is set to 70 °C and the rotation speed is set to 60 rpm. After the reaction was complete, the surface-modified sulfonic acid-modified bilayer PS template (modified PS template) was separated using a centrifuge. It was then washed three times with anhydrous ethanol to remove surface residues.
[0040] (3) Preparation of porous PS template: A porous structure was etched onto the surface of the modified PS template using a phase separation method. Using a 20 mL glass sample vial as the container, 0.5 g of modified PS template, 0.03 g of AIBN, and 0.3 g of PVP were added to a solvent containing 8 g of anhydrous ethanol and 2 g of deionized water. The mixture was ultrasonically cleaned for 30 min to ensure uniform dispersion. 0.2 g of EHMA and 0.5 g of n-decane were added to the dispersion, and the mixture was vortexed for 1 min, followed by purging with Ar for 20 min to remove air. The sample vial was sealed and placed in a water bath at 70°C for 1 hour. The sample was then separated using a centrifuge and washed three times with anhydrous ethanol.
[0041] Due to the introduction of sodium styrene sulfonate, the PS surface contains a large number of sulfonic acid groups. These sulfonic acid groups allow n-decane nanodroplets to enter the sulfonic acid-modified outer shell layer, causing the outer shell layer to swell and forming a P(S-NaSS) structure encapsulating the n-decane nanodroplets on the PS template surface. When the n-decane nanodroplets are removed, a porous PS template (1 micrometer in diameter) is obtained.
[0042] To prevent the pores from being covered by the subsequent SiO2 deposition process, EHMA was used to passivate the pores. EHMA is soluble in n-decane but insoluble in ethanol and water, therefore it will only adsorb into the surface pores. The pore size of the PS template can be adjusted by changing the amount of n-decane added, the heating time, and the heating temperature.
[0043] Figure 3 This is a scanning electron microscope image of a porous PS template.
[0044] (4) Preparation of porous silica: To deposit SiO2 onto the PS surface, the modified PS template was first surface-modified using PAH. 0.2 g of the porous PS template was added to an aqueous solution containing 0.08 g PAH and 0.23 g NaCl, and ultrasonically dispersed for 30 min. The mixture was stirred with a magnetic stirrer for 1 h, and then the PAH-modified porous PS template was filtered out. The PAH-modified porous PS template was added to a solvent containing 85 mL anhydrous ethanol and 15 mL deionized water, and ultrasonically dispersed for 20 min. 1.5 mL ammonia and 1.5 mL TEOS were added, and the mixture was ultrasonically dispersed at room temperature for 2 h to prevent adhesion during SiO2 deposition. After deposition, the sample was separated using a centrifuge and dried in a vacuum drying oven. The PS template was then removed from the sample using dichloromethane to obtain porous silica microspheres.
[0045] Figure 1 This invention relates to a porous polystyrene template and its synthesis pathway for porous spherical shell materials. Figure 4 The images show scanning electron microscope (SEM) images of porous silica with different surface pore sizes. The porous silica microspheres have a diameter of approximately 1.3 µm, a pore size of 200 nm, and a wall thickness of approximately 100 nm.
[0046] Example 2 The difference from Example 1 is that the amount of n-decane added in step (3) is 0.3 g. At this time, the concentration of organic droplets is low, and the pore size of the prepared porous PS template is 200 nm. The pore size of the porous shell-shaped SiO2 prepared by this template is about 100 nm.
[0047] Figure 5 Scanning electron microscope image of a porous PS template. Figure 6 This is a scanning electron microscope image of the porous shell-like SiO2 prepared using this template.
[0048] Example 3 The difference from Example 1 is that the heating temperature in step (3) is 70°C and the heating time is 2 h. At this time, the organic droplets have higher thermal reactivity and more sufficient reaction time, and the pore size of the prepared porous PS template increases to 400 nm. The pore size of the porous shell-shaped SiO2 prepared by this template is about 300 nm.
[0049] Figure 7 Scanning electron microscope image of a porous PS template. Figure 8 This is a scanning electron microscope image of the porous shell-like SiO2 prepared using this template.
[0050] Comparative Example 1 The difference from Example 1 is that the heating time in step (3) is changed to 15 min, while the rest of the steps are the same as in Example 1.
[0051] Figure 9 Scanning electron microscope image of a porous PS template. Figure 10 This is a scanning electron microscope image of the porous shell-like SiO2 prepared using this template. At this point, the reaction time was insufficient, resulting in small and irregular pore sizes in the prepared porous PS template, and the porous shell-like SiO2 prepared using this template had closed pores.
[0052] Comparative Example 2 The difference from Example 1 is that the heating time in step (3) is changed to 3 hours, while the rest of the steps are the same as in Example 1.
[0053] Figure 11 Scanning electron microscope image of a porous PS template. Figure 12 This is a scanning electron microscope image of the porous shell-shaped SiO2 prepared using this template. If the reaction time is too long, the resulting porous PS template will have excessively large and irregular pore sizes, making the porous shell-shaped SiO2 prepared using this template prone to breakage.
[0054] Comparative Example 3 The difference between this comparative example and Example 1 is that the amount of NaSS added in step (2) is zero, that is, it is a regular PS template at this time. The other steps are the same as in Example 1.
[0055] Figure 13 Comparison of SEM images of PS template under these conditions. In this case, the organic droplets do not etch the PS template, thus failing to form a non-double-layered surface porous structure.
[0056] Comparative Example 4 The difference from Example 1 is that NaSS with the same proportion as in step (2) is added in step (1), that is, it is a fully modified PS template and not a two-layer structure. The remaining steps are the same as in Example 1.
[0057] Figure 14 The SEM image of the PS template under these conditions shows that the droplets penetrate deep into the interior, leaving only tiny openings on the surface. At this point, the organic droplets have penetrated the fully modified PS template, and the surface pore size is uncontrollable.
[0058] Comparative Example 5 The difference from Example 1 is that in step (4), PAH is replaced with the commonly used modified material hexadecyltrimethylammonium bromide (CTAB), while the rest of the steps are the same as in Example 1.
[0059] Figure 15 Under these conditions, the SiO2 SEM image shows a closed surface and a fragmented shell. In this case, the surface pores of the porous PS template will be covered by CTAB, inducing SiO2 deposition within the pores, resulting in pore closure and preventing the synthesis of porous shell-like SiO2.
[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.
Claims
1. A method for preparing a porous polystyrene template with adjustable pore size, characterized in that: include, Use the PS microsphere as the basic PS template; Using PS microspheres as the core, they were dissolved with PVP, styrene, and sodium styrene sulfonate in a mixed solvent of anhydrous ethanol and deionized water. After ultrasonic dispersion, the mixture was purged with argon gas, AIBN was added, and the mixture was heated and stirred in an oil bath. After centrifugation and washing with anhydrous ethanol, a sulfonic acid-modified bilayer PS template was obtained. Sulfonic acid-modified bilayer PS template, along with AIBN and PVP, was dissolved in a mixed solvent of anhydrous ethanol and deionized water. After ultrasonic dispersion, isooctyl methacrylate and n-decane were added. The mixture was then purged with argon gas, heated in a water bath, centrifuged, and washed with anhydrous ethanol to obtain the final product.
2. The preparation method according to claim 1, characterized in that: The preparation method of the PS microspheres includes dissolving polyvinylpyrrolidone and azobisisobutyronitrile in a mixed solvent of anhydrous ethanol and deionized water, purging with argon gas, adding styrene oil bath for heating and stirring, centrifuging, and washing with anhydrous ethanol to obtain the microspheres.
3. The preparation method according to claim 1, characterized in that: The mass fraction of n-decane relative to the mixed solvent of anhydrous ethanol and deionized water is 3-5%.
4. The preparation method according to claim 1, characterized in that: The water bath heating time is 1-2 hours, and the temperature is 65-70℃.
5. The porous polystyrene template with adjustable pore size prepared by the preparation method according to claims 1 to 4.
6. The porous polystyrene template as described in claim 5, characterized in that: The porous polystyrene template has a PS microsphere core and a sulfonic acid-modified polystyrene layer as its outer shell, with a porous structure on its surface.
7. The porous polystyrene template as described in claim 6, characterized in that: The porous polystyrene template has a pore size of 200nm~400nm.
8. The application of the porous polystyrene template as described in claim 5 in porous spherical shells.
9. The application according to claim 8, characterized in that: The process includes adding a porous polystyrene template with adjustable pore size to an aqueous solution containing polyacrylamide hydrochloride and sodium chloride, ultrasonically dispersing and stirring, then filtering, dispersing the modified porous PS template in a mixed solvent of anhydrous ethanol and deionized water, adding ammonia and tetraethyl orthosilicate, ultrasonicating at room temperature, centrifuging and drying, and removing the PS template with dichloromethane.
10. The application as described in claim 9, characterized in that: The porous spherical shell has a pore size of 100nm~300nm, a diameter of 1.3μm, and a wall thickness of 100nm.