A self-adhesive sensing unit suitable for liquid environment and its application

Abstract

The present invention belongs to the technical field related to self-adhesive sensing, and discloses a self-adhesive sensing unit suitable for liquid environment and its application, wherein the self-adhesive sensing unit has a porous structure, and the constituent material of the self-adhesive sensing unit is a carbon nanomaterial. When the self-adhesive sensing unit is placed in a liquid, the liquid is adsorbed in the pores, and the self-adhesive sensing unit is adhered by the van der Waals force between the carbon nanomaterial and the carrier. When the pressure of the liquid environment changes, the movement of the charge contained in the adsorbed liquid in the pores realizes the sensing function. The present application can achieve long-term adhesion, and is small in size and easy to carry, and has sensitive monitoring, and can perform long-term monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field related to self-adhesive sensing, and more specifically, relates to a self-adhesive sensing unit suitable for a liquid environment and an application thereof. Background Art

[0002] Underwater target monitoring is of great significance to marine safety. At present, underwater target monitoring mainly relies on large sensor devices or underwater organism-mounted sensors. However, large sensor devices are bulky and have poor concealment; mounted sensors need to be implanted in or tied to organisms, which greatly restricts the life activities of underwater organisms and shortens the lifespan of underwater organisms. There is a lack of portable, non-destructive self-adhesive sensing materials to meet the needs of underwater target monitoring.

[0003] At present, the materials with underwater self-adhesive sensing function are mainly ion conductive hydrogel materials, including phenylboronic acid ionic liquid, poly (sulfobetaine-acrylic acid copolymer) hydrogel, etc. However, when ion conductive hydrogel is used underwater, there are the following two problems: First, the composition of ion conductive hydrogel is polymer material, which cannot adhere to water for a long time. The reason for the above problems is that when ion conductive hydrogel is used underwater, water molecules continuously penetrate into the microstructure of the hydrogel, straighten its bent polymer chain segments, swell its macrostructure, greatly reduce its adhesion strength, and finally cause desorption. For example, the upper limit of the underwater adhesion time of a fully physically cross-linked hydrogel composed of gelatin, tea polyphenols and urea is 336 hours (14 days); the adhesion time of a hydrogel made of polyacrylic acid, chitosan, tannic acid and aluminum ions in acidic and alkaline liquids is only 24 hours (1 day). Second, the sensing function of ion conductive hydrogel cannot be implemented underwater for a long time. The reason for the above problems is that when ion conductive hydrogel is used underwater, there is a substance exchange with the water environment, which causes its ion concentration to continue to decrease, thus causing its sensing performance to be seriously degraded until failure. Researchers hope to solve the problem of reduced ion concentration by using hydrophobic ionic liquids or constructing hydrophobic structures on the surface of the material, but the effect is still not ideal. Therefore, it is urgent to develop a new type of self-adhesive sensing material suitable for various liquid environments. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a self-adhesive sensing unit suitable for liquid environments and its application, which can achieve long-term adhesion, is small in size and easy to carry, has sensitive monitoring, and can perform long-term monitoring.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present invention, a self-adhesive sensing unit suitable for a liquid environment is provided, wherein the self-adhesive sensing unit has a porous structure, and the constituent material of the self-adhesive sensing unit is a carbon nanomaterial. When the self-adhesive sensing unit is placed in a liquid, the liquid is adsorbed in the pores, and the self-adhesive sensing unit is adhered by the van der Waals force between the carbon nanomaterial and the carrier. When the pressure of the liquid environment changes, the movement of the charges contained in the adsorbed liquid in the pores realizes the sensing function.

[0006] Preferably, the pore size of the porous structure is greater than 10 nm.

[0007] Preferably, the carbon nanomaterial is curved.

[0008] Preferably, the carbon nanomaterial is wavy in shape.

[0009] Preferably, the carbon nanomaterial includes carbon nanotubes, graphene or carbon black.

[0010] Preferably, the porosity of the self-adhesive sensing unit is 20% to 80%.

[0011] Preferably, the liquid environment comprises an acidic, alkaline or marine liquid environment.

[0012] Preferably, the density of the self-adhesive sensing unit is 10 mg / cm 3 -1000mg / cm 3 .

[0013] On the other hand, the present application provides an application of the above-mentioned self-adhesive sensor unit suitable for liquid environment. Before adhering the self-adhesive sensor unit to the carrier, it needs to be annealed in an argon atmosphere. The annealing temperature is 250-750°C, the gas flow rate is 200-1000sccm, and the annealing time is 0.1h-5h.

[0014] Preferably, when the self-adhesive sensing unit is used, it is firstly required to be adhered to the carrier surface by using a certain pre-pressure in the air, and then a certain pre-pressure is applied to the self-adhesive sensing unit in the liquid to absorb the liquid into the porous structure.

[0015] In general, compared with the prior art, the above technical solution conceived by the present invention provides a self-adhesive sensing unit suitable for a liquid environment and its application, which mainly has the following beneficial effects:

[0016] 1. The self-adhesive sensing unit can be adhered underwater by van der Waals force, carried on different carriers, and absorbs liquid greatly based on the pore structure of the self-adhesive sensing material, so that the charge in the liquid is fully adsorbed on the inner surface of the pore; when the pressure fluctuation generated by the detected target is sensed, the charge in the pore confined space moves, generating a real-time electrical signal corresponding to the pressure change, thereby realizing the sensing function.

[0017] 2. The pore design of the self-adhesive sensing material can increase the contact area between the self-adhesive sensing unit and the carrier and improve the adhesion strength; combined with the adjustment of the pore density, the sensing and adhesion functions can be coordinated and enhanced according to different application requirements.

[0018] 3. Oxygen-containing groups are inevitably introduced during the preparation of carbon nanomaterials. By high-temperature annealing in an argon atmosphere, the oxygen-containing groups can be reduced to prevent them from interfering with underwater sensing signals. At the same time, the removal of oxygen-containing groups can improve the corrosion resistance of the self-adhesive sensing material and greatly improve its durability in corrosive liquid environments such as acidic and alkaline.

[0019] 4. The self-adhesive sensing unit is suitable for different liquid environments, can be mounted and fixed on different carriers, and collects the water ripple fluctuations generated by the detected target, converts them into electrical signals, and realizes the sensing function.

[0020] 5. The adhesion function of the self-adhesive sensing unit is realized based on van der Waals force, and it has good stable adhesion in different liquid environments. The stable adhesion time in seawater exceeds 2200 hours, which is 6.5 times the adhesion time of hydrogel (336 hours). The adhesion time in acidic and alkaline liquid environments exceeds 300 hours, which is 13 times the adhesion time of hydrogel (24 hours).

[0021] 6. The sensing function of the self-adhesive sensing unit is realized based on the charge movement in the confined environment of the pore structure of the carbon nanomaterial, and can respond to a tiny pressure of 10Pa with a more sensitive response.

[0022] 7. The self-adhesive sensing unit has good structural stability and will not experience volume expansion and performance degradation due to the entry of water molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a partial structural schematic diagram of a self-adhesive sensing unit suitable for a liquid environment according to an embodiment of the present application;

[0024] Figure 2 It is a microscopic morphology of a self-adhesive sensing unit suitable for a liquid environment according to an embodiment of the present application;

[0025] Figure 3The present invention provides a self-adhesive sensing unit suitable for liquid environments, and provides adhesion stability in different liquid environments;

[0026] Figure 4 The adhesion strength of a self-adhesive sensing unit suitable for a liquid environment in seawater varies with the adhesion time according to an embodiment of the present application;

[0027] Figure 5A It is to detect the time spectrum signal of the passing of the ship by using the self-adhesive sensing unit suitable for liquid environment of the present application;

[0028] Figure 5B The self-adhesive sensing unit of the present application suitable for liquid environment detects the spectrum signal of the passing ship. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] The present invention provides a self-adhesive sensing unit suitable for a liquid environment. The self-adhesive sensing unit has a porous structure. The constituent material of the self-adhesive sensing unit is a carbon nanomaterial. When the self-adhesive sensing unit is placed in a liquid, the liquid is adsorbed in the pores. The self-adhesive sensing unit is adhered by the van der Waals force between the carbon nanomaterial and a carrier. When the pressure of the liquid environment changes, the movement of the charge contained in the adsorbed liquid in the pores realizes the sensing function.

[0031] In a further preferred embodiment, Figure 1 and Figure 2 As shown, the carbon nanomaterial is curved. In a further preferred embodiment, the shape of the carbon nanomaterial is wavy, circular, etc.

[0032] In a further preferred embodiment, the carbon nanomaterial includes carbon nanotubes, graphene or carbon black.

[0033] The liquid environment includes acidic liquid, alkaline liquid, ocean and other liquid environments.

[0034] The self-adhesive sensing unit may be a porous film, foam or other structure with a density of 10 mg / cm 3 -1000mg / cm 3 between.

[0035] In a further preferred embodiment, the porosity of the self-adhesive sensor unit is 20% to 80%. In a further preferred embodiment, the porosity of the self-adhesive sensor unit is 30% to 70%.

[0036] The self-adhesive sensing unit can be mounted on different carriers, including coatings, quartz, copper, stainless steel, acrylic, etc.

[0037] The pore size of the porous structure of the present application is greater than 10 nm, and its sensing performance (sensitivity, detection range, etc.) and adhesion performance (adhesion force, adhesion time, etc.) are significantly higher than those of the aggregate prepared from carbon nanotube powder.

[0038] On the other hand, the present application provides an application of the above-mentioned self-adhesive sensor unit suitable for liquid environment. The self-adhesive sensor unit needs to be annealed in an argon atmosphere before being adhered to the carrier. The annealing temperature is 250-750°C, the gas flow rate is 200-1000sccm, and the annealing time is 0.1h-5h. The sensing performance and corrosion resistance are improved by more than 10%.

[0039] When the self-adhesive sensing unit is used, it is firstly required to be adhered to the surface of the carrier by applying a certain pre-pressure in the air, and then a certain pre-pressure is applied in the liquid to absorb the liquid into the porous structure.

[0040] See also Figure 1 The present invention provides a self-adhesive sensing unit suitable for liquid environment. The self-adhesive sensing unit can be adhered underwater by van der Waals force, carried on different carriers, and absorbs liquid greatly based on the pore structure of the self-adhesive sensing unit, so that the charge in the liquid is fully adsorbed on the inner surface of the pore; when the pressure fluctuation generated by the detected target is sensed, the charge in the pore confined space moves, generating a real-time electrical signal corresponding to the pressure change, thereby realizing the sensing function. The pore design of the self-adhesive sensing material (wave-shaped, circular, etc.) can increase the contact area between the self-adhesive sensing material and the carrier, and improve the adhesion strength; combined with the adjustment of the pore density, the sensing and adhesion functions can be coordinated and enhanced according to different application requirements.

[0041] See also Figure 2 , a microscopic structure diagram of a self-adhesive sensing unit suitable for liquid environment. It can be seen that it has a pore structure. When it senses changes in external pressure, the movement of charges in the confined space in the pore structure generates an electrical signal to detect the pressure.

[0042] See also Figure 3The adhesion strength and duration of the self-adhesive sensing unit in different liquid environments are more than 300 hours in HCl, KOH, and seawater liquid environments, and more than 160 hours in ethanol environments, while the adhesion time of commercially available double-sided tape in HCl, KOH, seawater and ethanol environments does not exceed 10 hours.

[0043] See also Figure 4 , the adhesion stability of the self-adhesive sensing unit in different liquid environments. It can be seen that its adhesion time in the seawater environment exceeds 2200 hours (about 91 days).

[0044] See also Figure 5A and Figure 5B The self-adhesive sensing unit was mounted on the robotic fish to detect the current signal when a ship passed by. The current signal was collected and analyzed by an electrochemical workstation. The frequency spectrum of the ship passing by was obtained through fast Fourier transform. It can be seen that the frequency of the characteristic peak when the ship passed by was 0.07Hz, with high sensitivity.

[0045] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-adhesive sensing unit suitable for liquid environments, characterized in that: The self-adhesive sensing unit has a porous structure. The self-adhesive sensing unit is made of carbon nanomaterials. When the self-adhesive sensing unit is placed in a liquid, the liquid is adsorbed in the pores. The self-adhesive sensing unit is adhered to the carrier by the van der Waals force between the carbon nanomaterials and the carrier. When the pressure of the liquid environment changes, the movement of the charges contained in the adsorbed liquid in the pores realizes the sensing function. The carbon nanomaterial is in a curved shape.

2. The self-adhesive sensor unit according to claim 1, characterized in that The pore size of the porous structure is greater than 10 nm.

3. The self-adhesive sensor unit according to claim 1 or 2, characterized in that The carbon nanomaterial is in a wavy shape.

4. The self-adhesive sensor unit according to claim 1, characterized in that The carbon nanomaterial includes carbon nanotubes, graphene or carbon black.

5. The self-adhesive sensor unit according to claim 1, characterized in that The porosity of the self-adhesive sensing unit is 20% to 80%.

6. The self-adhesive sensor unit according to claim 1, characterized in that The liquid environment includes an acidic, alkaline or marine liquid environment.

7. The self-adhesive sensor unit according to claim 1, characterized in that The density of the self-adhesive sensing unit is 10 mg / cm 3 -1000mg / cm 3 .

8. An application of the self-adhesive sensing unit suitable for liquid environment according to any one of claims 1 to 7, characterized in that: Before the self-adhesive sensing unit is adhered to the carrier, it needs to be annealed in an argon atmosphere, with an annealing temperature of 250-750° C., a gas flow rate of 200-1000 sccm, and an annealing time of 0.1 h-5 h.

9. The use according to claim 8, characterized in that: When the self-adhesive sensing unit is used, it is firstly required to be adhered to the carrier surface by using a certain pre-pressure in the air, and then a certain pre-pressure is applied to the self-adhesive sensing unit in the liquid to absorb the liquid into the porous structure.

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