CN106301063A - A double-sided wearable triboelectric nanogenerator and its preparation method - Google Patents

Abstract

The invention provides a double-sided wearable friction nano generator and a preparation method thereof, wherein the friction nano generator comprises: the human body is used as a second electrode and is connected with the ground, the two friction thin films are both formed by flexible high molecular polymers, and the outer surfaces of the two friction thin films are modified with nano structures; the flexible high molecular polymer film layer can be worn on a human body and can be rubbed with the skin of the human body; the friction electrode layer is a voltage and current output electrode of the friction nano generator. The flexible material with the surface modified concave-convex nano structure is used as two high molecular polymer film layers, so that the roughness and the contact area of the friction surface are increased, and more induced charges are generated. The friction nano generator provided by the invention adopts a unique double-sided friction layer and a flexible material, can collect energy in different directions, and realizes higher energy output.

Description

A double-sided wearable triboelectric nanogenerator and its preparation method

technical field

The invention belongs to the fields of new energy development and micro-nano structure processing, and in particular relates to a double-sided wearable friction nanometer generator and a preparation method thereof.

Background technique

With the rapid development of modern technology, electronic equipment and systems are constantly evolving towards miniaturization, portability, and multi-function. Portable electronic products are becoming more and more closely related to our lives. At present, the use of wearable devices has become a new trend of mass consumption and New Fashion. How to supply power to these huge miniature portable electronic devices in real time has become an urgent problem to be solved in the development of industry and information technology.

Triboelectrification is a very common phenomenon in daily life. Depending on the difference in the triboelectric polarity of the contact material, triboelectric charge is formed on the contact surface to generate static electricity. It is a typical physical phenomenon in which mechanical energy is converted into electrical energy. In 2011, Professor Wang's research team invented the world's first triboelectric nanogenerator by making full use of the coupling effect of triboelectrification and electrostatic induction, and verified that the friction surface decorated with micro-nano structures can improve the power generation efficiency. In order to realize a portable and wearable triboelectric nanogenerator that can collect mechanical energy from the human body, in 2013, Professor Wang Zhonglin’s research group and Zhang Hulin’s research group from Chongqing University developed a single-electrode triboelectric nanogenerator based on human skin design at almost the same time. Composed of grounded polymer friction electrodes, when the human skin contacts the polymer surface, triboelectric charges are generated. Once the skin leaves the polymer surface, electrons flow to the ground, and repeated regular contact and separation can output AC current on the external circuit. Realize power generation. This single-electrode triboelectric nanogenerator is ideal for carrying around and powering portable electronic devices. However, this wearable triboelectric nanogenerator has only one friction surface that can be modified, so the energy conversion efficiency will inevitably decrease, and the structural manufacturing process is too simple and the repeatability is poor, which leads to serious restrictions on its application, and further in-depth research is urgently needed.

Contents of the invention

The technical problem to be solved by the present invention is: aiming at the defects of low efficiency and single processing method of the wearable frictional nanogenerator, the present invention provides a double-sided wearable frictional nanogenerator and its preparation method, the friction layer is changed from the current One side is upgraded to double side, energy is collected in more directions, and nanostructures are modified on the friction surface to increase the roughness and contact area of the friction surface, output higher voltage and current, and realize the wearable triboelectric nanogenerator. High energy output.

In order to solve the above technical problems, the technical solution provided by the present invention is: a double-sided wearable triboelectric nanogenerator, the triboelectric nanogenerator includes: the first high molecular polymer film layer that is sequentially stacked and distributed, the triboelectrode layer And the second high molecular polymer friction film layer, the human body is used as the second electrode, connected with the earth, both layers of friction film are formed by flexible high molecular polymer, and the outer surface is decorated with nanostructures; the said The flexible polymer film layer can be worn on the human body and rubs against the skin of the human body; the friction electrode layer is the voltage and current output electrode of the triboelectric nanogenerator.

In the aforementioned triboelectric nanogenerator, the high molecular polymer film is double-layered, and the friction surface that is in contact with the human body is double-sided.

In the aforementioned triboelectric nanogenerator, the two layers of the high molecular polymer film layer are integrated or separated, and the materials used are the same or different; wherein the material used is a flexible high molecular polymer polydimethyl Silicone (PDMS), polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polycarbonate (PC), UV curing adhesive NOA61 or mercapto-ene (Thiol- ene), the thickness is 0.1-2mm.

In the aforementioned triboelectric nanogenerator, the outer surface of the polymer film is modified with nanostructures, the size of the nanostructures is 10-500nm, and the depth is 1-30μm, wherein the nanostructures are nanotips, nanoneedles, nanocolumns, and nanoparticle .

In the aforementioned triboelectric nanogenerator, the triboelectrode layer is the first electrode, and the second electrode is human skin or clothing fibers.

In the aforementioned friction nanogenerator, the friction electrode layer is made of conductive materials, such as graphene, conductive glass, metal or alloy, wherein the metal is gold, silver, aluminum, nickel, copper, iron, titanium, tungsten.

In the aforementioned triboelectric nanogenerator, the thickness of the triboelectrode layer is 0.1-10 μm.

The second technical solution provided by the present invention is a method for preparing a double-sided wearable triboelectric nanogenerator, the method comprising:

Step (1) Preparation of double-sided nanostructure friction layer

Nano-scale structures are prepared on the outer surfaces of the two layers of polymer films, and the sides without structures are connected together to obtain a double-sided nano-structure friction layer;

Step (2) prepare triboelectrode

A conductive layer is added between two friction layers with no structure surface to collect the induced charges on the two friction surfaces to form a friction electrode;

Step (3) preparation of double-sided friction nanogenerator

The double-sided friction layer and the friction electrode in step (1) and step (2) are packaged and integrated, and the first friction layer, the friction electrode layer and the second friction layer are sequentially laminated to obtain a double-sided friction nanogenerator.

In the aforementioned preparation method of the frictional nanogenerator, in step (1), for the separate two-layer friction layer, nanoimprinting technology is used to prepare nanostructures on the surface of the two-layer high molecular polymer, and then the non-structured surface is bonded to the Together; for the integrated double-sided friction layer, optical exposure technology, dry etching process combined with double-sided imprinting technology is used to form a double-sided nanostructure at one time.

In the preparation method of the aforementioned friction nanogenerator, in step (2), for the separate two-layer friction layer, electron beam evaporation technology is used to plate a conductive layer on the back of one layer of polymer as the friction electrode; Double-sided friction layer, before the material is solidified and formed, the conductive material is embedded in the middle of the material to form an electrode layer and separate the two friction surfaces.

The preparation method of the aforementioned triboelectric nanogenerator, in step (3), utilizes heat-cured polydimethylsiloxane (PDMS) or UV-cured mercapto-ene (Thiol-ene) as an adhesive material, and the two-layer The friction layer and the friction electrode are integrated and packaged.

The advantage of the present invention compared with prior art is:

(1) The present invention adopts a double-sided friction layer, which can collect energy in different directions. At the same time, the concave-convex nanostructure is modified on the surface of the friction layer, so that the effect of friction with the human body is better, and higher energy output is realized.

(2) The present invention has a variety of configurations, many processing methods, high flexibility, and good process repeatability.

(3) The triboelectric nanogenerator provided by the present invention is flexible and can be attached to human skin or worn on the human body, realizing the purpose of powering portable electronic products anytime and anywhere.

Description of drawings

Figure 1 is a schematic diagram of a double-sided wearable triboelectric nanogenerator;

Figure 2 is a flow chart of the preparation of a triboelectric nanogenerator with a double-sided nanocolumn array structure;

Fig. 3 is the preparation flowchart of the triboelectric nanogenerator with double-sided nanotip array structure;

Fig. 4 is a microscope photo of the prepared nano-column array structure.

detailed description

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below through the following specific implementation manners.

The present invention is a double-sided wearable triboelectric nanogenerator and its preparation method. A flexible high molecular polymer with a surface-modified nanostructure is used as the friction layer. When the tribogenerator of the present invention is in regular contact with human skin , A periodic alternating current is formed in the external circuit between the friction electrode of the friction generator and the earth. Benming chooses flexible polymer materials that are harmless to the human body, which can be worn on the human body. At the same time, it adopts a double-sided friction layer, which can collect mechanical energy from more directions of the human body and achieve higher energy output of the generator.

As shown in Figure 1, a double-sided wearable triboelectric nanogenerator in a specific embodiment of the present invention includes a first polymer friction layer 1, a triboelectrode layer 2, and a second layer of polymer polymers that are sequentially stacked and distributed. The material friction layer 3; the outer surfaces of the two polymer layers are respectively decorated with an upper nano-array structure 4 and a lower nano-array structure 5. The outer surfaces of the two layers of high molecular polymer layers are in contact with the skin of the human body, and generate electrostatic charges at the friction electrode layer 2; the friction electrode layer 2 and the human body are electrodes of the friction nanogenerator, and the friction electrode layer 2 Form an external circuit with the earth, output voltage and current.

In the present invention, the materials selected for the first layer of high molecular polymer 1 and the second layer of high molecular polymer 3 must be flexible, can be worn on the human body and do not cause harm and discomfort to the human body, and materials that meet this condition All within the protection scope of the present invention, such as polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polycarbonate ( PC), UV curing glue NOA61 or mercapto-ene (Thiol-ene), the thickness is 0.1-2mm, the materials selected for the first high molecular polymer friction layer 1 and the second high molecular polymer friction layer 3 can be the same , can also be different. In the present invention, the materials of the first high molecular polymer friction layer 1 and the second high molecular polymer friction layer 3 are preferably the same, and the preferred high molecular polymer material is polyethylene terephthalate (PET) or mercapto-ene (Thiol-ene), the thickness is 1mm.

In the present invention, the outer surface of the friction layer is respectively decorated with an upper nano-array structure 4 and a lower nano-array structure 5 . The nano-array structure includes structures such as nano-tips, nano-needles, nano-pillars, nanoparticles, and nano-holes. The parameters of the nanostructure, namely width, depth, period, arrangement, etc., can be adjusted according to specific usage requirements. The parameters of the preferred nanostructure are: the shape is a nanopillar and nanotip array structure, the diameter of the nanopillar or the size of the nanotip 10-500nm, 1-30μm in depth, periodically and uniformly distributed on the surfaces of the friction layers 1 and 3; preferably, the period of the nano-array is 0.1-1μm. The nano-array structures 4 and 5 may be the same or different.

The friction electrode layer 2 has no special regulations on the selected material, and the materials that can form the conductive layer are all within the protection scope of the present invention, such as graphene, conductive glass, metal or alloy, wherein the metal is gold, silver, aluminum, nickel, Copper, iron, titanium, tungsten; alloys are alloys of the above metals. In the present invention, the triboelectrode layer 2 is preferably made of silver, which has good ductility, light weight, can be bent at will without breaking, and has a thickness of 0.1-10 μm, which does not affect the flexibility and bendability of the triboelectric nanogenerator.

As shown in Figure 2, the preparation method of the above-mentioned double-sided wearable triboelectric nanogenerator is described in detail below, and the method includes the following steps:

(1) Preparation of double-sided nanopillar array structure friction layer

Using nanopores as templates, a double-sided friction layer is obtained on two layers of high molecular polymer films by nanoimprinting technology.

A template that can be used in the present invention can be a porous alumina membrane.

The present invention adopts the UV-cured nano-imprinting technology of sacrificial templates to prepare the nano-column array structure, for example, a porous anodized aluminum template 21 with a diameter of 200nm and a depth of 5μm is used, the template area is 3cm×3cm, and the weight is 2g. Clean its surface. Prepare a liquid UV-curable mercapto-ene material with a viscosity of 3.5cp and a Young’s modulus of 1GPa. Use a dropper to drop a drop of liquid mercapto-ene material on the template, and gently tilt and shake the template to form a uniform layer with a thickness of 1mm. The mercapto-ene material layer 22, meanwhile, the mercapto-ene material will overcome the surface tension of the nanopore and flow into the hole to fill it completely. Place it under ultraviolet light for curing, the temperature is 21° C., the light intensity is 40 mW/cm ² , and the curing time is 1 min. The porous alumina template was dissolved by wet etching, and the template was etched away by NaOH aqueous solution with a concentration of 10g/mL. The corrosion rate was 6g/h, and the time was 20min. Finally, the nano-column structure of mercapto-ene material was left23 . The scanning electron micrograph of the nanocolumn array structure is shown in Fig. 5 . The diameter, depth and spacing of the nano-column structure in the present invention can be adjusted according to the preparation process conditions, such as the size of the template, the performance of the polymer, the corrosion time and temperature, so as to meet the requirements of the use conditions.

(2) Preparation of triboelectrode

A friction electrode is made between two high molecular polymer friction layers by using a conductive material, and an external circuit is formed between the earth and the ground to output voltage and current.

In the present invention, electron beam evaporation technology is used to evaporate a metal silver layer on the back of one layer of mercapto-ene nano-column film, and the working pressure of the coating film is set to 1.0×10 ^-3 Pa, and the temperature is 60-80°C. The power is 8000W, the electron beam current is 100mA, the coating rate is 0.1nm/s, the time is 50min, the thickness of the film layer is 300nm, and the friction electrode 24 is prepared.

(3) Preparation of double-sided triboelectric nanogenerators

Bond the two layers of mercapto-ene nanopillar films in steps (1) and (2).

In the present invention, a UV-cured mercapto-ene material is used to evenly coat a very thin layer of material on the back of a nano-column film, and a spin coating machine is used for spin coating with a thickness of 1 μm. The metal surface of the silver-coated nano-column structure layer was bonded to the material thin layer, air bubbles were extruded, and placed under an ultraviolet LED lamp for irradiation and curing with a light intensity of 20 mW/cm ² for 1 min. Due to the strong metal adhesion of the mercapto-ene material, a double-sided triboelectric nanogenerator 25 with a firm structure is obtained.

As shown in Figure 3, the preparation method of a double-sided wearable triboelectric nanogenerator in another embodiment is described in detail below, the method includes the following steps:

(1) Preparation of double-sided nanotip array structure friction layer

Using the micro-hole array as a mask, the optical exposure technology is used to make the nano-tip array structure mother board, and then the casting technology is used to make an imprint template.

The present invention uses optical exposure technology combined with a dry etching process to prepare a nanotip array structure imprint template, for example, a microhole array structure with a diameter of 3 μm and a period of 5 μm, which is arranged in a hexagonal or quadrilateral arrangement, is used as an exposure mask 31 . Using the i-line 34 optical exposure technology to expose the nano-column array structure 35 with a diameter of 3 μm, a height of 2 μm, and a period of 5 μm on the photoresist 32 based on quartz or glass 33 . Reactive ion etching (RIE) was used to perform rotary etching on the photoresist, with an inclination angle of 120°, an etching gas of sulfur hexafluoride, a flow rate of 20 sccm, an etching power of 150W, and a working pressure of 1.0×10 ^-2 Pa, the etching time is 30 min, and the nanotip array structure mother board 36 with an aperture of 2 μm, a height of 1 μm, and a period of 5 μm is obtained.

The present invention uses casting technology to make imprint templates, for example, polydimethylsiloxane (PDMS) is used as the template material, and the base liquid and curing agent are uniformly mixed at a ratio of 10:1 37, and cast on the nanotip array structure motherboard After the material is fully filled, place it in a vacuum oven, set the vacuum degree of the vacuum oven to 0.02Pa, the temperature to 80°C, and the heating time to 2h. Deflate and take it out, and gently remove the cured PDMS from the mother board to obtain a structure 38 complementary to the nanotip array structure, and make two imprint templates of PDMS according to this method.

The present invention uses soft printing technology to make a double-sided nano-tip structure friction layer, for example, two PDMS embossing templates are used to imprint on the two sides of the mercapto-ene material layer 311 respectively. The viscosity of the mercapto-ene material is 3.5cp. The modulus is 1GPa, and the curing energy density is 20mJ/cm ² . After UV curing, the PDMS imprint template was peeled off to obtain a double-sided nanotip array structure 312 , the diameter of the nanotips was 2 μm, the height was 1 μm, and the period was 5 μm.

(2) Preparation of triboelectrode

Silver nanowires are used as conductive materials embedded between two friction layers as friction electrodes. For example, in the process of making UV-curable adhesive NOA61 film 39, the silver nanowires are evenly spread and placed, and then the liquid NOA61 is evenly dripped Coated on the silver nanowire film layer, after UV curing, the silver nanowire and NOA61 film are bonded together; turn the NOA61 film over, and the silver nanowire surface is exposed on it, and also drip-coat NOA61, after UV curing, it is made into a middle The NOA61 film embedded in the silver nanowire conductive layer 310 has a thickness of 2 mm.

(3) Preparation of double-sided triboelectric nanogenerators

Combining the NOA61 thin film embedded in the conductive layer of silver nanowires in step (2) with the processing method in step (1) to obtain a double-sided triboelectric nanogenerator 312 embedded in the silver nanowire triboelectrode layer.

Parts not described in detail in the present invention belong to the known techniques of those skilled in the art.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (11)

1. A double-sided wearable triboelectric nanogenerator, characterized in that: the triboelectric nanogenerator comprises: the first high molecular polymer thin film layer, the triboelectric electrode layer and the second high molecular polymer film layer that are stacked in sequence The friction film layer, the human body as the second electrode, is connected to the earth, and the two layers of friction films are all formed by flexible polymers, and the outer surfaces are all decorated with nanostructures; the flexible polymer film layer can be It is worn on the human body and rubs against the skin of the human body; the friction electrode layer is the voltage and current output electrodes of the triboelectric nanogenerator. 2. The triboelectric nanogenerator according to claim 1, characterized in that: the high molecular polymer film is double-layered, and the friction surface that is in contact with the human body is double-sided. 3. The triboelectric nanogenerator according to claim 2, characterized in that: the two layers of the polymer film layer are integrated or separated, and the materials used are the same or different; The material is flexible polymer polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polycarbonate (PC), UV curable adhesive NOA61 or Thiol-ene, the thickness is 0.1-2mm. 4. The triboelectric nanogenerator according to claim 2, characterized in that: the outer surface of the polymer film is decorated with nanostructures, the size of the nanostructures is 10-500nm, and the depth is 1-30μm, wherein the nanostructures are Nanotips, nanoneedles, nanopillars, nanoparticles. 5. The triboelectric nanogenerator according to any one of claims 1-4, characterized in that: the triboelectric electrode layer is the first electrode, and the second electrode is human skin or clothing fibers. 6. The friction nanogenerator according to any one of claims 1-4, characterized in that: the friction electrode layer is made of conductive materials such as graphene, conductive glass, metal or alloy, wherein the metal is gold, silver, Aluminum, nickel, copper, iron, titanium, tungsten, and alloys of the above metals. 7. The triboelectric nanogenerator according to any one of claims 1-4, characterized in that: the thickness of the triboelectrode layer is 0.1-10 μm. 8. according to the preparation method of the friction nanogenerator described in any one of claim 1-7, it is characterized in that: the method comprises the steps: Step (1) Preparation of double-sided nanostructure friction layer Nano-scale structures are prepared on the outer surfaces of the two layers of polymer films, and the sides without structures are connected together to obtain a double-sided nano-structure friction layer; Step (2) prepare triboelectrode A conductive layer is added between two friction layers with no structure surface to collect the induced charges on the two friction surfaces to form a friction electrode; Step (3) preparation of double-sided friction nanogenerator The double-sided friction layer and the friction electrode in step (1) and step (2) are packaged and integrated, and the first friction layer, the friction electrode layer and the second friction layer are sequentially laminated to obtain a double-sided friction nanogenerator. 9. The preparation method of the frictional nanogenerator according to claim 8, characterized in that: in step (1), for the separate two-layer friction layer, nanoimprinting technology is used to prepare the two-layer high molecular polymer surface respectively Nanostructure, and then bond the unstructured surfaces together; for the integrated double-sided friction layer, use optical exposure technology, dry etching process combined with double-sided imprinting technology to form double-sided nanostructures at one time. 10. The preparation method of the frictional nanogenerator according to claim 8, characterized in that: in step (2), for the separated two-layer friction layer, electron beam evaporation technology is used on the back side of one layer of high molecular polymer The conductive layer is used as the friction electrode; for the integrated double-sided friction layer, the conductive material is embedded in the middle of the material before the material is cured and formed to form an electrode layer to separate the two friction surfaces. 11. The preparation method of the triboelectric nanogenerator according to claim 8, is characterized in that: in step (3), utilize thermosetting polydimethylsiloxane (PDMS) or the mercapto-alkene (Thiol -ene) is used as the bonding material to integrate and package the two friction layers and the friction electrodes.