WO2015035788A1

WO2015035788A1 - Liquid-based friction generator, generation method, sensor, and sensing method

Info

Publication number: WO2015035788A1
Application number: PCT/CN2014/076458
Authority: WO
Inventors: 林宗宏; 程纲; 王中林
Original assignee: 北京纳米能源与系统研究所
Priority date: 2013-09-16
Filing date: 2014-04-29
Publication date: 2015-03-19
Also published as: CN104467514B; CN104467514A

Abstract

A liquid-based friction generator, a generation method, and a sensor. The friction generator comprises a friction layer (10), an upper surface of which is provided with and in contact with a first conducting element (11), and a liquid (20) in which a second conducting element (21) is immersed. A lower surface of the friction layer and an upper surface of the liquid are arranged face to face, at least a part of the lower surface of the friction layer can depart from the upper surface of the liquid after contacting it, and an electric signal can be output by using the first conducting element and the second conducting element. For the friction generator, by using frictional electricity produced by a liquid and a solid friction layer, and according to a static electricity conduction principle, a friction generator that is based on contact between a liquid and a solid and has a simple structure is designed, and mechanical energy produced by liquid wave can be collected and then converted into electrical energy.

Description

Liquid-based friction generator and power generation method, sensor and sensing method thereof

Technical field

The present invention relates to the field of friction power generation technology, and more particularly to a friction generator and a power generation method for converting mechanical energy of liquid fluctuation into electric energy, and a sensor and a sensing method using the same. Background technique

In the process of the existence of nature and human life, various kinetic energy and potential energy will continue to be generated. How to turn these tiny energies into the driving force source we need is the direction that people are constantly searching for. In 2006, Wang Zhonglin's research group at the Georgia Institute of Technology in the United States proposed the concept of nano-generators, opening up a new category of energy conversion and application. On this basis, the research team led by Professor Wang Zhonglin, through the rational design of the device structure, makes the ancient phenomenon of triboelectricity show new application value and potential. The whole friction electric generator relies on the charging pump effect of the frictional electric potential, and the two friction layers coated with the metal electrodes and the first friction layer are bonded together to form a device, and the device is mechanically deformed under the action of external force, resulting in two Mutual friction occurs between the layer polymer films, thereby generating charge separation and forming a potential difference. The two metal plates act as the power output of the generator, and an induced charge can be generated on the surface by electrostatic induction. The induced charge flows through the external circuit driven by the frictional potential to form a current. However, current friction generator designs are limited to solids and solids and cannot utilize the mechanical energy contained in liquid motion in the environment. Summary of the invention

The present invention provides a liquid based contact friction generator capable of converting the energy of liquid fluctuations into electrical energy.

The improved liquid-based friction generator of the present invention comprises: a friction layer, wherein the upper surface of the friction layer is in contact with a first conductive element;

a liquid, the liquid being immersed without a second conductive element;

a lower surface of the friction layer is disposed to face the upper surface of the liquid, and a lower surface of the friction layer is at least partially separable from contact with an upper surface of the liquid; the first conductive element and the second conductive element The electrical signal is outputted outward.

Preferably, there is a difference in friction electrode sequence between the material of the friction layer and the liquid.

Preferably, the material of the friction layer is selected from an insulating material, and the insulating material comprises: aniline formaldehyde resin, polyoxymethylene, ethyl cellulose, polyamide nylon 11, polyamide nylon 66, wool and its fabric, silk and Fabric, paper, polyethylene glycol succinate, cellulose, cellulose acetate, polyethylene glycol adipate, diallyl polyphthalate, regenerated cellulose sponge, cotton and fabric thereof , polyurethane elastomer, Styrene-acrylonitrile copolymer, styrene-butadiene copolymer, wood, hard rubber, acetate, rayon, polymethyl methacrylate, polyvinyl alcohol, polyester, polyisobutylene, polyurethane elastic sponge, poly Ethylene terephthalate, polyvinyl butyral, butadiene-acrylonitrile copolymer, neoprene, natural rubber, polyacrylonitrile, poly(vinylidene chloride-co-acrylonitrile), poly double Phenol A carbonate, polychloroether, polyvinylidene chloride, poly(2,6-dimethylpolyphenylene oxide), polystyrene, polyethylene, polypropylene, polydiphenylpropane carbonate, Polyethylene terephthalate, polyimide, polyvinyl chloride, polydimethylsiloxane, polychlorotrifluoroethylene, polytetrafluoroethylene and parylene.

Preferably, the material of the friction layer is selected from the group consisting of: a silicon, a germanium, a compound of a group III and a group V, a compound of a group II and a group VI, and a compound of a group III-V and a group II-VI. a solid solution composed of a compound;

Alternatively, the material of the friction layer is selected from the group consisting of oxides of manganese, chromium, iron, copper, or one of silicon oxide, manganese oxide, chromium oxide, iron oxide, copper oxide, zinc oxide, Bi0 ₂ and Υ ₂ 0 ₃ . Combination of species or multiples.

Preferably, the lower surface of the friction layer comprises a micro/nano structure layer selected from the group consisting of nanowires, nanotubes, nanoparticles, nanorods, nanoflowers, nanochannels, microchannels, nanocones, Micron cones, nanospheres, and microspherical structures, as well as arrays formed from the foregoing structures.

Preferably, the micro/nano structure layer is directly formed when the friction layer is prepared;

Alternatively, the micro/nano structure layer is formed by embedding or coating a nano material layer on a lower surface of the friction layer; or the micro-nano structure layer is in a friction layer by photolithography, chemical etching or plasma etching. Preparation of the lower surface.

Preferably, the friction layer or the micro-nano structure layer is a hydrophilic or hydrophobic structure.

Preferably, the method further includes a space holding member that faces the surface of the upper surface of the friction layer and maintains a certain distance when the friction generator is in a static state or is not subjected to an external force, when the liquid The surface fluctuation may cause some or all of the lower surface of the friction layer to be in contact with the liquid surface to be separated; or, the generator may be separated when the generator is subjected to an external force to bring some or all of the lower surface of the friction layer into contact with the liquid surface.

Preferably, a part or all of the lower surface of the friction layer is separated from the liquid surface by a distance equal to or less than the certain distance.

Preferably, the certain distance is greater than the thickness of the friction layer; or the certain distance is greater than the distance from the upper surface of the liquid to the second conductive element.

Preferably, the certain distance is more than an order of magnitude greater than the thickness of the friction layer; or the certain distance is more than an order of magnitude greater than the distance from the upper surface of the liquid to the second conductive element.

Preferably, the position of the space holder is between the whole of the friction layer and the first conductive element and the second conductive element;

Alternatively, the space holder is coupled to a side of the friction layer and the first conductive element that faces away from the liquid. Preferably, the space holder is positioned between the friction layer and the first conductive element and the liquid; the space holder has a density smaller than the density of the liquid.

Preferably, the lower surface of the friction layer is a hydrophobic material, and the liquid is a polar liquid; or the lower surface of the friction layer is a hydrophilic material, and the liquid is a non-polar liquid.

Preferably, the polar liquid is water, formic acid, methanol, ethanol, n-propanol, isopropanol, n-butanol, acetic acid, dimethyl sulfoxide, dimethylformamide, acetonitrile or acetone;

The non-polar liquid is hexane, benzene, toluene, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran or dichloromethane.

Preferably, the upper surface and/or liquid of the friction layer is chemically modified.

Preferably, the chemical modification causes the friction layer and the liquid material to introduce a more electron-releasing functional group (ie, a strong electron donating group) on the surface of the positive polarity material, or The surface of the material introduces a more readily available electron functional group (strong electron withdrawing group);

Alternatively, the chemical modification causes a positive charge to be introduced on the surface of the positive polarity material in the friction layer and the liquid material; or a negative charge is introduced on the surface of the negative polarity material.

Preferably, the strong electron donating group comprises: an amino group, a hydroxyl group or an alkoxy group; and the strong electron withdrawing group comprises: an acyl group, a carboxyl group, a nitro group or a sulfonic acid group.

Preferably, the liquid is water, and the material of the friction layer and the micro-nano structure layer on the upper surface of the friction layer is polytetrafluoroethylene, polydimethylsiloxane, polyethylene, polypropylene, polystyrene, poly Methyl methacrylate or polyethylene terephthalate.

Preferably, the friction layer may be a hard material or a flexible material having a thickness ranging from 50 nm to 2 cm.

Preferably, the micro-nano structure layer has a thickness of between 20 ηιη and 20 μιη.

Preferably, the distance from the upper surface of the liquid to the second conductive member is 0.1 cm to 5 cm.

Preferably, the second conductive element is located directly below the friction layer, and the upper surface of the second conductive element is the same shape and size as the lower surface of the friction layer.

Preferably, the method further includes:

a first substrate, configured to fix the first conductive element;

And/or a second substrate for fixing the second conductive element.

Preferably, the space holder is made of an insulating material and is disposed between the first substrate and the second substrate.

Preferably, the material of the first substrate and/or the second substrate is a plexiglass sheet, a polyethylene sheet or a polyvinyl chloride sheet.

Preferably, the space holder is formed by an integral support body or a plurality of separate support units. Preferably, the material of the first conductive element or the second conductive element is selected from the group consisting of: a metal, a conductive oxide or a conductive polymer. Preferably, the first conductive element is a film formed by depositing on an upper surface of the friction layer. Preferably, the first conductive element and the second conductive element are hard materials or flexible materials, and the thickness thereof is between 10 nm and 500 μm.

Correspondingly, the present invention also provides a sensor, comprising the friction generator according to any one of the above, wherein the liquid is a liquid to be tested, and the electrical signal is related to a polarity or a dielectric coefficient of the liquid to be tested, Or related to metal ions and biomolecules in liquids.

Preferably, the liquid to be tested is water, and the water comprises ethanol, oil stain, metal ion or surfactant; or the temperature of the liquid to be tested may be changed.

Preferably, the micro/nano structure layer on the lower surface of the friction layer is a metal oxide, and the liquid to be tested contains an ortho-dihydroxy group, such as catechol, epicatechin, epigallocatechin, 3, 4-dihydroxyphenylacetic acid, alizarin, ascorbic acid or dopamine.

Correspondingly, the present invention further provides a liquid-based friction power generation method, comprising the steps of: providing a friction layer, wherein an upper surface of the friction layer is in contact with a first conductive element;

Providing a liquid, the liquid is immersed without a second conductive element; and the friction layer is disposed above the liquid body such that a lower surface of the friction layer is disposed to face the upper surface of the liquid;

The lower surface of the friction layer is brought into contact with and separated from the upper surface of the liquid, and an electrical signal is outputted to the external circuit between the first conductive element and the second conductive element; when the liquid is a conductor, the first The conductive element is not in contact with the liquid.

Preferably, a lower surface of the friction layer is periodically in contact with and separated from an upper surface of the liquid, and an alternating pulse electrical signal is outputted to the external circuit between the first conductive element and the second conductive element.

Preferably, the frequency of the period ranges from 0.5 Ηζ to 2 Ηζ.

Correspondingly, the present invention further provides a sensing method using the liquid-based friction generator according to any of the preceding claims, comprising the steps of:

Providing a correspondence between a parameter of the liquid in the friction generator and the output electrical signal under a set working condition; the parameter of the liquid includes a polarity or a dielectric coefficient of the liquid, or includes the liquid The concentration of metal ions or biomolecules;

Providing the friction generator including the liquid to be tested, and operating according to the set working condition; determining a parameter of the liquid to be tested according to the output electrical signal of the friction generator including the liquid to be tested. The liquid-based friction generator and the power generation method provided by the invention have the following beneficial effects: (1) A friction generator using liquid and solid friction is proposed for the first time, and the liquid is used as a friction material of the friction generator, and the friction power generation is utilized. And the principle of electrostatic conduction, using a simple generator structure, the possibility of collecting liquid mechanical energy in the environment is realized; and the electrical signal output of the generator provided by the invention can be directly utilized or stored; (2) In the friction generator, the micro-nano structure layer is directly formed on the lower surface of the friction layer, which can significantly improve the output performance of the electrical signal of the generator, breaking the previous need to prepare the friction layer and then form the nanostructure on the surface of the friction layer. The limitation greatly simplifies the preparation method and reduces the cost, and also provides a new way for the optimized output of the electrical signal;

(3) There are two important significances in designing the micro-nano structure layer on the lower surface of the friction layer. One is to increase the contact area between the friction layer and the liquid surface in combination with the fluctuation of the liquid, and the other is to collect a liquid with a relatively large polarity. Mechanical energy, such as water, this structure can increase the hydrophobicity of the friction layer, so that the water can be completely separated after contact with the friction layer to generate transfer charge, and the charge reaches the maximum density at the contact surface, providing a large electrical output;

(4) The hydrophobic micro-nanostructure layer will help detect substances that can cause a change in the dielectric constant or polarity of water, such as ethanol, temperature, oil, surfactants, metal ions or biomolecules. This effect is more pronounced especially with superhydrophobic nanostructures.

(5) By regulating the composition of the micro-nanostructure layer on the lower surface of the friction layer, the micro-nano structure layer can be used for qualitative and quantitative work on the analyte in the liquid by the selective calibration effect of the specific analyte. Regulatory.

(6) The liquid-based friction generator of the present invention has a size of a main component which can be adjusted in accordance with the area and volume of the liquid in the environment, and can be widely used in various fields. Moreover, the structure of the friction generator is simple, and all the materials are inexpensive and easy to obtain. Therefore, the friction generator of the invention is convenient to manufacture, low in cost, and easy to be industrialized and applied. DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the claims. The same reference numerals are used throughout the drawings to refer to the same parts. The drawings are not intended to be scaled to scale in actual size, with emphasis on the gist of the invention.

Figure 1 is a schematic view showing the structure of a liquid-based friction generator according to the present invention;

2 is a schematic structural view of a friction generator including a micro-nano structure layer on a lower surface of the friction layer of the present invention; FIG. 3 is a schematic view of the lower surface of the friction layer in contact with a liquid upper surface when the friction generator of the present invention is in operation;

4 is a schematic view showing the working principle of the friction generator of the present invention;

Figure 5 (a) and Figure 5 (b) is a schematic view showing the arrangement of the space holder of the friction generator of the present invention; Figure 6 and Figure 7 are schematic views showing the embodiment of the space holder of the friction generator of the present invention; Figure 8 (a) And Figure 8 (b) shows the operating state of a particular friction generator of the present invention, and its output voltage and current density test results;

Figure 9 shows a voltage diagram for charging the capacitor of 33 with the electrical outputs provided in Figures 8(a) and 8(b);

Figure 10 (a) and Figure 10 (b) are the linear electric motor operating frequency and friction generator output of the present invention a graph of changes in voltage and current density;

Figure 11 (a) and Figure 11 (b) are diagrams showing changes in current density of the friction generator in the up and down rocking motion as a function of the tilt angle;

Figure 12 is a graph showing changes in current density of a friction generator of the present invention as a sensor for detecting the concentration of ethanol in an aqueous solution;

Figure 13 is a graph showing current density variations of a friction generator of the present invention as a sensor for detecting the temperature of an aqueous solution. Detailed ways

The present invention will be further described in detail below with reference to the specific embodiments of the invention. It should be noted that in the drawings or the description of the specification, the same reference numerals are used for similar or identical parts. In addition, although an example of a parameter containing a particular value may be provided herein, the parameter need not be exactly equal to the corresponding value, but may approximate the corresponding value within an acceptable margin of error or design constraint. In addition, the directional terms mentioned in the following embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only referring to the directions of the drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

The liquid-based friction generator of the present invention generates electricity by contacting the friction layer material with the liquid in contact with the liquid, and collects the mechanical energy of the liquid fluctuations in the environment and converts it into electrical energy for use or storage. In addition, the friction generator can generate different electrical signals with different temperatures, dielectric constants or polar liquids. Therefore, the liquid-based friction generator of the present invention can also be used as a sensor for detecting liquids. Temperature, substances that can cause a change in the dielectric constant or polarity of water, such as oil stains, surfactants, etc.

A typical structure of the friction generator of the present invention is shown in FIG. 1. The friction generator includes: a friction layer 10, the upper surface of the friction layer 10 is in contact with the first conductive element 11; the liquid 20 is immersed in the liquid 20 without the second conductive element 21 The lower surface of the friction layer 10 is disposed to face the upper surface of the liquid 20, and the lower surface of the friction layer 10 can be separated after being at least partially in contact with the upper surface of the liquid 20; the outer surface is outputted through the first conductive member 11 and the second conductive member 21 electric signal. In the generator of the present invention, the first conductive element and the second conductive element are electrical signal output ends of the generator, and therefore, a wire for connecting the first conductive element and the second conductive element to the generator, respectively, is also included. For outputting electrical signals.

The friction generator of the present invention can have two modes of operation, one is that when the liquid 20 fluctuates, the upper surface of the liquid 20 can be separated from the lower surface of the friction layer 10 at least partially after separation, in the first conductive element 11 and the second An electrical signal output is generated between the conductive elements 21; another mode is that under the action of an external force, the lower surface of the friction layer 10 and the upper surface of the liquid 20 are close to each other until contact and then separated, at the first conductive element 11 and the second An electrical signal output is produced between the conductive elements 21. Of course, in the actual working process of the generator, these two modes may also exist at the same time. Regardless of the mode, the surface of the liquid surface and the surface of the friction layer are The reciprocal switching between the separated state and the contact state forms an AC pulse electrical signal output between the first conductive element and the second conductive element.

The function of the space holder 30 is such that when the friction generator is in a stationary state or is not subjected to an external force, the lower surface of the friction layer 10 and the upper surface of the liquid 20 face each other and maintain a certain distance. When the surface of the liquid 20 fluctuates, the lower surface of the friction layer 10 The two may be separated after being partially or completely in contact with the surface of the liquid 20; or, the two may be separated when the generator is subjected to an external force to bring some or all of the lower surface of the friction layer 10 into contact with the surface of the liquid 20. Preferably, a part or all of the lower surface of the friction layer is separated from the liquid surface by a distance equal to or less than the certain distance. Therefore, the position of the space holder 30 on the friction generator may be between the friction layer 10 and the first conductive element 20 and the second conductive element 21, and the space holder 30 is disposed on the friction layer 10 and the first embodiment in FIG. Between the two conductive elements 21; it is conceivable that the space holder 30 can also be disposed between the first conductive element 11 and the second conductive element 21, of course, in order to ensure the normal operation of the generator, the first conductive element 11 and the second conductive The space holder 30 between the elements 21 should be an insulator, which can be achieved by material selection of the space holder 30. The space holder 30 may be an elastic member or a non-elastic member. For the case where an external force is required to bring the friction layer into contact with and separate from the liquid surface, the space holder is preferably an elastic member such as a spring or an elastic organic substance. The skilled person can make an appropriate choice based on the actual use of the generator and should not limit the scope of protection of the present invention.

Referring to FIG. 2, preferably, at least the lower surface and the side surface of the first conductive member 11 are covered by the friction layer 10, and the first conductive member 11 is also prevented from contacting the liquid 20 when the friction layer 10 is in contact with the liquid 20, so that the friction generator is not normal. jobs. In the friction generator, a first substrate may be further included for fixing the first conductive element, and the friction layer 10 and the first conductive element 11 are integrally disposed on the first substrate 12 to accommodate the friction layer 10 and the first The thinner overall composition of a conductive element 11 ensures that the friction layer 10 can still maintain a certain strength or shape when the friction generator operates; for the case where the friction layer and the first conductive element are relatively small in size, the first substrate 12 is There is more choice for introducing a connection position for the space holder 11. Preferably, the upper surface of the first conductive member 11 is disposed on the lower surface of the first substrate 12, and the lower surface and the side surface of the first conductive member 11 are covered by the friction layer 10, so that the first conductive member 11 is coated by the first substrate 12. It is completely covered with the friction layer 10, and the contact of the first conductive member 11 with the liquid 20 can be well avoided. Similarly, a second substrate may be further included for fixing the second conductive element 21 such that the second conductive element 21 is disposed on the second substrate 22, and the introduction of the second substrate 22 is particularly suitable for the second conductive element size. The case where the smaller is not suitable for fixing the space holder 30, or the case where the second conductive member is light in weight is difficult to stabilize the position in the liquid. Preferably, the lower surface of the second conductive member 21 is disposed on the upper surface of the second substrate 22. For the case of including the first substrate 12 and the second substrate 22, the space holder 30 may be disposed between the first substrate 12 and the second substrate 22. Preferably, one end of the space holder 30 is connected to the first The substrate 12 has the other end attached to the second substrate 22 such that the lower surface of the friction layer 10 is opposed to the upper surface of the liquid 20 and maintained at a certain distance.

The first substrate 12 and the second substrate 22 may be a hard material or a flexible material. Optimal mining Use non-deformable insulating hard materials, such as plexiglass sheet, polyethylene sheet, polyvinyl chloride sheet, etc. The thickness thereof is not particularly limited and can be freely selected depending on the strength. Also, providing the first substrate and the second substrate can enhance the overall mechanical strength of the friction generator.

In order to improve the output performance of the friction generator, referring to FIG. 2, it is preferable to provide the micro/nano structure layer 13 of the order of nanometer, micrometer or submicron on the lower surface of all or part of the friction layer 10, when the liquid 20 fluctuates or the friction layer 10 approaches When the liquid 20 brings the lower surface of the friction layer 10 into contact with the upper surface of the liquid, the arrangement of the micro-nanostructure layer 13 can increase the effective contact area of the lower surface of the friction layer 10 and the upper surface of the liquid 20, and increase the surface charge density of both. The function of the micro/nano structure layer 13 on the lower surface of the friction layer can further control the affinity and hydrophobicity of the friction layer 10, in addition to further increasing the contact area between the lower surface of the friction layer and the upper surface of the liquid layer. Or a micro-nanostructure layer of a hydrophilic material to adjust the degree of separation of the friction layer from the liquid after each contact. Therefore, preferably, the liquid is water or an aqueous solution, and the micro-nanostructure layer 13 on the lower surface of the friction layer is a superhydrophobic nano material, such as a nanowire array structure such as zinc oxide, polytetrafluoroethylene, or polydimethylsiloxane. Especially the surface of the lotus leaf or superhydrophobic nanostructures such as insect feet.

The micro-nanostructure layer 13 is preferably a nanowire, a nanotube, a nanoparticle, a nanorod, a nanoflower, a nanogroove, a microgroove, a nanocone, a micron cone, a nanosphere, and a microspherical structure, and an array formed by the foregoing structure In particular, nanoarrays composed of nanowires, nanotubes or nanorods. The size of each such unit in the array is on the order of nanometers to micrometers, and the unit size and shape of the particular micro-nanostructure should not limit the scope of the invention. The micro/nano structure layer 13 on the lower surface of the friction layer 10 may be prepared on the lower surface of the friction layer by photolithography, chemical etching, plasma etching, or the like, or may be formed directly in the preparation of the friction layer material.

Further, in order to achieve the above object, the nano-material may be formed or coated on the lower surface of the friction layer to form the micro-nano structure layer 13. The nanomaterial may be selected from the group consisting of nanoparticles, nanotubes, nanowires, and nanorods. According to actual needs, it may be specifically selected from the group consisting of silica nanoparticles, silica nanowires, silica nanorods, silica nanotubes, polydimethylsiloxane nanoparticles, and polydimethylsiloxane nanowires. Or polydimethylsiloxane nanorods, polydimethylsiloxane nanotubes, polytetrafluoroethylene nanoparticles, polytetrafluoroethylene nanowires, polytetrafluoroethylene nanorods, and polytetrafluoroethylene nanotubes.

The friction generator of the present invention, whether the liquid fluctuation causes the lower surface of the friction layer to reciprocally switch between the separated state and the contact state, or whether the friction layer and the liquid surface are separated by controlling the movement of the friction layer Switching back and forth between the contact state, the process of forming an alternating current pulse output between the first conductive element and the second conductive element is similar, with the liquid fluctuation causing the lower surface of the friction layer to be in a separated state and a contact state with the upper surface of the liquid. For example, the working process of the pulse generator is specifically described in conjunction with the friction generator structure of FIG. 2 and FIG. 3, see FIG. 4:

(1) Referring to Fig. 2 and Fig. 4, in the case where the liquid is not fluctuating, the lower surface of the friction layer 10 (including the micro/nano structure layer 13) is completely separated from the liquid 20, and a certain gap is maintained, as shown in Fig. 4 (a). );

(2) Referring to Figures 3 and 4, in the case where the liquid 20 is fluctuating, the upper surface of the liquid 20 is rubbed The lower surface of the wipe layer 10 (or the micro-nanostructure layer of the lower surface) is in contact, and it is most desirable that the upper surface of the liquid 20 is in complete contact with the micro-nanostructure layer 13 of the friction layer 10, as shown in FIG. Since the micro-nanostructure layer 13 of the friction layer 10 and the position of the liquid in the friction electrode sequence are different, surface charge transfer occurs at the moment of contact to form a surface contact charge, wherein: the surface of the friction layer 10 generates a negative charge, and the liquid 20 The surface generates a positive charge, and the charge of the two charges is the same, as shown in Figure 4(b).

Among them, the principle of generating charge separation and forming a potential difference lies in the frictional electrification caused by the difference in the friction electrode sequence between the friction layer (or the micro/nano structure layer on the lower surface of the friction layer) and the liquid material. Here, the "friction electrode sequence" refers to the order in which the material is attracted to the charge according to the degree of attraction of the material. At the instant of contact between the two materials, the positive charge on the contact surface is from the surface of the material having a relatively negative polarity in the friction electrode sequence. Transfer to the surface of the material with a positive polarity in the friction electrode sequence. To date, there is no unified theory that can fully explain the mechanism of charge transfer. It is generally believed that this charge transfer is related to the surface work function of the material, and charge transfer is achieved by electron or ion transfer on the contact surface. It should be further explained that the transfer of charge does not require relative friction between the two materials as long as they are in contact with each other. The charge on the surface of two materials with different friction electrode polarity differences is called "contact charge" after contact friction and separation. It is generally believed that the charge is only distributed on the surface of the material, and the maximum depth of distribution is only about 10 Nano. It should be noted that the sign of the contact charge is a sign of the net charge, that is, a concentrated region where a negative charge may exist in a local region of the surface of the material having a positive contact charge, but the sign of the net charge of the entire surface is positive.

(3) When the liquid fluctuation disappears, the friction layer 10 starts to separate from the liquid 20, creating a gap. The most desirable condition is that the lower surface of the friction layer 10 is completely free of liquid residue, i.e., the friction layer 10 is completely separated from the liquid. Due to the presence of the gap, the negative charge on the lower surface of the friction layer 10 has a greater repulsion force on the first conductive element 11 than the positive charge on the upper surface of the liquid 20, and the upper surface of the liquid 20 The attraction of the positive charge to the electrons on the second conductive element 21 is greater than the repulsion of the negative charge on the lower surface of the friction layer 10. Therefore, electrons will flow from the first conductive member 11 through the external circuit to the second conductive member 21, and a positive charge is generated on the first conductive member 11, and a negative charge is generated on the second conductive member 21. This process produces a transient pulse current through the external circuit/load, see Figure 4(c). When the gap gradually increases to the gap (before the liquid 20 fluctuates), the number of electrons transferred from the external circuit also increases, and finally reaches equilibrium, as shown in (d) of Fig. 4.

(4) When the fluctuation of the liquid 20 occurs again, the electrons on the second conductive element 21 flow back to the first conductive element 11 again under the repulsive force of the negative charge on the lower surface of the friction layer 10, forming an instantaneous current in the opposite direction. , see (e) in Figure 4.

It can be seen that when the lower surface of the friction layer 10 and the upper surface of the liquid 20 are switched back and forth between the separated state and the contact state, the generated alternating pulse electrical signal is outputted by the lead wires of the first conductive element and the second conductive element, thereby forming Pulse signal.

The components of the liquid-based friction generator of the present invention will be described in detail below with reference to the accompanying drawings. Detailed instructions.

In the friction generator of the present invention, the requirements for the hardness, thickness, shape, material, and the distance between the friction layer and the liquid of the friction layer 10 are as follows:

(1) The present invention does not limit the friction layer 10 or the micro-nano structure layer 13 included in the lower surface of the friction layer must be a hard material, and a flexible material may also be selected because the hardness of the material does not affect the friction layer 10 and the liquid 20 The friction effect between them can be selected by a person skilled in the art according to the actual situation.

(2) The thickness of the friction layer 10 does not significantly affect the performance of the friction generator of the present invention, but factors such as the strength of the friction layer and the power generation efficiency need to be comprehensively considered in the preparation process. Preferably, the friction layer of the present invention is a thin layer having a thickness of 50 nm to 2 cm, preferably 100 nm to 1 cm, more preferably 500 nm to 5 mm, more preferably 1 μm to 2 mm, and these thicknesses are all for the technical solutions in the present invention. Be applicable. The thinner the thickness of the friction layer 10, the better, but due to the limitations of the prior art, it is most preferably 1 μηη - 100 μηη.

(3) The shape of the friction layer 10 and the micro-nano structure layer 13 on the lower surface of the friction layer is not particularly limited as long as it is ensured that the lower surface of the friction layer 10 and the upper surface of the liquid 20 are under the action of an external force (or when the liquid fluctuates). At least part of the contact can be. However, in order to obtain better AC pulse signal output performance, the performance of the lower surface of the friction layer is preferably matched with the properties of the liquid 20, such as the liquid 20 being a highly polar liquid water, and the composition and structure of the lower surface of the friction layer. A hydrophobic structure is preferred to ensure that the friction layer 10 and the liquid 20 are separated as much as possible to produce maximum contact charge density. On the contrary, the liquid 20 is a liquid having a small polarity, and the composition and structure of the lower surface of the friction layer 10 are preferably a hydrophilic structure, ensuring that the friction layer 10 and the liquid body 20 are separated as much as possible to produce the maximum contact charge density.

(4) The lower surface of the friction layer 10 and the liquid 20 are respectively composed of materials which are at different positions in the friction electrode sequence, so that the two can generate contact charges on the surface during the occurrence of friction. The greater the difference in electron abilities between the lower surface of the friction layer and the liquid 20 material (i.e., the farther apart the position in the friction electrode sequence), the stronger the AC pulse signal output by the generator. Therefore, the suitable material can be selected according to actual needs to prepare the micro-nano structure layer 13 and the liquid 20 of the friction layer 10 or the lower surface of the friction layer to obtain a better output effect.

In the friction generator of the present invention, the material of the friction layer 10 (or the micro/nano structure layer 13 on the lower surface of the friction layer) is an insulating material. Conventional insulating materials have triboelectric properties, which can be used as materials for the preparation of the friction layer 10. Here are some commonly used insulating materials and are ordered from positive polarity to negative polarity according to the friction electrode sequence: aniline formaldehyde resin, polyoxymethylene, ethyl Cellulose, polyamide 11, polyamide 6-6, wool and its woven fabric, silk and fabric, paper, polyethylene glycol succinate, cellulose, cellulose acetate, polyethylene glycol adipic acid Ester, diallyl polyphthalate, regenerated cellulose sponge, cotton and fabric, polyurethane elastomer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, wood, hard rubber, acetate , rayon, polymethyl methacrylate, polyvinyl alcohol, polyester (polyester), polyisobutylene, polyurethane elastic sponge, polyethylene terephthalate, polyvinyl butyral, butadiene-propylene Nitrile copolymer, neoprene, natural rubber, polyacrylonitrile, poly(vinylidene chloride-co-acrylonitrile), polybisphenol A carbonate, Polychloroether, polyvinylidene chloride, poly(2,6-dimethylpolyphenylene oxide), polystyrene, polyethylene, polypropylene, polydiphenylpropane carbonate, polyterephthalic acid Ethylene glycol ester, polyimide, polyvinyl chloride, polydimethylsiloxane, polychlorotrifluoroethylene, polytetrafluoroethylene, parylene, including parylene C, parylene N, Perry Lin D, Parylene HT and Parylene AF4.

Semiconductors also have triboelectric properties that tend to lose electrons relative to the insulator, often at the end of the list of friction electrode orders. Therefore, the semiconductor can also be used as a raw material for preparing the friction layer 10 instead of the insulator. Commonly used semiconductors include: silicon, germanium; Group III and V compounds such as gallium arsenide, gallium phosphide, etc.; Group II and VI compounds such as cadmium sulfide, zinc sulfide, etc.; and III-V compounds And Π - a solid solution composed of a VI compound, such as gallium aluminum arsenide, gallium arsenide phosphorus, and the like. In addition to the above crystalline semiconductor, there are amorphous glass semiconductors, organic semiconductors, and the like. Non-conductive oxides, semiconducting oxides, and complex oxides also have triboelectric properties and are capable of forming surface charges during the rubbing process, and thus can also be used as the friction layer of the present invention, such as oxides of manganese, chromium, iron, and copper. Also included are silicon oxide, manganese oxide, chromium oxide, iron oxide, copper oxide, zinc oxide, Bi0 ₂ and Y ₂ 0 ₃ .

For reasons of space, it is not exhaustive for all possible materials as friction layers. Only a few specific materials are listed here for reference, but it is obvious that these specific materials are not limiting as to the scope of protection of the present invention. Factors, because of the teachings of the invention, those skilled in the art can readily select other similar materials based on the friction layer material and the triboelectric properties of the liquid.

Preferably, the material of the micro-nanostructure layer is the same as the material of the friction layer. In a preferred embodiment of the present invention, the liquid 20 is made of water, and the friction layer 10 and the micro-nano structure layer 13 on the lower surface of the friction layer are made of a hydrophobic composition of polytetrafluoroethylene, polydimethylsiloxane, or polyethylene. , polypropylene (ΡΡ), polystyrene (PS), polymethyl methacrylate (PMMA) or polyethylene terephthalate (PET).

The existing template preparation method can be used to prepare the friction layer material and directly form the micro-nano structure layer on the lower surface of the friction layer material, and prepare the friction layer material first, and then prepare the Wiener structure layer on the surface of the friction layer. The method used in the invention simplifies the preparation method, reduces the cost, and provides a new way for the electric signal to optimize the output of the generator.

Further, the lower surface of the friction layer 10 and/or the liquid 20 may be chemically modified to further increase the amount of charge transfer at the moment of contact, thereby increasing the contact charge density and the output of the generator. Chemical modification is divided into the following two types:

One method is to compare the polarity of the friction layer with the liquid material, and introduce a more electron-releasing functional group (ie, a strong electron donating group) on the surface of the material with a positive polarity; or, on the surface of the material with a negative polarity Introducing a more readily available electron functional group (strong electron withdrawing group). This method can further increase the amount of transfer of charge when the friction layer and the liquid slide each other, thereby increasing the frictional charge density and the output power of the generator. Strong electron donating groups include: amino groups, hydroxyl groups, alkoxy groups, etc.; strong electron withdrawing groups include: acyl group, carboxyl group, nitro group, sulfonic acid group and the like. The introduction of the functional group can be carried out by a conventional method such as plasma surface modification. For example, a mixture of oxygen and nitrogen can be generated at a certain power to generate a plasma on the surface of the friction layer material. Into the amino group.

Alternatively, the polarity of the friction layer and the liquid material can be compared, and a positive charge can be introduced on the surface of the material having a positive polarity; or a negative charge can be introduced on the surface of the material having a negative polarity. The step of introducing a charge can be carried out by chemical bonding. For example, the ethyl orthosilicate may be modified by a sol-gel method on the surface of the polydimethylsiloxane friction layer to be negatively charged. A person skilled in the art can select a suitable modifying material and bond according to the electron-loss property and the type of surface chemical bond of the friction layer material and the liquid material to achieve the object of the present invention, and thus the chemically modified material capable of achieving the above object. Both methods and methods are within the scope of the invention.

(5) The present invention has no special requirement for the distance between the lower surface of the friction layer 10 and the upper surface of the liquid 20, but in order to transfer the contact charge generated during the rubbing to the conductive member as much as possible, the pitch is preferably smaller than that of the friction layer 10. The thickness is large, preferably greater than one order of magnitude; preferably also greater than the distance from the upper surface of the liquid to the second conductive element 21, and can be greater than an order of magnitude greater.

The first conductive element 11 and the second conductive element 21 serve as two electrodes of the friction generator, and need to have the characteristics of being electrically conductive, and a commonly used conductive material can be selected, and the selection of the specific electrode layer material is not a factor limiting the scope of the present invention. Materials commonly used in the art are: metals selected from the group consisting of gold, silver, platinum, aluminum, nickel, copper, titanium, chromium or selenium; from gold, silver, platinum, aluminum, nickel, copper, titanium, chromium and selenium, and An alloy formed by the above metal; a conductive oxide such as indium tin oxide ITO; the organic conductor is generally a conductive polymer selected from the group consisting of polypyrrole, polyphenylene sulfide, polyphthalocyanine compound, polyaniline and/or polythiophene. The selection of the specific conductive element material is not intended to limit the scope of the present invention. Preferably, the materials of the first conductive element 11 and the second conductive element 21 are copper, gold, silver or platinum. The friction motor including the first substrate or the second substrate may also directly bond the thicker conductive material to the substrate material to fix the first conductive member or the second conductive member.

In the friction generator of the present invention, the first conductive member 11 should be in close contact with the upper surface of the friction layer 10, and the second conductive member 21 should be completely covered by the liquid, that is, the second conductive member 21 is immersed in the liquid 20 to ensure the charge. Transmission efficiency; the first conductive member 11 may be prepared on the upper surface of the friction layer 10 by a deposition method such as electron beam evaporation, plasma sputtering, magnetron sputtering or evaporation. In addition, it is also possible to directly use the metal plate as the first conductive member and electrically connect it to the friction layer with a conductive paste.

The first conductive element 11 and the second conductive element 21 may be a thin film or a thin layer, and the thickness may be selected from the range of 10 nm to 2 cm, preferably 50 nm to 5 mm, more preferably 100 nm to 1 mm, and even more preferably 500 nm to 500 μm, more preferably 1 μm to 100 μm _{0. The} first conductive member and the second conductive member are not necessarily limited to being rigid or flexible, because the flexible conductive member can also function as a friction layer. Support and conductivity. The first conductive element 13 and the second conductive element 23 are connected to an external circuit through a wire or a thin layer of metal to output an electrical signal of the friction generator.

In the friction generator of the present invention, the distance from the upper surface of the liquid to the second conductive member is based on the liquid completely covering the second conductive member, preferably 0.1 cm to 5 cm. In the present invention, the second conductive is not limited The specific size of the component and the relative positional relationship with the friction layer, in order to ensure that the generator has a stable output electrical signal, preferably, the second conductive component is located directly under the friction layer, and the upper surface of the second conductive component and the friction layer The shape and size of the lower surface are the same.

In the friction generator of the present invention, the space holding member 30 serves to maintain a gap between the friction layer 10 and the liquid 20 without an external force. The space holder 30 can be made of a material having insulating properties.

Referring to Figures 5(a) and 5(b), the space holder 30 can be an integral support (see Figure 5).

( a) ), it may also be a plurality of separate support units (see Figure 5 (b)). The space holder 30 may be a spring U-shaped piece, which may be disposed only on one side of the friction generator or on both sides. The shape and position of the space holder 30 can be determined according to the shape, size, and relative position of the first conductive member 11, the friction layer 10, and the second conductive member 21. For example, a support unit may be attached around the friction layer 10 on the first conductive member 11, or the space holder may be directly bonded to the surface of the friction layer. Of course, for a friction generator that contacts and separates the lower surface of the friction layer from the upper surface of the liquid by controlling the movement of the friction layer, referring to FIG. 6, it is also possible to connect the space holder 31 only to the friction layer 10 and the first conductive The component 11 is integrally formed, in particular, on the side of the friction layer 10 and the first conductive element 20 that faces away from the liquid 20, for example, the space holder 31 is connected to the first conductive element on the first substrate. Or the friction layer 10, the space holder 31 is not connected to the second conductive member, and the movement of the friction layer 10 can be controlled by connecting other devices to the space holder 31, so that the lower surface of the friction layer 10 can be combined with the upper surface of the liquid 20. Contact and separation. If the space holder 31 is connected to a device capable of generating periodic motion, such as a linear motor, the friction layer 10 will periodically contact and separate from the liquid 10, enabling generation between the first conductive element 11 and the second conductive element 21. Periodic electrical signal output.

It has been found through experiments that the preferred frequency range for the periodic contact and separation of the friction layer from the liquid is from 0.5 Hz to 2 Hz.

Another arrangement of the space holder is also provided in other embodiments of the invention. A lighter weight material may be used as the space holder, the position of the space holder being between the friction layer and the first conductive element and the liquid, for example, the space holder is attached to the lower surface of the friction layer, or is connected to the first The lower surface of the substrate, the lighter weight holder, separates the friction layer (or micro-nanostructure layer) from the liquid. The specific material of the space holder is selected to be an insulating material having a density less than the density of the liquid, such as a styrofoam material. Referring specifically to Figure 7, the space holder 32 is placed on the lower surface of the first substrate 12 and ensures that the lower surface of the first friction layer 1 is separated from the liquid 20; the first conductive member 11, fixed to the first substrate a lower surface of the friction layer 10; the lower surface of the friction layer 10 includes a micro-nano structure layer 13 disposed in contact with the first conductive member 11 and completely covered by the friction layer; further comprising a second substrate 22 and a second substrate The second conductive element 21, the second conductive element is completely submerged in the liquid 20. The structure of the space holder may be an annular shape surrounding the friction layer or a plurality of support units surrounding the friction layer (see Fig. 5 (a) and Fig. 5

(b)), the overall volume of the space holder may be flexibly changed according to the total weight of the first conductive member, the friction layer and the insulating support layer, and the distance between the friction layer and the liquid, and is not particularly limited herein. The insulating support layer in this embodiment is not connected to the second conductive element or the second substrate, and is equivalent to floating the entirety of the first conductive element, the friction layer and the insulating support layer on the liquid. When the liquid 20 does not fluctuate, the lower surface of the friction layer 10 faces the upper surface of the liquid 20 to maintain a certain gap. When the liquid 20 fluctuates, the micro/nanostructure layer 13 on the lower surface of the friction layer 10 is in contact with the upper surface of the liquid 20, and surface charge transfer occurs between the friction layer 10 and the friction layer 20 due to the triboelectric effect.

Further, although the friction generator of the present embodiment has a space holder, the present invention is not limited thereto. Regardless of the means, as long as the lower surface of the friction layer of the friction generator (or the micro-nano structure layer) and the upper surface of the liquid can be switched back and forth between the separated state and the contact state, the first conductive element and the second conductive element can be An alternating pulse electrical signal is generated between them to effect the function of the liquid based friction generator of the present invention.

In the friction generator of the present invention, the liquid may be purified water, deionized water, polar liquid, non-polar liquid or other solution. The object of the present invention can be achieved as long as there is a difference in friction electrode sequence between the friction layer and the liquid material. When actually designing the friction generator, those skilled in the art can select appropriate friction according to the composition and polarity of the specific liquid. The layer material and the micro/nano structure layer on the lower surface of the friction layer. The lower surface of the friction layer is a hydrophobic material, and the liquid is preferably a polar liquid. Alternatively, the lower surface of the friction layer is a hydrophilic material, and the liquid is preferably a non-polar liquid. Typical polar liquids may be water, formic acid, methanol, ethanol, n-propanol, isopropanol, n-butanol, acetic acid, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetonitrile ( MeCN), acetone, etc.; the non-polar liquid may be selected from the group consisting of hexane, benzene, toluene, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran (THF), dichloromethane, and the like.

The performance of the friction generator of the present invention will be described below with a specific example. The first substrate 12 and the second substrate 22 are plexiglass sheets, the friction layer 10 is polydimethylsiloxane, and the micro-nano structure layer 13 on the lower surface of the friction layer is a tapered polydimethylsiloxane. The micro-structure, the liquid 20 is deionized water, the first conductive element 11 and the second conductive element 21 are copper thin films, and the first substrate is connected with a linear electric motor to cause a periodic change of contact and separation between the friction layer and the liquid, wherein The effective contact area of the friction layer with the liquid is 4 cm X 3 cm, the liquid is placed in a container with a bottom area of 11 cm X 7 cm, the second conductive element is submerged into the water to a depth of 2 cm, and the linear electric motor operates at a frequency of 2 At Hz, as shown in Figure 10 (a), the output voltage of the friction generator is 82 V. It can be seen that the friction layer and the water are in contact and separated, and the output repeatability is excellent. The stability is very good.

Figure 8 (a) is the open circuit voltage test result of the friction generator. The left and right halves are the first conductive element and the second conductive element are connected to the test equipment (the first conductive element is connected to the positive pole and the second conductive component is connected). The output voltage observed when the negative electrode is reversed (the first conductive element is connected to the negative electrode and the second conductive element is connected to the positive electrode). The test results show that the first conductive element and the second conductive element are connected to the test device when they are connected and reversed. The output voltage is the same value, which means that the tested voltage is the true output of the friction generator, not the background signal or system error.

Figure 8 (b) shows the current density test results of the friction generator. The results show that the friction generator can provide The output current density is 1.05 mA/m ² , and it can be seen that the friction layer and the water are in contact and separated, the output repeatability is excellent, indicating good stability; likewise, Figure 8 (b) left half And the right half is the current density observed by the first conductive element and the second conductive element in connection with the test setup, and the test result indicates that the first conductive element and the second conductive element are positively connected and opposite to the test device. The output current density observed at the time is the same value, which means that the observed current is the true output of the friction generator, not the background signal or system error. The output electrical signal of the friction generator can simultaneously drive 60 green LED lamps, indicating that the friction generator provided by the present invention can directly convert the energy of the liquid fluctuation into practical electrical energy.

Figure 9 shows the output of this friction generator for charging a commercial capacitor of 33. The measured voltage value can be charged to about 1.2 V in about ten minutes. It is confirmed that the output signal of the friction generator can be The charging of electrical appliances used in life clearly shows the potential of its application.

Figure 10 (a) In order to change the operating frequency of the linear electric motor to 2, 3, 4 and 5 Hz, the voltage output by the friction generator is 82 V, 23 V, 45 V and 52 V, respectively. The friction generator of the two solids as the friction layer varies differently, and the output voltage of the conventional friction generator does not change as the operating frequency of the linear electric motor changes. The inventor believes that the friction generator of the present invention causes the fluctuation of the water surface when the linear motor drives the friction layer to reciprocate up and down, and the area of the friction layer in contact with the water changes, causing a change in the output signal, which is also fully displayed. The characteristics of the liquid-based friction generator of the present invention, and the places to be considered in future design;

Figure 10 (b) In order to change the operating frequency of the linear electric motor to 2, 3, 4 and 5 Hz, the current density output by the friction generator is 1.05 mA/m ² 0.46 mA/m ² and 1.34 mA/m ² P 2.45 mA/m ² , this change is also different from the change of the traditional friction (two solid materials as two friction layers) generator, the current density of the traditional friction generator will only follow the operating frequency of the linear electric motor The increase is larger, the main reason is that the frequency of the linear motor simply affects the time when the electron flow of the external circuit reaches equilibrium. However, the frictional generator composed of the solid friction layer and the liquid of the present invention is when the linear electric motor drives the friction layer relative to When the liquid reciprocates up and down, it will cause fluctuations in the upper surface of the liquid, and the area in which the friction layer contacts the liquid changes, and the influence of the operating frequency of the linear electric motor causes a change in the output current density. The characteristics of the friction generator of the present invention are also fully shown, as well as the places to be considered in future design.

In addition, the inventors also used a flat-plate rocking device to simulate the fluctuation of water in the natural environment, repeatedly tilting the friction generator, as shown in Fig. 11 (a), and measuring the current density of the output of the friction generator, such as Figure 11 (b) shows that the liquid-based friction generator can provide a continuous AC pulse output in the case of liquid fluctuations. When the device swing angle is changed from 10° to 20°, the output current density can be 0.1. The mA/m ^{2 is} increased to approximately 0.6 mA/m ² , which is mainly due to the fact that the device swing angle becomes larger, and the contact area between the lower surface of the first friction layer and the liquid upper surface becomes larger, resulting in an increase in the amount of friction transfer charge and output. In addition, the inventors have carefully studied the friction generators for liquids of different dielectric constants or polarities, the output electrical signals of which are related to the properties such as the dielectric constant or polarity of the liquid, and therefore, the liquid-based friction generator of the present invention. It can also be used as a sensor. The liquid in the friction generator is the liquid to be tested, and the electrical signal is related to the polarity or dielectric constant of the liquid to be tested, or to metal ions and biomolecules in the liquid. The sensor can be used to detect a factor in a liquid that causes a change in the dielectric constant or polarity of the liquid, such as a substance in which the liquid to be tested is water, a substance that causes a change in the dielectric constant or polarity of the water, such as ethanol, oil, metal ions or a surface. The active agent or the like, or the temperature of the liquid to be tested may be changed, and the temperature change may also cause a change in the polarity or dielectric coefficient of the liquid to be tested. In addition, the sensor of the present invention can also detect metal ions and biomolecules in the liquid, because when the liquid includes metal ions or biomolecules, the contact charge of the friction layer or the liquid changes when the liquid contacts and separates from the friction layer, and It is related to the concentration of metal ions or biomolecules.

Therefore, in the sensor using the friction generator, a change in the dielectric constant or polarity of the upper surface of the liquid or liquid or a change in the metal ion or biomolecule in the liquid causes a contact charge when it is separated from the friction layer. Affected, and the amplitude of the alternating current pulse outputted between the first conductive element and the second conductive element is also changed, that is, the alternating current pulse generated by the friction generator is modulated by the change of the dielectric constant or polarity of the liquid to be detected. This is the basic working principle of the liquid-based friction generator of the present invention.

Figure 12 is a diagram of a sensor (liquid-based friction generator) for testing the concentration of ethanol in an aqueous solution. It can be found that the ethanol content is from 1% to 20%, and the output current density of the friction generator decreases almost linearly. It can be seen that the output value of the electrical signal of the friction generator is very stable and is a good detection method. In addition, we also use the above-mentioned friction generator to detect the water temperature, the water temperature changes from 25 ° C to 75 ° C, see Figure 13, the output current density of the friction generator also decreases linearly, indicating that the friction generator can also be used to detect The temperature of the liquid.

In addition, as a sensor, by adjusting the composition of the micro/nano structure layer on the lower surface of the friction layer, the micro-nano structure layer has a selective calibration effect on a specific analyte, and once the micro-nano structure layer captures the analyte in the liquid, The frictional property with water changes and affects the electrical output, and the analyte can be qualitatively and quantitatively manipulated by this change, and has flexible controllability; the micro/nano structural layer is a metal oxide such as titanium dioxide. , iron oxide or zirconium dioxide, etc. The liquid to be tested contains an ortho-dihydroxy group such as catechol, epicatechin, epigallocatechin, 3,4-dihydroxyphenylacetic acid, alizarin, ascorbic acid or dopamine. The metal oxide is in contact with these components in the liquid), which changes the triboelectric properties between the lower surface of the friction layer and the liquid, thereby affecting the output electrical signal of the generator, which can be qualitative or quantitative depending on the electrical signal. The analyte in the liquid is measured.

The sensor network will be the fundamental driving force for the future economic development. Traditional sensors include mechanical sensors, chemical sensors, biosensors, photoelectric sensors, and gas sensors. Sensors are information that is noteworthy in the environment (such as light intensity, wind speed, heavy metal content or specific biomolecules in the human body) A device that converts an electrical signal into an electrical signal for recording analysis. As technology continues to advance, its use is becoming more widespread, including in chemical analysis, medical diagnostics, the food industry, or environmental monitoring. However, current sensor designs are too complex and require power-driven sensors to work, and are not able to accommodate the multi-point distribution of the sensor network. By using the process provided by the invention, the friction generator which is in contact with the liquid and the solid can be used to associate the parameter of the liquid with the output electric signal box of the friction generator to realize self-driven liquid sensing, which can be conveniently used in the liquid. Quantitative or qualitative analysis of certain parameters is a simpler method of detection and will be a breakthrough in the field of sensors.

Corresponding to the liquid-based friction generator provided by the present invention, the present invention also provides a liquid-based friction power generation method, comprising the steps of:

Providing a friction layer, the upper surface of the friction layer is in contact with a first conductive element;

Preferably, the lower surface of the friction layer is periodically contacted and separated from the upper surface of the liquid, and an alternating pulse electrical signal is output between the first conductive element and the second conductive element. Preferably, the frequency of the period ranges from 0.5 Hz to 2 Hz.

The lower surface of the friction layer is brought into contact with and separated from the upper surface of the liquid. There are two ways, one way is to provide control of the movement of the friction layer to adjust the distance between the lower surface of the friction layer and the upper surface of the liquid. Another way is that the fluctuation of the liquid itself causes the lower surface of the friction layer to contact and separate from the upper surface of the liquid.

In the liquid-based friction power generation method of the present invention, the friction layer, the liquid, the first conductive element and the second conductive element and the friction layer, the liquid, the first conductive element in the liquid-based friction generator and The material, structure, size, and the like of the second conductive member may be identical and will not be repeated herein.

The liquid-based friction generator method of the present invention can be applied to rivers, lakes or seawater in nature to collect mechanical energy generated by liquid fluctuations and convert it into practical electrical energy. The liquid-based friction generator method of the present invention can also be applied in the field of controllable contact power generation, for collecting mechanical energy generated by machinery, human body, etc., especially mechanical energy that has not yet been utilized, and converting part of these mechanical energy into Electrical energy is utilized.

Corresponding to the above sensor, the present invention also provides a sensing method using the liquid-based friction generator, comprising the steps of:

Providing a correspondence between a parameter of the liquid in the friction generator and the output electrical signal under a set working condition; the parameter of the liquid includes a polarity or a dielectric coefficient of the liquid, or the like The concentration of metal ions or biomolecules;

Providing the friction generator including the liquid to be tested, and operating according to the set working condition; determining a parameter of the liquid to be tested according to an output electrical signal of the friction generator including the liquid to be tested.

The set working conditions described herein refer to the contact area of the friction layer and the liquid in the friction generator, the contact frequency, and the like, that is, the other parts of the generator other than the liquid and the contact area and the contact frequency during power generation are preset. The predetermined relationship between the parameter of the liquid in the generator and the output electrical signal of the generator obtained in advance, and the output electrical signal of the friction generator including the liquid to be tested obtained under the same working condition, can be obtained. Parameters such as temperature, polarity, and composition of the liquid.

Detailed ways:

I. River water and sea water fluctuation energy collector

Using a porous alumina with a length and width of 15 cm as a template, pour the polydimethylsiloxane mixture and bake at 120 °C for 1 hour, then remove it to obtain the lower surface. A cylindrical array (micro/nano contact layer) of a polydimethylsiloxane film (friction layer).

Two pieces of plexiglass sheet (first substrate and second substrate) each having a length and a width of 20 cm and a thickness of 0.05 cm were taken, and the surface was plated with aluminum having a length and a width of 15 cm and a thickness of 150 nm. The film, one piece will serve as the first substrate and the first conductive element, and the other will serve as the second substrate and the second conductive element.

Next, the upper surface of the polydimethylsiloxane film having a columnar array on the surface is tiled toward the first conductive member on the first conductive member covered with the polydimethylsiloxane mixture at 60 ° C. Bake for 12 hours to form a contact arrangement of the friction layer with the first conductive element. Two pieces of styrofoam with a size of 2 cmX 20 cm and a thickness of 2 cm were adhered to the lower surface of the friction layer in parallel.

The first conductive element and the second conductive element are led out by wires, and the second substrate is placed in river water or sea water to complete a friction generator that can be used to collect the fluctuating mechanical energy of river water or sea water in the environment.

Second, the surfactant sensor

A columnar array of polytetrafluoroethylene can be obtained by using a porous alumina template having a size of 4 cm X 4 cm and a commercial film of the same area and thickness of 75 μm at a high temperature of 400 ° C for 40 minutes. a friction layer of ethylene and a micro-nano structure layer on the lower surface of the friction layer. Then, the upper surface of the columnar array polytetrafluoroethylene film was plated with a copper film having a size of 3 cm X 3 cm and a thickness of 100 nm as the first conductive member. Finally, the copper film was applied to the polyethylene sheet and adhered to a polyethylene sheet (first substrate) having a size of 5 cm X 5 cm and a thickness of 0.1 cm.

Take another piece of the same polyethylene sheet (second substrate), and also apply a copper film with a size of 3 cm X 3 cm and a thickness of 100 nm as the second conductive element on the upper surface, and the lower surface of the polyethylene sheet Adhere to a container with a bottom surface size of 10 cm X 10 cm and inject water to a depth of 2 cm to completely cover the second conductive element. Leading the first conductive element and the second conductive element with a wire, connecting the linear electric motor and controlling the contact and separation of the friction layer with water, and the operating frequency is fixed at 1 Hz, comparing The concentration of the surfactant-containing agent can be known from the friction generator output of the pure water and the surfactant-containing water sample.

As a friction generator of the sensor, a polytetrafluoroethylene film having a columnar array on the surface can effectively increase the hydrophobicity of the PTFE membrane and improve the AC pulse signal output performance of the sensor.

Third, the oil sensor

A plexiglass having a thickness of 0.8 mm and a size of 2 cm X 2 cm was used as the first substrate, and a metal aluminum plate having a thickness of 0.02 mm and a size of 1.5 cm X 1.5 cm was adhered to the lower surface as the first conductive member. And connecting the lead wires to the first conductive element.

Then, a polydimethylsiloxane film having a thickness of ΙΟΟμιη and having a pyramid shape was used as the friction layer. The pyramidal polydimethylsiloxane film is formed by first applying a layer of photoresist on the silicon wafer and forming a side length in the micrometer or submicron on the photoresist by photolithography. a square array of square windows, which is then chemically etched by hot potassium hydroxide to form a template of an array of pyramid-shaped recessed structures; then poured into a mixture of polydimethylsiloxane at 60 ° C After baking for 12 hours, and then removing it, a polydimethylsiloxane film of the pyramidal array of the mask below was obtained. The upper surface of the pyramidal polydimethylsiloxane film is spread on a first conductive member covered with a polydimethylsiloxane mixture, and baked again at 60 ° C for 12 hours. Finally, the device is attached to a linear electric motor.

In addition, a metal aluminum sheet having a thickness of 0.02 mm and a size of 1.5 cm X 1.5 cm was used as the second conductive member, and placed in a container having an area of 11 cm X 7 cm, and the second conductive member was taken out by the wire. The container is filled with water to a depth of 1.5 cm, completely covering the second conductive element, and the linear electric motor is connected and controls the contact and separation of the friction layer with water. The operating frequency is fixed at 2 Hz, compared with the pure water and sewage samples. The electrical signal output can be used to know the degree of contamination of the oil.

In the sensor, when the micro-structured polydimethylsiloxane on the surface is in contact with an aqueous solution under an external force, the contact with the aqueous solution of the polydimethylsiloxane film increases the contact area, and thus has a very high contact area. Good AC pulse signal output performance.

Heretofore, various embodiments of the present invention have been described in detail in conjunction with the drawings. In light of the above description, those skilled in the art should have a clear understanding of the liquid-based friction generator of the present invention, the power generation method, and the sensor using the same and its preparation method.

Furthermore, implementations not shown or described in the drawings are in a form known to those of ordinary skill in the art. Further, the above definitions of the various elements and methods are not limited to the specific structures or shapes mentioned in the embodiments, and those skilled in the art can simply and well replace them.

The specific embodiments of the present invention have been described in detail with reference to the preferred embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Rights request

1. A liquid-based friction generator, characterized by including:

a friction layer, the upper surface of which is in contact with a first conductive element;

Liquid, the second conductive element is not immersed in the liquid;

The lower surface of the friction layer is disposed face to face with the upper surface of the liquid, and the lower surface of the friction layer can be separated from the upper surface of the liquid at least partially; the first conductive element and the second conductive element Output electrical signals between them.

2. The triboelectric generator according to claim 1, characterized in that there is a triboelectrode sequence difference between the material of the friction layer and the liquid.

3. The friction generator according to claim 1 or 2, characterized in that the material of the friction layer is selected from insulating materials, and the insulating materials include: aniline formaldehyde resin, polyformaldehyde, ethyl cellulose, polyethylene Amide nylon 11, polyamide nylon 66, wool and its fabrics, silk and its fabrics, paper, polyethylene glycol succinate, cellulose, cellulose acetate, polyethylene glycol adipate, polyphthalate Diallyl dicarboxylate, regenerated cellulose sponge, cotton and its fabrics, polyurethane elastomer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, wood, hard rubber, acetate, rayon, poly Methyl methacrylate, polyvinyl alcohol, polyester, polyisobutylene, polyurethane elastic sponge, polyethylene terephthalate, polyvinyl butyral, butadiene-acrylonitrile copolymer, neoprene, Natural rubber, polyacrylonitrile, poly(vinylidene chloride-CO-acrylonitrile), polybisphenol A carbonate, polychloroether, polyvinylidene chloride, poly(2,6-dimethylpolyphenylene oxide) material), polystyrene, polyethylene, polypropylene, polydiphenylpropane carbonate, polyethylene terephthalate, polyimide, polyvinyl chloride, polydimethylsiloxane, polytrimethylsiloxane One or a combination of chlorofluoroethylene, polytetrafluoroethylene and parylene.

4. The triboelectric generator according to claim 1 or 2, characterized in that the material of the friction layer is selected from semiconductors, and the semiconductors include: silicon, germanium, Group III and V compounds, II and Group VI compounds, and solid solutions composed of Group III-V compounds and Group II-VI compounds;

Alternatively, the material of the friction layer is selected from oxides of manganese, chromium, iron, and copper, or one of silicon oxide, manganese oxide, chromium oxide, iron oxide, copper oxide, zinc oxide, BiO ₂ and Y ₂ _{O 3} A combination of species or species.

5. The triboelectric generator according to any one of claims 1 to 4, characterized in that the lower surface of the friction layer includes a micro-nano structure layer, and the micro-nano structure layer is selected from the group consisting of nanowires, nanotubes, and nanostructures. Particles, nanorods, nanoflowers, nanochannels, microchannels, nanocones, microcones, nanospheres and microsphere structures, and arrays formed by the aforementioned structures.

6. The friction generator according to claim 5, characterized in that the micro-nano structure layer is directly formed when preparing the friction layer;

Alternatively, the micro-nano structure layer is formed by dotting or coating a nanomaterial layer on the lower surface of the friction layer; or, the micro-nano structure layer is formed by photolithography, chemical etching or plasma etching on the friction layer. The lower surface of the layer is prepared.

7. The triboelectric generator according to claim 5 or 6, characterized in that the friction layer or micro-nano structure layer has a hydrophilic or hydrophobic structure.

8. The friction generator according to any one of claims 1 to 7, further comprising a space holder. When the friction generator is in a stationary state or not acted upon by external force, the space holder causes the friction generator to rotate. The lower surface of the friction layer faces the upper surface of the liquid and maintains a certain distance. When the liquid surface fluctuates and makes part or all of the lower surface of the friction layer contact the liquid surface, the two can be separated; or, when the generator is subjected to external force to cause friction Part or all of the lower surface of the layer can be separated after contact with the liquid surface.

9. The friction generator according to claim 8, wherein the distance between part or all of the lower surface of the friction layer and the liquid surface after contact is less than or equal to the certain distance.

10. The friction generator according to claim 8 or 9, characterized in that the certain distance is larger than the thickness of the friction layer; or the certain distance is larger than the distance from the upper surface of the liquid to the second conductive element.

11. The friction generator according to claim 8 or 9, characterized in that, the certain distance is greater than the thickness of the friction layer by more than one order of magnitude; or the certain distance is greater than the distance from the upper surface of the liquid to the second conductive element. More than an order of magnitude.

12. The friction generator according to any one of claims 1 to 11, characterized in that the position of the space holder is between the whole body composed of the friction layer and the first conductive element and the second conductive element; Alternatively, the space holder is connected to a side of the whole body composed of the friction layer and the first conductive element facing away from the liquid.

13. The triboelectric generator according to any one of claims 1 to 11, characterized in that the position of the space holder is between the friction layer and the first conductive element as a whole and the liquid; the space The density of the holder is less than the density of the liquid.

14. The triboelectric generator according to any one of claims 1 to 13, characterized in that the lower surface of the friction layer is made of hydrophobic material, and the liquid is a polar liquid;

Alternatively, the lower surface of the friction layer is made of hydrophilic material, and the liquid is a non-polar liquid.

15. The triboelectric generator according to claim 14, wherein the polar liquid is water, formic acid, methanol, ethanol, n-propanol, isopropanol, n-butanol, acetic acid, dimethyl sulfoxide, dimethyl sulfoxide, Methylformamide, acetonitrile or acetone;

16. The friction generator according to any one of claims 1 to 15, characterized in that the upper surface and/or the liquid of the friction layer are chemically modified.

17. The triboelectric generator according to claim 16, characterized in that the chemical modification enables the introduction of functional groups that are more prone to lose electrons on the surface of the material with positive polarity among the two materials of the friction layer and the liquid. Electron-donating groups, or introducing functional groups that are more likely to obtain electrons on the surface of materials with negative polarity, that is, strong absorbers electronic group;

Alternatively, the chemical modification causes the friction layer and the liquid to introduce positive charges on the surface of the material with positive polarity; or, introduce negative charges on the surface of the material with negative polarity.

18. The triboelectric generator according to claim 17, wherein the strong electron-donating group includes: amino group, hydroxyl group or alkoxy group; the strong electron-withdrawing group includes: acyl group, carboxyl group, nitro group or Sulfonic acid group.

19. The triboelectric generator according to any one of claims 1 to 17, characterized in that the liquid is water, and the material of the friction layer and the micro-nano structure layer on the upper surface of the friction layer is polytetrafluoroethylene, Polydimethylsiloxane, polyethylene, polypropylene, polystyrene, polymethyl methacrylate or polyethylene terephthalate.

20. The solid-liquid triboelectric generator according to any one of claims 1 to 19, characterized in that the friction layer can be a hard material or a flexible material, and its thickness ranges from 50 nm to 2cm.

21. The solid-liquid friction generator according to claims 1-20, characterized in that the thickness of the micro-nano structure layer is between 20 nm and 20 μm.

22. The friction generator according to claims 1-21, characterized in that the distance from the upper surface of the liquid to the second conductive element is 0.1 cm to 5 cm.

23. The friction generator according to claims 1-21, characterized in that the second conductive element is located directly below the friction layer, and the upper surface of the second conductive element and the lower surface of the friction layer are The shape and size are the same.

24. The friction generator according to any one of claims 1 to 23, further comprising: a first substrate for fixing the first conductive element;

and/or, a second substrate for fixing the second conductive element.

25. The friction generator according to claim 24, wherein the space holder is made of insulating material and is disposed between the first substrate and the second substrate.

26. The friction generator according to claim 24 or 25, characterized in that the material of the first substrate and/or the second substrate is a organic glass plate, a polyethylene plate or a polyvinyl chloride plate.

27. The friction generator according to any one of claims 8 to 26, characterized in that the space holder is formed of: an integrated support body or a plurality of separate support units.

28. The triboelectric generator according to any one of claims 1 to 27, characterized in that the material of the first conductive element or the second conductive element is selected from: metal, conductive oxide or conductive polymer.

29. The friction generator according to any one of claims 1 to 28, wherein the first conductive element is a thin film deposited on the upper surface of the friction layer.

30. The friction generator according to any one of claims 1 to 29, characterized in that the first conductive element and the second conductive element are hard materials or flexible materials, and their thickness is between 10 nm and 500 μm. between.

31. A sensor, characterized in that it includes the friction generator according to any one of claims 1 to 30, the liquid is a liquid to be measured, and the electrical signal is inversely related to the polarity or dielectric of the liquid to be measured. The coefficient is related to metal ions and biomolecules in the liquid.

32. The sensor according to claim 31, wherein the liquid to be measured is water, and the water contains ethanol, oil, metal ions or surfactants; or the temperature of the liquid to be measured can be changed.

33. The sensor according to claim 31, characterized in that the micro-nano structure layer on the lower surface of the friction layer is a metal oxide, and the liquid to be measured contains ortho-dihydroxyl groups, such as catechol, epinephrine Catechin, epigallocatechin, 3,4-dihydroxyphenylacetic acid, alizarin, ascorbic acid or dopamine.

34. A liquid-based friction power generation method, characterized by including the steps:

Provide a friction layer, the upper surface of the friction layer is in contact with a first conductive element;

Provide a liquid, and the second conductive element is not immersed in the liquid; dispose the friction layer above the liquid, so that the lower surface of the friction layer and the upper surface of the liquid are arranged face to face;

The lower surface of the friction layer is brought into contact with and separated from the upper surface of the liquid, and an electrical signal is output to an external circuit between the first conductive element and the second conductive element; when the liquid is a conductor, the first conductive element The conductive element is not in contact with the liquid.

35. The triboelectric power generation method according to claim 34, wherein the lower surface of the friction layer and the upper surface of the liquid are in periodic contact and separation, and the first conductive element and the second conductive element are outputs AC pulse electrical signals to the external circuit.

36. The friction power generation method according to claim 35, characterized in that the frequency range of the period is 0.5Hz-2Hz.

37. A sensing method, characterized by using the liquid-based friction generator according to any one of claims 1-30, including the steps:

Provide a corresponding relationship between the parameters of the liquid in the friction generator and the output electrical signal under set working conditions; the parameters of the liquid include the polarity or dielectric coefficient of the liquid, or include the Concentration of metal ions or biomolecules;

Provide the friction generator containing the liquid to be measured and operate according to the set working conditions; determine the parameters of the liquid to be measured according to the output electrical signal of the friction generator containing the liquid to be measured.