A temperature self-compensated strain sensor sensitive layer composite material and a preparation method thereof

Abstract

The application provides a temperature self-compensation strain sensor sensitive layer composite material and a preparation method thereof, and belongs to the technical field of functional materials. The composite material is prepared from raw materials including the following mass percentages: metal nanoparticles 25-35%, insulating oxide nanoparticles 2-3%, dispersing agent 0.1-0.5%, and the balance solvent; the metal nanoparticles have a positive temperature coefficient of resistance; and the insulating oxide nanoparticles include aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles or chromium oxide nanoparticles. The composite material provided by the application can be used as a sensitive layer of a temperature self-compensation strain sensor, can avoid strain signal disturbance caused by environmental temperature changes, can make the strain sensor have a temperature self-compensation function, and can further simplify the system of the strain sensor without using an external circuit and without changing the size and structure of the strain sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional materials, in particular to a temperature self-compensation strain sensor sensitive layer composite material and a preparation method thereof. BACKGROUND

[0002] In order to solve the disturbance caused by temperature change, the existing strain sensor usually adopts an auxiliary circuit for temperature compensation, and the most commonly used is a Wheatstone bridge circuit. This method uses two strain gauges of the same material, one as a working strain gauge installed on the surface of the test piece, and the other as a compensation strain gauge which does not bear strain and only changes in resistance value with temperature. In the working process, the working strain gauge and the compensation strain gauge are connected to the adjacent arms of the bridge, and both are in the same temperature field. When the test piece is not strained, the bridge parameters are adjusted so that the output voltage of the bridge is zero; when the test piece is strained, the compensation strain gauge can offset the resistance change caused by temperature change, so that the output voltage value of the bridge is only related to the strain and is not related to the temperature. In the existing scheme, the compensation strain gauge in the bridge circuit can be designed in the external circuit of the strain gauge, or the strain gauge can be designed to have both working strain gauge and compensation strain gauge, simplifying the external circuit. For the existing method of using an auxiliary circuit for strain gauge temperature compensation, if an external circuit is used, the sensor circuit will be complicated, and it is difficult to fix the compensation strain gauge; if the strain gauge structure itself is designed to have a compensation strain gauge, the manufacturing difficulty of the sensor will be increased, and the size and thickness of the sensor will be increased, which cannot be prepared in a narrow space. This makes the strain sensor system complex and increases the cost of the device.

[0003] Therefore, it is a difficult problem to be solved in the field to provide a composite material which has a temperature compensation function itself, so that the strain sensor prepared by the composite material does not need to use an external circuit and does not need to change the size and structure of the strain sensor. SUMMARY

[0004] The present application aims to provide a temperature self-compensation strain sensor sensitive layer composite material and a preparation method thereof. The temperature self-compensation strain sensor prepared by the temperature self-compensation strain sensor sensitive layer composite material provided by the present application does not need to use an external circuit and does not need to change the size and structure of the strain sensor, so that the strain sensor itself has a temperature compensation function.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides a temperature self-compensation strain sensor sensitive layer composite material, which is prepared from raw materials including the following mass percentages: metal nanoparticles 25-35%, insulating oxide nanoparticles 2-3%, dispersing agent 0.1-0.5%, and the balance solvent;

[0007] The metal nanoparticles have a positive temperature coefficient of resistance.

[0008] The insulating oxide nanoparticles include aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles or chromium oxide nanoparticles.

[0009] Preferably, the mass ratio of the metal nanoparticles to the insulating oxide nanoparticles is (8.33-17.5):1.

[0010] Preferably, the particle size of the insulating oxide nanoparticles is 5-10 nm.

[0011] Preferably, the metal nanoparticles include gold nanoparticles, silver nanoparticles or copper nanoparticles.

[0012] Preferably, the particle size of the metal nanoparticles is 50-100 nm.

[0013] Preferably, the metal nanoparticles and the insulating oxide nanoparticles are both spherical in shape.

[0014] Preferably, the dispersant includes polyvinylpyrrolidone.

[0015] Preferably, the solvent includes ethylene glycol or triethylene glycol monomethyl ether.

[0016] The present application also provides a preparation method of the temperature self-compensating strain sensor sensitive layer composite material described in the above technical solution, which comprises the following steps:

[0017] (1) mixing the metal nanoparticles, the insulating oxide nanoparticles, the dispersant and the solvent, and then performing ultrasonic treatment to obtain a slurry;

[0018] (2) solidifying the slurry obtained in the step (1) to obtain the temperature self-compensating strain sensor sensitive layer composite material.

[0019] Preferably, the solidification method in the step (2) is sintering at a temperature of 140-160℃ for 1.5-2.5 h.

[0020] The application provides a temperature self-compensating strain sensor sensitive layer composite material, which is prepared from raw materials including the following mass percentages: metal nanoparticles 25-35%, insulating oxide nanoparticles 2-3%, dispersant 0.1-0.5% and the balance solvent; the metal nanoparticles have a positive temperature coefficient of resistance; and the insulating oxide nanoparticles include aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles or chromium oxide nanoparticles. The application realizes a near-zero temperature coefficient of resistance by controlling the content of the metal nanoparticles and the insulating oxide nanoparticles, and offsetting the positive temperature coefficient of resistance of the metal and the negative temperature coefficient of resistance of the tunneling effect. The application uses aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles or chromium oxide nanoparticles as the insulating oxide nanoparticles, so that the insulating effect is provided and the tunneling effect of electrons occurs, thereby showing a negative temperature coefficient of resistance and offsetting the positive temperature coefficient of resistance of the metal, and realizing the temperature self-compensation function of the composite material.

[0021] The results of the examples show that the temperature self-compensating strain sensor sensitive layer composite material provided by the application has a temperature coefficient of resistance less than 150ppm / ℃ in a working temperature range of 10-60℃. When the composite material provided by the application is used as a sensitive layer to prepare a thin film strain sensor, the temperature coefficient of resistance of the material performance of the strain sensor can be regulated, the disturbance of the environmental temperature change on the strain signal can be avoided, the strain sensor is not sensitive to the temperature influence, and the strain sensor system is simplified without using an external circuit or changing the size and structure of the strain sensor. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A schematic diagram of the raw material composition of the composite material provided by the application; wherein 1 is metal nanoparticles, 2 is oxide nanoparticles, and 3 is a dispersant and a solvent;

[0023] Figure 2 An SEM image of the temperature self-compensating strain sensor sensitive layer composite material prepared in Example 1 of the application. DETAILED DESCRIPTION

[0024] The application provides a temperature self-compensating strain sensor sensitive layer composite material, which is prepared from raw materials including the following mass percentages: metal nanoparticles 25-35%, insulating oxide nanoparticles 2-3%, dispersant 0.1-0.5% and the balance solvent; the metal nanoparticles have a positive temperature coefficient of resistance; and the insulating oxide nanoparticles include aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles or chromium oxide nanoparticles.

[0025] The raw material for preparing the temperature self-compensation strain sensor sensitive layer composite material in the present application comprises 25-35% of metal nanoparticles by mass percentage, preferably 27-33%, and more preferably 28-32%. The present application uses metal nanoparticles as the strain material, and controls the content within the above range, which is more conducive to achieving near-zero temperature coefficient of resistance, thereby achieving the temperature compensation function.

[0026] In the present application, the metal nanoparticles have a positive temperature coefficient of resistance.

[0027] In the present application, the metal nanoparticles preferably comprise gold nanoparticles, silver nanoparticles or copper nanoparticles.

[0028] In the present application, the metal nanoparticles preferably have a particle size of 50-100 nm, and more preferably 60-90 nm.

[0029] In the present application, the metal nanoparticles preferably have a spherical morphology.

[0030] The raw material for preparing the temperature self-compensation strain sensor sensitive layer composite material in the present application comprises 2-3% of insulating oxide nanoparticles by mass percentage, preferably 2.1-2.9%, and more preferably 2.2-2.8%. The present application uses insulating oxide nanoparticles, which can provide insulation and make electrons have tunneling effect, showing a negative temperature coefficient of resistance, thereby offsetting the positive temperature coefficient of resistance of metal, and further achieving the temperature self-compensation function of the composite material.

[0031] In the present application, the insulating oxide nanoparticles comprise aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles or chromium oxide nanoparticles.

[0032] In the present application, the insulating oxide nanoparticles preferably have a particle size of 5-10 nm, and more preferably 6-9 nm.

[0033] In the present application, the insulating oxide nanoparticles preferably have a spherical morphology.

[0034] In the present application, the mass ratio of the metal nanoparticles to the insulating oxide nanoparticles is preferably (8.33-17.5):1, and more preferably (9-12):1.

[0035] The raw material for preparing the temperature self-compensation strain sensor sensitive layer composite material in the present application comprises 0.1-0.5% of dispersant by mass percentage, and more preferably 0.2-0.4%. The present application adds dispersant and controls the content within the above range, which is more conducive to the uniform dispersion and sufficient contact of the metal nanoparticles and the insulating oxide nanoparticles at the nanoscale.

[0036] In the present application, the dispersant preferably includes polyvinylpyrrolidone. The present application is more conducive to improving the dispersibility of the nanoparticles by selecting the above-mentioned kind of dispersant.

[0037] The raw materials for preparing the temperature self-compensating strain sensor sensitive layer composite material in the present application include a solvent in an amount of 5-20% by mass. The present application can make the composite material into a slurry by adding the solvent, which is conducive to the dispersion of the nanoparticles and the use of the composite material.

[0038] In the present application, the solvent preferably includes ethylene glycol or triethylene glycol monomethyl ether. The present application is more conducive to the sufficient dispersion of the nanoparticles and the sufficient volatilization of the solvent during use by selecting the above-mentioned kind of solvent.

[0039] The schematic diagram of the composition of the raw materials of the composite material provided by the present application is shown in Figure 1 . Among them, 1 is a metal nanoparticle, 2 is an insulating oxide nanoparticle, and 3 is a dispersant and a solvent. Figure 1 As can be seen, the metal nanoparticles have a large particle size and are dispersed with insulating oxide nanoparticles in the middle. The two are uniformly dispersed in the solvent by the dispersant, so that there is a nanoscale insulating gap between the metal nanoparticles in the prepared composite material.

[0040] When the composite material provided by the present application is used as a sensitive layer in a thin film strain sensor, the material performance of the strain sensor can be controlled by the temperature coefficient of resistance, which can avoid the disturbance of environmental temperature changes on the strain signal, so that the strain sensor has a temperature self-compensation function, and the strain sensor system is simplified without using an external circuit or changing the size and structure of the strain sensor.

[0041] The present application also provides a preparation method of the temperature self-compensating strain sensor sensitive layer composite material described in the above technical solution, which comprises the following steps: (1) mixing metal nanoparticles, insulating oxide nanoparticles, a dispersant and a solvent, and then performing ultrasonic treatment to obtain a slurry;

[0042] (2) solidifying the slurry obtained in the step (1) to obtain a temperature self-compensating strain sensor sensitive layer composite material.

[0043] The present application mixes metal nanoparticles, insulating oxide nanoparticles, a dispersant and a solvent, and then performs ultrasonic treatment to obtain a slurry.

[0044] In the present application, the mixing operation is preferably stirring. The present application does not have special requirements for the parameters of stirring, and can ensure that the components are uniformly mixed.

[0045] The present application does not have special requirements for the parameters of the ultrasonic treatment, and can ensure that the components are sufficiently and uniformly mixed.

[0046] After obtaining the slurry, the slurry is solidified to obtain a composite material with temperature compensation function.

[0047] In the present application, the solidification method is preferably sintering at a temperature of 140-160℃ for 1.5-2.5h, and more preferably sintering at a temperature of 150℃ for 2h. The present application can make the solvent in the slurry fully volatilize by using the above solidification method and parameters.

[0048] The temperature self-compensation strain sensor sensitive layer composite material prepared by the preparation method has more uniform dispersion.

[0049] The technical solutions in the present application will be described clearly and completely in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0050] Embodiment 1

[0051] A temperature self-compensation strain sensor sensitive layer composite material is prepared from the following raw materials in mass percentage: metal nanoparticles 30%, insulating oxide nanoparticles 2.5%, dispersant 0.1%, and the balance solvent.

[0052] The mass ratio of the metal nanoparticles to the insulating oxide nanoparticles is 12:1; the metal nanoparticles have a positive temperature coefficient of resistance, the metal nanoparticles are silver nanoparticles, and the particle size of the metal nanoparticles is 50nm; the insulating oxide nanoparticles are silicon oxide nanoparticles, and the particle size of the insulating oxide nanoparticles is 4nm; the metal nanoparticles and the insulating oxide nanoparticles both have a spherical morphology.

[0053] The dispersant is polyvinylpyrrolidone.

[0054] The solvent is triethylene glycol monomethyl ether.

[0055] The preparation method of the above composite material is as follows:

[0056] (1) The metal nanoparticles, the insulating oxide nanoparticles, the dispersant, and the solvent are mixed by stirring and then subjected to ultrasonic treatment to obtain a slurry;

[0057] (2) The slurry obtained in the step (1) is solidified to obtain a composite material with temperature compensation function; the solidification method is sintering at 150℃ for 2h.

[0058] Embodiment 2

[0059] A temperature self-compensated strain sensor sensitive layer composite material is prepared from raw materials in the following mass percentages: metal nanoparticles 30%, insulating oxide nanoparticles 0.1%, dispersant 0.1%, and the balance solvent;

[0060] The mass ratio of the metal nanoparticles to the insulating oxide nanoparticles is 10:1, and the other technical features are the same as those of Embodiment 1.

[0061] Embodiment 3

[0062] A temperature self-compensated strain sensor sensitive layer composite material is prepared from raw materials in the following mass percentages: metal nanoparticles 30%, insulating oxide nanoparticles 3.33%, dispersant 0.1%, and the balance solvent;

[0063] The mass ratio of the metal nanoparticles to the insulating oxide nanoparticles is 9:1, and the other technical features are the same as those of Embodiment 1.

[0064] The temperature self-compensated strain sensor sensitive layer composite material prepared in step (2) of Embodiment 1 of the present application is observed for its microstructure by scanning electron microscopy, and the SEM image obtained is as shown in FIG. 1. Figure 2 As can be seen from FIG. 1, the silver nanoparticles (AgNPs) in the cured composite material have a particle size of 50 nm, and the silicon dioxide nanoparticles (SiO2) have a particle size of 4 nm and are uniformly distributed in the interstices of the silver nanoparticles. Figure 2 The composite material provided by Embodiment 1 of the present application is subjected to average resistance temperature coefficient (TCR) testing, that is, the sample size of the composite material provided by Embodiment 1 of the present application is controlled to be substantially 120 mm in length, 1 mm in width, and 0.1 mm in thickness by controlling the working distance and the number of repeated printing in the inkjet printing process. The average resistance temperature coefficient (TCR) is calculated with reference to “GB / T6148-2005 Resistance Temperature Coefficient Test Method for Precision Resistance Alloys”; the relative change of the resistance is divided by the temperature difference that causes the change in the two given temperature ranges (i.e., t0-t, in the range of 10-60℃) to obtain the average resistance temperature coefficient (TCR), and the calculation formula is shown as Formula ①.

[0065]

[0066]

[0067] Wherein, Rt is the resistance value at t℃, Ω; R t0 t0℃, Ω; t: test temperature, ℃; t0: reference temperature, ℃.

[0068] ​According to the above test results, the composite material has a temperature coefficient of resistance less than 150 ppm / °C in a working temperature range of 10-60 °C.

[0069] The above merely describes the preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A temperature self-compensated strain sensor sensitive layer composite material, characterized in that, It is prepared from raw materials comprising the following mass percentages: 25-35% metal nanoparticles, 2-3% insulating oxide nanoparticles, 0.1-0.5% dispersant, and the balance being solvent; The temperature coefficient of resistance of the metal nanoparticles is a positive temperature coefficient. The particle size of the metal nanoparticles is 50~100nm; The insulating oxide nanoparticles include aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles, or chromium oxide nanoparticles. The insulating oxide nanoparticles have a particle size of 5~10 nm; Both the metal nanoparticles and the insulating oxide nanoparticles are spherical in shape. The metal nanoparticles include gold nanoparticles, silver nanoparticles, or copper nanoparticles. The solvent includes ethylene glycol or triethylene glycol monomethyl ether.

2. The temperature self-compensated strain sensor sensitive layer composite material according to claim 1, characterized in that, The dispersant includes polyvinylpyrrolidone.

3. The method for preparing the temperature self-compensating strain sensor sensitive layer composite material as described in any one of claims 1 to 2, characterized in that, include: (1) Metal nanoparticles, insulating oxide nanoparticles, dispersant and solvent are mixed and then ultrasonically treated to obtain a slurry; (2) The slurry obtained in step (1) is cured to obtain a temperature self-compensating strain sensor sensitive layer composite material.

4. The preparation method according to claim 3, characterized in that, The curing method in step (2) is to sinter at a temperature of 140~160℃ for 1.5~2.5h.

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