A polyaniline / carbon nanotube / silver nanowire hydrophobic electrode, a preparation process and application thereof

Abstract

This invention discloses a hydrophobic electrode made of polyaniline / carbon nanotubes / silver nanowires, its preparation process, and its application. The hydrophobic electrode is prepared from polyaniline, carbon nanotubes, and silver nanowires. In this hydrophobic electrode, silver nanowires are uniformly dispersed in the material, forming a relatively complete conductive network; carbon nanotubes are wound around the surface of polyaniline, forming micro- and nano-scale protrusions, while also being distributed throughout the conductive network of silver nanowires and in contact with them; carbon nanotubes are wrapped and attached to the surface of polyaniline, dispersed throughout the composite material. This invention uses a mixture of polyaniline and carbon nanotubes before incorporating silver nanowires. To enhance hydrophobicity, the composite material undergoes high-temperature heating treatment, resulting in a low surface energy and a micro- and nano-rough structure. This invention involves fewer chemical reagents, has a simple preparation process, good safety, short preparation time, does not produce toxic or polluting gases, and possesses certain anti-corrosion properties.

Description

Technical Field

[0001] This invention belongs to the field of new energy technology, and more specifically, it relates to a hydrophobic electrode made of polyaniline / carbon nanotubes / silver nanowires, its preparation process, and its application. Background Technology

[0002] With the continuous depletion of fossil fuels, people have realized the arrival of the energy crisis and have begun to continuously research and develop new energy sources in order to solve the energy shortage problem. my country has abundant water resources, and rainwater is an important component of these resources. If fully utilized, it can certainly replace some fossil fuels for human use. Currently, research on raindrop energy harvesting mainly focuses on triboelectric nanogenerators (TENGs). Since being proposed by Professor Wang Zhonglin in 2012, TENGs have received increasing attention. Their basic principle is based on the coupling of triboelectric charging and electrostatic induction. Using this principle, not only can mechanical energy, especially low-frequency energy, be harvested from the environment, but raindrop energy can also be harvested, making it an important research direction for TENGs at present. There are generally two types of raindrop energy harvesting: solid-liquid triboelectric nanogenerators and solid-solid triboelectric nanogenerators. In solid-liquid triboelectric nanogenerators, water droplets can act as a friction layer, increasing the contact area of ​​the friction material and reducing frictional losses. When water droplets fall on the surface of the friction material, due to the difference in electronegativity between the two, positive and negative charges are generated on the contact surface, which then form a current under the action of an external circuit. Electrodes are needed for the conduction of TENG electrical signals during the process of collecting raindrop energy. To facilitate the contact and separation of raindrops from the electrodes and the conduction of electrical signals, it is essential to prepare electrodes with good hydrophobic and electrical conductivity.

[0003] Polyaniline (PANI) is a widely studied polymer. Due to its conjugated electronic structure, it exhibits conductivity under acid-doped conditions and hydrophobicity in its intrinsic state. PANI also possesses some corrosion-resistant properties. Furthermore, PANI is advantageous in its preparation due to readily available raw materials, simple synthesis, and low cost. Clearly, polyaniline has become the preferred material for preparing conductive hydrophobic electrodes. However, the inherent hydrophobic and conductive properties of polyaniline alone are far from sufficient for its application in TENG electrodes. To broaden the application range of polyaniline, further improvements are needed in enhancing its hydrophobicity and conductivity.

[0004] Numerous studies have been conducted on improving the conductivity and hydrophobicity of polyaniline, but most approaches only improve one property simultaneously, failing to achieve simultaneous improvements in both. To enhance hydrophobicity, three main methods can be summarized: one is to maintain the original structure and properties of polyaniline by coating its surface with a superhydrophobic material. This method typically requires an adhesive between the polyaniline and the superhydrophobic material, and the material is prone to separation during use. Another method involves directly surface-actively treating the polyaniline to achieve a superhydrophobic effect, but this offers little improvement in conductivity. The final method involves doping with hydrophobic materials such as polystyrene and polytetrafluoroethylene. While this method also achieves superhydrophobicity, it reduces the conductivity of the polyaniline. To enhance conductivity, the main method involves doping with conductive materials such as carbon-based materials and metal particles. Although this improves conductivity, hydrophobicity is often overlooked. Meanwhile, in terms of enhancing hydrophobicity and conductivity, most current research on doping focuses on how to disperse polyaniline and dopants evenly and how to enhance conductivity, while relatively little research has been done on hydrophobicity. Summary of the Invention

[0005] One objective of this invention is to provide a hydrophobic electrode made of polyaniline / carbon nanotubes / silver nanowires, and another objective is to provide a fabrication process and application of the hydrophobic electrode to overcome the shortcomings of the prior art.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A hydrophobic electrode made of polyaniline / carbon nanotubes / silver nanowires is disclosed.

[0008] Furthermore, in this hydrophobic electrode, silver nanowires are uniformly dispersed throughout the material, forming a relatively complete conductive network that enhances the conductivity of carbon nanotubes. Carbon nanotubes are wrapped around the surface of polyaniline, forming micro- and nano-scale protrusions, thereby achieving the superhydrophobic properties of the material. Simultaneously, carbon nanotubes are also distributed throughout the entire silver nanowire conductive network, contacting the silver nanowires and enhancing conductivity. Carbon nanotubes are also wrapped and attached to the surface of polyaniline, dispersed throughout the composite material. Furthermore, it has been verified that no chemical reaction occurs between polyaniline and carbon nanotubes, and no new chemical bonds are formed.

[0009] Furthermore, the resistivity of this hydrophobic electrode can reach 13.3 Ω / cm. -2 Meanwhile, when the ratio of polyaniline to carbon nanotubes is 1:12, the hydrophobicity reaches its maximum, with a contact angle of 151°, achieving a superhydrophobic level.

[0010] Furthermore, the hydrophobic electrode also includes N-methylpyrrolidone or dimethylformamide or other solvents with the same function for dissolving polyaniline.

[0011] The preparation method of the polyaniline / carbon nanotube / silver nanowire hydrophobic electrode includes the following steps:

[0012] (1) First, prepare polyaniline dispersion and carbon nanotube dispersion, mix them thoroughly, and then add silver nanowires to the mixed polyaniline / carbon nanotube mixture. At room temperature of 25℃ and 40kHz frequency, sonicate for 5 minutes to obtain the mixed polyaniline / carbon nanotube / silver nanowire composite material.

[0013] (2) Coating the polyaniline / carbon nanotube / silver nanowire composite material onto the substrate, drying it at room temperature, and then heating it will produce a polyaniline / carbon nanotube / silver nanowire hydrophobic electrode.

[0014] Furthermore, in step (1), polyaniline is first dissolved in a solvent to fully disperse it, and then fully dispersed by magnetic stirring. The carbon nanotube dispersion is placed in an ultrasonic cleaner and ultrasonically treated for 5 minutes at a room temperature of 25°C and a frequency of 40kHz. Then, the dispersed polyaniline is added and magnetically stirred to mix it evenly.

[0015] Furthermore, in step (2), the required substrate is first cut into the desired shape using a laser cutting machine.

[0016] Furthermore, in step (2), the heating conditions are: heating at 200°C for 10 minutes.

[0017] The application of the polyaniline / carbon nanotube / silver nanowire hydrophobic electrode in raindrop energy harvesters may enable the fabrication of triboelectric nanogenerators.

[0018] Specifically, using fluorinated ethylene propylene copolymer (FEP) as the friction layer, and the prepared polyaniline / carbon nanotube / silver nanowire hydrophobic electrode as the electrode, a TENG was fabricated, and current and voltage were tested using water droplets.

[0019] Advantages and beneficial effects of the present invention:

[0020] This invention uses a mixture of polyaniline and carbon nanotubes, which is then incorporated into silver nanowires. To enhance hydrophobicity, the composite material undergoes high-temperature heating treatment, resulting in a low surface energy and a micro / nano rough structure. To enhance conductivity, silver nanowires are doped, significantly improving conductivity without compromising hydrophobicity. This invention involves few chemical reagents, has a simple preparation process, good safety, short preparation time, does not produce toxic or polluting gases, and possesses certain anti-corrosion properties.

[0021] The material prepared in this invention is a liquid with a certain degree of fluidity, enabling the fabrication of electrodes of arbitrary shapes and allowing for large-scale manufacturing. When the composite material is used to create electrodes for a TENG (Tunneling Engraving System), and FEP (Feed Polyethylene) and tap water are used as friction materials, a voltage of 150V and a current of 160μA can be generated, demonstrating its applicability to TENGs for raindrop energy harvesting. Attached Figure Description

[0022] Figure 1 This is an image showing the contact angle of a polyaniline / carbon nanotube / silver nanowire composite material.

[0023] Figure 2 This is a scanning electron microscope image of a polyaniline / carbon nanotube / silver nanowire composite material.

[0024] Figure 3 This is a structural diagram of a polyaniline / carbon nanotube / silver nanowire composite material.

[0025] Figure 4 This is the infrared spectrum of a polyaniline / carbon nanotube / silver nanowire composite material.

[0026] Figure 5 This is the Raman spectrum of a polyaniline / carbon nanotube / silver nanowire composite material.

[0027] Figure 6 It is a QR code and grid-like shape diagram made of polyaniline / carbon nanotube / silver nanowire composite material.

[0028] Figure 7 This is a voltage diagram of a TENG fabricated using a polyaniline / carbon nanotube / silver nanowire composite material as an electrode.

[0029] Figure 8 This is a current diagram of a TENG fabricated using a polyaniline / carbon nanotube / silver nanowire composite material as an electrode.

[0030] Figure 9 This is a structural diagram of TENG.

[0031] Figure 10 This is the schematic diagram of TENG. Detailed Implementation

[0032] The technical solution of the present invention will be further described and illustrated below with reference to the embodiments.

[0033] Example 1

[0034] A method for preparing a hydrophobic electrode made of polyaniline / carbon nanotube / silver nanowire includes the following steps:

[0035] (1) Preparation method of polyaniline / carbon nanotube / silver nanowire composite material: Weigh 5g of polyaniline and add it to reaction bottle 1. Add 25g of NMP to dissolve and disperse. Stir magnetically for 1h to obtain a well dissolved polyaniline dispersion. Weigh an appropriate amount of carbon nanotube dispersion and silver nanowire and put them into two centrifuge tubes respectively. Place them in an ultrasonic cleaner and sonicate at 25℃ and 40kHz for 5min to make the carbon nanotube dispersion and silver nanowire disperse evenly. Set aside for later use. Weigh the two well dispersed liquids according to different ratios of polyaniline mixture: carbon nanotube = 2:1 / 1.5:1 / 1:1 / 1:1.5 / 1:2. Add them to reaction bottle 2 respectively. Stir magnetically for 2h to make the two substances fully mixed. Polyaniline / carbon nanotube mixed electrodes with different ratios can be obtained. At the same time, silver nanowire conductive material is added to enhance conductivity. Weigh out the ultrasonically dispersed silver nanowires and the uniformly mixed polyaniline and carbon nanotube dispersions and add them to a centrifuge tube in a ratio of 0.2:1 / 0.4:1 / 0.6:1 / 0.8:1 / 1:1. After ultrasonic treatment at room temperature (25℃) and 40kHz frequency for 10 minutes, polyaniline / carbon nanotube / silver nanowire mixtures with different ratios can be obtained.

[0036] (2) Preparation method of hydrophobic and conductive electrode of polyaniline / carbon nanotube / silver nanowire composite material: The required shape is drawn using CAD or other drawing software. A mask is placed on the substrate and the mask is cut by adjusting the speed and power of the laser cutting machine to cut out the shape drawn by CAD or other drawing software. The mask of the part of the desired pattern is removed, and then the prepared polyaniline / carbon nanotube / silver nanowire mixture is coated onto the substrate with the mask removed. After drying at room temperature, the remaining mask is removed. The hydrophobic properties of the composite material are tested. The material initially has superhydrophobic properties, but it is found that the hydrophobicity is gradually destroyed as the number of water droplets increases. In order to further improve the hydrophobic properties of the material, the material is heat-treated. It is heated at 200°C for 10 minutes on a heating table and cooled at room temperature to obtain the polyaniline / carbon nanotube / silver nanowire conductive and hydrophobic material. In the experiment, to verify the feasibility of the scheme, QR codes and grid patterns were drawn using CAD software. A glass substrate was used, with Kapton single-sided adhesive applied to the top. The laser cutting machine speed was adjusted to 20 m / s and the power to 10 W to obtain the QR codes and grid patterns (to verify that the electrodes could be fabricated into any shape, they were fabricated into shapes such as QR codes). Then, the portion of Kapton double-sided adhesive to be coated on the electrodes was removed, and a polyaniline / carbon nanotube / silver nanowire composite material was applied. After drying at room temperature, the remaining Kapton adhesive was removed, and the electrode was heated at 200℃ for 10 minutes on a heating stage to obtain the QR code and grid electrode patterns. The grid electrode pattern is shown below. Figure 6 As shown.

[0037] The hydrophobic electrode prepared in Example 1 was subjected to performance testing:

[0038] To characterize the surface morphology of the polyaniline / carbon nanotube / silver nanowire composite material, scanning electron microscopy was used. Simultaneously, infrared and Raman spectroscopy were performed to characterize the bonding between the materials. Performance characterization of the polyaniline / carbon nanotube / silver nanowire composite material: A mixture of polyaniline / carbon nanotube / silver nanowire was coated onto a glass slide and heated at 200℃ for 10 min on a heating stage. The resistivity of the resulting composite material was measured using a DMM-6500 Keithley digital multimeter, and the contact angle was measured using a high-speed camera. The contact angle is shown in the figure. Figure 1 As shown in the figure, the contact angle of the prepared polyaniline / carbon nanotube / silver nanowire composite material is 151°, demonstrating that the composite material possesses superhydrophobic properties. During the contact process between water droplets and the material surface, rapid separation can be achieved without raindrop residue. Scanning electron microscopy was used to analyze the surface morphology of the polyaniline / carbon nanotube / silver nanowire composite material, and the test images are shown in the figure. Figure 2 As shown in the image, the scanning electron microscope (SEM) image of the polyaniline / carbon nanotube / silver nanowire composite material reveals that the coarser fibers are silver nanowires, uniformly dispersed throughout the material to form a relatively complete conductive network, enhancing conductivity. The finer fibers are carbon nanotubes, which are visibly wrapped around the polyaniline surface, forming micro- and nano-scale protrusions, thus achieving the material's superhydrophobic properties. Simultaneously, the carbon nanotubes are also distributed throughout the silver nanowire conductive network, contacting the silver nanowires and enhancing conductivity. To more clearly illustrate the structure of the composite material, as shown... Figure 3 As shown, a general structural diagram was drawn using 3ds Max. The thicker fibers are silver nanowires, forming the entire conductive network. The finer fibers are carbon nanotubes, distributed within the conductive network of silver nanowires. The granular particles are polyaniline particles with carbon nanotubes wrapped and attached to their surfaces, dispersed throughout the composite material. Fourier transform infrared spectroscopy and Raman spectroscopy were used to characterize the polyaniline / carbon nanotube / silver nanowire composite material for the presence of new chemical bonds. The test results are shown in the figure. Figure 4 and Figure 5As shown in the diagram, in the infrared spectrum, peak 1117 cm⁻¹ corresponds to the benzene ring -CH bending vibration, peaks 1494 / 1580 cm⁻¹ to the benzene ring skeletal vibration, peak 1291 cm⁻¹ to the polyaniline -CN stretching vibration, peak 3568 / 3614 cm⁻¹ to the polyaniline -NH stretching vibration, peak 1379 cm⁻¹ to the carbon nanotube -CH bending vibration, and peak 2927 / 2856 cm⁻¹ to the carbon nanotube -CH stretching vibration. In the Raman spectrum, the highest peak corresponds to the stretching vibration of the carbon nanotube ring -CC⁻. The combination of infrared and Raman spectroscopy demonstrates that no chemical reaction occurred between polyaniline and carbon nanotubes, and no new chemical bonds were formed.

[0039] Performance testing verified that the conductivity of the conductive hydrophobic electrode was significantly improved, and the resistivity of the hydrophobic electrode containing silver nanowires could reach 13.3 Ω / cm. -2 The resistivity of hydrophobic electrodes without silver nanowires can reach 1.1 kΩ / cm. -2 Furthermore, the resistivity gradually decreases with increasing silver nanowire content. Simultaneously, the hydrophobicity is maximized when the ratio of polyaniline to carbon nanotubes is 1:12; water droplets can roll freely on the composite surface, achieving a contact angle of 151°, reaching a superhydrophobic level. In other ratios, the electrode is either non-hydrophobic or exhibits hydrophilic behavior. The addition of silver nanowires also did not affect the hydrophobicity of the hydrophobic electrode.

[0040] Comparative experiments on different ratios of polyaniline to carbon nanotubes revealed that the contact angle initially increased and then decreased with increasing carbon nanotube content, reaching a maximum at a ratio of 1:12. After that, the contact angle gradually decreased with further increases in carbon nanotube content until hydrophilicity was observed. Regarding resistivity, a slight upward trend was observed with increasing polyaniline content, but the overall change was not significant.

[0041] Example 2:

[0042] Fabrication of a raindrop energy harvester composed of polyaniline / carbon nanotubes / silver nanowires as hydrophobic electrodes:

[0043] Using ITO glass as a substrate, FEP (fiber ethylene oxide) was attached as a friction layer on the ITO-containing side, and copper wires were used to lead out the ITO electrodes. Kapton adhesive was applied as a mask to the FEP surface. A rectangle 1 mm wide and 4 cm long was cut using a laser cutter. The rectangle was then peeled off, and a mixture of polyaniline / carbon nanotubes / silver nanowires was applied. After drying at room temperature, the remaining Kapton adhesive was peeled off, and the mixture was heated at 100°C for 10 minutes on a heating stage. The TENG (transfer encapsulation process) was then completed. Its basic structure is as follows: Figure 9As shown. Under laboratory conditions, current and voltage tests were conducted using tap water at a height of 15 cm above the fabricated device. The principle behind the generation of the electrical signal is as follows. Figure 10 As shown, when a water droplet lands on the FEP surface, the droplet induces a positive charge, and the FEP induces a negative charge. When the droplet moves to the position of the hydrophobic electrode, due to the potential difference, electrons in the external circuit flow towards the droplet, generating a current signal. When the droplet leaves the hydrophobic electrode, due to the reduced contact area, the induced positive charge decreases, and electrons in the droplet flow towards the external circuit, creating a current in the opposite direction. This continues until the droplet completely leaves the material surface, at which point the electrical signal disappears. This process repeats, forming a cycle. The voltage signal is acquired using an oscilloscope, such as... Figure 7 As shown, it can generate a 150V voltage. The current signal is acquired using an SR570, as shown... Figure 8 As shown, it can generate a current of 160μA.

[0044] Based on the above embodiments, the present invention continues to describe in detail the technical features involved therein and the functions and roles of these technical features in the present invention, so as to help those skilled in the art to fully understand the technical solution of the present invention and reproduce it.

[0045] Finally, although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A hydrophobic electrode made of polyaniline / carbon nanotubes / silver nanowires, characterized in that, The hydrophobic electrode is made of polyaniline, carbon nanotubes and silver nanowires; the silver nanowires are uniformly dispersed in the composite material to form a relatively complete conductive network. Carbon nanotubes are wrapped around the surface of polyaniline, forming micro- and nano-scale protrusions. The carbon nanotubes are also distributed throughout the conductive network of silver nanowires and are in contact with the silver nanowires. Carbon nanotubes are wrapped and attached to the surface of polyaniline and dispersed throughout the composite material. The ratio of polyaniline to carbon nanotubes is 1:

12.

2. The hydrophobic electrode as described in claim 1, characterized in that, The resistivity of this hydrophobic electrode can reach 13.3 Ω / cm. -2 .

3. The hydrophobic electrode as described in claim 1, characterized in that, When the ratio of polyaniline to carbon nanotubes is 1:12, the contact angle reaches 151°.

4. The hydrophobic electrode as described in claim 1, characterized in that, The method for preparing this hydrophobic electrode includes the following steps: (1) First, prepare polyaniline dispersion and carbon nanotube dispersion, mix them thoroughly, then add silver nanowires to the well mixed polyaniline / carbon nanotube mixture, and perform ultrasonic treatment to obtain the well mixed polyaniline / carbon nanotube / silver nanowire composite material. (2) Coating the polyaniline / carbon nanotube / silver nanowire composite material onto the substrate, drying it at room temperature, and then heating it will produce a polyaniline / carbon nanotube / silver nanowire hydrophobic electrode.

5. The hydrophobic electrode as described in claim 4, characterized in that, In step (1), the polyaniline is first dissolved in a solvent to ensure that it is fully dispersed, and then it is further dispersed by magnetic stirring. The polyaniline is then ultrasonically treated for 5 minutes at a room temperature of 25°C and a frequency of 40kHz. After that, the dispersed polyaniline is added and magnetically stirred to ensure that it is mixed evenly.

6. The hydrophobic electrode as described in claim 4, characterized in that, In step (2), the desired shape of the substrate is first cut using a laser cutting machine.

7. The hydrophobic electrode as described in claim 4, characterized in that, In step (2), the heating conditions are: heating at 200℃ for 10 minutes.

8. A hydrophobic electrode made of polyaniline / carbon nanotubes / silver nanowires, as described in claim 1, characterized in that... The hydrophobic electrode has applications in raindrop energy harvesters or can be used to fabricate triboelectric nanogenerators.

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