WO2021012743A1 - 一种自储水自补水pH传感器 - Google Patents

一种自储水自补水pH传感器 Download PDF

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Publication number
WO2021012743A1
WO2021012743A1 PCT/CN2020/087566 CN2020087566W WO2021012743A1 WO 2021012743 A1 WO2021012743 A1 WO 2021012743A1 CN 2020087566 W CN2020087566 W CN 2020087566W WO 2021012743 A1 WO2021012743 A1 WO 2021012743A1
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layer
self
inlet
outlet
water
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PCT/CN2020/087566
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English (en)
French (fr)
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张西良
卢成轩
陈成
宗圣康
倪梦瑶
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江苏大学
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Priority to US17/287,110 priority Critical patent/US11307169B2/en
Publication of WO2021012743A1 publication Critical patent/WO2021012743A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/4166—Systems measuring a particular property of an electrolyte
    • G01N27/4167—Systems measuring a particular property of an electrolyte pH
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/28—Electrolytic cell components
    • G01N27/30—Electrodes, e.g. test electrodes; Half-cells
    • G01N27/302—Electrodes, e.g. test electrodes; Half-cells pH sensitive, e.g. quinhydron, antimony or hydrogen electrodes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
    • G01N1/14—Suction devices, e.g. pumps; Ejector devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/28—Electrolytic cell components
    • G01N27/30—Electrodes, e.g. test electrodes; Half-cells
    • G01N27/301—Reference electrodes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
    • G01N2001/1031—Sampling from special places
    • G01N2001/1037—Sampling from special places from an enclosure (hazardous waste, radioactive)
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
    • G01N1/14—Suction devices, e.g. pumps; Ejector devices
    • G01N2001/1418—Depression, aspiration

Definitions

  • the invention belongs to the field of soil and substrate pH sensors, and specifically relates to a self-storing and self-replenishing pH sensor.
  • the pH in-situ detection of the cultivation soil and substrate is one of the foundations and keys to realize the automation and intelligence of cultivation.
  • Cultivation soil and substrate are a heterogeneous system composed of a variety of minerals and organic particles, a certain amount of water and air. The particles are loose, the gaps are large, and the composition and moisture change greatly, making the soil and the substrate show different Physical and chemical properties, which bring great difficulties to the in-situ detection of soil and substrate pH. It is of great significance to research and develop a new type of pH sensor, improve its detection sensitivity and adaptability, and reduce detection errors.
  • the pH value refers to the concentration of hydrogen ions.
  • Hydrogen ions are produced by the ionization of acid in water, exist with water, and are easily attracted by water molecules to generate hydronium ions (H 3 O + ), which move with water molecules.
  • aqueous solution such as soil and substrate
  • effective hydrogen ions can be formed and exist in the form of hydronium ions H 3 O + . It performs a reversible electrochemical reaction on the surface of the metal/metal oxide working electrode inserted into the soil and the substrate to form an electrochemical equilibrium, generate a Nernst response, and detect the voltage of the working electrode relative to the reference electrode, which can realize the effect of the soil, substrate, etc.
  • glass electrodes are widely used. They have the advantages of high sensitivity, long-term stability, and wide measurement range, but they have long response time, high impedance, and poor mechanical properties such as compression and bending resistance.
  • Real-time in-situ detection of pH in heterogeneous systems such as soil and substrate.
  • there have been more and more researches on all-solid-state pH sensors which have significant advantages in terms of mechanical strength, miniaturization, and high temperature and pressure resistance.
  • Chinese patent ZL200710030222.8 is based on the integrated all-solid-state pH electrochemical sensor of nano-tungsten oxide and its preparation method, which discloses an integrated flat-plate all-solid-state pH electrochemical sensor, but its response time is longer and the water content is relatively high. The accuracy of low semi-solid measurement results is still limited; another example is the Chinese patent ZL201410215729.0 all-solid-state integrated pH composite electrode device and its electrode preparation method, which discloses an all-solid composite electrode with certain strength and piercing ability. It can be used to measure the pH of solids, semi-solids and solutions, but its reproducibility is poor and is greatly affected by moisture content.
  • Microfluidics technology is a technology for precise observation, manipulation and detection of fluids on a microscale. It has significant advantages in application fields such as drug screening, food inspection, environmental monitoring, and chemical analysis. At present, with the help of MEMS-related processing technology, there are many applications and researches in micro-sensors and detection.
  • the Chinese patent ZL200880102829.5 microfluidic sensor composite structure discloses a biosensor with a microfluidic structure. By inducing capillary phenomenon in the microfluidic channel, the automatic introduction of biological mixtures such as serum is realized, which is convenient for carrying and mass production. advantage.
  • Another example is the Chinese patent 201380076240.3 microfluidic sensing device and system, which discloses a multi-channel microfluidic diagnostic system that can meet the requirements of cell culture, cell transplantation, and cell analysis.
  • the current microfluidic technology has the advantages of simple production and low driving energy consumption, and its application in sensors and detection is a new development trend.
  • the current microfluidic technology has the advantages of simple production and low driving energy consumption, and its application in sensors and detection is a new development trend.
  • the current microfluidic technology has the advantages of simple production and low driving energy consumption, and its application in sensors and detection is a new development trend.
  • the current microfluidic technology has the advantages of simple production and low driving energy consumption, and its application in sensors and detection is a new development trend.
  • there are still shortcomings such as insufficient water storage and transportation and easy blockage of microfluidic channels.
  • the present invention provides a self-storing and self-replenishing pH sensor, which solves the limitation of accurate in-situ pH detection due to the large influence of water content and low water content in the existing soil and matrix pH in-situ detection process.
  • the application of microfluidic technology to pH electrochemical sensors has problems such as low water volume and easy blocking.
  • the function of self-storage and self-replenishment can be realized. Under normal water content, the pH sensor can automatically absorb and store water, and under low water content, the pH sensor can self-replenish water for realizing soil, substrate, etc.
  • In-situ pH detection of heterogeneous systems improves the accuracy of in-situ pH detection of soil and substrate.
  • a self-storing and self-replenishing pH sensor comprising a substrate, a working electrode, a reference electrode, a first piezoelectric micropump, a water storage device and a second piezoelectric micropump ;
  • the working electrode, the reference electrode, the first piezoelectric micropump, the water storage device and the second piezoelectric micropump are arranged on a substrate;
  • the working electrode and the reference electrode are respectively connected to the pad through electrode leads;
  • the second piezoelectric micropump, the water storage device and the first piezoelectric micropump are connected in sequence, and the outlet of the first piezoelectric micropump is used to flow liquid to the working electrode.
  • the front surface of the substrate is slotted, including a first rectangular slot, a second rectangular slot, an electrode lead slot and a land slot;
  • the working electrode is installed in the first rectangular groove; the reference electrode is installed in the second rectangular groove; the electrode leads are respectively installed in the electrode lead grooves; the pads are installed in the land grooves.
  • the working electrode includes a first Cr connection layer, an Sb layer, an Sb 2 O 3 layer, and a first Nafion layer from bottom to top; the first Cr connection layer is connected to the substrate.
  • the reference electrode includes a second Cr connection layer, an Ag layer, an AgCl layer and a second Nafion layer from bottom to top; the second Cr connection layer is connected to the substrate.
  • the first piezoelectric micropump includes a third Cr connection layer, a first pump cavity, a first inlet valve, a first outlet valve, a first inlet, a first outlet, a first pump membrane, a first pressure Electric dual chip and first housing;
  • the bottom of the first casing is provided with a third Cr connection layer, which is connected to the substrate;
  • the first casing is provided with a first pump cavity, and the first pump cavity is provided with a first inlet and a second An outlet;
  • the first inlet is provided with a first inlet valve, the first outlet is provided with a first outlet valve;
  • the first inlet is connected with the water outlet of the water storage device;
  • the first pump membrane is arranged on the inner wall of the top of the first housing, and the first piezoelectric bimorph is mounted on the first pump membrane.
  • the first outlet is also provided with a first filtering device.
  • the second piezoelectric micropump includes a fifth Cr connection layer, a second pump cavity, a second inlet valve, a second outlet valve, a second inlet, a second outlet, a second pump membrane, and a second pressure Electric double chip and second housing;
  • the bottom of the second shell is provided with a fifth Cr connecting layer, which is connected to the base;
  • the second shell is provided with a second inlet and a second outlet;
  • the second inlet is provided with a second An inlet valve, the second outlet is provided with a second outlet valve;
  • the second inlet is used to communicate with the surrounding matrix, and the second outlet is connected to the first water inlet of the water storage device;
  • the second pump membrane is arranged on the inner wall of the top of the second housing, and the second piezoelectric bimorph is mounted on the second pump membrane.
  • the second inlet is also provided with a second filtering device.
  • the water storage device includes a fourth Cr connection layer, a cavity, a first hydrophilic silica, a first micro-nano texture layer, a third shell, a second hydrophilic silica layer and a second Two micro-nano texture layer;
  • a fourth Cr connection layer is provided on the bottom of the third housing, and the fourth Cr connection layer is connected to the base;
  • the third housing is provided with a cavity, the lower part of the cavity is provided with a water outlet and a first water inlet, the top of the cavity is provided with a second water inlet, and the second water inlet is provided with a water storage device inlet valve;
  • the bottom of the cavity is provided with a first hydrophilic silica, and a first micro-nano texture layer is provided on the first hydrophilic silica;
  • the outer surface of the third shell is provided with a second hydrophilic silica layer, and a second micro-nano texture layer is provided on the second hydrophilic silica layer.
  • first micro-nano texture layer and the second micro-nano texture layer are grooves, and the contact angle between the grooves and water molecules is less than 5°.
  • the beneficial effect of the present invention is that the self-storage and self-replenishing pH sensor of the present invention adopts a piezoelectric micro-pump, which can not only control the automatic absorption and storage of water around the working electrode of the sensor, but also control It realizes the automatic replenishment of water around the working electrode of the sensor, and has the advantages of simple manufacture, small size, low energy consumption, strong anti-interference and easy control.
  • Both the outer top layer and the inner bottom layer of the pH sensor water storage device of the present invention adopt a micro-nano texture structure, which has super-hydrophilic properties.
  • the integrated micro-pump characteristic of water delivery to the water storage device increases the self-storage capacity of the pH sensor, and Improve the self-replenishing ability of the sensor when water is lacking.
  • Fig. 1 is a front view of a pH sensor with self-storage and self-replenishment according to an embodiment of the present invention
  • FIG. 2 is a front front view of a pH sensor substrate capable of self-storing and self-replenishing water according to an embodiment of the present invention
  • Figure 3 is a cross-sectional view in the direction of Figure 1A-A;
  • Figure 4 is a sectional view in the direction of Figure 1B-B;
  • Figure 5 is a cross-sectional view in the direction of Figure 1C-C;
  • Fig. 6 is a schematic diagram of microfluidics in a water absorption mode of a piezoelectric micropump according to an embodiment of the present invention
  • Fig. 7 is a schematic diagram of microfluidics in a piezoelectric micro-pumped water mode according to an embodiment of the present invention.
  • substrate 101, first rectangular groove; 102, second rectangular groove; 103, lead groove; 104, pad groove; 2. working electrode; 201, first Cr connection layer; 202, Sb layer; 203. Sb 2 O 3 layer; 204, first Nafion layer; 3. Reference electrode; 301, second Cr connection layer; 302, Ag layer; 303, AgCl layer; 304, second Nafion layer; 4. Electrode lead 401, Ni connection layer; 402, Ag layer; 403, silicone resin layer; 5.
  • first and second are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined with “first” and “second” may explicitly or implicitly include one or more of these features. In the description of the present invention, “plurality” means two or more, unless otherwise specifically defined.
  • the terms “installed”, “connected”, “connected”, “fixed” and other terms should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. , Or integrally connected; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication between two components.
  • installed can be a fixed connection or a detachable connection.
  • it can be a mechanical connection or an electrical connection
  • it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication between two components.
  • the specific meaning of the above-mentioned terms in the present invention can be understood according to specific circumstances.
  • FIG. 1 shows a preferred embodiment of the self-storage and self-replenishing pH sensor of the present invention.
  • the self-storage and self-replenishing pH sensor includes a substrate 1, a working electrode 2, a reference electrode 3, a first pressure Electric micro pump 6, water storage device 7, and second piezoelectric micro pump 8;
  • the working electrode 2, the reference electrode 3, the first piezoelectric micropump 6, the water storage device 7, and the second piezoelectric micropump 8 are arranged on the substrate 1; the working electrode 2 and the reference electrode 3 respectively pass through the electrode
  • the lead 4 is connected to the pad 5, and an electrical signal is drawn through the electrode lead 4 and the pad 5 to facilitate subsequent detection circuit processing.
  • the second piezoelectric micropump 8, the water storage device 7 and the first piezoelectric micropump 6 are connected in sequence, and the outlet of the first piezoelectric micropump 6 is used to flow liquid to the surface of the working electrode 2 for moisture Absorption, storage and replenishment.
  • the substrate 1 is slotted on the front surface, including a first rectangular slot 101, a second rectangular slot 102, an electrode lead slot 103 and a land slot 104; the working electrode 2 is installed In the first rectangular groove 101; the reference electrode 3 is installed in the second rectangular groove 102; the electrode leads 4 are respectively installed in the electrode lead groove 103; the pad 5 is installed in the land groove 104.
  • the substrate 1 is an alumina ceramic material with a thickness of 1.5 mm or more, and a shape of a rectangle with a length of 4 cm and a width of 2 cm.
  • the first rectangular groove 101 and the second rectangular groove 102 have a length L1 of about 0.3 cm.
  • the width L2 is about 0.2cm
  • the electrode lead groove length L3 is about 0.6cm
  • the width L4 is about 0.1cm
  • the pad groove 104 is about 0.15cm in length L5
  • the width L6 is about 0.1cm
  • the groove depth is about 2.5 ⁇ m.
  • the working electrode 2 includes a first Cr connection layer 201, an Sb layer 202, an Sb 2 O 3 layer 203, and a first Nafion layer 204 from bottom to top;
  • a Cr connection layer 201 is connected to the substrate 1.
  • the thickness of the first Cr connection layer 201 is about 60 nm; the thickness of the Sb layer 202 is 150 nm, and the thickness of the Sb 2 O 3 layer 203 is 120 nm; the thickness of the first Nafion layer 204 is about 0.5 ⁇ m;
  • the Nafion layer 204 has the effect of selectively permeating cations, can effectively isolate the reductive anions with strong interference in the soil and the matrix, and reduce the interference to the detection of the working electrode.
  • the thickness of the second Cr connection layer 301 is about 60 nm; the Ag layer 302 and the AgCl layer 303 are deposited on the second Cr connection layer 301, and the thickness of the Ag layer 302 and the AgCl layer 303 are respectively about 150 nm and 120 nm; the second Nafion The layer 304 is spin-coated on the surface of the AgCl layer 303.
  • the thickness of the second Nafion layer 304 is about 0.5 ⁇ m; the second Nafion layer 304 has the effect of selectively permeating cations and can effectively isolate the soil and the matrix with strong interference The reducing anion reduces the interference to the detection of the working electrode.
  • the electrode lead groove 103 is connected to the substrate 1 through a Ni layer 401, and an Ag layer 402 and a silicone resin layer 403 are sequentially deposited on the Ni layer 401.
  • the Ni layer 401 The thickness is about 60 nm, the thickness of the Ag layer 402 is about 150 nm, and the thickness of the silicone resin layer is about 180 nm.
  • the first piezoelectric micropump 6 includes a third Cr connection layer 601, a first pump cavity 602, a first inlet valve 603, a first outlet valve 604, and a first The inlet 605, the first outlet 606, the first pump membrane 607, the first piezoelectric bimorph 608 and the first housing 609; the bottom of the first housing 609 is provided with a third Cr connection layer 601, and the third Cr connection
  • the layer 601 is connected to the substrate 1;
  • the first housing 609 is provided with a first pump cavity 602, and the first pump cavity 602 is provided with a first inlet 605 and a first outlet 606;
  • the first inlet 605 is provided with a first An inlet valve 603, the first outlet 606 is provided with a first outlet valve 604;
  • the first inlet 605 is connected to the water outlet of the water storage device 7;
  • the first pump membrane 607 is arranged on the inner wall of the top of the first housing 609 ,
  • the first piezoelectric bimorph 608 is
  • the first inlet 605 is connected to the water outlet of the water storage device 7 to absorb the moisture in the water storage device 7 into the first pump cavity 602 and discharge it to the electrode surface from the first outlet 611;
  • the body 609 is bonded to the substrate 1 through the third Cr connecting layer 601; the first pump chamber 602, the first inlet valve 603 and the first outlet valve 604 are on the back of the first housing 609 by wet etching and etching techniques.
  • the shape of the first pump cavity 602 is a circular hole with a diameter of about 6mm.
  • the thickness of the first inlet valve 603 and the first outlet valve 604 is about 40nm.
  • the first inlet valve 603 is located at the entrance of the first pump cavity 602.
  • An outlet valve 604 is located at the outer outlet of the first pump chamber 602; the first inlet channel 605 and the first outlet channel 606 are formed by KOH anisotropic corrosion on both sides of the first housing 609, and the remaining is removed with hydrofluoric acid KOH, the nozzle depth is about 1mm; the first pump film 607 is spin-coated with PDMS film on the surface of the first housing 609 and dried to form the first pump film 607, the thickness of the first pump film 607 is about 200 ⁇ m; the first pump film The first piezoelectric bimorph 608 is glued on top of 607 as a driver.
  • the length of the first piezoelectric bimorph 608 is 4mm and 5mm, respectively; an electrical signal is applied to the first piezoelectric bimorph 608, and the first piezoelectric bimorph 608 is in the electric field.
  • the bending deformation occurs under the action, and the first PDMS pump membrane 607 is driven to change the volume of the first pump cavity 602.
  • the first nylon filter 610 and the first fiber filter 611 are respectively bonded at the first outlet channel 606 to form a first filter device to prevent impurities in the matrix from being mixed into the micro pump, causing micro first The pump chamber 602 is blocked.
  • the first nylon filter 610 has a mesh inner diameter of 200-400 mesh, which can trap coarse particles with a diameter greater than 0.038mm-0.075mm outside the micropump, and only water molecules, ions, fine particles and flocs pass through the outer layer Filter;
  • the inner first fiber filter material 611 is made of acrylic yarn material, which absorbs small particles and flocs with a diameter of less than 0.038mm ⁇ 0.075mm, and only allows water molecules and ions to pass.
  • the second piezoelectric micropump 8 includes a fifth Cr connection layer 801, a second pump cavity 802, a second inlet valve 803, a second outlet valve 804, and a second The inlet 805, the second outlet 806, the second pump membrane 807, the second piezoelectric bimorph 808 and the second housing 809; the bottom of the second housing 809 is provided with a fifth Cr connection layer 801, the fifth Cr connection The layer 801 is connected to the substrate 1; the second housing 809 is provided with a second inlet 805 and a second outlet 806; the second inlet 805 is provided with a second inlet valve 803, and the second outlet 806 is provided with a second Outlet valve 804; the second inlet 805 is used to communicate with the surrounding matrix, the second outlet 806 is connected to the first water inlet of the water storage device 7; the second pump membrane 807 is arranged on the top of the second housing 809 The second piezoelectric bimorph 808 is mounted on the second pump membrane 811
  • the second pump cavity 802, the second inlet valve 803, and the second outlet valve 804 are formed through wet etching and etching on the back of the second housing 809, and the shape of the second pump cavity 802 is about A 4mm round hole, the thickness of the second inlet valve 803 and the second outlet valve 804 is about 20nm; the second inlet channel 805 and the second outlet channel 806 are formed by KOH anisotropic corrosion on both sides of the second housing 809, Hydrofluoric acid is used to remove the remaining KOH, the nozzle depth is about 0.5mm; the second pump film 807 spin-coated PDMS film on the surface of the second housing 809 and dried to form a second pump film 807, the thickness of the second pump film 807 is about 100 ⁇ m; the second piezoelectric bimorph 808 is bonded above the second pump film 807 as a driver, and the length of the second piezoelectric bimorph 808 is 2mm and 3mm respectively; electrical signals are applied to the second piezoelectric bimorph
  • the second nylon filter 810 has a mesh inner diameter of 200-400 mesh, which can trap coarse particles with a diameter greater than 0.038mm-0.075mm outside of the micropump, and only water molecules, ions, fine particles and flocs pass through;
  • the second fiber filter material 811 of the layer is made of acrylic yarn material, which absorbs small particles and flocs with a diameter of less than 0.038mm ⁇ 0.075mm, and only allows water molecules and ions to pass.
  • the water storage device 7 includes a fourth Cr connection layer 701, a cavity 702, a first hydrophilic silica 703, a first micro/nano texture layer 704, and a first The third shell 705, the second hydrophilic silica layer 706 and the second micro-nano texture layer 707; the bottom of the third shell 705 is provided with a fourth Cr connecting layer 701, the fourth Cr connecting layer 701 and the substrate 1 connected; the third housing 705 is provided with a cavity 702, the lower part of the cavity 702 is provided with a water outlet and a first water inlet; the top of the cavity 702 is provided with a second water inlet, the second The water inlet is provided with a water storage device inlet valve 708, the water storage device inlet valve 708 is provided with a third filter device, and the second water inlet is in contact with the external matrix.
  • the bottom of the cavity 702 is provided with a first hydrophilic silica 703, and a first micro-nano texture layer 704 is provided on the first hydrophilic silica 703; the outer surface of the third shell 705 A second hydrophilic silica layer 706 is provided, and a second micro-nano texture layer 707 is provided on the second hydrophilic silica layer 706.
  • the first micro-nano texture layer 704 and the second micro-nano texture layer 707 are nano-grooves, so that the contact angle of the surface with water molecules is less than 5°, and has super-hydrophilicity.
  • the second water inlet of the water storage device 7, the first outlet 606 of the first piezoelectric micropump 6 and the second inlet 805 of the second piezoelectric micropump 8 of the present invention all adopt a filter with a double-layer filtering mechanism.
  • the device has a simple and compact structure.
  • the outer layer is made of nylon filter screen, and the inner layer of fiber filter material is made of acrylic yarn. It has the advantages of high porosity, large dirt interception, and large water flow per unit area. It can effectively prevent soil and matrix.
  • the impurities mixed into the cavity block the microfluidic channel.
  • FIGS 6 and 7 are schematic diagrams of water flow in the piezoelectric micro-pump water suction mode and pumping water mode of the present invention.
  • the water content sensor detects the moisture content of soil and substrate during the working process of the present invention.
  • the water information is transmitted to the main control device, and the main control device judges the water content.
  • the main control device controls the second piezoelectric micropump 8 to turn on to absorb the surrounding water and transport it to the water storage device 7 for storage.
  • the main control device judges that the water content of the soil and substrate is lower than the pH detection threshold
  • the main control device controls the first piezoelectric micropump 6 to turn on to absorb and transport the water from the water storage device 7 to the electrode surface.
  • first piezoelectric micropump 6 and the second piezoelectric micropump 8 are the same. Take the first piezoelectric micropump 6 as an example.
  • the first piezoelectric micropump 6 enters the water suction mode, and the first piezoelectric bimorph 608 drives the first pump membrane 607 to move upward, the internal volume of the first pump cavity 602 increases, the pressure of the internal fluid decreases, and the external fluid passing through the inlet
  • the positive internal pressure causes the first inlet valve 603 in the first pump chamber 602 to automatically open, and the positive pressure at the outlet causes the first outlet valve 604 outside the first pump chamber 602 to automatically close. Flow into the first pump cavity 602 under the action of the pressure difference;
  • the first piezoelectric micropump 6 enters the water pumping mode
  • the first piezoelectric bimorph 608 drives the first pump membrane 607 to move downward
  • the internal volume of the first pump cavity 602 decreases and the internal fluid pressure increases
  • the first inlet valve 603 located in the first pump chamber 602 is automatically closed by the external and internal negative pressure at the inlet
  • the first outlet valve located outside the first pump chamber 602 is caused by the external and internal negative pressure at the outlet.
  • 604 automatically opens, and fluid flows out from the outlet channel under the action of pressure difference, realizing one-way drive of the fluid medium.
  • the preparation method of the pH sensor of the present invention includes the following steps:
  • Making substrate 1 Choose rectangular alumina ceramic with a shape of about 6cm in length, about 4cm in width, and a thickness of 1.5mm or more as the substrate material.
  • Two rectangular grooves with length L1 about 0.5cm and width L2 about 0.4cm include the first rectangular groove. 101 and a second rectangular groove 102; and a rectangular electrode lead groove 103 and a land groove 104 are sequentially opened on the right side of the first rectangular groove 101 and the second rectangular groove 102;
  • Making working electrode 2 Depositing the first Cr connection layer 201 on the first rectangular groove 101 of the substrate 1 by magnetron sputtering, and then obtaining the Sb layer 202 and the Sb 2 O 3 layer 203 in sequence by electrochemical deposition, Sb 2 O 3 The layer 203 is above the Sb layer 202; then the first Nafion layer 204 is coated on the outer surface of the Sb 2 O 3 layer 203 by spin coating.
  • Making reference electrode 3 Depositing the second Cr connection layer 301 in the second rectangular groove 102 of the substrate 1 by magnetron sputtering, and then obtaining the Ag layer 302 and the AgCl layer 303 sequentially by electrochemical deposition, and the AgCl layer 303 is on the Ag layer Above; then the second Nafion layer 304 is coated on the outer surface of the AgCl layer 303 by spin coating.
  • the first pump cavity 602 is etched through the back of the first housing 609 by wet etching and etching technology, and the first inlet is obtained by anisotropic corrosion on both sides of the first housing 509 using KOH Channel 605 and first outlet channel 606, and use hydrofluoric acid to remove excess KOH;
  • the first inlet valve 603, the first outlet valve 604 and the first pump membrane 607 are all made of PDMS, the PDMS solution and curing agent are 10:1 The ratio is mixed, and then cured in different molds at 75°C for 2.5 hours.
  • the mold is placed in a vacuum chamber to remove bubbles to obtain the first pump membrane 607, the first inlet valve 603 and the first outlet valve 604, respectively.
  • the first pump membrane 607, the first inlet valve 603 and the first outlet valve 604 are respectively bonded to the top of the pump cavity, the inside of the inlet and the outside of the outlet; a third Cr connecting layer 601 is deposited on the surface of the substrate 1, and the processed first
  • the shell 609 is connected above the third Cr connection layer 601, and the first PZT piezoelectric bimorph 608 is bonded on the first shell 609, and the first inlet 605 is connected with the water storage device 7 with an adhesive.
  • the first 610 nylon filter and the first fiber filter 611 are bonded at the outlet of the micro pump to obtain a filter structure;
  • the second pump cavity 802 is carved through the back of the second housing 809 by wet etching and etching technology, and the second inlet is obtained by anisotropic corrosion on both sides of the second housing 809 using KOH Channel 805 and the second outlet channel 806, and use hydrofluoric acid to remove excess KOH;
  • the second inlet valve 803, the second outlet valve 804 and the second pump membrane 807 are all made of PDMS, and the PDMS solution and curing agent are 10:1 The ratio is mixed, and then cured in different molds at 75°C for 2.5 hours.
  • the mold is placed in a vacuum chamber to remove bubbles to obtain the second pump membrane 807, the second inlet valve 803 and the second outlet valve 804, respectively.
  • the second pump membrane 807, the second inlet valve 803 and the second outlet valve 804 are respectively bonded to the top of the pump cavity, the inside of the inlet and the outside of the outlet; a third Cr connecting layer 801 is deposited on the surface of the substrate 1, and the processed second
  • the shell 809 is connected above the third Cr connecting layer, and the second PZT piezoelectric bimorph 808 is bonded on the second shell 809.
  • the second outlet 806 is connected with the water storage device 7 with an adhesive.
  • the second nylon filter 810 and the second fiber filter 811 are bonded at the inlet of the pump to obtain a filter structure;
  • the cavity 702 is obtained by etching the back of the polyethylene shell 705 by anisotropic corrosion, the fourth Cr connecting layer 701 is sequentially deposited on the surface of the substrate 1, and the hydrophilic second layer is deposited on the inner surface of the polyethylene shell 705
  • a silicon oxide layer 703, and a micro-textured layer 704 is made on the surface of the hydrophilic silicon dioxide layer 703, and a hydrophilic silicon dioxide layer 706 is deposited on the outer surface of the polyethylene shell 705, and grooves 707 are micro-textured .
  • Ni connection layer 401 and Ag layer 402 are sequentially deposited on electrode lead groove 103 of substrate 1 by magnetron sputtering, and then silicone resin layer 403 is obtained on the surface of Ag layer 402 by spin coating.
  • the pH sensor of the present invention realizes the in-situ detection of heterogeneous systems such as soil and substrate, can automatically absorb and store water in the soil, substrate or the water, and automatically replenish water when the water in the soil or substrate is insufficient.
  • the invention further improves the performance of the pH sensor in the in-situ pH detection of the solid and semi-solid heterogeneous system, and solves the limitation of low moisture content on the pH in-situ detection.
  • the integrated micropump technology and surface hydrophilicity of the present invention have the characteristics of water self-transportation, combined with the advantages of high mechanical strength and easy miniaturization of the all-solid pH sensor, and provide a pH based on microfluid theory and superhydrophilic theory.
  • the sensor based on the pH sensor, can realize the function of self-storing and self-replenishing water. Under normal water content, the pH sensor can automatically absorb and store water. Under low water content, the pH sensor can self-replenish water to achieve soil, matrix and other non- The pH in-situ detection of homogeneous system improves the accuracy of in-situ pH detection of soil and substrate.

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Abstract

一种自储水自补水pH传感器，包括基底（1）、工作电极（2）、参比电极（3）、第一压电式微泵（6）、储水装置（7）和第二压电式微泵（8）；工作电极（2）、参比电极（3）、第一压电式微泵（6）、储水装置（7）和第二压电式微泵（8）设置在基底（1）上；工作电极（2）和参比电极（3）分别通过电极引线（4）与焊盘（5）连接；第二压电式微泵（8）、储水装置（7）和第一压电式微泵（6）依次连通，第一压电式微泵（6）的出口用于将液体流至工作电极（2）。基于pH传感器，可以实现自储水自补水的功能，解决了现有土壤、基质pH原位检测过程中受含水量影响大、含水量低对pH准确原位检测限制，以及微流体技术应用于pH电化学传感器存在水量偏少、易阻塞等问题，提高了土壤、基质pH原位检测准确性。

Description

一种自储水自补水pH传感器 技术领域
本发明属于土壤、基质pH传感器领域，具体涉及一种自储水自补水pH传感器。
背景技术
栽培土壤、基质pH原位检测是实现栽培自动化智能化基础和关键之一。栽培土壤、基质是由多种矿物质及有机物颗粒、一定量水分和空气混合组成的一种非均相体系，颗粒松散、间隙大，组分、水分变化大，使得土壤、基质表现出不同的物化特性，这给土壤、基质pH原位检测带来极大困难。研究开发新型pH传感器，提高其检测灵敏度和适应性，降低检测误差意义重大。
pH值是指氢离子浓度值。氢离子是由酸在水中电离产生，随水而存在，极易被水分子吸引生成水合氢离子(H 3O +)，随水分子运移。在土壤、基质等非均相体系水溶液中，可以形成有效的氢离子，并以水合氢离子H 3O +的形式存在。其在插入土壤、基质中金属/金属氧化物工作电极表面与电极进行可逆的电化学反应，形成电化学平衡，产生能斯特响应，检测工作电极相对参考电极电压，可实现对土壤、基质等非均相体系氢离子浓度pH值原位检测。但是当土壤、基质等非均相体系水分不足时，工作电极表面及周围水溶液匮乏，难以在工作电极表面集聚形成有效的氢离子及其水溶液，进而影响pH传感器的原位检测。
目前pH检测方法中，玻璃电极是应用较为普遍的一种，具有高灵敏度、长期稳定性、测量范围广优点，但响应时间长、阻抗高，且由于抗压和抗弯等机械性能差，不适于土壤、基质等非均相体系pH实时原位检测。近年来，对全固态pH传感器的研究越来越多，在机械强度、微型化、耐高温高压等方面具有显著优点。如中国专利ZL200710030222.8基于纳米氧化钨的集成化全固态pH电化学传感器及其制备方法，公开一种集成化的平板式全固态pH电化学传感器，但是其响应时间较长，对含水量较低的半固体测量结果的准确性仍受到限制；又如中国专利ZL201410215729.0全固态一体式pH复合电极装置及其电极的制备方法，公开一种全固态复合电极，具有一定强度和穿刺能力，可用于固体、半固体及溶液pH进行测量，但是其重现性差，受水分含量影响大。
微流体技术是一种在微尺度下对流体实施精密观测、操控与检测的技术，在药品筛选、食品检验、环境监测、化学分析等应用领域有显著优点。目前，借助MEMS相关加工技术，在微型传感器及检测方面应用研究很多。如中国专利ZL200880102829.5微流体传感器复合结构，公开了一种微流体结构的生物传感器，通过在微流体通道中诱导毛细现象，实现血清等 生物混合物的自动引入，具有方便携带和大规模生产的优点。又如中国专利201380076240.3微流体感测装置和系统，公开了一种多通道的微流体诊断系统，可以满足细胞培养、细胞移植以及细胞分析等要求。
综上，目前微流体技术具有制作简单、驱动能耗低等优势，其在传感器及检测方面应用是新的发展趋势。但是将其直接应用在土壤、基质pH电化学传感器中，仍然存在储水输水量偏少、微流体通道易阻塞等不足。
发明内容
针对上述现有技术问题，本发明提供了一种自储水自补水pH传感器，解决现有土壤、基质pH原位检测过程中受含水量影响大、含水量低对pH准确原位检测限制，以及微流体技术应用于pH电化学传感器存在水量偏少、易阻塞等问题。基于本发明所述pH传感器，可以实现自储水自补水的功能，在正常含水量下pH传感器能够自动吸水、储水，在低含水量下pH传感器能够自补水，用于实现土壤、基质等非均相体系的pH原位检测，提高土壤、基质pH原位检测准确性。
本发明解决其技术问题所采用的技术方案是：一种自储水自补水pH传感器，包括基底、工作电极、参比电极、第一压电式微泵、储水装置和第二压电式微泵；
所述工作电极、参比电极、第一压电式微泵、储水装置和第二压电式微泵设置在基底上；
所述工作电极和参比电极分别通过电极引线与焊盘连接；
所述第二压电式微泵、储水装置和第一压电式微泵依次连通，所述第一压电式微泵的出口用于将液体流至工作电极。
上述方案中，所述基底正面开槽，包括第一长方形槽、第二长方形槽、电极引线槽和焊盘槽；
所述工作电极安装在第一长方形槽；所述参比电极安装在第二长方形槽；所述电极引线分别安装在电极引线槽；所述焊盘安装在焊盘槽。
上述方案中，所述工作电极从下至上依次包括第一Cr连接层、Sb层、Sb 2O 3层、第一Nafion层；所述第一Cr连接层与基底连接。
上述方案中，所述参比电极从下至上依次包括第二Cr连接层、Ag层、AgCl层和第二Nafion层；所述第二Cr连接层与基底连接。
上述方案中，所述第一压电式微泵包括第三Cr连接层、第一泵腔、第一入口阀、第一出口阀、第一入口、第一出口、第一泵膜、第一压电双晶片和第一壳体；
所述第一壳体的底部设有第三Cr连接层，第三Cr连接层与基底连接；所述第一壳体内设有第一泵腔，第一泵腔的设有第一入口和第一出口；所述第一入口设有第一入口阀，第一 出口设有第一出口阀；所述第一入口与储水装置的出水口连接；
所述第一泵膜设置在第一壳体顶部的内壁，所述第一压电双晶片安装在第一泵膜上。
进一步的，所述第一出口还设有第一过滤装置。
上述方案中，所述第二压电式微泵包括第五Cr连接层、第二泵腔、第二入口阀、第二出口阀、第二入口、第二出口、第二泵膜、第二压电双晶片和第二壳体；
所述第二壳体的底部设有第五Cr连接层，第五Cr连接层与基底连接；所述第二壳体设有第二入口和第二出口；所述第二入口设有第二入口阀，所述第二出口设有第二出口阀；所述第二入口用于与周围基质相通，所述第二出口与储水装置的第一入水口连接；
所述第二泵膜设置在第二壳体顶部的内壁，所述第二压电双晶片安装在第二泵膜上。
进一步的，所述第二入口还设有第二过滤装置。
上述方案中，所述储水装置包括第四Cr连接层、腔体、第一亲水二氧化硅、第一微纳织构层、第三壳体、第二亲水二氧化硅层和第二微纳织构层；
所述第三壳体的底部设有第四Cr连接层，第四Cr连接层与基底相连；
所述第三壳体内设有腔体，所述腔体的下部设有出水口和第一入水口，所述腔体的顶部设有第二入水口，第二入水口设有储水装置入口阀；
所述腔体的底部设有第一亲水二氧化硅，在所述第一亲水二氧化硅上设置第一微纳织构层；
所述第三壳体的外表面设有第二亲水二氧化硅层，在第二亲水二氧化硅层上设置第二微纳织构层。
进一步的，所述第一微纳织构层和第二微纳织构层为凹槽，且凹槽与水分子接触角小于5°。
与现有技术相比，本发明的有益效果是：本发明所述自储水自补水pH传感器采用压电式微泵，既可以控制实现对传感器工作电极周围水分的自动吸取与储存，又可以控制实现对传感器工作电极周围自动补充水分，具有制造简单、体积小、耗能低、抗干扰性强和控制容易等优点。本发明的pH传感器储水装置外部顶层和内部底层皆采用微纳织构结构，具有超亲水性，综合微泵向储水装置输水的特性，增大了pH传感器的自储水量，并提高了水分缺乏时传感器的自补水的能力。
附图说明
本发明的上述和/或附加的方面和优点从结合下面附图对实施例的描述中将变得明显和容易理解，其中：
图1为本发明一实施方式自储水自补水的pH传感器正面主视图；
图2为本发明一实施方式的自储水自补水的pH传感器基底正面主视图；
图3为图1A-A方向的剖视图；
图4为图1B-B方向的剖视图；
图5为图1C-C方向的剖视图；
图6为本发明一实施方式的压电式微泵吸水模式下微流体示意图；
图7为本发明一实施方式的压电式微泵送水模式下微流体示意图。
图中，1、基底；101、第一长方形槽；102、第二长方形槽；103、引线槽；104、焊盘槽；2、工作电极；201、第一Cr连接层；202、Sb层；203、Sb 2O 3层；204、第一Nafion层；3、参比电极；301、第二Cr连接层；302、Ag层；303、AgCl层；304、第二Nafion层；4、电极引线；401、Ni连接层；402、Ag层；403、硅氧树脂层；5、焊盘；501、锡层；6、第一压电式微泵；601、第三Cr连接层；602、第一泵腔；603、第一入口阀；604、第一出口阀；605、第一入口；606、第一出口；607、第一泵膜；608、第一压电双晶片；609、第一壳体；610、第一尼龙滤网；611、第一纤维滤料；7、储水装置；701、第四Cr连接层；702、腔体；703、第一亲水二氧化硅；704、第一微纳织构层；705、第三壳体；706、第二亲水二氧化硅层；707、第二微纳织构层；708、储水装置入口阀；8、第二压电式微泵；801、第五Cr连接层；802、第二泵腔；803、第二入口阀；804、第二出口阀；805、第二入口；806、第二出口；807、第二泵膜；808、第二压电双晶片；809、第二壳体；810、第二尼龙滤网；811、第二纤维滤料。
具体实施方式
下面详细描述本发明的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，旨在用于解释本发明，而不能理解为对本发明的限制。
在本发明的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“轴向”、“径向”、“竖直”、“水平”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本发明的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
在本发明中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等术语 应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本发明中的具体含义。
如图1所示为本发明所述自储水自补水pH传感器的一种较佳实施方式，所述自储水自补水pH传感器包括基底1、工作电极2、参比电极3、第一压电式微泵6、储水装置7和第二压电式微泵8；
所述工作电极2、参比电极3、第一压电式微泵6、储水装置7和第二压电式微泵8设置在基底1上；所述工作电极2和参比电极3分别通过电极引线4与焊盘5连接，通过电极引线4和焊盘5引出电信号，方便后续检测电路处理。
所述第二压电式微泵8、储水装置7和第一压电式微泵6依次连通，所述第一压电式微泵6的出口用于将液体流至工作电极2的表面，进行水分的吸收、储存与补充。
如图2所示，根据实施例，优选的，所述基底1正面开槽，包括第一长方形槽101、第二长方形槽102、电极引线槽103和焊盘槽104；所述工作电极2安装在第一长方形槽101；所述参比电极3安装在第二长方形槽102；所述电极引线4分别安装在电极引线槽103；所述焊盘5安装在焊盘槽104。在本实施例中优选的，所述基底1为厚1.5mm以上氧化铝陶瓷材料，形状为长4cm、宽2cm的长方形，其中第一长方形槽101和第二长方形槽102为长度L1约0.3cm，宽度L2约0.2cm，电极引线槽长度L3约0.6cm，宽度L4约0.1cm，焊盘槽104长度L5约0.15cm，宽度L6约0.1cm；其中开槽深度约2.5μm。
如图3所示，根据实施例，优选的，所述工作电极2从下至上依次包括第一Cr连接层201、Sb层202、Sb 2O 3层203、第一Nafion层204；所述第一Cr连接层201与基底1连接。优选的，第一Cr连接层201厚度约60nm；所述Sb层202厚度为150nm，Sb 2O 3层203厚度为120nm；所述第一Nafion层204层厚度约为0.5μm；所述第一Nafion层204具有对阳离子选择透过的作用，能够有效隔离土壤、基质中具有强干扰性的还原性阴离子，减少对工作电极检测的干扰。
优选的，第二Cr连接层301厚度约60nm；所述第二Cr连接层301上方沉积Ag层302和AgCl层303，Ag层302和AgCl层303厚度分别约150nm和120nm；所述第二Nafion层304在AgCl层303表面旋涂而成，第二Nafion层304厚度约0.5μm；所述第二Nafion层304具有对阳离子选择透过的作用，能够有效隔离土壤、基质中具有强干扰性的还原性阴离子，减少对工作电极检测的干扰。
如图4所示，根据实施例，优选的，所述电极引线槽103，通过Ni层401与基底1连接， Ni层401上方依次沉积Ag层402和硅氧树脂层403，所述Ni层401厚度约60nm，Ag层402厚度约150nm，硅氧树脂层厚度约180nm。
如图5所示，根据实施例，优选的，所述第一压电式微泵6包括第三Cr连接层601、第一泵腔602、第一入口阀603、第一出口阀604、第一入口605、第一出口606、第一泵膜607、第一压电双晶片608和第一壳体609；所述第一壳体609的底部设有第三Cr连接层601，第三Cr连接层601与基底1连接；所述第一壳体609内设有第一泵腔602，第一泵腔602的设有第一入口605和第一出口606；所述第一入口605设有第一入口阀603，第一出口606设有第一出口阀604；所述第一入口605与储水装置7的出水口连接；所述第一泵膜607设置在第一壳体609顶部的内壁，所述第一压电双晶片608安装在第一泵膜607上。优选的，所述第一入口605与储水装置7的出水口连接，将储水装置7内的水分吸收到第一泵腔602内，并从第一出口611排出到电极表面；第一壳体609通过第三Cr连接层601粘结在基底1上；所述第一泵腔602、第一入口阀603和第一出口阀604通过湿法腐蚀和刻蚀技术在第一壳体609背面刻穿形成，第一泵腔602形状为直径约6mm的圆孔，第一入口阀603和第一出口阀604厚度约为40nm；第一入口阀603位于第一泵腔602内入口处，第一出口阀604位于第一泵腔602外侧出口处；所述第一入口通道605和第一出口通道606在第一壳体609两侧使用KOH异向腐蚀而成，并用氢氟酸除去剩余的KOH，喷口深度约1mm；所述第一泵膜607在第一壳体609面旋涂PDMS膜并烘干形成第一泵膜607，第一泵膜607厚度约200μm；所述第一泵膜607上方粘合第一压电双晶片608作为驱动器，第一压电双晶片608的长度分别为4mm和5mm；向第一压电双晶片608施加电信号，第一压电双晶片608在电场作用下发生弯曲变形，进而驱动第一PDMS泵膜607改变第一泵腔602容积。
根据实施例，优选的，所述第一出口通道606处分别粘结第一尼龙滤网610、第一纤维滤料611形成第一过滤装置，防止基质中杂质混入微泵中，造成微第一泵腔602阻塞。所述第一尼龙滤网610网孔内径为200～400目，能将直径大于0.038mm～0.075mm的粗颗粒截留在微泵之外，仅水分子、离子、细颗粒与絮体通过外层滤网；内层第一纤维滤料611采用丙纹丝材料，吸附直径小于0.038mm～0.075mm小颗粒与絮体杂质，仅允许水分子、离子通过。
如图5所示，根据实施例，优选的，所述第二压电式微泵8包括第五Cr连接层801、第二泵腔802、第二入口阀803、第二出口阀804、第二入口805、第二出口806、第二泵膜807、第二压电双晶片808和第二壳体809；所述第二壳体809的底部设有第五Cr连接层801，第五Cr连接层801与基底1连接；所述第二壳体809设有第二入口805和第二出口806；所述第二入口805设有第二入口阀803，所述第二出口806设有第二出口阀804；所述第二入口805用于与周围基质相通，所述第二出口806与储水装置7的第一入水口连接；所述第二泵 膜807设置在第二壳体809顶部的内壁，所述第二压电双晶片808安装在第二泵膜807上。根据实施例，优选的，所述第二入口805还设有第二过滤装置；所述第二过滤装置包括第二尼龙滤网810和第二纤维滤料811。
优选的，所述第二泵腔802、第二入口阀803和第二出口阀804通过湿法腐蚀和刻蚀技术在第二壳体809背面刻穿形成，第二泵腔802形状为直径约4mm的圆孔，第二入口阀803和第二出口阀804厚度约为20nm；所述第二入口通道805和第二出口通道806在第二壳体809两侧使用KOH异向腐蚀而成，并用氢氟酸除去剩余的KOH，喷口深度约0.5mm；所述第二泵膜807在第二壳体809面旋涂PDMS膜并烘干形成第二泵膜807，第二泵膜807厚度约100μm；所述第二泵膜807上方粘合第二压电双晶片808作为驱动器，第二压电双晶片808的长度分别为2mm和3mm；向第二压电双晶片808施加电信号，第二压电双晶片808在电场作用下发生弯曲变形，进而驱动第二PDMS泵膜807改变第二泵腔802容积；所述第二入口通道805处分别粘结第二尼龙滤网810、第二纤维滤料811形成过滤装置，防止基质中杂质混入微泵中，造成微第二泵腔802阻塞。所述第二尼龙滤网810网孔内径为200～400目，能将直径大于0.038mm～0.075mm的粗颗粒截留在微泵之外，仅水分子、离子、细颗粒与絮体通过；内层第二纤维滤料811采用丙纹丝材料，吸附直径小于0.038mm～0.075mm小颗粒与絮体杂质，仅允许水分子、离子通过。
如图5所示，根据实施例，优选的，所述储水装置7包括第四Cr连接层701、腔体702、第一亲水二氧化硅703、第一微纳织构层704、第三壳体705、第二亲水二氧化硅层706和第二微纳织构层707；所述第三壳体705的底部设有第四Cr连接层701，第四Cr连接层701与基底1相连；所述第三壳体705内设有腔体702，所述腔体702的下部设有出水口和第一入水口；所述腔体702的顶部设有第二入水口，第二入水口设有储水装置入口阀708，储水装置入口阀708处设有第三过滤装置，第二入水口与外部基质接触。
所述腔体702的底部设有第一亲水二氧化硅703，在所述第一亲水二氧化硅703上设置第一微纳织构层704；所述第三壳体705的外表面设有第二亲水二氧化硅层706，在第二亲水二氧化硅层706上设置第二微纳织构层707。
根据实施例，优选的，所述第一微纳织构层704和第二微纳织构层707为纳米凹槽，使表面与水分子接触角小于5°，具有超亲水性。
本发明所述储水装置7的第二入水口、第一压电式微泵6的第一出口606和第二压电式微泵8的第二入口805处皆采用具有双层过滤作用机制的过滤装置，结构简单、小巧，其外层采用尼龙滤网，内层纤维滤料采用丙纹丝材料，具有孔隙率高、截污量大，单位面积过水量大的优点，可以有效防止土壤、基质中的杂质混入腔体中，阻塞微流体通道。
如图6、图7所示，为本发明所述压电式微泵吸取水模式和泵送水模式下水分流动示意图，本发明工作过程中通过含水量传感器检测土壤、基质水分含量，含水量传感器将水分信息传输给主控装置，主控装置进行含水量判断，当含水量处于正常水平时，主控装置控制第二压电式微泵8打开，将周围水分进行吸取并输运到储水装置7进行存储，当主控装置判断土壤、基质含水量低于pH检测阈值时，主控装置控制第一压电式微泵6打开，将储水装置7的水吸取并输运到电极表面。第一压电式微泵6和第二压电式微泵原理8相同，以第一压电式微泵6为例。当第一压电式微泵6进入吸取水模式，第一压电双晶片608带动第一泵膜607向上移动时，第一泵腔602内容积增大，内流体压强减少，通过入口处的外内正压作用使位于第一泵腔602内的第一入口阀603自动打开，同时通过出口处的外内正压作用使位于第一泵腔602外的第一出口阀604自动关闭，流体在压差作用下流入第一泵腔602；
相反，当第一压电式微泵6进入泵送水模式时，第一压电双晶片608带动第一泵膜607向下移动时，第一泵腔602内容积减小，内流体压强增大，通过入口处的外内负压作用使位于第一泵腔602内的第一入口阀603自动关闭，同时通过出口处的外内负压作用使位于第一泵腔602外的第一出口阀604自动打开，流体在压差作用下从出口通道流出，实现流体介质单向驱动。
本发明所述pH传感器，其制备方法包括以下步骤：
制作基底1：选用形状长约6cm、宽约4cm，厚度1.5mm以上的长方形氧化铝陶瓷作为基底材料，正面开两个长L1约0.5cm，宽L2约0.4cm的长方形槽包括第一长方形槽101和第二长方形槽102；并在第一长方形槽101和第二长方形槽102右侧依次开长方形电极引线槽103和焊盘槽104；
制作工作电极2：通过磁控溅射沉积在基底1的第一长方形槽101沉积第一Cr连接层201，然后通过电化学沉积依次得到Sb层202和Sb 2O 3层203，Sb 2O 3层203在Sb层202上方；然后通过旋涂法在Sb 2O 3层203外表面涂覆第一Nafion层204。
制作参比电极3：通过磁控溅射沉积在基底1的第二长方形槽102沉积第二Cr连接层301，然后通过电化学沉积依次得到Ag层302和AgCl层303，AgCl层303在Ag层上方；然后通过旋涂法在AgCl层303外表面涂覆第二Nafion层304。
制作第一压电式微泵6：通过湿法腐蚀和刻蚀技术在第一壳体609背面刻穿得到第一泵腔602、使用KOH在第一壳体509两侧异向腐蚀得到第一入口通道605和第一出口通道606，并用氢氟酸除去多余的KOH；第一入口阀603、第一出口阀604和第一泵膜607均由PDMS制造，将PDMS溶液与固化剂以10:1的比例混合，然后在75℃的不同模具中固化2.5小时，最后将模具置于真空室中除去气泡分别得到第一泵膜607、第一入口阀603和第一出口阀604， 利用粘结剂将第一泵膜607、第一入口阀603和第一出口阀604分别粘结在泵腔顶部、入口内侧和出口外侧；在基底1表面沉积第三Cr连接层601，将处理好的第一壳体609连接在第三Cr连接层601上方，并在第一壳体609上方粘结第一PZT压电双晶片608，利用粘结剂将第一入口605与储水装置7相连接，在微泵的出口处粘结尼龙滤网第一610和第一纤维滤料611得到过滤结构；
制作第二压电式微泵8：通过湿法腐蚀和刻蚀技术在第二壳体809背面刻穿得到第二泵腔802，使用KOH在第二壳体809两侧异向腐蚀得到第二入口通道805和第二出口通道806，并用氢氟酸除去多余的KOH；第二入口阀803、第二出口阀804和第二泵膜807均由PDMS制造，将PDMS溶液与固化剂以10:1的比例混合，然后在75℃的不同模具中固化2.5小时，最后将模具置于真空室中除去气泡分别得到第二泵膜807、第二入口阀803和第二出口阀804，利用粘结剂将第二泵膜807、第二入口阀803和第二出口阀804分别粘结在泵腔顶部、入口内侧和出口外侧；在基底1表面沉积第三Cr连接层801，将处理好的第二壳体809连接在第三Cr连接层上方，并在第二壳体809上方粘结第二PZT压电双晶片808，利用粘结剂将第二出口806与储水装置7相连接，在微泵的入口处粘结第二尼龙滤网810和第二纤维滤料811得到过滤结构；
制作储水装置7：通过异向腐蚀在聚乙烯壳体705背面刻蚀得到腔体702，在基底1表面依次沉积第四Cr连接层701，在聚乙烯壳体705内部表面沉积亲水性二氧化硅层703，并在亲水性二氧化硅层703表面通过制作微织构层704，聚乙烯壳体外部表面705沉积亲水性二氧化硅层706，并微织构化出凹槽707。
制作电极引线4：通过磁控溅射沉积在基底1的电极引线槽103上依次沉积Ni连接层401和Ag层402，然后通过旋涂法在Ag层402表面得到硅氧树脂层403。
本发明所述pH传感器实现了土壤、基质等非均相体系的原位检测，能够自动吸收、储存土壤、基质或的水分，并在土壤、基质中水分匮乏时进行自动补水。本发明在对固体、半固体非均相体系pH原位检测中，进一步提高了pH传感器性能，解决低水分含量对pH原位检测的限制。
本发明综合微泵技术和表面亲水性具有水分自输运特点，结合全固态pH传感器的机械强度高、易微型化的优点，以微流体理论、超亲水理论为基础，提供一种pH传感器，基于该pH传感器，可以实现自储水自补水的功能，在正常含水量下pH传感器能够自动吸水、储水，在低含水量下pH传感器能够自补水，用于实现土壤、基质等非均相体系的pH原位检测，提高土壤、基质pH原位检测准确性。
应当理解，虽然本说明书是按照各个实施例描述的，但并非每个实施例仅包含一个独立 的技术方案，说明书的这种叙述方式仅仅是为清楚起见，本领域技术人员应当将说明书作为一个整体，各实施例中的技术方案也可以经适当组合，形成本领域技术人员可以理解的其他实施方式。
上文所列出的一系列的详细说明仅仅是针对本发明的可行性实施例的具体说明，它们并非用以限制本发明的保护范围，凡未脱离本发明技艺精神所作的等效实施例或变更均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种自储水自补水pH传感器，其特征在于，包括基底(1)、工作电极(2)、参比电极(3)、第一压电式微泵(6)、储水装置(7)和第二压电式微泵(8)；
    所述工作电极(2)、参比电极(3)、第一压电式微泵(6)、储水装置(7)和第二压电式微泵(8)设置在基底(1)上；
    所述工作电极(2)和参比电极(3)分别通过电极引线(4)与焊盘(5)连接；
    所述第二压电式微泵(8)、储水装置(7)和第一压电式微泵(6)依次连通，所述第一压电式微泵(6)的出口用于将液体流至工作电极(2)。
  2. 根据权利要求1所述的自储水自补水pH传感器，其特征在于，所述基底(1)正面开槽，包括第一长方形槽(101)、第二长方形槽(102)、电极引线槽(103)和焊盘槽(104)；
    所述工作电极(2)安装在第一长方形槽(101)；所述参比电极(3)安装在第二长方形槽(102)；所述电极引线(4)分别安装在电极引线槽(103)；所述焊盘(5)安装在焊盘槽(104)。
  3. 根据权利要求1所述的自储水自补水pH传感器，其特征在于，所述工作电极(2)从下至上依次包括第一Cr连接层(201)、Sb层(202)、Sb 2O 3层(203)、第一Nafion层(204)；所述第一Cr连接层(201)与基底(1)连接。
  4. 根据权利要求1所述的自储水自补水pH传感器，其特征在于，所述参比电极(3)从下至上依次包括第二Cr连接层(301)、Ag层(302)、AgCl层(303)和第二Nafion层(304)；所述第二Cr连接层(301)与基底(1)连接。
  5. 根据权利要求1所述的自储水自补水pH传感器，其特征在于，所述第一压电式微泵(6)包括第三Cr连接层(601)、第一泵腔(602)、第一入口阀(603)、第一出口阀(604)、第一入口(605)、第一出口(606)、第一泵膜(607)、第一压电双晶片(608)和第一壳体(609)；
    所述第一壳体(609)的底部设有第三Cr连接层(601)，第三Cr连接层(601)与基底(1)连接；所述第一壳体(609)内设有第一泵腔(602)，第一泵腔(602)的设有第一入口(605)和第一出口(606)；所述第一入口(605)设有第一入口阀(603)，第一出口(606)设有第一出口阀(604)；所述第一入口(605)与储水装置(7)的出水口连接；
    所述第一泵膜(607)设置在第一壳体(609)顶部的内壁，所述第一压电双晶片(608)安装在第一泵膜(607)上。
  6. 根据权利要求5所述的自储水自补水pH传感器，其特征在于，所述第一出口(606)还设有第一过滤装置。
  7. 根据权利要求1所述的自储水自补水pH传感器，其特征在于，所述第二压电式微泵(8)包括第五Cr连接层(801)、第二泵腔(802)、第二入口阀(803)、第二出口阀(804)、第二 入口(805)、第二出口(806)、第二泵膜(807)、第二压电双晶片(808)和第二壳体(809)；
    所述第二壳体(809)的底部设有第五Cr连接层(801)，第五Cr连接层(801)与基底(1)连接；所述第二壳体(809)设有第二入口(805)和第二出口(806)；所述第二入口(805)设有第二入口阀(803)，所述第二出口(806)设有第二出口阀(804)；所述第二入口(805)用于与周围基质相通，所述第二出口(806)与储水装置(7)的第一入水口连接；
    所述第二泵膜(807)设置在第二壳体(809)顶部的内壁，所述第二压电双晶片(808)安装在第二泵膜(807)上。
  8. 根据权利要求7所述的自储水自补水pH传感器，其特征在于，所述第二入口(805)还设有第二过滤装置。
  9. 根据权利要求1所述的自储水自补水pH传感器，其特征在于，所述储水装置(7)包括第四Cr连接层(701)、腔体(702)、第一亲水二氧化硅(703)、第一微纳织构层(704)、第三壳体(705)、第二亲水二氧化硅层(706)、第二微纳织构层(707)；
    所述第三壳体(705)的底部设有第四Cr连接层(701)，第四Cr连接层(701)与基底(1)相连；
    所述第三壳体(705)内设有腔体(702)，所述腔体(702)的下部设有出水口和第一入水口，所述腔体(702)的顶部设有第二入水口，第二入水口设有储水装置入口阀(708)；
    所述腔体(702)的底部设有第一亲水二氧化硅(703)，在所述第一亲水二氧化硅(703)上设置第一微纳织构层(704)；
    所述第三壳体(705)的外表面设有第二亲水二氧化硅层(706)，在第二亲水二氧化硅层(706)上设置第二微纳织构层(707)。
  10. 根据权利要求9所述的自储水自补水pH传感器，其特征在于，所述第一微纳织构层(704)和第二微纳织构层(707)为凹槽，且凹槽与水分子接触角小于5°。
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