Composite nano carbon material / polyaniline hollow microsphere
By introducing a conductive bridge between the electrode and the droplet, the problem of limited electron transfer was solved, and the mass production and structural control of nano-carbon materials/polyaniline hollow microspheres were realized, which have excellent electronic conductivity and rich reaction interfaces.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG UNIV OF TECH
- Filing Date
- 2026-01-28
- Publication Date
- 2026-04-28
AI Technical Summary
In existing technologies, electron transfer between the electrode and the dispersed droplets is limited, making it difficult to achieve uniform electron transport and shell growth. Furthermore, traditional chemical oxidation polymerization methods suffer from difficulties in controlling the reaction rate and safety hazards.
Electrochemical polymerization was used to introduce a conductive bridge between the electrode and the droplet. Through conductive bridging and interface engineering, the electron transport channel was opened up. Nanomaterials/polyaniline hollow microspheres were prepared using the Pickering emulsion system with droplets as templates.
The mass production of conductive composite materials has been achieved, avoiding the use of hazardous oxidants. The size and shell thickness of hollow microspheres can be precisely controlled. The material has both high specific surface area and multi-component, multi-level shell structure, and possesses excellent electronic conductivity and abundant reaction interfaces.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer composite materials, and in particular to a method for preparing polyaniline-based composite hollow microspheres. Background Technology
[0002] Nanomaterial / conductive polymer composites are a class of functional materials that combine high conductivity, chemical stability, and structural designability, and are widely used in electromagnetic absorption, energy storage, electrocatalysis, and sensing (ACS Applied Materials & Interfaces, 2011, 3(3), 782-788). Nanomaterials (such as carbon nanotubes and graphene) have excellent electron transport capabilities and specific surface area, while conductive polymers (such as polyaniline and polypyrrole) have tunable electrochemical activity and doping characteristics (Chemical Society Reviews, 2017, 46, 151-152). The combination of the two can not only achieve synergistic conductivity, but also construct multi-scale interfaces to enhance dielectric polarization effects (Chemical Engineering Journal, 2020, 389, 124500). In addition, the microstructure of the composite material has a significant impact on its performance, especially the hollow microsphere structure, which is considered an ideal form for realizing high-performance electrofunctional materials due to its lightweight, high specific surface area, and multi-level interface advantages.
[0003] The preparation of composite materials with hollow microsphere structures mainly relies on template methods. Although hard template methods (such as using silica or polystyrene spheres as templates) can precisely control the morphology, the template removal process is complex, costly, and prone to structural collapse or residual pollution (Critical Reviews in Solid State & Materials Sciences, 2009, 34(1), 75-87). In contrast, soft template methods using emulsion droplets as templates have become an important alternative for preparing hollow composite structures due to their advantages such as interface self-assembly driven, template tunability, and environmental friendliness (Acta Chim. Sinica 2017, 75, 391-397). However, conventional chemical oxidative polymerization methods in this system have problems such as difficulty in controlling the reaction rate, non-uniform polymerization process, and difficulty in adjusting the shell structure, and require the use of strong oxidants, which pose certain safety hazards.
[0004] Electrochemical polymerization, with its unique confined reaction region and controllable reaction process, offers a new perspective for the directional and controllable growth of conductive polymers on template surfaces. Previous studies have shown that electrochemical reactions can occur on the surface of Pickering emulsion droplets, confirming the feasibility of establishing electronic communication between the electrode and the dispersed droplets (Electrochimica Acta, 2007, 53, 1175-1181; Nature Catalysis, 2022, 5, 1110-1119). However, these interfacial reactions are still limited by inefficient electron transfer, and extended electron transfer pathways within the emulsion are difficult to achieve (Nature Synthesis, 2025, 4, 479-487). Therefore, achieving uniform electron transport and uniform shell growth across all emulsion droplets is challenging.
[0005] This invention proposes a novel strategy for electrochemical fabrication based on a Pickering emulsion system. By introducing a conductive bridge between the electrode and the droplet, an electron transport channel is established, overcoming the electron transfer barrier between the electrode and the dispersed droplet. This method enables the electrochemical synthesis of monodisperse carbon nanomaterials / polyaniline hollow microspheres using dispersed droplets as templates, providing a completely new technical pathway for the controllable fabrication of conductive composite materials. Summary of the Invention
[0006] This invention provides a composite carbon nanomaterial / polyaniline hollow microsphere, which overcomes the problem of limited electron transfer between electrodes and dispersed droplets in existing technologies through conductive bridging and interface engineering. This enables the batch electrochemical preparation of conductive composite materials with hollow structures using dispersed droplets as templates. The size and shell thickness of the prepared hollow microspheres, as well as the ratio of carbon nanomaterial to polyaniline in the hollow microspheres, can be controlled by emulsion parameters and current / voltage parameters.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a composite carbon nanomaterial / polyaniline hollow microsphere, which is prepared by the following method: Aniline is dissolved in an acidic electrolyte aqueous solution to obtain an acidic electrolyte aqueous solution of aniline. Nano-carbon materials are dispersed in the acidic electrolyte aqueous solution of aniline to a final concentration of 0.3–2 mg / L. An organic solvent is then added, and homogenization is performed to obtain a stable oil-in-water Pickering emulsion of the nano-carbon materials. The Pickering emulsion is injected into the anode chamber of a three-electrode electrolytic cell and allowed to stand for phase separation to obtain a high internal phase emulsion layer. Electropolymerization is carried out on the emulsion system at a constant temperature of 8–30°C and a constant current of 0.1–10 mA. The reaction is terminated when the voltage reaches 1V vs SHE. Finally, the resulting reaction solution is post-treated to obtain the composite nano-carbon material / polyaniline hollow microspheres. In the acidic electrolyte aqueous solution of aniline, the concentration of aniline is 0.05–0.5 M, and the concentration of the acidic electrolyte is 0.005–1 M. (The three-electrode H-type electrolytic cell consists of a cathode chamber filled with acidic electrolyte and equipped with a counter electrode, an anode chamber filled with emulsion and equipped with a working electrode and a reference electrode, and a diaphragm or sand core for separating the two chambers. The diaphragm or sand core can prevent conductive microspheres generated during the electrochemical process from forming a conductive channel between the two electrodes, thus avoiding potential short circuit risks.)
[0008] Furthermore, the nano-carbon material is one or more of carbon nanotubes, graphene, carbon oxide nanotubes, graphene oxide, sulfonated carbon nanotubes, sulfonated graphene, amination carbon nanotubes, or amination graphene.
[0009] Furthermore, in the acidic electrolyte aqueous solution of aniline, the acidic electrolyte is one or more of sulfuric acid, hydrochloric acid, perchloric acid, or camphor sulfonic acid.
[0010] Furthermore, the organic solvent is one or more of cyclohexane, toluene, n-heptane, or dichloromethane (an important basis for selecting these organic solvents is that their density differs significantly from that of the electrolyte aqueous solution, and the dispersed droplets prepared by them can spontaneously undergo a sedimentation or float enrichment process under the density difference, thereby self-assembling to obtain a high internal phase emulsion layer).
[0011] Furthermore, the volume ratio of the acidic electrolyte aqueous solution to the organic solvent is 1:0.5 to 2.
[0012] Furthermore, the homogenization process is performed using a high-speed disperser or an ultrasonic generator, with a processing time of 0.5-2 minutes.
[0013] Further, the post-processing is as follows: water is added to the obtained reaction solution, and after standing and separation, the lower aqueous phase is removed to obtain the upper liquid. This operation is repeated 1-5 times for the upper liquid, and the upper system is collected. A co-solvent is added to the upper system, and after stirring and separation, the upper organic phase is removed. The lower liquid is collected, and this operation is repeated 1-5 times to obtain a dispersion of hollow microspheres. Water is added to the dispersion of hollow microspheres, and the mixture is shaken and washed to remove the lower aqueous phase. This process is repeated 1-5 times to obtain a pure aqueous dispersion of hollow microspheres. The mixture is then freeze-dried to obtain the composite carbon nanomaterial / polyaniline hollow microspheres.
[0014] Furthermore, the co-solvent is one of a 50wt% aqueous solution of ethanol, a 50wt% aqueous solution of isopropanol, or a 50wt% aqueous solution of acetonitrile.
[0015] Furthermore, in the acidic electrolyte aqueous solution of aniline, the concentration of aniline is 0.05-0.2M.
[0016] Furthermore, the carbon nanomaterial is preferably carbon oxide nanotubes.
[0017] The composite carbon nanomaterial / polyaniline hollow microspheres prepared in this invention have a multi-level structure consisting of a carbon nanomaterial / polyaniline composite layer as the inner layer and a polyaniline particle deposition layer as the outer layer. The inner layer refers to a composite layer of carbon nanomaterial / polyaniline composite tubes and polyaniline particles formed by in-situ electropolymerization of conductive carbon nanomaterials adsorbed on the surface of emulsion droplets. The carbon nanomaterial / polyaniline composite tubes are partially exposed in the cavity. The outer layer refers to a deposition layer on the surface of the inner layer where polyaniline particles continue to grow. The particle size of the polyaniline particles is 50-500 nm. Based on the amount of carbon nanomaterial and aniline monomer added, the particle size of the hollow microspheres is 10-200 μm. The shell thickness of the hollow microspheres is 1-10 μm. The mass percentage of polyaniline in the hollow microspheres is 40-90 wt%.
[0018] The technical principle of the preparation method of composite carbon nanomaterial / polyaniline hollow microspheres described in this invention is as follows: When the electrode is inserted into a high-internal-phase Pickering emulsion stabilized by nano-carbon materials, with an acidic electrolyte aqueous solution containing aniline as the continuous phase and an organic solvent as the dispersed phase, the electrode is directly exposed to the continuous phase. Upon application of a certain voltage, aniline undergoes electrochemical polymerization on the electrode surface, generating conductive polyaniline particles or fibers. The newly generated polyaniline acts as a conductive bridge, connecting the electrode to the nano-carbon materials adsorbed on the droplet surface, enabling electron transfer of aniline on the nano-carbon material surface. This achieves in-situ electrodeposition of polyaniline, gradually forming a composite shell structure on the droplet template. Furthermore, because the polyaniline grown on the nano-carbon material surface has a relatively large macroscopic size (approximately hundreds of nanometers to several micrometers), significantly larger than the distance between droplets in the high-internal-phase emulsion (approximately tens of nanometers), these polyaniline structures can span the droplet gaps, allowing droplets far from the electrode to also achieve conductive connections with the electrode, forming a nano-carbon material / polyaniline composite shell. As the conductive network expands, this electropolymerization process gradually spreads throughout the entire emulsion system. It is worth noting that polyaniline has a low degree of crosslinking and a soft texture. During subsequent solvent replacement and washing processes, the polyaniline particles or fibers, which act as conductive bridges, will peel off from the droplet surface, ultimately yielding independent composite carbon nanomaterials / polyaniline hollow microspheres. The method described in this invention overcomes the problem of limited electron transfer between the electrode and the dispersed droplets in the prior art, enabling the batch electrochemical preparation of conductive composite materials with hollow structures using dispersed droplets as templates.
[0019] The formation process and principle of the multi-level shell structure of composite carbon nanomaterials / polyaniline hollow microspheres: Once the electrode establishes a conductive connection with the carbon nanomaterial, the aniline cations enriched on the surface of the carbon nanomaterial promote the preferential deposition of the generated polyaniline on its surface, forming a tightly coated carbon nanomaterial / polyaniline composite tube. This composite tube and the electrode construct a stable conductive network with a high specific surface area. Subsequently, aniline in the aqueous phase continuously diffuses to the surface of the composite tube, continuously polymerizing to form polyaniline particles, creating a dense polyaniline shell coating structure. Due to the lack of aniline monomers in the oil phase, the polyaniline particles have a thin coating layer on the oleophilic side of the carbon nanomaterial, with some areas exposed in the cavity, constituting the inner shell structure of the hollow microsphere. As the polymerization reaction continues, the polyaniline particles further deposit, eventually forming the outer shell, thus constructing a composite hollow microsphere with multi-level shells.
[0020] Compared with existing technologies, the beneficial effects of this invention are as follows: 1) This invention uses electrochemical polymerization instead of traditional chemical oxidative polymerization, avoiding the use of dangerous oxidants such as ammonium persulfate, and can prepare independent composite carbon nanomaterials / polyaniline hollow microspheres in one step using emulsion droplets as templates; 2) This invention can precisely control the structural characteristics of the hollow microspheres, such as their size and shell thickness, as well as the ratio of nano-carbon materials and polyaniline in the hollow microspheres, by adjusting the emulsion parameters and current / voltage parameters.
[0021] 3) The hollow microspheres prepared in this invention possess both the hollow characteristics of high specific surface area and unique multi-component, multi-level shells in their structure. They are constructed from highly conductive carbon nanomaterials and cost-effective, intrinsically redox-active polyaniline. This design enables the material to simultaneously possess excellent electronic conductivity and abundant reaction interfaces. Attached Figure Description
[0022] Figure 1 An optical microscope image of the carbon nanotube-stabilized oil-in-water emulsion prepared in Example 4 of this invention; Figure 2 This is an optical microscope image of the emulsion after electrochemical polymerization in Example 4 of the present invention; Figure 3 The images shown are scanning electron microscope (SEM) images of the composite carbon nanotube / polyaniline hollow microspheres prepared in Example 4 of this invention; (a) SEM image of the intact composite carbon nanotube / polyaniline hollow microspheres; (b) SEM image of a local high-magnification area of the outer surface of the microspheres corresponding to (a); (c) SEM image of the broken composite carbon nanotube / polyaniline hollow microspheres; and (d) SEM image of a local high-magnification area of the inner surface of the microspheres corresponding to (c).
[0023] Figure 4 An optical microscope image of the emulsion droplets prepared in Example 9 of this invention; Figure 5 This is a scanning electron microscope image of the composite graphene / polyaniline hollow microspheres prepared in Example 9 of the present invention. Detailed Implementation
[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] 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.
[0026] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing them from the market or by existing methods.
[0027] Example 1
[0028] Preparation of Pickering emulsion: Weigh 69.8 mg of aniline and add it to 15 mL of 0.5 M sulfuric acid solution. Stir until completely dissolved to obtain a 0.05 M aniline aqueous solution. Then weigh 9 mg of carbon oxide nanotubes and add them to the above aniline aqueous solution. Sonicate for 10 min to obtain a uniform dispersion. Add 15 mL of cyclohexane to the dispersion and disperse it at 12 krpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 90%. The emulsion was subjected to linear voltammetry at 10 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.57 V vs SHE from the scan curve. Electropolymerization was then performed in constant current mode at 2 mA. The initial voltage was 0.59 V vs SHE, slightly higher than the oxidation potential. As the conductive polymer formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.52 V. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, stopping when the voltage reached 1 V vs SHE. The total reaction time was approximately 10.5 h. Post-treatment: The electropolymerized mixture was removed from the electrolytic cell and transferred to a beaker. At this point, the system consisted of a hollow microsphere filled with cyclohexane on top and an aqueous solution on the bottom. Deionized water was added to the system, and the lower aqueous phase was removed. This step was repeated 5 times to remove unreacted aniline monomers, soluble oligomers, and electrolytes from the water. Then, a 50 wt% ethanol aqueous solution was added to the system and stirred. Ethanol extraction of cyclohexane resulted in an upper cyclohexane / ethanol mixed phase, a middle layer of hollow microspheres, and a lower aqueous phase. After removing the upper layer, another 50 wt% ethanol aqueous solution was added and stirred to separate the layers. This process was repeated 5 times to completely replace the cyclohexane with ethanol, resulting in an ethanol-water dispersion of hollow microspheres. Deionized water was then added to the system, and the lower aqueous phase was removed. This step was repeated 5 times to remove a large amount of ethanol from the water. Finally, the obtained hollow microsphere dispersion was frozen at 0 °C for 4 h, and then freeze-dried for 8 h to obtain 69.3 mg of dried composite carbon nanotube / polyaniline hollow microspheres.
[0029] Characterization of the emulsion and product: The droplet size of the obtained Pickering emulsion was statistically analyzed using an optical microscope equipped with ImageJ software; the morphology characteristics of the carbon nanotube / polyaniline composite hollow microspheres, including microsphere diameter and shell thickness, were observed and measured using a scanning electron microscope. Yield: The yield was calculated as the ratio of the mass of the obtained composite carbon nanotube / polyaniline hollow microspheres to the sum of the masses of the added carbon nanomaterials and aniline.
[0030] Example 2
[0031] Preparation of Pickering emulsion: Weigh 139.6 mg of aniline and add it to 15 mL of 0.5 M sulfuric acid solution. Stir until completely dissolved to obtain a 0.1 M aniline aqueous solution. Then weigh 12 mg of carbon oxide nanotubes and add them to the above aniline aqueous solution. Sonicate for 10 min to obtain a uniform dispersion. Add 15 mL of cyclohexane to the dispersion and disperse it at 12 krpm for 0.5 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 92%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 10 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.54 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode at a current setting of 2 mA. The initial voltage was 0.55 V vs SHE, slightly higher than the oxidation potential. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.51 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase. The reaction was stopped when the voltage reached 1 V, with a total reaction time of approximately 14 h. Post-treatment, emulsion and product characterization, and yield calculation were performed in the same manner as described in Example 1, ultimately yielding 127.3 mg of dried composite carbon nanotube / polyaniline hollow microspheres.
[0032] Example 3
[0033] Preparation of Pickering emulsion: Weigh 209.4 mg of aniline and add it to 15 mL of 0.5 M perchloric acid solution. Stir until completely dissolved to obtain a 0.15 M aniline aqueous solution. Then weigh 12 mg of carbon oxide nanotubes and add them to the above aniline aqueous solution. Sonicate for 10 min to obtain a uniform dispersion. Add 15 mL of toluene to the dispersion and disperse it at 12 krpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 92%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 25 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.55 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode with a current set at 2 mA, at which point the initial voltage was 0.55 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.51 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, and the reaction was stopped when the voltage reached 1 V. The total reaction time was approximately 21 h. The post-treatment, emulsion and product characterization, and yield calculation were the same as described in Example 1, ultimately yielding 132.8 mg of dried composite carbon nanotube / polyaniline hollow microspheres.
[0034] Example 4
[0035] Preparation of Pickering emulsion: Weigh 279.2 mg of aniline and add it to 15 mL of 0.5 M hydrochloric acid solution. Stir until completely dissolved to obtain a 0.2 M aniline aqueous solution. Then weigh 15 mg of carbon oxide nanotubes and add them to the above aniline aqueous solution. Sonicate for 10 min to obtain a uniform dispersion. Add 7.5 mL of toluene to the dispersion and disperse it at 12 krpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 81%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 8 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.55 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode at a current setting of 4 mA, with an initial voltage of 0.62 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.58 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, and the reaction was stopped when the voltage reached 1 V. The total reaction time was approximately 17 h. Post-treatment, emulsion and product characterization, and yield calculation were performed in the same manner as described in Example 1, ultimately yielding 208.9 mg of dried composite carbon nanotube / polyaniline hollow microspheres.
[0036] Example 5
[0037] Preparation of Pickering emulsion: 279.2 mg of aniline was weighed and added to 15 mL of 0.4 M sulfuric acid. The mixture was stirred until completely dissolved, yielding a 0.2 M aniline aqueous solution. Subsequently, 7.5 mg of carbon oxide nanotubes were weighed and added to the aniline aqueous solution, and the mixture was ultrasonically treated for 5 min to obtain a uniform dispersion. 15 mL of dichloromethane was added to the dispersion and dispersed using a high-speed disperser at 12 krpm for 2 min to obtain a stable oil-in-water Pickering emulsion. The emulsion was transferred to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets settled and accumulated to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 82%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 30 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.59 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode with a current set at 1 mA, at which point the initial voltage was 0.61 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.53 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, and the reaction was stopped when the voltage reached 1 V. The total reaction time was approximately 30 h.
[0038] Post-processing: The electropolymerized mixture was removed from the electrolytic cell and transferred to a beaker. At this point, the system consisted of a lower layer of hollow microspheres filled with cyclohexane and an upper aqueous solution. Deionized water was added to the system, and the lower aqueous phase was removed. This step was repeated 5 times to remove unreacted aniline monomers, soluble oligomers, and electrolytes from the water. Then, 50 wt% ethanol aqueous solution was added to the system and stirred. The ethanol extracted dichloromethane, resulting in a lower cyclohexane / ethanol mixed phase, an intermediate layer of hollow microspheres, and an upper aqueous phase. After removing the lower solution, another 50 wt% ethanol aqueous solution was added and stirred to separate the layers. This process was repeated 5 times to completely replace the dichloromethane with ethanol, resulting in an ethanol-water dispersion of hollow microspheres. Subsequently, deionized water was added to the system, and the lower aqueous phase was removed. This step was repeated 5 times to remove a large amount of ethanol from the water. The obtained hollow microsphere dispersion was finally frozen at 0 °C for 4 h, and then freeze-dried for 8 h to obtain 183.5 mg of dried carbon nanotube / polyaniline composite hollow microspheres. The emulsion and product characterization and yield calculation were performed in the same manner as described in Example 1.
[0039] Example 6
[0040] Preparation of Pickering emulsion: Weigh 698 mg of aniline and add it to 15 mL of 0.005 M sulfuric acid solution. Stir until completely dissolved to obtain a 0.5 M aniline aqueous solution. Then weigh 15 mg of carbon oxide nanotubes and add them to the above aniline aqueous solution. Sonicate for 10 min to obtain a uniform dispersion. Add 30 mL of cyclohexane to the dispersion and disperse it at 12 krpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 79%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 10 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.55 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode at a current of 10 mA, with an initial voltage of 0.66 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.61 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, and the reaction was stopped when the voltage reached 1 V. The total reaction time was approximately 40 h. Post-treatment, emulsion and product characterization, and yield calculation were performed in the same manner as described in Example 1, ultimately yielding 420.7 mg of dried composite carbon nanotube / polyaniline hollow microspheres.
[0041] Example 7
[0042] Preparation of Pickering emulsion: Weigh 69.8 mg of aniline and add it to 15 mL of 0.4 M perchloric acid solution. Stir until completely dissolved to obtain a 0.05 M aniline aqueous solution. Then weigh 7.5 mg of carbon oxide nanotubes and add them to the above aniline aqueous solution. Sonicate for 10 min to obtain a uniform dispersion. Add 10 mL of n-heptane to the dispersion and disperse it at 12 krpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 85%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 10 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.57 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode with a current set at 5 mA, resulting in an initial voltage of 0.71 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.6 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, and the reaction was stopped when the voltage reached 1 V. The total reaction time was approximately 11 h. Post-treatment, emulsion and product characterization, and yield calculation were performed in the same manner as described in Example 1, ultimately yielding 51.8 mg of dried composite carbon nanotube / polyaniline hollow microspheres.
[0043] Example 8
[0044] Preparation of Pickering emulsion: Weigh 69.8 mg of aniline and add it to 15 mL of 0.2 M perchloric acid solution. Stir until completely dissolved to obtain a 0.05 M aniline aqueous solution. Then weigh 12 mg of carbon oxide nanotubes and add them to the above aniline aqueous solution, and sonicate for 5 min to obtain a uniform dispersion. Add 10 mL of n-heptane to the dispersion and disperse it at 12 krpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 91%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 10 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.64 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode at a current setting of 0.5 mA, with an initial voltage of 0.66 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.58 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, and the reaction was stopped when the voltage reached 1 V. The total reaction time was approximately 10 h. Post-treatment, emulsion and product characterization, and yield calculation were performed in the same manner as described in Example 1, ultimately yielding 30.3 mg of dried composite carbon nanotube / polyaniline hollow microspheres.
[0045] Example 9
[0046] Preparation of Pickering emulsion: Weigh 139.6 mg of aniline and add it to 15 mL of 0.5 M sulfuric acid solution. Stir until completely dissolved to obtain a 0.1 M aniline aqueous solution. Then weigh 18 mg of graphene oxide and add it to the above aniline aqueous solution, and sonicate for 10 min to obtain a uniform dispersion. Add 15 mL of cyclohexane to the dispersion and disperse it at 12 krpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 86%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 10 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.58 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode with a current set to 1 mA, at which point the initial voltage was 0.6 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.54 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, and the reaction was stopped when the voltage reached 1 V. The total reaction time was approximately 21 h. Post-treatment, emulsion and product characterization, and yield calculation were performed in the same manner as described in Example 1, ultimately yielding 86.7 mg of dried composite graphene / polyaniline hollow microspheres.
[0047] Example 10
[0048] Preparation of Pickering emulsion: Weigh 139.6 mg of aniline and add it to 15 mL of 0.2 M hydrochloric acid solution. Stir until completely dissolved to obtain a 0.1 M aniline aqueous solution. Then weigh 30 mg of graphene oxide and add it to the above aniline aqueous solution, and sonicate for 10 min to obtain a uniform dispersion. Add 30 mL of cyclohexane to the dispersion and disperse it at 12 k rpm for 1 min using a high-speed disperser to obtain a stable oil-in-water Pickering emulsion. Transfer the emulsion to the anode chamber of a three-electrode H-type electrolytic cell. After standing for 2 min, the emulsion droplets float and accumulate to form a high internal phase emulsion layer with an internal phase volume fraction of approximately 77%. Electropolymerization: The above emulsion was subjected to linear voltammetry at 22 °C, with a potential range of 0–1 V vs SHE and a scan rate of 100 mV / s. The oxidation potential of aniline was determined to be approximately 0.58 V vs SHE from the scan curve. Electropolymerization was then carried out in constant current mode with a current set at 5 mA, resulting in an initial voltage of 0.65 V vs SHE. As the conductive polymer was formed, the effective electrode area increased, causing the reaction voltage to gradually decrease to 0.59 V vs SHE. Subsequently, due to a significant decrease in monomer concentration, the voltage began to gradually increase, stopping when the voltage reached 1 V. The total reaction time was approximately 33 h. The post-processing was the same as described in Example 1, ultimately yielding 130.6 mg of dried composite carbon nanotube / polyaniline composite hollow microspheres.
[0049] Table 1: Main reaction conditions and average size of emulsion droplets formed in Examples 1-10.
[0050]
[0051] Table 2: Diameter, shell thickness, and yield of composite carbon nanomaterials / polyaniline hollow microspheres prepared under the conditions of Examples 1-10
[0052] Table 1 shows the main reaction conditions and the average size of the emulsion droplets formed in Examples 1-10. The carbon nanomaterial used in Examples 1-8 was carbon nanotube oxide, while the carbon nanomaterial used in Examples 9 and 10 was graphene oxide. Table 2 shows the electropolymerization conditions using the emulsions in Table 1 under constant current mode, as well as the diameter, shell thickness, and yield of the resulting composite carbon nanomaterial / polyaniline hollow microspheres. As can be seen from the data in both tables, although there are significant differences in the emulsion formation conditions such as oil-water volume ratio, oil phase type, carbon material feed amount, and electrolyte composition among the examples, the average size of the emulsion droplets also varies widely from 41 to 230 μm. However, the diameter of the microspheres obtained in the corresponding examples is always close to the droplet size, indicating the template effect of the droplets during the electropolymerization process. When the aniline monomer concentration is greater than 0.2 M, the shell thickness of the obtained microspheres has a wider range, which is attributed to the increased monomer concentration in the droplet gap leading to a thicker polyaniline particle deposition layer on the outer surface of the prepared microspheres. Furthermore, in the examples with smaller average droplet size, the overall yield of hollow microspheres was higher, while the yield of examples with larger droplet size was relatively lower. This may be because the reduction in droplet size leads to an increase in the total interfacial area of the emulsion, allowing aniline in the aqueous phase to be more fully utilized at the oil-water interface and participate in polymerization, thereby improving the product yield of hollow microspheres.
Claims
1. A composite nano-carbon material / polyaniline hollow microsphere, characterized in that, Prepared by the following method: Aniline is dissolved in an acidic electrolyte aqueous solution to obtain an acidic electrolyte aqueous solution of aniline. Nano-carbon materials are dispersed in the acidic electrolyte aqueous solution of aniline to a final concentration of 0.3–2 mg / L. An organic solvent is then added, and homogenization is performed to obtain a stable oil-in-water Pickering emulsion of the nano-carbon materials. The Pickering emulsion is injected into the anode chamber of a three-electrode electrolytic cell and allowed to stand for phase separation to obtain a high internal phase emulsion layer. Electropolymerization is carried out on the emulsion system at a constant temperature of 8–30°C and a constant current of 0.1–10 mA, and the reaction is terminated when the voltage reaches 1V vs SHE. Finally, the resulting reaction solution is post-treated to obtain the composite nano-carbon material / polyaniline hollow microspheres. In the acidic electrolyte aqueous solution of aniline, the concentration of aniline is 0.05–0.5 M, and the concentration of the acidic electrolyte is 0.005–1 M. The volume ratio of the acidic electrolyte aqueous solution to the organic solvent is 1:0.5–2.
2. The composite carbon nanomaterial / polyaniline hollow microspheres as described in claim 1, characterized in that, The nano-carbon material is one or more of carbon nanotubes, graphene, carbon oxide nanotubes, graphene oxide, sulfonated carbon nanotubes, sulfonated graphene, amination carbon nanotubes, or amination graphene.
3. The composite carbon nanomaterial / polyaniline hollow microspheres as described in claim 1, characterized in that, In the acidic electrolyte aqueous solution of aniline, the acidic electrolyte is one or more of sulfuric acid, hydrochloric acid, perchloric acid, or camphor sulfonic acid.
4. The composite carbon nanomaterial / polyaniline hollow microsphere as described in claim 1, characterized in that, The organic solvent is one or more of cyclohexane, toluene, n-heptane, or dichloromethane.
5. The composite carbon nanomaterial / polyaniline hollow microspheres as described in claim 1, characterized in that, The homogenization process is performed using a high-speed disperser or an ultrasonic generator, with a processing time of 0.5-2 minutes.
6. The composite carbon nanomaterial / polyaniline hollow microspheres as described in claim 1, characterized in that, The post-processing is as follows: water is added to the obtained reaction solution, and after standing and separation, the lower aqueous phase is removed to obtain the upper liquid. This operation is repeated 1-5 times, and the upper system is collected. A co-solvent is added to the upper system, and after stirring and separation, the upper organic phase is removed. The lower liquid is collected, and this operation is repeated 1-5 times to obtain a dispersion of hollow microspheres. Water is added to the dispersion of hollow microspheres, and the mixture is shaken and washed to remove the lower aqueous phase. This process is repeated 1-5 times to obtain a pure aqueous dispersion of hollow microspheres. The mixture is then freeze-dried to obtain the composite carbon nanomaterial / polyaniline hollow microspheres.
7. The composite carbon nanomaterial / polyaniline hollow microspheres as described in claim 6, characterized in that, The co-solvent is one of 50wt% ethanol aqueous solution, 50wt% isopropanol or 50wt% acetonitrile aqueous solution.
8. The composite carbon nanomaterial / polyaniline hollow microspheres as described in claim 1, characterized in that, In the acidic electrolyte aqueous solution of aniline, the concentration of aniline is 0.05-0.2M.
9. The composite carbon nanomaterial / polyaniline hollow microspheres as described in claim 1, characterized in that, The carbon nanomaterial is carbon oxide nanotube.