High-efficiency fluorine surface modification method for detonation-synthesized diamond

Abstract

In an embodiment, in order to subject functional groups on the surface of detonation-synthesized diamond to high-efficiency fluorine functionalization, oxygen is removed from the surface of the detonation-synthesized diamond by using hydrogen gas, followed by a treatment process through fluorine functionalization, thereby controlling the oxygen and fluorine contents on the surface of the detonation-synthesized diamond. Through this, provided is a surface modification method for detonation-synthesized diamond, which enables surface-treated detonation-synthesized diamond to have maximized fluorine functionalization and superhydrophobicity while being well dispersed in a polar solvent.

Description

High-efficiency fluorine surface modification method of explosively synthesized diamond

[0001] A highly functionalization method of fluorine-doped detonation diamond is provided.

[0002] Explosion-synthesized diamonds are formed by the instantaneous high temperatures and high pressures generated when TNT / RDX, a carbon source, is detonated in a sealed chamber. Depending on the method used to form these synthetic diamonds, they can be categorized into nanodiamonds measuring approximately 2–10 nm in size and polycrystalline diamonds measuring 0.1–100 μm. These synthetic diamonds possess the highest hardness among existing synthetic materials and possess excellent physicochemical properties, such as heat resistance, wear resistance, and chemical resistance. Consequently, they are attracting significant attention as a cutting-edge new material in the industry.

[0003] Explosion-synthesized diamonds are primarily used as additives to enhance the functionality of products currently in industrial use. Accordingly, to apply explosion-synthesized diamonds to industrial applications, the interaction between the functional groups of the diamond particles and the medium can be controlled by modifying the diamond surface.

[0004] Explosion-synthesized diamonds have attracted significant attention as hard coating and surface coating materials due to their high hardness and excellent scratch and wear resistance. In particular, covalent bonding of other molecules to the surface of explosion-synthesized diamonds creates functional groups, making them chemically very useful. Recently, interest has been growing in materials that exhibit superhydrophobic properties and are well-dispersed in polar solvents.

[0005] One embodiment is to propose a fluorine functionalization method that maximizes the fluorine functionalization efficiency and is well dispersed in a polar solvent when performing fluorine functionalization treatment on the surface of an explosive synthetic diamond.

[0006] One embodiment involves performing a process for removing oxygen from the surface of an explosively synthesized diamond using hydrogen gas, followed by a process for performing a fluorine functionalization treatment to efficiently perform surface functionalization of an explosively synthesized diamond, thereby controlling the oxygen and fluorine content of the surface of the explosively synthesized diamond. This provides a method for surface modification of an explosively synthesized diamond, which maximizes fluorine functionalization and has superhydrophobic properties while being well dispersed in a polar solvent.

[0007] According to one embodiment, the explosive synthetic diamond has about 10 to 20% of oxygen functional groups such as CO, C=O, COOH, and COH on the surface, and when the surface of the explosive synthetic diamond is subjected to fluorine functionalization using fluorine gas, about 1.3% of fluorine functionalization can be induced on the surface.

[0008] According to one embodiment, by controlling the oxygen functionalization concentration and maximizing the fluorination efficiency on the surface of the explosively synthesized diamond, a surface functional group having superhydrophobicity while being well dispersed in alcohols (ethanol, methanol, isopropyl alcohol, etc.) and polar organic solvents can be induced on the surface of the explosively synthesized diamond.

[0009] Figures 1a to 1d are FT-IR graphs of fluorinated samples of explosive synthetic diamond according to comparative examples.

[0010] Figures 2a to 2d are XPS graphs for fluorination-treated samples of explosive synthetic diamond according to comparative examples.

[0011] Figures 3a to 3d are XPS analysis graphs and results for analyzing the oxygen element content (atomic oxygen percentage) according to the hydrogen gas treatment temperature.

[0012] Figures 4a to 4d are XPS analysis graphs and results for analyzing the oxygen element and fluorine element content according to the fluorine functionalization treatment temperature after hydrogen gas treatment.

[0013] Figures 5a and 5b are photographs showing the wettability evaluation of a fluorine-functionalized sample of an explosive synthetic diamond that was not treated with hydrogen gas (Figure 5a) and a fluorine-functionalized sample after being treated with hydrogen gas at 500°C (Figure 5b), respectively.

[0014] Figures 6a and 6b are diagrams showing the results of measuring the contact angle of a sample on bare glass (Figure 6a) and a fluorine-functionalized sample (Figure 6b) after hydrogen gas treatment at 500°C.

[0015] Figures 7a and 7b are graphs showing the results of particle size analysis for IPA of a fluorine-functionalized sample of explosive synthetic diamond without hydrogen gas treatment (Figure 7a) and a fluorine-functionalized sample after hydrogen gas treatment at 500°C (Figure 7b).

[0016] Figures 8a and 8b are graphs showing the evaluation of dispersion in butyl acetate by applying tip sonication to a synthetic diamond sample that was not subjected to hydrogen / fluorine gas treatment (Figure 8a) and a sample that was subjected to hydrogen gas treatment at 500°C and then fluorine functionalization treatment at 300°C (Figure 8b), respectively.

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted to clearly explain the present invention, and the same reference numerals are used for identical or similar components throughout the specification. In addition, detailed descriptions of widely known and publicly known technologies are omitted.

[0018] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0019] Then, a method for highly efficient fluorine surface modification of explosive synthetic diamond according to one embodiment is described in detail.

[0020] A method for highly efficient fluorine surface modification of explosive synthetic diamond includes a step of treating explosive synthetic diamond with hydrogen gas, and a step of treating the hydrogen gas-treated explosive synthetic diamond with fluorine gas.

[0021] In the hydrogen gas treatment step, the explosively synthesized diamond reacts with hydrogen gas in an inert gas atmosphere. Furthermore, the hydrogen gas treatment step may include controlling the concentration of oxygen functional groups on the surface of the hydrogen gas-treated explosively synthesized diamond.

[0022] In the fluorine gas treatment step, the hydrogen gas-treated explosive synthetic diamond reacts with fluorine gas in an inert gas atmosphere. Furthermore, the fluorine gas treatment step may include controlling the fluorination concentration on the surface of the fluorine gas-treated explosive synthetic diamond.

[0023] A method for highly efficient fluorine surface modification of explosively synthesized diamond includes controlling the oxygen content and fluorine content of the explosively synthesized diamond.

[0024] Explosion-synthesized diamonds treated with hydrogen and then fluorine gas can be dispersed well in polar solvents. Examples of polar solvents include water, ethanol, and isopropyl alcohol. Furthermore, explosion-synthesized diamonds treated with hydrogen and then fluorine gas can be dispersed well in non-polar solvents. Examples of non-polar solvents include butyl acetate, hexane, toluene, and oil. Thus, explosion-synthesized diamonds treated with hydrogen and then fluorine gas have excellent dispersibility in both polar and non-polar solvents by controlling the oxygen and fluorine content.

[0025] Comparative example: Fluorination treatment of explosively synthesized diamond

[0026] Explosion-synthesized diamond powder is dried at 80°C for 2 hours to remove moisture. The sample is then placed in a tube furnace, vacuumed to 0.1 bar for fluorination, and purged at 1 bar with argon (Ar) gas. This process is repeated more than 20 times. This creates an inert gas atmosphere within the tube furnace. Fluorine gas (F210% in Ar) is then injected into the tube furnace at a flow rate of 60 ml / min. By maintaining the furnace temperature at 300°C for 1 to 7 hours, the fluorination concentration on the surface of the explosion-synthesized diamond is controlled.

[0027] Next, pellets were manufactured through a drying process of 200 mg of KBr, 1 mg of synthetic diamond (DND), and 150°C for 24 hours, and the results of FT-IR measurement are shown in Figures 1a to 1d. Referring to Figure 1a, after fluorine gas treatment, 2923 cm -1 (CH3) and 2852cm -1 A peak of (CH2) is generated, 3184 / 2923cm -1(CO / CF) and 1262 / 2923cm -1 It is shown that a fluorine functional group is formed in (CO / CF). In addition, referring to Figures 1a to 1d, it is shown that even when the fluorination treatment time increases from 1 hour to 7 hours, the fluorine functionalization does not tend to improve rapidly.

[0028] Next, the results of quantifying fluorine functionalization through XPS analysis are shown in Figs. 2a to 2d. Referring to Fig. 2a, it can be seen that the F1s peak is clearly generated after fluorine functionalization. Figs. 2b to 2d show the XPS results for C1s, O1s, and F1s, respectively. Referring to Fig. 2b, the width of the C1s peak decreases after 1 hour of fluorine treatment. Referring to Fig. 2c, the O1s peak decreases in intensity after 1 hour of fluorine treatment, which means that the oxygen content decreases. Referring to Fig. 2d, the F1s peak shows an increase in peak intensity when comparing the results after 1 hour and 5 hours of fluorine treatment, which means that the fluorine content increases.

[0029] Next, based on the XPS analysis results, the results of analyzing the element content of F1s are shown in Table 1 below.

[0030] DND-F 1-hour element concentration (%) DND-F 5-hour element concentration (%) C1s 89.3% 87.6% F1s 10.7% 12.4%

[0031] Referring to Table 1, fluorine doping increases from 10.7% to 12.4%. According to the comparative examples, fluorine doping is interpreted as a competitive reaction induced by the oxygen functional groups present in DND. Accordingly, to optimize fluorine doping, experiments were conducted to increase the fluorine doping content by controlling the oxygen content in Step 1 and performing fluorine doping in Step 2, depending on the reactor temperature, as described in Examples 1 and 2 below.

[0032] Example 1: Hydrogen gas treatment of explosively synthesized diamonds

[0033] Explosion-synthesized diamond powder is dried at 80°C for 2 hours to remove moisture. The sample is then placed in a tube furnace, vacuumed to 0.1 bar for hydrogen gas treatment, and purged to 1 bar with argon (Ar) gas. This process is repeated more than 20 times. This creates an inert gas atmosphere within the tube furnace. Hydrogen gas (50% in Ar) is then injected into the tube furnace at a flow rate of 60 ml / min. By maintaining the furnace temperature at 300–700°C for 3 hours, the concentration of oxygen functional groups on the surface of the explosion-synthesized diamond is controlled.

[0034] Example 2: Fluorination treatment of explosively synthesized diamond

[0035] In Example 1 described above, the hydrogen-treated explosively synthesized diamond powder sample is placed in a tube furnace, a vacuum is induced to 0.1 bar for fluorination treatment, and the steps of injecting argon (Ar) gas and purging to 1 bar are repeated 20 or more times. Accordingly, the inside of the tube furnace is induced into an inert gas atmosphere. Thereafter, fluorine gas (F210% in Ar) is injected into the tube furnace at a flow rate of 60 ml / min. The tube furnace temperature is maintained at 300 to 700°C for 3 hours, thereby controlling the fluorination concentration on the surface of the explosively synthesized diamond.

[0036] In one embodiment, the efficiency of fluorine functionalization can be maximized when the oxygen functional groups of about 10 to 20 atomic % on the surface of the explosive synthesis diamond generated during the explosive synthesis process are controlled to 1 to 10 atomic %.

[0037] According to Example 1, when hydrogen gas treatment is performed on explosively synthesized diamonds at temperatures ranging from 300 to 700°C, the oxygen element percentage can be controlled to approximately 1 to 13%. A fluorine functionalization process is applied to the explosively synthesized diamonds with controlled oxygen element percentages, and the concentrations of fluorine, oxygen, and carbon are analyzed using XPS. Figures 3a to 3d and Figures 4a to 4b show the XPS analysis results.

[0038] The results of the analysis of oxygen and fluorine element contents according to hydrogen gas treatment and fluorine functionalization treatment are shown in Table 2 below.

[0039] Step / Conditions Step 1 (Hydrogen gas treatment) Step 2 (Fluorination treatment) Sample name C1O1N1C1O1N1F1DND89.7%9.4%0.9%75.4%9.9%0.8%13.9%300℃91.3%7.4%1.4%83.3%3.9%1.2%11.6%400℃95.2%4.5%0.3%82.5%5.1%0.7%11.7%500℃95.7%3.3%1.0%76.3%2.7%0.6%20.4%600℃96.82.1%1.1%76.8%4.0%0.7%18.4%700℃96.32.1%1.6%79.6%6.7%0.7%13.0%

[0040] Referring to Table 2, the elemental % of fluorine, oxygen, and carbon are shown, the hydrogen gas treatment temperature is 300~700℃, and the fluorination treatment temperature is 300~700℃. When the oxygen concentration is controlled through hydrogen gas treatment in Step 1, the oxygen content decreases compared to C1s as the temperature increases. In order to confirm the degree of fluorine doping according to the temperature of fluorination treatment, the samples treated with hydrogen gas at 300~700℃ (oxygen content controlled) were subjected to fluorine functionalization treatment at the same temperature as the hydrogen gas treatment temperature. Contrary to the expectation that fluorine functionalization would be improved at higher temperatures, referring to the F1 content, fluorine functionalization is inhibited as the oxygen concentration increases above 500℃. On the other hand, in the fluorine functionalization at 300~500℃, the fluorine content% increases as the oxygen concentration decreases. Accordingly, the optimal temperature for controlling oxygen concentration through hydrogen treatment is 300°C to 700°C, and the optimal temperature for fluorine treatment is 300°C to 500°C. The optimal oxygen concentration in detonation synthetic diamond (DND) is maintained at 2.1% to 9.4% during the hydrogen gas treatment step.

[0041] Figures 5a and 5b show the results of evaluating the wettability in water of a fluorine-functionalized sample of an explosion-synthesized diamond that was not treated with hydrogen gas at 300°C (Figure 5a) and a fluorine-functionalized sample that was treated with hydrogen gas at 500°C and then treated with hydrogen gas at 500°C (Figure 5b). The fluorine-functionalized sample of an explosion-synthesized diamond that was not treated with hydrogen gas has oxygen (9.9%) and fluorine (13.9%) (the oxygen:hydrogen ratio is 1:1.4), and thus shows a phenomenon of precipitation in water. On the other hand, the fluorine-functionalized sample that was treated with hydrogen gas at 500°C and then treated with hydrogen gas has oxygen (2.7%) and fluorine (20.4%) (the oxygen:hydrogen ratio is 1:7.5), and thus shows water-repellent properties.

[0042] Figures 6a and 6b show the contact angles of a sample on bare glass and a sample treated with hydrogen gas at 500°C and then fluorine-functionalized at 500°C, respectively. Referring to Figure 6b, superhydrophobicity is confirmed, with a superhydrophobicity of approximately 146.32°. Accordingly, the explosively synthesized diamond treated with hydrogen and then fluorine gas can have a water repellency of approximately 140° or higher.

[0043] Fluorine-functionalized, explosively synthesized diamonds require good dispersion in polar solvents for material processing. In one embodiment, the degree of dispersion in polar or organic solvents can vary depending on the coexistence ratio of oxygen and fluorine in the explosively synthesized diamond, and an optimal ratio can be derived.

[0044] Figures 7a and 7b are graphs showing the dispersibility in polar solvents of a 500°C fluorine-functionalized sample (Figure 7a) after hydrogen gas treatment at 500°C and a 300°C fluorine-functionalized sample of explosively synthesized diamond without hydrogen gas treatment (Figure 7b), respectively. As shown in Figures 7a and 7b, in the 300°C fluorine-functionalized sample of explosively synthesized diamond without hydrogen gas treatment, the oxygen:fluorine ratio is 1:1.4 and the particle size is approximately 800 nm, which is highly aggregated. However, in the 500°C fluorine-functionalized sample after hydrogen gas treatment at 500°C, the oxygen:fluorine ratio is 1:7.5 and the particle size is approximately 150 nm, which shows very high dispersibility.

[0045] Figures 8a and 8b are graphs evaluating the dispersion in butyl acetate using tip sonication for an explosion-synthesized diamond sample that was not subjected to hydrogen / fluorine gas treatment (Figure 8a) and a sample that was treated with hydrogen gas at 500°C and then fluorine-functionalized at 500°C (Figure 8b), respectively. Referring to Figures 8a and 8b, the particle size of the explosion-synthesized diamond sample that was not treated with hydrogen / fluorine gas is 2,375 nm, and the particle size of the sample that was treated with hydrogen gas and fluorine-functionalized is 191.9 nm.

[0046] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. A step of treating explosive synthetic diamonds with hydrogen gas, and Step of treating hydrogen gas-treated explosive synthetic diamonds with fluorine gas A method for highly efficient fluorine surface modification of explosive synthetic diamond, comprising:

2. In paragraph 1, A method for highly efficient fluorine surface modification of explosive synthetic diamond, wherein in the above hydrogen gas treatment step, the explosive synthetic diamond reacts with hydrogen gas in an inert gas atmosphere.

3. In paragraph 2, A method for highly efficient fluorine surface modification of explosive synthetic diamond, which controls the concentration of oxygen functional groups on the surface of the hydrogen gas-treated explosive synthetic diamond in the above hydrogen gas treatment step.

4. In paragraph 2, A method for highly efficient fluorine surface modification of explosive synthetic diamond, wherein in the above fluorine gas treatment step, the hydrogen gas-treated explosive synthetic diamond reacts with fluorine gas in an inert gas atmosphere.

5. In paragraph 4, A highly efficient fluorine surface modification method for explosive synthetic diamond, which controls the fluorination concentration on the surface of the fluorine gas-treated explosive synthetic diamond in the above fluorine gas treatment step.

6. In paragraph 1, A method for highly efficient fluorine surface modification of explosive synthetic diamond, which controls the oxygen content and fluorine content of the explosive synthetic diamond.

7. In paragraph 1, A highly efficient fluorine surface modification method of explosive synthetic diamond, wherein the fluorine gas-treated explosive synthetic diamond is dispersed in a polar solvent.

8. In paragraph 1, A highly efficient fluorine surface modification method of explosive synthetic diamond, wherein the fluorine gas-treated explosive synthetic diamond is dispersed in a non-polar solvent.

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