CN114323852B

CN114323852B - Preparation method and application of laser-induced graphene without pinning effect

Info

Publication number: CN114323852B
Application number: CN202111607224.5A
Authority: CN
Inventors: 韩琳; 张宇; 韩应宽; 韩云蕊
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2023-08-29
Anticipated expiration: 2041-12-27
Also published as: CN114323852A

Abstract

The invention relates to the technical field of super-hydrophobic materials, and discloses a preparation method and application of laser-induced graphene without pinning effect, wherein the preparation method comprises the following steps: ultrasonically cleaning the polyimide film with deionized water; designing a graphene pattern to be processed, and guiding the pattern into a laser engraving machine; setting laser power and engraving speed of a laser engraving machine, and performing laser treatment on the polyimide film to obtain laser-induced graphene with pinning effect; and (3) dropwise adding an organic solvent on the surface of the graphene or soaking the graphene in the organic solvent, and airing at room temperature to obtain the laser-induced graphene without the pinning effect. The method disclosed by the invention can be used for preparing the laser-induced graphene without the pinning effect, is low in process cost, efficient and stable, has superhydrophobicity, and has good application prospects in the fields of analyte concentration detection, oil-water separation, anti-icing and the like.

Description

Preparation method and application of laser-induced graphene without pinning effect

Technical Field

The invention relates to the technical field of super-hydrophobic materials, in particular to a preparation method and application of laser-induced graphene without pinning effect.

Background

The solid surface may be classified as super-hydrophilic, hydrophobic or super-hydrophobic depending on its wettability with water. Superhydrophobic surfaces have the ability to remain dry, self-cleaning, and avoid biofouling. Therefore, the super-hydrophobic surface has wide application prospects, such as sea water desalination, biological pollution prevention, energy devices, biomedical devices, medicines, heat transfer and the like. Superhydrophobic surfaces are typically materials with low surface chemical energy and micro-nano scale surface roughness that minimize the contact angle between liquid and solid surfaces. Superhydrophobic surfaces generally fall into two categories: low adhesion water surfaces and high adhesion water surfaces. The switching of liquid-solid bonding can be realized by adjusting chemical components or surface morphology.

Graphene has attracted worldwide attention for the past decade due to its unique physical properties such as high specific surface area, high conductivity, good mechanical strength and stability. Researchers have demonstrated that graphene has broad application prospects in the aspects of electronic devices, energy storage, electrochemical catalysis and the like. The current commonly used graphene preparation methods include a mechanical stripping method, a Chemical Vapor Deposition (CVD) method and a laser induced graphene (Laser induced graphene, LIG) method. Mechanical stripping and CVD are complex and expensive techniques, commonly used for laboratory proof of concept, not suitable for practical production. The Laser Induced Graphene (LIG) method is a simple, low-cost and expandable method for preparing graphene by taking polyimide as a raw material and preparing a porous graphene structure through laser treatment. Since discovery, laser-induced graphene has been widely used in microfluidic systems, electronic devices, catalytic systems, water purification systems, and biosensors. In order to provide different material properties, a common modification of the graphene structure is the introduction of functional groups and/or active species at the graphene surface or edges.

Through the change of the structure or the group of the surface of the graphene, the super-hydrophobic graphene material can be obtained, and the super-hydrophobic graphene can be applied to waterproofing and self-cleaning. Scientific researchers report the process conditions of LIG under different atmospheres, and obtain graphene samples with different surface morphologies and surface chemical properties, so as to generate a superhydrophilic or superhydrophobic graphene surface according to the introduced gas environment. Laser-induced graphene is prepared by scientific researchers based on bionic surfaces, but the biggest problem of the methods is complex process, and special graphene surface structures are designed to realize superhydrophobicity, so that the method is difficult to realize industrially.

Disclosure of Invention

In order to solve the technical problems, the invention provides a preparation method and application of laser-induced graphene without a pinning effect, so as to achieve the purposes of being capable of preparing the laser-induced graphene without the pinning effect, low in process cost, efficient and stable.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

a preparation method of laser-induced graphene without pinning effect comprises the following steps:

(1) Ultrasonically cleaning the polyimide film with deionized water;

(2) Designing a graphene pattern to be processed, and guiding the pattern into a laser engraving machine;

(3) Setting laser power and engraving speed of a laser engraving machine, and performing laser treatment on the polyimide film to obtain laser-induced graphene with pinning effect;

(4) And (3) dropwise adding an organic solvent on the surface of the graphene or soaking the graphene in the organic solvent, and airing at room temperature to obtain the laser-induced graphene without the pinning effect.

In the above scheme, the organic solvent comprises one of ethanol, methanol, acetone, isopropanol, petroleum ether, cyclohexane, dichloromethane and acetonitrile.

In the scheme, the laser power in the step (3) is 0.1-10W, and the engraving speed is 60-120mm/s.

In the above scheme, the laser engraving machine is a semiconductor laser engraving machine with the wavelength of 460nm or a gas laser with the wavelength of 1064 nm.

In the scheme, in the step (4), the soaking time is more than 1 minute.

In the scheme, in the step (1), the ultrasonic time is 10-30min.

The application of the laser-induced graphene without the pinning effect in analyte concentration detection, which is prepared by the preparation method, comprises the following specific steps:

dripping mixed liquid containing the analyte and the Raman enhancement nano particles on the surface of the laser-induced graphene without the pinning effect, and forming an aggregated Raman enhancement nano particle cluster with the analyte on the surface of the laser-induced graphene without the pinning effect after the liquid is evaporated to dryness; the analyte is then detected at the nanoparticle cluster aggregation region using a raman detection device.

The application of the laser-induced graphene without the pinning effect in oil-water separation, which is prepared by the preparation method, comprises the following specific processes:

preparing a filter hole array on a polyimide film by using high-power laser, then performing laser engraving on the polyimide film by using low-power laser to form a graphene oil-water separation film, and finally, treating the graphene oil-water separation film in room temperature air by using an organic solvent; then placing the treated graphene oil-water separation film at the bottom of a container with holes, and pouring an oil-water mixture into the container; due to the oleophylic superhydrophobicity of the graphene oil-water separation membrane, oil permeates the graphene oil-water separation membrane under the action of gravity or pressure, and water stays in a container above the graphene oil-water separation membrane, so that oil-water separation is realized.

The application of the laser-induced graphene prepared by the preparation method in anti-icing is provided.

Through the technical scheme, the preparation method and the application of the laser-induced graphene without the pinning effect provided by the invention have the following beneficial effects:

1. according to the invention, the polyimide film is subjected to laser treatment, so that the laser-induced graphene (LIG) with a pinning effect can be obtained, and the surface of the graphene is provided with a fibrous graphene fluff microstructure; and then, treating by using an organic solvent to obtain the laser-induced graphene (EtOH-LIG) without the pinning effect, wherein most of fibrous graphene fluff microstructure on the surface of the treated graphene disappears, and the surface morphology and the surface chemical structure are changed. Therefore, after the treatment by the organic solvent, the surface of the graphene can be changed from a state with the pinning effect to a state without the pinning effect.

2. The preparation method of the invention is simple, low in cost, high-efficiency and stable, and can be used for large-area preparation.

3. The laser-induced graphene (EtOH-LIG) without the pinning effect has good application prospects in the fields of analyte concentration detection, oil-water separation, anti-icing and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

Fig. 1 is a schematic flow diagram of a preparation method of laser-induced graphene without pinning effect, which is disclosed in the embodiment of the invention;

FIG. 2 shows a scanning electron microscope topography of a laser induced graphene prepared according to an embodiment of the present invention, (a) a scanning electron microscope surface topography of LIG, (b) a scanning electron microscope surface topography of EtOH-LIG, (c) a scanning electron microscope cross-section topography of LIG, and (d) a scanning electron microscope cross-section topography of EtOH-LIG;

fig. 3 is a view of the LIG surface of a water droplet photographed by an optical microscope at different inclination angles, (a) 0 °, (b) 18 °, (c) 180 °, (d) 90 °;

FIG. 4 is a state diagram of water drops captured by a high-speed camera as a function of time after falling on LIG surfaces and EtOH-LIG surfaces, (a) LIG surfaces, (b) EtOH-LIG surfaces;

FIG. 5 shows the variation of contact angle and rolling angle of water drops on LIG surface and EtOH-LIG surface under different pH values;

FIG. 6 is a graph of contact angle and roll angle of a water drop on an EtOH-LIG surface over time;

FIG. 7 is a Raman spectrum of LIG and EtOH-LIG;

FIG. 8 is a zeta potential plot of LIG and EtOH-LIG at different pH values;

FIG. 9 is XPS spectra of LIG and EtOH-LIG;

FIG. 10 is a graph showing the comparison of contact angle and rolling angle of a water droplet on a graphene surface after treatment with different organic solvents;

FIG. 11 is a schematic illustration of droplet variation of an EtOH-LIG surface in nanoparticle aggregation Raman enhancement applications;

FIG. 12 is a scanning electron microscope image of the aggregation morphology of gold nanoparticles on LIG and EtOH-LIG surfaces, (a) EtOH-LIG, and (b) LIG;

FIG. 13 is a SERS intensity plot of LIG and EtOH-LIG surfaces;

fig. 14 (a) is an optical microscope image of the prepared graphene oil-water separation film, (b) is a scanning electron microscope image of the prepared graphene oil-water separation film, and (c) is a schematic view of the prepared graphene oil-water separation film when oil-water separation is performed;

fig. 15 is an optical microscope image of the contact angle of GPL100 lubricating oil and water on the surface of graphene oil-water separation membrane, (a) GPL100 lubricating oil, (b) water;

fig. 16 (a) is a diagram of an oil-water separator constructed using the prepared graphene oil-water separator, (b) is a diagram of an oil-water separator after pouring GPL100 lubricating oil and water, and (c) is a diagram of an oil-water separation effect;

fig. 17 is an optical view of the icing condition of water droplets on the surfaces of LIG and EtoH-LIG, (a) being LIG and (b) being EtoH-LIG.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The invention provides a preparation method of laser-induced graphene without pinning effect, which is shown in fig. 1 and comprises the following steps:

(1) Ultrasonically cleaning the polyimide film with deionized water for 20min;

(2) Designing a graphene pattern to be processed on a computer, and guiding the pattern into a laser engraving machine; the laser engraving machine is a semiconductor laser engraving machine with the wavelength of 460 nm;

(3) Setting the laser power of a laser engraving machine to be 10W, and performing laser treatment on the polyimide film at the engraving speed of 100mm/s to obtain LIG, wherein the graphene surface is provided with a fibrous graphene fluff microstructure, as shown in (a) and (c) in fig. 2;

(4) And (3) dripping ethanol on the surface of the graphene or soaking the graphene in the ethanol for 5 minutes, airing at room temperature (volatilizing the ethanol to be clean) to obtain EtOH-LIG, wherein most of fibrous graphene fluff microstructure on the surface of the treated graphene disappears, and the surface morphology and the surface chemical structure are changed, as shown in (b) and (d) in fig. 2.

And (3) carrying out surface performance test on the LIG prepared in the step (3) and the EtOH-LIG prepared in the step (4).

As shown in fig. 3, which is a state diagram of the LIG surface of the water drop under different inclination angles, which is photographed by the optical microscope, it can be seen from fig. 3 that when the LIG is inclined at different angles (18 °, 90 °, 180 °), the water drop remains in the original position; indicating that the water droplets were pinned to the LIG surface.

As shown in fig. 4, a state diagram of time change when water drops shot by the high-speed camera fall on the surfaces of the LIG and the EtoH-LIG is shown in fig. 4 (a), the water drops are pinned immediately after falling on the surface of the LIG, and the water drops can repeatedly jump on the surface of the EtoH-LIG after falling on the surface of the EtoH-LIG as shown in fig. 4 (b).

As shown in fig. 5, the contact angle and the rolling angle of the water drop on the surfaces of LIG and EtoH-LIG under the condition of different pH values, it can be seen from fig. 5 that the contact angle and the rolling angle of the water drop with different pH values on the surfaces of LIG and EtoH-LIG are not changed greatly.

As shown in fig. 6, a histogram of the contact angle and the rolling angle of the water drop on the EtoH-LIG surface with time is shown, and as can be seen from fig. 6, the contact angle and the rolling angle of the water drop on the EtoH-LIG surface are not greatly changed within 14 days, which indicates that the EtoH-LIG surface has good stability.

Fig. 7 is a raman spectrum of LIG and EtoH-LIG, and it can be seen from fig. 7 that the ratio of D peak to G peak of EtoH-LIG is changed, which indicates that the structure of graphene is changed after ethanol treatment.

Fig. 8 is a zeta potential diagram of LIG and EtoH-LIG at different pH values, and as can be seen from fig. 8, the zeta potential neutralization potential of graphene after ethanol treatment shifts rightward, which indicates that the chemical composition and structure of graphene are changed.

Fig. 9 shows XPS spectra of LIG and EtoH-LIG, and fig. 9 shows that the C, O, N content of graphene after ethanol treatment is changed, which indicates that the composition structure of graphene after ethanol treatment is changed.

In the invention, ethanol can be replaced by methanol, acetone, isopropanol, petroleum ether, cyclohexane, methylene dichloride or acetonitrile, and similar effects can be obtained. Fig. 10 is a graph showing the comparison of the contact angle and the rolling angle of a water drop on the surface of the treated laser-induced graphene after the ethanol is replaced by different organic solvents in the embodiment of the invention, and as can be seen from fig. 10, the contact angle of the graphene is increased and the rolling angle is decreased after the methanol, the acetone, the isopropanol, the petroleum ether, the cyclohexane, the dichloromethane or the acetonitrile are treated, and the laser-induced graphene with the pinning effect is changed into the laser-induced graphene without the pinning effect. It is stated that similar effects of ethanol treatment can be obtained after methanol, acetone, isopropanol, petroleum ether, cyclohexane, methylene chloride or acetonitrile treatment. While the contact angle of the liquid drop on the surface of the laser-induced graphene treated with dimethyl sulfoxide (DMSO) was reduced, indicating that not all organic solvent treatments could obtain the effect of the present invention.

Application example:

1. use in analyte concentration detection

In order to verify the effect of the invention on the concentration detection of the analyte, the surface enhanced Raman is adopted for analysis, and the analysis is compared with the detection of the graphene which is not treated by ethanol.

Firstly, preparing rhodamine 6G (R6G) solution with the concentration of 10 ⁷ M, mixing the R6G solution with the same volume with the gold nanoparticle solution (gold nanoparticles are prepared by adopting a sodium citrate reduction method, and the particle size is 45 nm).

Respectively taking LIG and EtOH-LIG in the embodiment of the invention, dropwise adding 18ul of the prepared mixed solution on the LIG and EtOH-LIG, airing, and respectively placing under a Raman instrument to measure the Raman spectrum of R6G. As can be seen from fig. 11, after the nanoparticle droplets were dropped onto the EtoH-LIG surface, the liquid gradually volatilized and the droplets gradually became smaller over time, eventually leaving the nanoparticles on the graphene surface. As can be seen from fig. 12 (b), the nanoparticle solution cannot form highly aggregated nanoparticle clusters on the LIG surface, whereas the nanoparticles can form highly aggregated nanoparticle clusters on the EtoH-LIG surface, as shown in fig. 12 (a). It is evident from FIG. 13 that the EtOH-LIG treated with ethanol according to the present invention significantly improves the characteristic peak of the detection molecule R6G.

2. Application in oil-water separation

Firstly, preparing a filter hole array (with the distance of 2mm and the diameter of 250 mu m) on a polyimide film by using a high-power laser with the power of 50W, then performing laser engraving on the polyimide film by using a low-power laser with the power of 2W to form a graphene oil-water separation film, and finally, treating the graphene oil-water separation film by using ethanol in room temperature air. An optical microscope image of the prepared graphene oil-water separation film is shown in fig. 14 (a), a scanning electron microscope image thereof is shown in fig. 14 (b), and oil-water separation is performed by using the prepared graphene oil-water separation film is shown in fig. 14 (c).

As shown in fig. 15, the contact angle of GPL-100 lubricating oil on the surface of the graphene oil-water separation film was 0 °, while the contact angle of water on the surface of the graphene oil-water separation film was 164 °.

As shown in fig. 16 (a), the oil-water separator constructed by using the prepared graphene oil-water separation film is shown in fig. 16 (b), after the GPL100 lubricating oil and water are poured into the upper container, as shown in fig. 16 (c), the GPL-100 lubricating agent can pass through the graphene oil-water separation film, and the graphene oil-water separation film treated by ethanol has superhydrophobicity, so that water is repelled, and cannot pass through the oil-water separation film, thereby realizing oil-water separation.

3. Use in anti-icing

In an environment of-15 ℃, respectively dripping water drops on the surfaces of LIG and EtOH-LIG, wherein after 20min, the water drops on the surfaces of LIG are frozen as shown in (a) of fig. 17; the water droplets have good rolling property on the EtOH-LIG surface, and can immediately roll away under extremely small angles without icing on the surface, thereby achieving the deicing effect, as shown in (b) of fig. 17.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The preparation method of the laser-induced graphene without the pinning effect is characterized by comprising the following steps of:

(1) Ultrasonically cleaning the polyimide film with deionized water;

(4) Dropwise adding an organic solvent on the surface of graphene or soaking the graphene in the organic solvent, and airing at room temperature to obtain laser-induced graphene without pinning effect;

the organic solvent comprises one of ethanol, methanol, acetone, isopropanol, petroleum ether, cyclohexane, dichloromethane and acetonitrile; the laser power in the step (3) is 0.1-10W, and the engraving speed is 60-120mm/s.

2. The method for preparing the laser-induced graphene without the pinning effect according to claim 1, wherein the laser engraving machine is a semiconductor laser engraving machine with a wavelength of 460nm or a gas laser with a wavelength of 1064 nm.

3. The method for preparing the laser-induced graphene without the pinning effect according to claim 1, wherein in the step (4), the soaking time is more than 1 minute.

4. The method for preparing the laser-induced graphene without the pinning effect according to claim 1, wherein in the step (1), the ultrasonic time is 10-30min.

5. Use of the laser-induced graphene without pinning effect prepared by the preparation method according to claim 1 in analyte concentration detection, wherein the specific process is as follows:

6. The application of the laser-induced graphene without pinning effect prepared by the preparation method of claim 1 in oil-water separation is characterized by comprising the following specific processes:

7. The use according to claim 6, wherein the organic solvent comprises one of ethanol, methanol, acetone, isopropanol, petroleum ether, cyclohexane, dichloromethane, acetonitrile.

8. Use of the laser-induced graphene prepared by the preparation method of claim 1 in anti-icing.