Method for stable dispersion of graphene oxide in strongly acidic aqueous solutions and applications thereof
Patent Information
- Application Number
- CN202610768406.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-30
- Publication Date
- 2026-09-29
AI Technical Summary
然而，在强酸性（pH＜2）条件下，部分含氧官能团发生质子化，片层表面电荷减弱，体系静电排斥作用下降，同时氧官能团之间容易形成较强氢键，从而导致片层间重新聚集并形成大尺寸团聚体，进而沉降
针对强酸性环境下的氧化石墨烯氢键诱导团聚问题提出专门解决方案，可实现pH＜2条件下最高1.2g/L的稳定分散浓度。引入了ζ电位判据，便于分散稳定性量化评价与工程控制。
Abstract
Description
Technical Field
[0001] This application relates to the field of nanomaterial dispersion and electrochemical material preparation, and more specifically, it relates to a method for the stable dispersion of graphene oxide in strongly acidic aqueous solutions and its application. Background Technology
[0002] Graphene oxide has a surface rich in oxygen-containing functional groups such as hydroxyl, carboxyl, and epoxy groups, which generally give it good hydrophilicity and dispersibility in neutral or weakly alkaline media. However, under strongly acidic conditions (pH < 2), some oxygen-containing functional groups are protonated, reducing the surface charge of the sheets and decreasing the electrostatic repulsion of the system. At the same time, strong hydrogen bonds easily form between the oxygen functional groups, leading to the re-aggregation of the sheets and the formation of large aggregates, which then settle.
[0003] For electroplating, electrodeposition, and acidic functional slurry systems, the working medium is often in a low pH range. If graphene oxide cannot maintain stable dispersion under these conditions, it will not only experience rapid sedimentation but also cause problems such as fluctuations in subsequent system components, reduced co-deposition efficiency, increased product performance dispersion, and equipment pipeline blockage. Existing dispersion processes are mostly developed for neutral systems and are difficult to balance anti-agglomeration ability and high concentration stability in strong acid environments. Therefore, establishing a stable dispersion method for graphene oxide suitable for strong acid environments is of great significance for its engineering applications. Summary of the Invention
[0004] In order to stabilize graphene oxide in a strongly acidic environment and alleviate the problem of agglomeration and sedimentation, this application provides a method for stabilizing the dispersion of graphene oxide in a strongly acidic aqueous solution and its application.
[0005] In a first aspect, this application provides a method for the stable dispersion of graphene oxide in a strongly acidic aqueous solution, employing the following technical solution: A method for stably dispersing graphene oxide in a strongly acidic aqueous solution includes the following steps: Deionized water is heated to 40–60°C, and one or both of dodecylbenzene sulfonate or alkyl quaternary ammonium salts are added as surfactants at a concentration of 0.05–5 g / L. The mixture is stirred until fully dissolved. Ultrasonic conditions with a power of 300–1200 W and high-shear stirring conditions with a speed of 3000–20000 rpm are set, and graphene oxide is slowly added. Ultrasonic and stirring time is 10–120 min, and the mixture is stirred until homogeneous, so that the final graphene dispersion concentration is 0.1–1.2 g / L. The pH of the dispersion system is adjusted to 0–2. The absolute value of the zeta potential measured at 25°C and pH < 2 is greater than or equal to 15 mV, thus obtaining a homogeneous dispersion.
[0006] By adopting the above technical solution, the viscosity of the system is reduced and the molecular thermal motion is enhanced by using a 40-60℃ warm water bath, which helps to weaken the hydrogen bonding between graphene sheets and improve the adsorption efficiency of surfactants.
[0007] By using dodecylbenzene sulfonate or alkyl quaternary ammonium salt as surfactants, a stable layer with both electrostatic repulsion and steric hindrance is constructed on the surface of graphene sheets, effectively suppressing secondary aggregation in strong acid environments.
[0008] The synergistic effect of ultrasound and high-shear stirring can break up existing agglomerates and prevent them from re-agglomerating, significantly improving the stable dispersion ability of graphene oxide in strong acid media.
[0009] By slowly adding graphene oxide, instantaneous secondary agglomeration caused by excessively high local concentrations is avoided, thus improving the operability and repeatability of the high-concentration system.
[0010] By introducing an absolute value of ζ potential not less than 15mV as a criterion for stable dispersion, the feasibility of this method in quality control, parameter optimization, and industrial scale-up is improved.
[0011] Ultimately, graphene oxide can achieve stable dispersion in a strongly acidic environment, effectively alleviating the problem of agglomeration and sedimentation.
[0012] Optionally, the surfactant is one or two of sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, ammonium dodecylbenzenesulfonate, alkyltrimethyl quaternary ammonium salt, hexadecyltrimethylammonium bromide, and benzyldimethylalkylammonium chloride.
[0013] Optionally, the amount of surfactant added is 0.1 to 2 g / L.
[0014] Optionally, the ultrasonic power is 350-800W and the duration is 20-60min.
[0015] Optionally, the high-shear stirring speed is 5000-15000 rpm, and the time is 20-60 min.
[0016] Optionally, the slow addition can be any of the following methods: dripping, quantitative addition using a peristaltic pump, or batch addition.
[0017] Optionally, the pH of the dispersion system is adjusted to 0.5–1.8.
[0018] The absolute range of the three zeta potentials measured at 25°C and pH < 2 was 0.5–1 mV.
[0019] Optionally, the uniformly dispersed liquid shows no obvious sedimentation visible to the naked eye within 1 hour of standing.
[0020] Secondly, this application provides an application of a method for the stable dispersion of graphene oxide in a strongly acidic aqueous solution, employing the following technical solution: An application of a method for the stable dispersion of graphene oxide in a strongly acidic aqueous solution, wherein the uniform dispersion obtained by the method can be used to prepare acidic electroplating solutions, electrodeposition systems, conductive pastes or composite material precursors.
[0021] In summary, this application has the following beneficial effects: A specific solution is proposed to address the hydrogen bond-induced aggregation problem of graphene oxide under strongly acidic conditions, achieving a stable dispersion concentration of up to 1.2 g / L at pH < 2. A zeta potential criterion is introduced to facilitate the quantitative evaluation and engineering control of dispersion stability. Detailed Implementation
[0022] The present application will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments shall be performed under conventional conditions or conditions recommended by the manufacturer, and the raw materials used in the following embodiments shall be commercially available unless otherwise specified.
[0023] Graphene oxide, using a concentrated solution, was purchased from Changzhou Sixth Element New Material Co., Ltd., model SE3522, with a solid content of 1%. Example Example
[0024] A method for stably dispersing graphene oxide in a strongly acidic aqueous solution includes the following steps: Deionized water was heated to 50°C, and sodium dodecylbenzenesulfonate was added as a surfactant at a concentration of 0.5 g / L. The mixture was stirred until fully dissolved. An ultrasonic device was activated, set to 400 W for 30 minutes. Simultaneously, a high-shear mixer was started, set to 8000 rpm. Graphene oxide concentrate was slowly added dropwise at a rate of 5 ml / min, with stirring for 30 minutes until homogeneous. The final graphene dispersion concentration was 0.5 g / L. The pH of the dispersion was adjusted to 1.5. A homogeneous dispersion was obtained when the absolute value of the zeta potential (ζ-potential) measured at 25°C and pH=1.5 was greater than or equal to 15 mV. The absolute ζ-potential of the dispersion was measured three times, with each measurement spaced 90 seconds apart. The measured values were relatively stable, and the three measurements were very close, with a range of only 1 mV. This indicates that the dispersion has excellent electrostatic stability, uniform particle dispersion, no significant agglomeration, and good repeatability and homogeneity.
[0025] The uniformly dispersed liquid showed no significant sedimentation after standing for 1 hour.
[0026] This dispersion is suitable for preparing acidic electroplating solutions, electrodeposition systems, conductive pastes, or composite material precursors with pH ≥ 1 and graphene oxide concentration ≤ 1.2 g / L. Example
[0027] A method for stably dispersing graphene oxide in a strongly acidic aqueous solution includes the following steps: Deionized water was heated to 55°C, and sodium dodecylbenzenesulfonate and hexadecyltrimethylammonium bromide were added as surfactants. The amount of sodium dodecylbenzenesulfonate added was 0.5 g / L, and the amount of hexadecyltrimethylammonium bromide added was 0.2 g / L. The mixture was stirred until fully dissolved. The ultrasonic device was turned on and set to ultrasonic conditions of 500 W for 40 min. At the same time, the high shear device was started and set to high shear stirring conditions of 10000 rpm. The concentrated graphene oxide solution was slowly added dropwise and stirred for 40 min until homogeneous. The final graphene dispersion concentration was 1.2 g / L. The pH of the dispersion system was adjusted to 1.2. The absolute value of the zeta potential measured at 25°C and pH=1.2 was greater than or equal to 15 mV, and a homogeneous dispersion was obtained. Furthermore, the absolute value of the zeta potential of the dispersion was measured three times, with each measurement result 90 seconds apart. The values were relatively stable after measurement, and the three measurements were very close, with a range of 0.8 mV. This indicates that the dispersion has excellent electrostatic stability, uniform particle dispersion, no obvious agglomeration, and good repeatability and uniformity of the system.
[0028] The uniformly dispersed liquid showed no significant sedimentation after standing for 1 hour.
[0029] This dispersion is suitable as a precursor dispersion for high-concentration acidic functional systems with pH ≥ 1 and graphene oxide concentration ≤ 1.2 g / L. Example
[0030] A method for stably dispersing graphene oxide in a strongly acidic aqueous solution includes the following steps: Deionized water was heated to 45°C, and hexadecyltrimethylammonium bromide was added as a surfactant at a concentration of 0.3 g / L. The mixture was stirred until fully dissolved. An ultrasonic device was activated at 350 W for 20 minutes, while a high-shear mixer was started at 6000 rpm. Concentrated graphene oxide solution was added in batches, with stirring time of 20 minutes each time, until homogeneous. The final graphene dispersion concentration was 0.3 g / L. The pH of the dispersion system was adjusted to 1.8. A homogeneous dispersion was obtained when the absolute value of the zeta potential (ζ-potential) measured at 25°C and pH=1.8 was greater than or equal to 15 mV. The absolute value of the ζ-potential of the dispersion was measured three times, with each measurement 90 seconds apart. The measured values were relatively stable, and the three measurements were very close, with a range of only 0.9 mV. This indicates that the dispersion has excellent electrostatic stability, uniform particle dispersion, no obvious agglomeration, and good repeatability and homogeneity.
[0031] The uniformly dispersed liquid showed no significant sedimentation after standing for 1 hour.
[0032] The resulting dispersion exhibits good fluidity and short-term stability, making it suitable for preparing acidic electrodeposition systems with pH ≥ 1 and graphene oxide concentration ≤ 1.2 g / L.
[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that no surfactant was added.
[0034] The obtained dispersed system showed obvious aggregation and sedimentation in a short period of time, and could not achieve stable dispersion.
[0035] Comparative Example 2 The difference between this comparative example and Example 1 is that the reduced graphene oxide concentrate was added to the dispersion system rapidly in one go. It was found that due to the instantaneous increase in local concentration, the system exhibited significant flocculation and aggregation, and the dispersion stability decreased significantly.
[0036] Comparative Example 3 The difference between this comparative example and Example 1 is that the deionized water was heated to 80°C.
[0037] Dispersion: No obvious aggregation, but poor dispersion stability.
[0038] The absolute value of the zeta potential of the dispersion was measured three times, with each measurement 90 seconds apart. The value was relatively stable after measurement, and the range of the three measurements was 3.8 mV. Although there was no obvious agglomeration, the dispersion stability was poor. This proves that the warm water bath reduced the viscosity of the system and enhanced the molecular thermal motion, which is beneficial to weakening the hydrogen bonding between graphene sheets and improving the adsorption efficiency of surfactants. High temperature, on the contrary, destroyed this effect.
[0039] Comparative Example 4 The difference between this comparative example and Example 1 is that only ultrasonic dispersion was used, without high-shear stirring.
[0040] Dispersion: No obvious aggregation, but poor dispersion stability.
[0041] The absolute value of the zeta potential of the dispersion was measured three times, with each measurement result 90 seconds apart. The value was relatively stable after measurement, and the range of the three measurements was 4.2 mV. Although there was no obvious aggregation, the dispersion stability was poor, which proves that ultrasonic dispersion and high shear stirring have excellent synergistic effects.
[0042] Comparative Example 5 The difference between this comparative example and Example 1 is that only high-shear stirring was performed, without ultrasonic dispersion.
[0043] Dispersion: No obvious aggregation, but poor dispersion stability.
[0044] The absolute value of the zeta potential of the dispersion was measured three times, with each measurement result 90 seconds apart. The value was relatively stable after measurement, and the range of the three measurements was 4.6 mV. Although there was no obvious aggregation, the dispersion stability was poor, which proves that ultrasonic dispersion and high shear stirring have excellent synergistic effects.
[0045] As can be seen from the examples and comparative examples, the dispersion method of this application provides a specific solution to the problem of hydrogen bond-induced agglomeration of graphene oxide under strong acidic conditions. Through multiple control methods, including warm water bath, surfactant adsorption, synergistic effect of ultrasonic / high-shear stirring, and slow addition of graphene oxide, a uniform and stable graphene oxide dispersion under strong acidic conditions is obtained. Specifically, the warm water bath reduces the viscosity of the system and enhances molecular thermal motion, which helps to weaken the hydrogen bond interaction between graphene sheets and improves the surfactant adsorption efficiency. Using dodecylbenzene sulfonate or alkyl quaternary ammonium salts as surfactants, adsorption on the surface of graphene sheets constructs a stable layer with both electrostatic repulsion and steric hindrance, effectively suppressing secondary agglomeration in strong acidic environments. The synergistic effect of ultrasonic and high-shear stirring can break up existing agglomerates and prevent their re-agglomeration, significantly improving the stable dispersion ability of graphene oxide in strong acidic media. The slow addition of graphene oxide powder, reduced graphene oxide powder, or their concentrate avoids instantaneous secondary agglomeration caused by excessively high local concentrations, improving the operability and repeatability of high-concentration systems. The absence of any one of these methods will result in poor dispersion effects.
[0046] Finally, by introducing an absolute value of ζ potential greater than or equal to 15mV and the magnitude of the range as a criterion for stable dispersion, the feasibility of this method in quality control, parameter optimization, and industrial scale-up is improved, facilitating quantitative evaluation and engineering control of dispersion stability.
[0047] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A method for stably dispersing graphene oxide in a strongly acidic aqueous solution, characterized in that, Includes the following steps: Deionized water is heated to 40–60°C, and one or both of dodecylbenzene sulfonate or alkyl quaternary ammonium salts are added as surfactants at a concentration of 0.05–5 g / L. The mixture is stirred until fully dissolved. Ultrasonic conditions with a power of 300–1200 W and high-shear stirring conditions with a speed of 3000–20000 rpm are set, and graphene oxide is slowly added. Ultrasonic and stirring time is 10–120 min, and the mixture is stirred until homogeneous, so that the final graphene dispersion concentration is 0.1–1.2 g / L. The pH of the dispersion system is adjusted to 0–2. The absolute value of the zeta potential measured at 25°C and pH < 2 is greater than or equal to 15 mV, thus obtaining a homogeneous dispersion.
2. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The surfactant is one or two of sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, ammonium dodecylbenzenesulfonate, alkyltrimethyl quaternary ammonium salt, hexadecyltrimethylammonium bromide, and benzyldimethylalkylammonium chloride.
3. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The amount of surfactant added is 0.1 to 2 g / L.
4. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The ultrasonic power is 350–800W, and the duration is 20–60 minutes.
5. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The high-shear stirring speed is 5000-15000 rpm, and the time is 20-60 min.
6. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The slow addition can be any of the following methods: dripping, quantitative addition using a peristaltic pump, or batch addition.
7. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The pH of the dispersion system is adjusted to 0.5–1.
8.
8. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The absolute range of the three zeta potentials measured at 25°C and pH < 2 was 0.5–1 mV.
9. The method for stable dispersion of graphene oxide in a strongly acidic aqueous solution according to claim 1, characterized in that, The uniformly dispersed liquid showed no obvious sedimentation visible to the naked eye within 1 hour of standing.
10. The application of the method for stable dispersion of graphene oxide in strongly acidic aqueous solution according to any one of claims 1 to 9, characterized in that, The uniform dispersion prepared by this method can be used to prepare acidic electroplating solutions, electrodeposition systems, conductive pastes, or composite material precursors.