CN113203770B

CN113203770B - Odor sensor and preparation method thereof

Info

Publication number: CN113203770B
Application number: CN202110509166.6A
Authority: CN
Inventors: 詹阳; 董文秀
Original assignee: Shenzhen Institute of Advanced Technology of CAS
Current assignee: Shenzhen Institute of Advanced Technology of CAS
Priority date: 2021-05-11
Filing date: 2021-05-11
Publication date: 2023-06-27
Anticipated expiration: 2041-05-11
Also published as: CN113203770A

Abstract

The invention provides an odor sensor, which comprises a sensing device; the sensing device comprises an electrode layer, a flexible substrate and a sensing layer which are sequentially arranged, wherein the flexible substrate and the sensing layer are respectively different flexible polymers, and can generate potential difference under the action of external force; the sensing layer is provided with a plurality of hole sites, the flexible substrate is exposed from the hole sites, and chemical modifier is arranged on the hole sites to form an odor sensing unit; the chemical modifier is different at least a part of the pore sites in the plurality of pore sites, and the chemical modifier is used for combining with the gas to change the potential, so that the gas with different odors combines with the different chemical modifier to generate a reaction. The difference of the electronic capability between the flexible substrate and the sensing layer can generate a power supply, and the odor sensor can be used in an environment with energy shortage without an external power supply. The plurality of odor sensing units increase the density of recognition sites, can recognize more odors, and increase the binding probability of gases in the air and recognition sites.

Description

Odor sensor and preparation method thereof

Technical Field

The invention relates to the technical field of odor sensors, in particular to an odor sensor and a preparation method thereof.

Background

With the development of micro-electro-mechanical systems and sensing technology, odor identification can identify different gas molecules, including food odor, gas odor generated by organisms, gas odor generated by fermentation, explosive and dangerous gases, and gas odor transmitted by other pipelines. Therefore, the odor identification can be applied to various fields including food preservation, security and protection, anti-terrorism, health monitoring and the like.

The micro-electromechanical system and the sensing system normally work and usually need external power supply to supply power, so that the existing odor sensor needs a fixed socket power supply or battery power supply, and the reliability of the sensing effect can be ensured only by replacing the power supply at regular time when the battery power supply is adopted. This makes the limitations of the existing odour sensor usage scenarios large and the effect difficult to guarantee. In addition, the existing odor sensor only recognizes a single odor gas, or even if it is capable of sensing a plurality of odor gases, it cannot recognize a plurality of odor gases, and is only suitable for a single odor gas recognition in a simple environment. If the number of sensors is increased to realize multi-odor sensing and identification in complex environments, the cost of safety monitoring is greatly increased.

Disclosure of Invention

In view of this, in order to overcome the above-mentioned drawbacks of the prior art, the present invention proposes an odor sensor that generates self-powered current using the nano-generator principle.

Specifically, the odor sensor includes: a sensing device;

the sensing device comprises an electrode layer, a flexible substrate and a sensing layer which are sequentially arranged, wherein the flexible substrate and the sensing layer are adjacently arranged, and the flexible substrate and the sensing layer are different flexible polymers and can generate potential difference under external force; the sensing layer is provided with a plurality of hole sites, the flexible substrate is exposed from the hole sites, and chemical modifier is arranged on the hole sites to form an odor sensing unit; the chemical modifier is different at least a portion of the pore sites in the plurality of pore sites, and is used for carrying out combination reaction with gas to change potential, and the gas with different odors is combined with the different chemical modifier to generate reaction. The flexible substrate and the sensing layer are made of materials with different triboelectric properties, the difference of the electronic capacity exists between the flexible substrate and the sensing layer, a driving power supply can be generated, an external power supply is not needed in the use process of the odor sensor, the problem that the existing odor sensor is limited by the power supply is solved, and potential safety hazards caused by frequent charge and discharge are avoided.

In some embodiments, the odor sensor further comprises an isolation layer, two sensing devices are respectively arranged on two sides of the isolation layer, and the electrode layer of each sensing device is attached to the surface of the isolation layer. The odor sensor is provided with the double-surface odor sensing units, the two sensing devices are independent flexible self-driving devices, sensing can be carried out, different chemical modifier agents are added on different odor sensing units, the density of recognition sites can be improved, more odors can be recognized, and the combination probability of gas and recognition sites in the air is increased.

Preferably, the material of the flexible substrate comprises polydimethylsiloxane, and the material of the sensing layer comprises polypyrrole, so that a good electric signal output effect can be achieved. In addition, the materials have the characteristics of no toxicity and strong stability, have biocompatibility, and the odor sensor applying the materials has medical prospect.

Alternatively, the odor sensing units may have various arrangements, and may be arranged in a linear configuration; alternatively, the odor sensing units are arranged in a two-dimensional array structure.

The invention also provides a smell recognition system which comprises the smell sensor, a collection unit and a remote receiving unit, wherein the collection unit receives the recognition signal of the smell sensor unit and further comprises a wireless data transmission module, and the collection unit and the remote receiving unit perform wireless data transmission. When the odor identification system is practically applied, the acquisition unit acquires the potential change information of the odor sensing unit, and the remote receiving unit receives and processes the information sent by the acquisition unit at the remote end through a wireless transmission means, so that the accuracy of odor identification is further ensured.

The invention also provides a preparation method of the sensing device, which is used for preparing the sensing device required by the odor sensor and comprises the following steps:

etching a metal plate to form a pore plate for manufacturing the odor sensing unit;

spin-coating a flexible polymer on the surface of the etched metal plate to form a flexible substrate;

secondarily etching the metal plate;

removing the metal plate, and electrochemically depositing a flexible polymer on one side surface of the flexible substrate to form a sensing layer;

an electrode layer is added on the other side surface of the flexible substrate;

and carrying out chemical modification on the surface of the odor sensing unit.

Further, the "etching the aperture plate on the sheet metal member" includes: and forming the pore plate by ultraviolet lithography and wet etching the metal plate.

The operation of etching to form pore plates on the metal plate forms a plurality of holes arranged in a linear structure on the metal plate; or, a plurality of holes arranged in a two-dimensional array structure are formed in the sheet metal piece.

Preferably, the flexible polymer comprises polydimethylsiloxane and polypyrrole.

The invention also provides a smell identification method, which adopts the smell sensor to carry out smell identification: the odor sensor presets an odor code based on a voltage change generated by the odor sensing unit for gases with different odors; the acquisition unit receives the identification signal of the odor sensing unit; and comparing the identification signal with the odor code to perform odor identification. The number of digits of the odor codes of the odor sensors can be increased by arranging a plurality of odor sensing units on a single sensing device, so that the aim of identifying various gases is fulfilled. The odor sensor with the double-layer structure further increases the number of digits of odor codes, thereby achieving the purpose of identifying more gases.

In summary, the odor sensor provided by the invention can realize detection and data transmission without an external power supply for odor identification, and can be applied to a scene with energy shortage. The gas recognition device has the advantages that the purpose of recognizing various gases is achieved by adopting various one-dimensional and two-dimensional structures, the gas recognition device can be used for odor recognition in complex environments, and recognition accuracy is guaranteed. The device itself is flexible and can be worn or attached to the body or other structural surface.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a sensor device manufacturing flow for an odor sensor of the present invention;

FIG. 2 is a schematic diagram of a linear self-driven scent recognition architecture;

FIG. 3 is a schematic diagram of an odor sensor having a dual layer sensing device;

FIG. 4 is a schematic diagram of a scent sensor circuit design employing a single layer sensing device;

FIG. 5 is a schematic diagram of a scent sensor circuit design employing a dual layer sensing device;

FIG. 6a is a schematic diagram of the odor sensing unit numbering of the sensing device;

FIG. 6b is an example of an odor encoding mechanism of an odor sensor of the present invention;

fig. 7 is a schematic diagram of a scent identification system with wireless transmission function.

Reference numerals:

1-a sensing device; 11-sheet metal parts; 12-an odor sensing unit; 13-a flexible substrate; 14-a sensing layer; 15-an electrode layer; 2-isolating layer; 3-an acquisition unit; 4-remote receiving units.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The invention provides a smell sensor which adopts the principle of a nano generator to generate self-powered current and designs multiple recognition sites to recognize smell.

Example 1

The embodiment provides a sensing device of an odor sensor and a preparation method thereof. Referring to fig. 1 of the specification, the process flow for preparing the self-driven flexible smell sensing device comprises the following steps:

etching the metal plate 11 to form an orifice plate for manufacturing an odor sensing unit 12 for sensing gas;

spin coating a layer of flexible polymer on the surface of the pore plate formed by etching to form a flexible substrate 13;

secondarily etching the metal plate 11;

removing the sheet metal piece 11, and electrochemically depositing a layer of flexible polymer on the surface of the flexible substrate 13 to form a sensing layer 14;

an electrode layer 15 is added on the other side surface of the flexible substrate 13;

the surface of the odour sensing unit 12 on the sensor device 1 is chemically modified.

Wherein the flexible substrate 13 and the sensing layer 14 are made of materials with different triboelectric properties, the flexible substrate 13 and the sensing layer 14 have a difference in electron obtaining capability, and the sensing device 1 can generate a potential difference under the action of external force. For example, the sensor device 1 is bent by an external force, and can generate electricity based on the triboelectric principle while being bent. In a specific preparation process, the materials of the flexible substrate 13 and the sensing layer 14 may be selected from various polymer materials, for example: polymethyl methacrylate, polyvinyl alcohol, polyethylene terephthalate, polychloroprene, polydimethylsiloxane, polytetrafluoroethylene, polydiphenol carbonate, polypyrrole, polyimide and polyester. For reasons of brevity, it is not intended to be exhaustive of all possible materials, but only to list a few specific materials. It was found through experiments that when the material of the flexible substrate 13 and the material of the sensing layer 14 differ more in electron capability, the generated electric signal is stronger, so that appropriate materials are selected as the flexible substrate 13 and the sensing layer 14 according to the characteristics of the above materials to obtain the optimal electric signal output performance.

The chemical modifier on the surface of the odor sensing unit 12 can adsorb odor substances in the gas and react to change the potential. The sensor device of the present embodiment is modified with different chemical modifiers on at least a part of the surfaces of the plurality of odor sensing units 12, and can recognize different odors according to the reaction that can be generated by the combination between the gases of different odors and the different chemical modifiers, so that a single sensor device 1 can be used for odor recognition in a complex environment.

The single sensing device 1 prepared by the above method comprises an electrode layer 15, a flexible substrate 14 and a sensing layer 13 which are sequentially arranged, wherein the flexible substrate 14 and the sensing layer 13 are different flexible polymers, and can generate potential difference under external force. The sensing layer 13 has a plurality of hole sites from which the flexible substrate 14 is exposed, and the surface of the hole sites is provided with chemical modifiers capable of undergoing a binding reaction with a gas to change the potential to form the odor sensing unit 12. Among the plurality of pore sites, at least a portion of the pore sites have different chemical modifiers, and the gas having different odors combines with the different chemical modifiers to react, thereby identifying the gas having different odors. Preferably, the chemical modifier is different on the surface of each hole site, and can identify more odors. Because the sensor device 1 has good flexibility, the sensor device can be worn or attached to the skin of a human body or other structural surfaces for use.

Example 2

This example provides a specific process for preparing a sensor device 1 using the method of example 1, comprising:

etching the metal copper by ultraviolet lithography and wet method, wherein a plurality of holes arranged in a two-dimensional array structure are formed on the etched metal copper surface for manufacturing the odor sensing unit 12;

spin-coating a layer of Polydimethylsiloxane (PDMS) on the surface of the etched copper to form a flexible substrate 13;

etching metal copper by a secondary wet method;

removing metallic copper, and electrochemically depositing polypyrrole (Ppy) on the PDMS surface to form a sensing layer 14;

copper electrodes are added on the other side surface of the flexible substrate 13 to serve as electrode layers 15;

each of the odor sensing units 12 is chemically modified with a different chemical modifier.

In this embodiment, polydimethylsiloxane is used as the flexible substrate 13, and polypyrrole is used as the sensing layer 14, so that a good electrical signal output effect can be achieved. In addition, the two materials have the characteristics of no toxicity and strong stability, have biocompatibility, and the odor sensor applying the materials has medical prospect.

In some embodiments, a plurality of holes may be etched in the metallic copper surface to form a linear array for making the scent sensing unit 12. Referring to fig. 2 of the drawings, a linear-structured odor sensor may be provided at the front end of a rod-like detector for exploring other spaces and self-starting power generation gas detection by swinging.

Example 3

The present embodiment provides an odor sensor having a dual surface odor sensing unit 12, wherein the sensing device 1 is prepared using the method of embodiment 1. Referring to fig. 3 of the specification, the odor sensor of the present embodiment includes a dual-layer sensor device 1 and an isolation layer 2, the two sensor devices 1 are respectively disposed on two sides of the isolation layer 2, and an electrode layer 15 of each sensor device 1 is attached to a surface of the isolation layer 2 to encapsulate the two sensor devices 1 together. Preferably, the isolation layer 2 is a polydimethylsiloxane film, and has soft texture, no toxicity or harm and environmental protection.

The two sensing devices 1 on the odor sensor with the double-surface odor sensing unit 12 are independent flexible self-driven devices, can sense, can improve the density of recognition sites and recognize more odors, and can increase the combination probability of gas and recognition sites in the air.

Example 4

The present example provides an odor sensor of the sensor device 1 prepared by applying the method of example 1 and a method for odor identification using the odor sensor.

Referring to fig. 4 and 5, there are schematic diagrams of the circuit design of the odor sensor using the single-layer sensor device 1 and the odor sensor using the double-layer sensor device 1, respectively. In the process of manufacturing the sensor device 1, the electrode layer 15 and the circuit wiring are connected to each independent odor sensing unit 12 when the electrode layer 15 is added, the chemical modifier of the odor sensing unit 12 reacts with the gas to generate potential change to form an identification signal, the odor sensor is connected with the acquisition unit 3, and each odor sensing unit 12 can transmit the independent identification signal to the acquisition unit 3 through the circuit wiring. In the preparation of a specific odor sensor, the acquisition unit 3 may be used as a part of the odor sensor or may be separately disposed outside the odor sensor and connected to the odor sensor.

The recognition principle of the odour sensor is shown in fig. 6a and 6b, where the coding of different odours is achieved on the sensor device 1 according to the respective differences of the different odour sensor units 12. For example: in the air, each of the odor sensing units 12 outputs a high level (1), and when the odor i occurs, (2) the output voltage of the odor sensing unit 12 decreases (0), while the output levels of the other odor sensing units 12 are unchanged; when the smell II appears, the output voltage of the smell sensing unit 12 (3) is reduced by (0), and the output level of the other smell sensing units 12 is unchanged; when the odor iii occurs, the output voltages of the odor sensing units (12) of (3) and (6) are simultaneously reduced by (0), while the output levels of the other odor sensing units 12 are unchanged. The acquisition unit 3 compares the received recognition signal outputted from the smell sensing unit 12 with a preset smell code, thereby recognizing the corresponding smell.

The smell recognition method using the smell sensor provided by the invention comprises the following steps: the odor sensor presets an odor code based on the potential variation generated by the odor sensing unit 12 for the gases of different odors; the acquisition unit 3 receives the identification signal of the odor sensing unit 12; the scent recognition is performed by comparing the recognition signal with the scent code.

The odor sensor of the present invention achieves the object of recognizing various gases by increasing the number of digits of odor codes of the odor sensor by providing a plurality of odor sensing units 12 on a single sensing device 1. The odor sensor with the double-layer structure further increases the number of digits of the odor codes, thereby achieving the purpose of identifying more odors.

Example 5

The embodiment provides an odor identification system with a wireless transmission function. Referring to fig. 7 of the description, the scent recognition system includes a scent sensor, a collection unit 3, and a remote receiving unit 4. When the odor identification system provided by the embodiment is actually applied, the acquisition unit 3 acquires the identification signal of the odor sensing unit 12, a wireless data transmission module is arranged in the acquisition unit 3, and the remote receiving unit 4 is arranged to receive the information transmitted by the acquisition unit 3 at the remote end through a wireless transmission means. In the present embodiment, the acquisition unit 3 transmits the acquired identification signal of the odor sensing unit 12 to the remote receiving unit 4, and then processes the identification signal.

In some embodiments, the collecting unit 3 has an identifying module for comparing the identifying signal with the smell code to perform smell identification, and the collecting unit 3 sends the identifying signal and/or the smell identifying result to the remote receiving unit 4, so as to further ensure the accuracy of smell identification.

In summary, the odor sensor provided by the invention can realize detection and data transmission without external power supply, and can be applied to scenes with energy shortage, including outdoor, outdoor and other environments. The gas recognition device has the advantages that the purpose of recognizing various gases is achieved by adopting various one-dimensional and two-dimensional structures, the gas recognition device can be used for odor recognition in complex environments, and recognition accuracy is guaranteed. The device itself is flexible and can be worn or attached to the body or other structural surface.

The foregoing description is only of the preferred embodiments of the present invention, and there are no limitations to the present invention, but rather, the embodiments may be modified in various ways, and the technical features of the above embodiments may be combined with each other, so that any modification, equivalent replacement, improvement, etc. that are within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims

1. A smell recognition system is characterized by comprising a smell sensor, an acquisition unit and a remote receiving unit,

the odor sensor includes:

a sensing device;

the sensing device comprises an electrode layer, a flexible substrate and a sensing layer which are sequentially arranged, wherein the flexible substrate and the sensing layer are different flexible polymers, and can generate potential difference under external force;

the sensing layer is provided with a plurality of hole sites, the flexible substrate is exposed from the hole sites, and chemical modifier is arranged on the hole sites to form an odor sensing unit;

the chemical modifier is different at least a part of the pore sites in a plurality of pore sites, the chemical modifier is used for carrying out combination reaction with gas to change potential, and the gas with different odors is combined with the different chemical modifier to generate reaction;

the sensor comprises a substrate, a plurality of electrode layers, an insulating layer, a plurality of sensor devices, a plurality of electrode layers, a plurality of insulating layers and a plurality of insulating layers, wherein the two sensor devices are respectively arranged on two sides of the insulating layer;

the odor sensing units are arranged in a linear structure;

or, the odor sensing units are arranged in a two-dimensional array structure;

the material of the flexible substrate comprises polydimethylsiloxane, and the material of the sensing layer comprises polypyrrole;

the acquisition unit receives the identification signal of the smell sensing unit, the acquisition unit further comprises a wireless data transmission module, and the acquisition unit and the remote receiving unit perform wireless data transmission.

2. A method of manufacturing a sensor device for manufacturing the sensor device of claim 1, comprising:

secondarily etching the metal plate;

and carrying out chemical modification on the surface of the odor sensing unit.

3. The method of manufacturing a sensor device of claim 2, wherein etching the aperture plate on the sheet metal member comprises: and forming the pore plate by ultraviolet lithography and wet etching the metal plate.

4. The method of manufacturing a sensor device according to claim 2, wherein the step of etching the aperture plate on the metal plate forms a plurality of apertures arranged in a linear structure on the metal plate;

or, forming a plurality of holes arranged in a two-dimensional array structure on the metal plate.

5. The method of manufacturing a sensor device of claim 2, wherein the flexible polymer comprises polydimethylsiloxane and polypyrrole.

6. A method of odor identification using the odor identification system of claim 1, the method comprising:

the odor sensor presets an odor code based on potential changes generated by the odor sensing unit for gases with different odors;

the acquisition unit receives the identification signal of the odor sensing unit;

and comparing the identification signal with the odor code to perform odor identification.