Preparation method of high-density super-soft graphene film

Abstract

The invention provides a preparation method of a high-density super-soft graphene film, and belongs to the field of preparation methods of graphene films, and the preparation method comprises the following steps: firstly, preparing a rotary silicon substrate, and cleaning the silicon substrate for later use; dripping the graphene composite solution onto a silicon substrate, and rotating the silicon substrate; after the graphene composite solution on the silicon substrate is dried, preparing a graphene film; the graphene film is taken down and dried, multi-section calendaring treatment and vacuum curve calendaring treatment are carried out, and a finished product obtained after calendaring is introduced into a material collecting roller to be collected into a roller; according to the preparation method, the prepared graphene film is subjected to multi-section rolling and vacuum curve rolling treatment, so that the graphene film retains a micro-fold structure and can provide enough strain space in the stretching and bending process, the super-flexible graphene film is formed, and structural damage can be effectively avoided.

Description

Technical Field The invention belongs to the field of graphene film preparation methods, and particularly relates to a high-density ultra-flexible graphene film preparation method. Background Art

[0002] Graphene is a new material with carbon atoms connected by sp2 hybridization tightly stacked into a single-layer two-dimensional honeycomb lattice structure. Graphene has excellent optical, electrical and mechanical properties, and has important application prospects in materials science, micro-nano processing, energy, biomedicine and drug delivery. It is considered to be a revolutionary material in the future. The arrangement of carbon atoms in graphene is the same as that of graphite monoatomic layer, with sp2 hybrid orbital bonding, and has the following characteristics: carbon atoms have 4 valence electrons, 3 of which form sp2 bonds, that is, each carbon atom contributes an unbonded electron located in the pz orbital, and the pz orbital of the neighboring atom is perpendicular to the plane to form a π bond, and the newly formed π bond is half-filled. Studies have confirmed that the coordination number of carbon atoms in graphene is 3, the bond length between each two adjacent carbon atoms is 1.42×10-10 meters, and the angle between bonds is 120°. In addition to the honeycomb layered structure of hexagonal rings linked to other carbon atoms by σ bonds, the pz orbital of each carbon atom perpendicular to the layer plane can form a large polyatomic π bond that runs through the entire layer (similar to a benzene ring), thus having excellent conductive and optical properties.

[0003] In the prior art, the release of gas during the thermal reduction of graphene leads to the formation of a large number of pore structures between layers, which weakens the interaction between the layers and causes the graphene foam film to be loose and porous and lack flexibility. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a high-density ultra-flexible graphene film, aiming to solve the problem in the prior art that the release of gas during the thermal reduction process leads to the formation of a large number of pore structures between layers, weakening the interlayer interaction, causing the graphene foam film to be loose and porous and lack flexibility.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a high-density ultra-flexible graphene film comprises the following steps: S1, first prepare a rotating silicon substrate, and clean the silicon substrate for standby use; S2, dropping the graphene composite solution onto the silicon substrate, and rotating the silicon substrate; S3, after the graphene composite solution on the silicon substrate becomes dry, a graphene film is obtained; S4, removing and drying the graphene film, performing multi-stage calendering treatment and vacuum curve calendering treatment, and introducing the calendered finished product onto a receiving roller for receiving into a tube.

[0006] As a preferred solution of the present invention, the cleaning of the silicon substrate in step S1 comprises the following steps: S101, placing the silicon substrate in an acetone solution and ultrasonically cleaning it for 25-35 minutes; S102, then cleaning the silicon substrate with isopropyl alcohol and deionized water in sequence; S103. Finally, dry in a vacuum drying oven to obtain a pollution-free silicon substrate.

[0007] As a preferred solution of the present invention, in step S2, the silicon substrate rotates at speeds of 800 r / min, 1000 r / min and 1800 r / min respectively.

[0008] As a preferred solution of the present invention, in step S2, the graphene composite solution is evenly dripped onto the silicon substrate.

[0009] As a preferred solution of the present invention, the multi-stage calendering process in step S3 includes a support plate and a calendering roller, wherein the calendering roller is arranged on the upper side of the support plate, and a plurality of evenly distributed segmented strips are fixed on the circumferential surface of the calendering roller.

[0010] As a preferred solution of the present invention, the vacuum calendering process comprises a vacuum box, and a feed port and a discharge port are respectively provided at both side ends of the vacuum box, and a curve calendering mechanism is provided in the vacuum box.

[0011] As a preferred solution of the present invention, the curve rolling mechanism is composed of a first curve roller group, a second curve roller group and a third curve roller group. The two rollers in each group of the first curve roller group, the second curve roller group and the third curve roller group are distributed opposite to each other up and down. The gap between the two rollers in the first curve roller group and the third curve roller group on both sides is higher than the discharge port, and the gap between the two rollers of the second curve roller group in the middle is lower than the height of the discharge port.

[0012] As a preferred solution of the present invention, a vacuum extraction device is also provided on the top of the vacuum box.

[0013] As a preferred solution of the present invention, a first guide roller group is provided between the support plate and the vacuum box.

[0014] As a preferred solution of the present invention, a second guide roller group and a third guide roller group are provided in the vacuum box, the second guide roller group is arranged on the side close to the feed port, and the third guide roller group is arranged on the side close to the discharge port.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a multi-stage calendering process to retain the micro-wrinkle structure of graphene; the vacuum calendering curve is designed to discharge the gas inside the graphene in an orderly and uniform manner, so that the prepared graphene film has a higher density and a better use effect.

[0016] 2. In the present invention, the prepared graphene film is subjected to multi-stage calendering and vacuum curve calendering treatment, so that the graphene film retains a micro-wrinkle structure and can provide sufficient strain space during stretching and bending, forming an ultra-flexible graphene film, which can effectively avoid structural damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a structural schematic diagram of the calendering process in the present invention; Figure 2 It is a cross-sectional structural schematic diagram of the calendering process in the present invention; Figure 3 The figure is a process flow chart of the method for preparing a high-density ultra-flexible graphene film according to the present invention.

[0018] In the figure: 101, support plate; 102, calendering roller; 103, segmented strip; 104, first guide roller group; 105, vacuum box; 106, feed port; 107, vacuum extraction device; 108, second guide roller group; 109, third guide roller group; 110, discharge port; 120, curve calendering mechanism; 121, first curve roller group; 122, second curve roller group; 123, third curve roller group. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1-3 , the present invention provides the following technical solutions: A method for preparing a high-density ultra-flexible graphene film comprises the following steps: S1, first prepare a rotating silicon substrate, and clean the silicon substrate for standby use; Wherein, the cleaning of the silicon substrate in step S1 includes the following steps: S101, placing the silicon substrate in an acetone solution and ultrasonically cleaning it for 25-35 minutes; S102, then cleaning the silicon substrate with isopropyl alcohol and deionized water in sequence; S103, finally drying in a vacuum drying oven to obtain a pollution-free silicon substrate; S2, dropping the graphene composite solution onto the silicon substrate, and rotating the silicon substrate; Wherein, in step S2, the silicon substrate is rotated at a speed of 800 r / min, 1000 r / min and 1800 r / min respectively. When the graphene composite solution is initially dripped onto the silicon substrate, the silicon substrate is rotated at a speed of 800 r / min. After the dripping is completed, the rotation speed of the silicon substrate is accelerated to 1000 r / min, so that the graphene composite solution is evenly spread on the silicon substrate, so that the prepared film becomes thinner. At this time, the silicon substrate is rotated for 10-15 minutes, and finally the silicon substrate is rotated at a speed of 1800 r / min to accelerate the evaporation of the solvent, so that the film becomes dry and easy to remove; S3, after the graphene composite solution on the silicon substrate becomes dry, a graphene film is obtained; S4. The graphene film is removed and dried, and subjected to multi-stage calendering and vacuum curve calendering treatments, and the calendered product is introduced into a receiving roller for collecting into a tube; by subjecting the prepared graphene film to multi-stage calendering and vacuum curve calendering treatments, the graphene film retains a micro-wrinkle structure, which can provide sufficient strain space during stretching and bending, thereby forming an ultra-flexible graphene film, which can effectively avoid structural damage.

[0021] Specifically, the multi-stage calendering process in step S3 includes a support plate 101 and a calendering roller 102 . The calendering roller 102 is arranged on the upper side of the support plate 101 , and a plurality of evenly distributed segmented strips 103 are fixed on the circumferential surface of the calendering roller 102 .

[0022] In this embodiment: a support plate 101 and a calendering roller 102 are provided, the support plate 101 is used to support the graphene film, a plurality of evenly distributed segmented strips 103 are integrally formed on the surface of the calendering roller 102, and a gap is left between the top of the support plate 101, the graphene film passes through the gap, and is squeezed and segmented by the segmented strips 103, retaining the graphene micro-wrinkle structure, so that the graphene film can provide sufficient strain space during the stretching and bending process, and then is transmitted into the vacuum box 105 for curve calendering to form an ultra-flexible graphene film, which can effectively avoid structural damage; the calendering roller 102 is driven to rotate by a motor drive device, so that the calendering roller 102 rotates to the side close to the vacuum box 105, which can better transmit the graphene film.

[0023] Specifically, the vacuum calendering process includes a vacuum box 105 , and both side ends of the vacuum box 105 are respectively provided with a feed port 106 and a discharge port 110 , and a curve calendering mechanism 120 is provided in the vacuum box 105 .

[0024] In the present embodiment: the vacuum box 105 has a vacuum environment. The vacuum extraction device 107 is provided on the top of the vacuum box 105. The vacuum extraction device 107 can evacuate the vacuum box 105. The gaps at the feed port 106 and the discharge port 110 are small and can only accommodate the graphene film, which will not affect the vacuum extraction device 107 from evacuating the vacuum box 105. The incoming film is subjected to curve calendering by the curve calendering mechanism 120, so that the graphene film is stretched and bent to form an ultra-flexible graphene film.

[0025] Specifically, the curve rolling mechanism 120 is composed of a first curve roller group 121, a second curve roller group 122 and a third curve roller group 123. The two rollers in each group of the first curve roller group 121, the second curve roller group 122 and the third curve roller group 123 are arranged opposite to each other up and down. The gap between the two rollers in the first curve roller group 121 and the third curve roller group 123 on both sides is higher than the discharge port 110, and the gap between the two rollers in the second curve roller group 122 in the middle is lower than the height of the discharge port 110.

[0026] In this embodiment: the first curve roller group 121, the second curve roller group 122 and the third curve roller group 123 are composed, and the two rollers in each group of the first curve roller group 121, the second curve roller group 122 and the third curve roller group 123 are arranged opposite to each other up and down, the first curve roller group 121 and the third curve roller group 123 are at the same position and at the same height, and the second curve roller group 122 is slightly lower than the first curve roller group 121 and the third curve roller group 123, so that the graphene film is bent and stretched when passing between the first curve roller group 121, the second curve roller group 122 and the third curve roller group 123, so that the gas in the film can be better squeezed out, and the first curve roller group 121, the second curve roller group 122 and the third curve roller group 123 are all driven to rotate by a motor belt drive drive device, so that the two rollers in the first curve roller group 121, the second curve roller group 122 and the third curve roller group 123 rotate simultaneously inward toward the discharge port 110.

[0027] Specifically, a vacuum extraction device 107 is further provided on the top of the vacuum box 105 .

[0028] Specifically, a first guide roller group 104 is provided between the support plate 101 and the vacuum box 105 .

[0029] In this embodiment: the first guide roller group 104 is composed of two opposing rollers, which are driven to rotate by a motor belt drive device, so that the two rollers rotate simultaneously inwardly toward the discharge port 110, so that the film calendered by the segmented strip 103 can be conducted by the first guide roller group 104 more smoothly and fluently into the vacuum box 105.

[0030] Specifically, a second guide roller group 108 and a third guide roller group 109 are provided in the vacuum box 105 . The second guide roller group 108 is arranged on a side close to the feed port 106 , and the third guide roller group 109 is arranged on a side close to the discharge port 110 .

[0031] In the present embodiment: the second guide roller group 108 and the third guide roller group 109 are each composed of two opposing roller bodies, which are driven to rotate by a motor belt drive device, so that the two roller bodies rotate simultaneously inwardly toward the discharge port 110, so that the graphene film entering the vacuum box 105 through the feed port 106 can be better introduced into the curve calendering mechanism 120, and at the same time, the film calendered by the curve calendering mechanism 120 can be transmitted more smoothly and fluently through the third guide roller group 109 to be rolled up at the discharge port 110.

[0032] In the present invention, a multi-stage calendering process is adopted to retain the micro-wrinkle structure of graphene; a vacuum calendering curve is designed to discharge the internal gas of the graphene in an orderly and uniform manner, so that the density of the prepared graphene film is higher and the use effect is better; by performing multi-stage calendering and vacuum curve calendering treatment on the prepared graphene film, the graphene film retains the micro-wrinkle structure and can provide sufficient strain space during stretching and bending, forming an ultra-flexible graphene film, the number of bending times reaches more than 100,000 times (R2, 180°), avoiding structural damage, and increasing the density of the graphene film to more than 2.0g / m.

[0033] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a high-density ultra-flexible graphene film, characterized in that: The steps include: S1, first prepare a rotating silicon substrate, and clean the silicon substrate for standby use; S2, dropping the graphene composite solution onto the silicon substrate, and rotating the silicon substrate; S3, after the graphene composite solution on the silicon substrate becomes dry, a graphene film is obtained; S4, removing and drying the graphene film, performing multi-stage calendering treatment and vacuum curve calendering treatment, and introducing the calendered finished product onto a receiving roller for receiving into a tube.

2. The method for preparing a high-density ultra-flexible graphene film according to claim 1, characterized in that: The silicon substrate cleaning in step S1 includes the following steps: S101, placing the silicon substrate in an acetone solution and ultrasonically cleaning it for 25-35 minutes; S102, then cleaning the silicon substrate with isopropyl alcohol and deionized water in sequence; S103. Finally, dry in a vacuum drying oven to obtain a pollution-free silicon substrate.

3. A method for preparing a high-density ultra-flexible graphene film according to claim 2, characterized in that: In the step S2, the silicon substrate rotates at speeds of 800 r / min, 1000 r / min and 1800 r / min respectively.

4. The method for preparing a high-density ultra-flexible graphene film according to claim 3, characterized in that: In step S2, the graphene composite solution is evenly dropped onto the silicon substrate.

5. The method for preparing a high-density ultra-flexible graphene film according to claim 4, characterized in that: The multi-stage calendering process in step S3 includes a support plate (101) and a calendering roller (102), wherein the calendering roller (102) is arranged on the upper side of the support plate (101), and a plurality of evenly distributed segmented strips (103) are fixed on the circumferential surface of the calendering roller (102).

6. The method for preparing a high-density ultra-flexible graphene film according to claim 5, characterized in that: The vacuum calendering process comprises a vacuum box (105), wherein two side ends of the vacuum box (105) are respectively provided with a feed port (106) and a discharge port (110), and a curve calendering mechanism (120) is provided inside the vacuum box (105).

7. A method for preparing a high-density ultra-flexible graphene film according to claim 6, characterized in that: The curve rolling mechanism (120) is composed of a first curve roller group (121), a second curve roller group (122) and a third curve roller group (123), wherein the two rollers in each group of the first curve roller group (121), the second curve roller group (122) and the third curve roller group (123) are arranged opposite to each other in an upper and lower direction, and the gap between the two rollers in the first curve roller group (121) and the third curve roller group (123) located on both sides is higher than the discharge port (110), and the gap between the two rollers in the second curve roller group (122) located in the middle is lower than the height of the discharge port (110).

8. The method for preparing a high-density ultra-flexible graphene film according to claim 7, characterized in that: A vacuum extraction device (107) is also provided on the top of the vacuum box (105).

9. The method for preparing a high-density ultra-flexible graphene film according to claim 8, characterized in that: A first guide roller group (104) is provided between the support plate (101) and the vacuum box (105).

10. The method for preparing a high-density ultra-flexible graphene film according to claim 9, characterized in that: A second guide roller group (108) and a third guide roller group (109) are provided in the vacuum box (105); the second guide roller group (108) is arranged on a side close to the feed port (106), and the third guide roller group (109) is arranged on a side close to the discharge port (110).

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