A method for preparing a morphology-controllable silica gel structure based on stimulus response

Abstract

The present invention, applicable to the field of nanomaterial synthesis technology, provides a method for preparing morphologically controllable silica gel structures based on a stimulus-responsive approach. The method comprises the following steps: dissolving an amphiphilic polymer in an organic solvent, then adding an alcohol and a small amount of aqueous solution to form a stable oil-in-water system; subsequently, hydrolyzing and polymerizing a silicon source under the catalysis of ammonia molecules, generating silica gel rod-like structures under the structural guidance of the amphiphilic polymer; and dynamically adjusting the reaction temperature and time during the growth of the silica gel rods to stimulate the growth process, thereby producing single-segment, double-segment, and triple-segment silica gel rod-like structures of varying lengths. This method is simple, economical, reproducible, and high-yield, contributing to further understanding of the mechanism of colloidal growth and the development of novel colloidal structures, thereby broadening the application prospects of colloidal materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterial synthesis, and in particular relates to a method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner. Background Art

[0002] Colloidal particles have attracted considerable attention due to their wide-ranging applications in fields such as antibacterial coatings, biomimetic motion, and electro-optical devices. The design of novel colloidal particles and the development of colloidal structures are of great theoretical and technological significance. By prescribing experimental parameters such as precursors, catalysts, templates, stabilizer molecules, pH, temperature, and relative reagent concentrations, colloidal particles with diverse morphologies, including spheres, bowls, fibers, and rods, can be synthesized. However, in nature, many complex morphologies are formed by stimuli from changes in the surrounding environment during growth. This stimuli-responsive morphological transformation induced by environmental or reaction conditions provides a promising approach for the design and development of novel colloidal particles and colloidal structures. Here, we propose a stimuli-responsive method for the preparation of morphologically controllable colloidal structures. By dynamically adjusting the reaction temperature and time during colloidal growth, the colloidal growth process is stimulated, resulting in single-, double-, and triple-segmented silica colloidal rods of varying lengths. This approach is crucial for understanding the mechanisms of colloidal growth and for the development and application of novel colloidal morphologies. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner, aiming to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner comprises the following steps:

[0006] Step S1, mixing an amphiphilic polymer with an organic solvent to obtain a clear and transparent mixed solution;

[0007] Step S2, adding the aqueous solution and the alcohol solution to the mixed solution of step S1 to obtain a stable water-in-oil system;

[0008] Step S3, adding an ammonia source to the mixed solution of step S2;

[0009] Step S4, adding a silicon source to the mixed solution of step S3, mixing well, and then standing at a constant temperature to react, so that the silicon source is hydrolyzed and condensed to form silicon oxide rod-shaped colloid;

[0010] Step S5, transferring the reaction system of step S4 to a 50-80°C oil bath and reacting for 3-10 minutes;

[0011] Step S6, removing the reaction system of step S5 from the oil bath environment, and then allowing it to react at a constant temperature;

[0012] Step S7, transferring the reaction system of step S6 to a 50-80°C oil bath again and reacting for 3-10 min;

[0013] Step S8, removing the reaction system of step S7 from the oil bath environment, and then allowing it to react at a constant temperature;

[0014] Step S9: Collect the final product of step S8, and obtain the target product after centrifugation, water washing, alcohol washing and drying.

[0015] Furthermore, in step S1, the amphiphilic polymer is polyvinyl pyrrolidone with a molecular weight of 40 kg / mol.

[0016] Furthermore, in step S1, the organic solvent is n-pentanol with a concentration of 98%.

[0017] Furthermore, in step S2, the aqueous solution is ultrapure water with a resistivity of 18.2 MΩ.

[0018] Furthermore, in step S2, the alcohol solution is ethanol with a concentration of 98%.

[0019] Furthermore, in step S3, the ammonia source is aqueous ammonia with a concentration of 27 wt%.

[0020] Furthermore, in step S4, the silicon source is tetraethyl orthosilicate with a concentration of 98%.

[0021] Furthermore, in step S4, the mixing method is one or more combinations of vortex vibration, ultrasound, stirring, and shaking.

[0022] Furthermore, in steps S4, S6 and S8, the constant temperature static reaction refers to reacting at 20-25° C. for 1-8 h.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This stimulus-responsive method for preparing morphologically controllable silica gel structures is simple, economical, reproducible, and high-yield. By dynamically adjusting the reaction temperature during the growth of the gel to stimulate the growth process, the method produces silica gel rod-like structures of varying morphologies. This approach is of great significance for further understanding the mechanisms of colloidal growth, constructing novel colloidal morphologies, and expanding the application of colloidal materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the synthesis method of the present invention.

[0026] Figure 2 This is a scanning electron microscope photograph of the three-segment silica colloidal rod structure material obtained in Example 1, which is Example 2.

[0027] Figure 3 In the figure, (a) is a scanning electron microscope photograph of the single-stage silica colloidal rod-shaped structure material obtained in Example 3, and (b) is a corresponding transmission electron microscope photograph; (c) is a scanning electron microscope photograph of the sample obtained by constant temperature static reaction for 2 h in Example 4, and (d) is a corresponding transmission electron microscope photograph; (e) is a scanning electron microscope photograph of the sample obtained by constant temperature static reaction for 3 h in Example 4, and (f) is a corresponding transmission electron microscope photograph.

[0028] Figure 4 In the figure, (a) and (b) are scanning electron microscope photos of the two-stage silica colloidal rod structure material obtained in Example 5, and (c) is the corresponding transmission electron microscope photo; (d) is a scanning electron microscope photo of the sample obtained in Example 6 with a first-stage reaction time of 2 h and a second-stage reaction time of 8 h, and (e) is the corresponding transmission electron microscope photo; (f) is a transmission electron microscope photo of the sample obtained in Example 6 with a first-stage reaction time of 3 h and a second-stage reaction time of 6 h. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0031] According to one embodiment of the present invention, a method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner is provided, comprising the following steps:

[0032] Step S1, mixing an amphiphilic polymer with an organic solvent to obtain a clear and transparent mixed solution;

[0033] Step S2, adding the aqueous solution and the alcohol solution to the mixed solution of step S1 to obtain a stable water-in-oil system;

[0034] Step S3, adding an ammonia source to the mixed solution of step S2;

[0035] Step S4, adding a silicon source to the mixed solution of step S3, mixing well, and then standing at a constant temperature to react, so that the silicon source is hydrolyzed and condensed to form silicon oxide rod-shaped colloid;

[0036] Step S5, transferring the reaction system of step S4 to a higher temperature environment for static reaction;

[0037] Step S6: transferring the reaction system of step S5 out of the high temperature environment and continuing the reaction at a constant temperature;

[0038] Step S7, transferring the reaction system of step S6 to a higher temperature environment again for static reaction;

[0039] Step S8, transferring the reaction system of step S7 out of the high temperature environment and continuing the reaction at a constant temperature;

[0040] Step S9: Collect the final product of step S8, and obtain the target product after centrifugation, water washing, alcohol washing and drying.

[0041] In an embodiment of the present invention, preferably, the preparation method specifically comprises the following steps:

[0042] Step S1, adding the amphiphilic polymer to an organic solvent and stirring with ultrasonic waves until it is completely dissolved to obtain a clear and transparent mixed solution;

[0043] Step S2, adding the aqueous solution and the alcohol solution to the mixed solution of step S1, and gently stirring for 2 h to obtain a stable water-in-oil system;

[0044] Step S3, adding an ammonia source as a catalyst dropwise into the mixed solution of step S2;

[0045] Step S4: adding a silicon source to the mixed solution of step S3, vortexing for 5 minutes, and allowing to react at a constant temperature of 20°C for 2 hours. When the silicon source diffuses to the water-oil interface, it is hydrolyzed into silicate oligomers. The negatively charged silicate oligomers polymerize under the structural guidance of the amphiphilic polymer and the catalytic action of ammonia molecules to form silica rod-shaped colloids.

[0046] Step S5, transferring the reaction system of step S4 to a 70°C oil bath and allowing to react for 5 minutes;

[0047] Step S6: The reaction system of step S5 was transferred out of the 70°C oil bath and continued to react at a constant temperature of 20°C for 4 hours;

[0048] Step S7, the reaction system of step S6 was transferred to a 70°C oil bath again and allowed to react for 5 minutes;

[0049] Step S8: The reaction system of step S7 was transferred out of the 70°C oil bath and continued to react at a constant temperature of 20°C for 4 hours;

[0050] Step S9: Collect the final product of step S8, remove the reaction system mother liquor and small particle impurities by centrifugation, water washing and alcohol washing, and dry it in a 65° C. oven for 12 h to obtain the target product: a three-segment silica colloidal rod structure.

[0051] As a preferred embodiment of the present invention, in step S1, the amphiphilic polymer is polyvinyl pyrrolidone with a molecular weight of 40 kg / mol.

[0052] In the embodiment of the present invention, preferably, the role of polyvinyl pyrrolidone is to minimize the oil-water interfacial tension, stabilize the oil-water interface, and induce the silicon source to polymerize into a rod-like structure through a structural guiding effect.

[0053] As a preferred embodiment of the present invention, in step S1, the organic solvent is n-pentanol with a concentration of 98%.

[0054] In the embodiment of the present invention, preferably, an organic solvent is used to construct the oil phase, and the organic solvent is n-pentanol with a volume of 10 mL.

[0055] As a preferred embodiment of the present invention, in step S2, the aqueous solution is ultrapure water with a resistivity of 18.2 MΩ.

[0056] In the embodiment of the present invention, preferably, an aqueous solution is used as the aqueous phase in the water-in-oil solution, and the aqueous solution is ultrapure water with a volume of 280 μL.

[0057] As a preferred embodiment of the present invention, in step S2, the alcohol solution is ethanol with a concentration of 98%.

[0058] In the embodiment of the present invention, preferably, alcohol is used to adjust the oil-water interfacial tension, and the alcohol is ethanol with a volume of 960 μL.

[0059] As a preferred embodiment of the present invention, in step S3, the ammonia source is ammonia water with a concentration of 27 wt%.

[0060] In the embodiment of the present invention, preferably, the ammonia source is used to catalyze the polymerization of silicate oligomers, and the ammonia source is ammonia water with a volume of 120 μL.

[0061] As a preferred embodiment of the present invention, in step S4, the silicon source is tetraethyl orthosilicate with a concentration of 98%.

[0062] In the embodiment of the present invention, preferably, a silicon source is used as a reaction precursor to provide raw materials for the growth of silicon rods, and the silicon source is tetraethyl orthosilicate in an amount of 100 μL.

[0063] As a preferred embodiment of the present invention, in step S4, the mixing method is one or more combinations of vortex vibration, ultrasound, stirring, and shaking.

[0064] In the embodiment of the present invention, preferably, the mixing method is vortex vibration.

[0065] As a preferred embodiment of the present invention, in steps S4, S6 and S8, the constant temperature static reaction refers to reacting at 20-25°C for 1-8 hours.

[0066] In the embodiment of the present invention, the reaction temperature is preferably 20° C., and the reaction time is preferably 4 h.

[0067] As a preferred embodiment of the present invention, in steps S5 and S7, the static reaction in a relatively high temperature environment refers to reacting in an oil bath at 50-80° C. for 3-10 min.

[0068] In the embodiment of the present invention, the reaction temperature is preferably 70° C., and the reaction time is preferably 5 min.

[0069] Example 1: 1000 mg of polyvinyl pyrrolidone with a molecular weight of 40 kg / mol was dispersed in 10 mL of n-pentanol and ultrasonically stirred until completely dissolved; 280 μL of ultrapure water and 960 μL of anhydrous ethanol were then added and stirred for 2 h (at a speed of 500 rpm); 120 μL of ammonia water (27 wt%) and 100 μL of tetraethyl orthosilicate (98 wt%) were then added and vortexed for 5 min; the reaction was allowed to stand at 20°C for 2 h; the reaction system was then transferred to a 70°C oil bath and allowed to stand for 5 min; the reaction system was then transferred out of the 70°C oil bath and continued to stand at 20°C for 4 h; the reaction system was then transferred to a 70°C oil bath again and allowed to stand for 5 min; the reaction system was then transferred out of the 70°C oil bath and continued to stand at 20°C for 4 h; the reaction mother liquor and small particle impurities were removed by centrifugal water washing and alcohol washing, and the mixture was dried in an oven at 65°C for 12 h obtained the target product in the form of white powder: a three-segment silica colloidal rod structure. Figure 1 Synthesis schematic.

[0070] Example 2: The three-stage silica colloidal rod-shaped structure material sample obtained in Example 1 was characterized by scanning electron microscopy. Figure 2 .like Figure 2 As shown, the obtained colloidal rods exhibited an obvious three-segment structure.

[0071] Example 3: 1000 mg of polyvinyl pyrrolidone with a molecular weight of 40 kg / mol was dispersed in 10 mL of n-pentanol and ultrasonically stirred until completely dissolved; 280 μL of ultrapure water and 960 μL of anhydrous ethanol were then added and stirred for 2 h (at a speed of 500 rpm); 120 μL of ammonia water (27 wt%) and 100 μL of tetraethyl orthosilicate (98 wt%) were then added and vortexed for 5 min; the mixture was allowed to react at a constant temperature of 20°C for 1 h; the reaction mother liquor and small particle impurities were removed by centrifugal washing with water and alcohol, and the mixture was dried in an oven at 65°C for 12 h to obtain a white powdery product: a single-stage silica colloidal rod structure, see for details. Figure 3 (a) and Figure 3 (b).

[0072] Example 4 is similar to Example 3 except that the constant temperature static reaction time is extended. Figure 3 (c) and Figure 3 (d), reaction time was 2 h; Figure 3 (e) and Figure 3 (f) The reaction time was 3 h. Compared with Example 3, as the reaction time was prolonged, the length of the colloidal rods gradually increased from ~250 nm to ~450 nm. This indicates that the length of each colloidal rod segment can be controlled by controlling the reaction time.

[0073] Example 5: Disperse 1000 mg of polyvinylpyrrolidone (40 kg / mol) in 10 mL of n-pentanol and ultrasonically stir until completely dissolved. Then, add 280 μL of ultrapure water and 960 μL of anhydrous ethanol and stir for 2 h (at 500 rpm). Then, add 120 μL of aqueous ammonia (27 wt%) and 100 μL of tetraethyl orthosilicate (98 wt%) and vortex for 5 min. Incubate at 20°C for 2 h. Then, transfer the reaction system to a 70°C oil bath and incubate for 5 min. Afterwards, remove the reaction system from the 70°C oil bath and continue incubating at 20°C for 4 h. Remove the reaction mother liquor and small particulate impurities by centrifugal washing with water and alcohol, and dry in a 65°C oven for 12 h to obtain a white powdery product: a two-segment silica colloidal rod structure. See [see ]. Figure 4 (a) Figure 4 (b) and Figure 4 (c).

[0074] Example 6 is similar to Example 5 in most respects, except that the constant temperature static reaction time at each stage of this example is adjusted. Figure 4 (d) and Figure 4 (e), the first stage reaction time is 2 h, and the second stage reaction time is 8 h. Figure 4(f) The first-stage reaction time is 3 h, and the second-stage reaction time is 6 h. This shows that the length ratio of each segment of the silica gel rod structure can be controlled by adjusting the constant temperature static reaction time at each stage.

[0075] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive method, characterized in that: The following steps are involved: Step S1, mixing an amphiphilic polymer with an organic solvent to obtain a clear and transparent mixed solution; Step S2, adding the aqueous solution and the alcohol solution to the mixed solution of step S1 to obtain a stable water-in-oil system; Step S3, adding an ammonia source to the mixed solution of step S2; Step S4: adding a silicon source to the mixed solution of step S3, mixing well, and then standing at a constant temperature for reaction, wherein the silicon source is hydrolyzed and condensed to form silicon oxide rod-shaped colloid; Step S5, transferring the reaction system of step S4 to a 50-80°C oil bath and reacting for 3-10 min; Step S6, removing the reaction system of step S5 from the oil bath environment, and then allowing it to react at a constant temperature; Step S7, transferring the reaction system of step S6 to a 50-80°C oil bath again and reacting for 3-10 min; Step S8, removing the reaction system of step S7 from the oil bath environment, and then allowing it to react at a constant temperature; Step S9: Collect the final product of step S8, and obtain the target product after centrifugation, water washing, alcohol washing and drying.

2. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner according to claim 1, characterized in that: In the step S1, the amphiphilic polymer is polyvinyl pyrrolidone with a molecular weight of 40 kg / mol.

3. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner according to claim 1, characterized in that: In step S1, the organic solvent is n-pentanol with a concentration of 98%.

4. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner according to claim 1, characterized in that: In step S2, the aqueous solution is ultrapure water with a resistivity of 18.2 MΩ·cm.

5. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner according to claim 1, characterized in that: In step S2, the alcohol solution is ethanol with a concentration of 98%.

6. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive manner according to claim 1, characterized in that: In step S3, the ammonia source is aqueous ammonia with a concentration of 27 wt%.

7. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive method according to claim 1, characterized in that: In step S4, the silicon source is tetraethyl orthosilicate with a concentration of 98%.

8. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive method according to claim 1, wherein: In step S4, the mixing method is one or more combinations of vortex vibration, ultrasound, stirring, and shaking.

9. The method for preparing a morphology-controllable silica gel structure based on a stimulus-responsive method according to claim 1, wherein: In the steps S4, S6 and S8, the constant temperature static reaction means reacting at 20-25° C. for 1-8 hours.

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