An acetylene black flexible pressure sensor based on seepage principle and its preparation method

Abstract

The present invention relates to the field of sensor technology, and in particular to a flexible acetylene black pressure sensor based on the seepage principle and a method for preparing the same. The method comprises the following steps: adding acetylene black powder to a PDMS solution to obtain an acetylene black / PDMS mixed solution, pouring the solution into a mold, and subjecting the solution to a curing treatment to obtain a partially cured intermediate dielectric layer; and sequentially stacking an insulating layer and a plate on each end surface of the intermediate dielectric layer to obtain the acetylene black flexible pressure sensor. The present invention utilizes acetylene black and PDMS materials as the intermediate dielectric layer of the sensor. Based on the seepage principle, the spacing between conductive particles (acetylene black particles), which is closely related to sensing performance, is adjusted by controlling the acetylene black ratio and the PDMS curing time. This results in a microcapacitor formed between every two conductive particles, thereby producing a capacitive pressure sensor with higher sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to an acetylene black flexible pressure sensor based on the seepage principle and a preparation method thereof. Background Art

[0002] In recent years, flexible electronic devices have attracted considerable attention due to their advantages such as lightweight, stretchable, and flexibility. With the development of system integration technology, they are widely used in intelligent robots and wearable devices. The rapidly developing flexible pressure sensors are an indispensable component of flexible electronic devices. Flexible pressure sensors are mainly divided into piezoelectric, resistive, and capacitive types. Existing piezoelectric sensors have high requirements for piezoelectric materials. Factors such as the elastic modulus and stiffness of the piezoelectric material determine the natural frequency and dynamic characteristics of the piezoelectric device. Environmental factors also affect the material, resulting in high manufacturing costs and limited application scope. Resistive sensors have weak output signals and increased nonlinear effects at high strains. Furthermore, changes in time and environment can significantly affect the detection data. Flexible capacitive pressure sensors, on the other hand, are widely used in many fields due to their simple manufacturing process, cost-effectiveness, low temperature cross-sensitivity, fast response, and reliable performance.

[0003] However, the existing flexible capacitive pressure sensors are unable to meet the needs of flexible device development in terms of stability and response speed. How to obtain higher sensitivity, faster response speed and more stable output has always been one of the difficulties of capacitive pressure sensors.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an acetylene black flexible pressure sensor based on the seepage principle and a preparation method thereof, aiming to solve the problems of low sensitivity, slow response speed and poor stability of the existing capacitive pressure sensors.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for preparing an acetylene black flexible pressure sensor based on the seepage principle comprises the following steps:

[0008] Providing PDMS solution;

[0009] Adding acetylene black powder to the PDMS solution and stirring to obtain an acetylene black / PDMS mixed solution;

[0010] The acetylene black / PDMS mixed solution is poured into a mold and cured to obtain an intermediate dielectric layer in a partially cured state;

[0011] A first insulating layer and a first electrode are stacked in sequence on the first surface of the intermediate dielectric layer, and a second insulating layer and a second electrode are stacked in sequence on the second surface of the intermediate dielectric layer to obtain an acetylene black flexible pressure sensor; wherein the first surface and the second surface are opposite surfaces of the intermediate dielectric layer.

[0012] In the method for preparing the acetylene black flexible pressure sensor based on the seepage principle, the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is less than or equal to 2.5wt%.

[0013] In the method for preparing the acetylene black flexible pressure sensor based on the seepage principle, the curing treatment is carried out in a vacuum drying oven at 70-90° C., and the curing time is 10-30 minutes.

[0014] The method for preparing the acetylene black flexible pressure sensor based on the seepage principle, wherein the method for preparing the PDMS solution comprises the steps of: mixing the PDMS prepolymer and the curing agent in a weight ratio of (8-12):1 to obtain the PDMS solution.

[0015] The method for preparing the acetylene black flexible pressure sensor based on the percolation principle, wherein the material of the first insulating layer and the material of the second insulating layer are independently selected from one of silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, polyimide, polyethylene, polyvinylidene fluoride, and polytetrafluoroethylene.

[0016] In the method for preparing the acetylene black flexible pressure sensor based on the percolation principle, the first electrode plate and the second electrode plate are independently selected from one of copper foil and silicon carbide conductive electrode plate.

[0017] The method for preparing the acetylene black flexible pressure sensor based on the percolation principle comprises the following steps: the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is 2.0 wt %; and the curing treatment is carried out in a vacuum drying oven at 80° C. for 20 minutes.

[0018] The method for preparing the acetylene black flexible pressure sensor based on the seepage principle, wherein the mold is a cylindrical mold with a diameter of 15 mm and a height of 1.5 mm.

[0019] An acetylene black flexible pressure sensor based on the seepage principle is manufactured using the above-mentioned method for preparing an acetylene black flexible pressure sensor based on the seepage principle; the acetylene black flexible pressure sensor based on the seepage principle includes a first electrode plate, a first insulating layer, an intermediate dielectric layer, a second insulating layer, and a second electrode plate stacked in sequence.

[0020] In the acetylene black flexible pressure sensor based on the percolation principle, the first electrode plate and the second electrode plate are both copper foils; and the first insulating layer and the second insulating layer are both polyimide films.

[0021] Beneficial effects: The present invention provides an acetylene black flexible pressure sensor based on the seepage principle and a preparation method thereof, the preparation method comprising the steps of: providing a PDMS solution; adding acetylene black powder to the PDMS solution, stirring to obtain an acetylene black / PDMS mixed solution; pouring the acetylene black / PDMS mixed solution into a mold, and subjecting it to a curing treatment to obtain an intermediate dielectric layer in a non-completely cured state; and sequentially stacking an insulating layer and a plate on the two end faces of the intermediate dielectric layer to obtain an acetylene black flexible pressure sensor. The present invention uses acetylene black and PDMS materials as the intermediate dielectric layer of the sensor. Based on the seepage principle, the spacing between the conductive particles (acetylene black) that is closely related to the sensing performance is adjusted by controlling the proportion of acetylene black and the curing time of PDMS, so that a microcapacitor is formed between every two conductive particles, and the spacing between the conductive particles affects the electrical properties of the microcapacitor, thereby preparing a new capacitive pressure sensor with higher sensitivity, and achieving 0.248kPa in the range of 4-50kPa. -1 The sensitivity is 5 times that of pure PDMS sensors, and the response time is 250ms. That is, the present invention has the characteristics of high sensitivity, fast response time and good stability, and has broad application prospects in wearable and real-time detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the percolation principle in the present invention, where (a) is pure PDMS, (b) is PDMS with fewer conductive particles, (c) is PDMS with moderate conductive particles, and (d) is PDMS with many conductive particles;

[0023] Figure 2 (a) is a schematic diagram of the preparation process of the acetylene black flexible pressure sensor of the present invention, Figure 2 (b) is a schematic diagram of the electrical test of the acetylene black flexible pressure sensor. Figure 2 (c) is a size comparison diagram of the acetylene black flexible pressure sensor;

[0024] Figure 3 Figures 1 and 2 show the test results of the flexible pressure sensor with different acetylene black concentrations in Example 1, where (a) is a graph showing the relative change in sensitivity of the flexible pressure sensor with different acetylene black concentrations, and (b) is a histogram showing the sensitivity of the flexible pressure sensor with different acetylene black concentrations.

[0025] Figure 4Figures 1 and 2 show the capacitance response and sensitivity data of the acetylene black flexible pressure sensor at different curing times in Example 1, where (a) is pure PDMS, (b) is PDMS with 2 wt% acetylene black, and (c) is PDMS with 2.5 wt% acetylene black.

[0026] Figure 5 Schematic diagram of the pressure load on the sensor at different curing times in Example 1;

[0027] Figure 6 These are stability characterization data diagrams of the acetylene black flexible pressure sensor in Example 1, where (a) is a dynamic response data diagram to pressures from 1 kPa to 250 kPa, and (b) is a real-time response data diagram. DETAILED DESCRIPTION

[0028] The present invention provides an acetylene black flexible pressure sensor based on the seepage principle and a method for preparing the same. To clarify the objectives, technical solutions, and effects of the present invention, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention.

[0029] In the embodiments and patent claims, unless otherwise specified herein, the words "a," "an," "the," and "the" may include plural forms. If the embodiments of the present invention include descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features.

[0030] It should be further understood that the wording "comprising" used in the description of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. The wording "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0031] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0032] The present invention provides a method for preparing an acetylene black flexible pressure sensor based on the seepage principle, comprising the steps of:

[0033] Step S10: providing a PDMS solution;

[0034] Step S20: adding acetylene black powder to the PDMS solution and stirring to obtain an acetylene black / PDMS mixed solution;

[0035] Step S30: pouring the acetylene black / PDMS mixed solution into a mold and subjecting it to curing treatment to obtain an intermediate dielectric layer in a partially cured state;

[0036] Step S40: stacking a first insulating layer and a first electrode in sequence on the first surface of the intermediate dielectric layer, and stacking a second insulating layer and a second electrode in sequence on the second surface of the intermediate dielectric layer to obtain an acetylene black flexible pressure sensor; wherein the first surface and the second surface are opposite surfaces of the intermediate dielectric layer.

[0037] In this embodiment, acetylene black and PDMS (polydimethylsiloxane) materials are used as the intermediate dielectric layer of the capacitive pressure sensor. By controlling the proportion of acetylene black in the intermediate dielectric layer and the curing time, an intermediate dielectric layer in a non-completely cured state is obtained. The intermediate dielectric layer in a non-completely cured state can make the sensor have an appropriate Young's modulus, and every two adjacent conductive particles can form a micro-capacitor; when pressure is applied to the sensor, the distance between every two adjacent conductive particles will decrease, resulting in ε r Increase, thereby increasing the capacitance of the sensor, and then preparing a new capacitive pressure sensor with higher sensitivity, namely acetylene black flexible pressure sensor.

[0038] In some embodiments, the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is less than or equal to 2.5 wt %. Specifically, the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is greater than 0 but less than or equal to 2.5 wt %. When the mass percentage of the acetylene black powder is within this range, the prepared acetylene black flexible pressure sensor can achieve improved sensitivity.

[0039] In a specific embodiment, the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is 1.0 wt%-2.5 wt%. When the proportion of acetylene black is too low (the concentration is too low), the distance between the acetylene black particles, which are conductive particles, is large, the dielectric constant is small, the rate of change of capacitance and the change in sensor sensitivity are also small. Although its sensitivity is improved compared with the capacitive sensor of the prior art, it cannot detect small forces and cannot meet some requirements for small force detection. When the proportion of acetylene black is too high, the distance between the acetylene black particles is too small, and electrons will migrate between the conductive particles, forming a continuous conductive network, resulting in large dielectric loss, causing the dielectric constant to decrease sharply and the sensor sensitivity to decrease sharply.

[0040] In a preferred embodiment, the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is 2.0 wt%; when the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is 2.0 wt%, the acetylene black flexible pressure sensor shows optimal sensor sensitivity, which is mainly affected by the seepage principle.

[0041] Specifically, the percolation principle is widely used to increase the dielectric constant of composite materials; in composite materials, when a fraction of a material has a percolation threshold f c When the topological microstructure changes and the internal dielectric properties are critical, the closer the concentration of conductive particles is to the percolation threshold, the larger the dielectric constant is. Based on this principle, the power relationship of the dielectric constant near the percolation threshold is given:

[0042] ε eff ∝(f c -f ACET ) -S ,

[0043] where ε eff is the effective dielectric constant, f c is the percolation threshold, s is the corresponding critical exponent, and f ACET is the mass concentration of acetylene black. Figure 1 As shown in Figure 2, in a composite material, every two adjacent conductive particles can form a micro-capacitor. Figure 1 As shown in (b) and (c), f ACET 《f c The concentration of conductive particles is small in the state, and the distance between conductive particles in this state is smaller than f ACET <f c The conductive particles in the state are spaced far apart, so when f ACET <f c When f ACETWhen it increases, it is equivalent to a decrease in the spacing between the two microcapacitors and an increase in the dielectric constant of the composite material; Figure 1 As shown in (c) and (d), f ACET ≥f c The conductive particles in the state are too dense. ACET ≥f c When the dielectric constant decreases sharply, a continuous conductive network is formed.

[0044] In this embodiment, the mass concentration threshold of the acetylene black powder is 2.0 wt%. When the concentration of acetylene black as a conductive particle is lower than the percolation threshold (2.0 wt%), the closer the acetylene black concentration is to the percolation threshold, the greater the dielectric constant, and the rate of change of capacitance and sensor sensitivity will also increase. When the acetylene black concentration reaches or exceeds the percolation threshold, the acetylene black is too dense in the PDMS, resulting in a continuous conductive network layer by layer in the PDMS. At this time, the dielectric constant drops sharply, and the change in capacitance and sensor sensitivity will also decrease. Therefore, when the mass percentage of acetylene black powder in the acetylene black / PDMS mixed solution is 2.0 wt%, the acetylene black flexible pressure sensor exhibits optimal sensor sensitivity.

[0045] In some embodiments, the curing treatment is carried out in a vacuum drying oven at 70-90°C for 10-30 minutes. Curing within this temperature range for 10-30 minutes can produce an intermediate dielectric layer in a non-completely cured state, thereby improving the sensitivity, stability and response time of the acetylene black flexible pressure sensor.

[0046] Specifically, when the curing time is too long, the hardness of the intermediate dielectric layer will increase significantly, resulting in an increase in its Young's modulus. When the same pressure is applied, the distance between the sensors does not change much, resulting in The change in d is minimal; however, too short a curing time results in a viscous intermediate dielectric layer, making it impossible to form. Specifically, when heating and curing the acetylene black / PDMS mixed solution to form the intermediate dielectric layer, too long a curing time will make the sensor harder, making it difficult to compress, resulting in a small capacitance change and reduced sensor sensitivity. However, too short a curing time will soften the sensor and make it more compressible, leading to particle adhesion and reduced sensor sensitivity.

[0047] In a preferred embodiment, the curing treatment is carried out in a vacuum drying oven at 80° C., and the curing time is 20 minutes.

[0048] In some embodiments, in step S10, the method for preparing the PDMS solution includes the steps of: mixing a PDMS prepolymer and a curing agent in a weight ratio of (8-12):1 to obtain a PDMS solution.

[0049] In a preferred embodiment, the PDMS prepolymer and the curing agent are mixed in a weight ratio of 10:1 to obtain a PDMS solution.

[0050] In some embodiments, the material of the first insulating layer and the material of the second insulating layer are independently selected from one of silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, polyimide, polyethylene, polyvinylidene fluoride, and polytetrafluoroethylene.

[0051] In some embodiments, the first electrode plate and the second electrode plate are independently selected from one of copper foil and silicon carbide conductive electrode plate; using copper foil as the material of the upper and lower electrode plates can make the sensor have better conductivity and thus improve its performance such as reaction speed; and using silicon carbide conductive electrode plates as the upper and lower electrode plates, at the same time, because silicon carbide has excellent high temperature resistance, corrosion resistance and other properties, the final sensor can be applied to more usage scenarios.

[0052] Specifically, an insulating layer is first stacked on the two end surfaces of the intermediate dielectric layer, and then a plate is stacked; the purpose of stacking the insulating layer first is to prevent the acetylene black particles on the surface of the intermediate dielectric layer from combining with the wire end, avoiding affecting the stability of the data during electrical characterization, and playing an insulating role.

[0053] In some embodiments, the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is 2.0 wt %; the curing treatment is carried out in a vacuum drying oven at 80° C. for 20 minutes; the sensitivity of the sensor prepared under these parameters reaches 0.248 kPa in the pressure range of 4-50 kPa. -1 and 0.025kPa in the pressure range of 50-250kPa -1 , and has good stability and a fast response time of 250ms, and has broad application prospects in many fields such as wearable devices, industrial / environmental monitoring and consumer electronics.

[0054] In some embodiments, the mold is a cylindrical mold with a diameter of 15 mm and a height of 1.5 mm, which can produce a disc-shaped intermediate dielectric layer with moderate thickness and diameter.

[0055] In addition, the present invention also provides an acetylene black flexible pressure sensor based on the seepage principle, and the acetylene black flexible pressure sensor based on the seepage principle is prepared using the above-mentioned preparation method of the acetylene black flexible pressure sensor based on the seepage principle; the acetylene black flexible pressure sensor based on the seepage principle includes a first electrode plate, a first insulating layer, an intermediate dielectric layer, a second insulating layer, and a second electrode plate stacked in sequence.

[0056] In this embodiment, an acetylene black flexible pressure sensor based on the seepage principle is proposed. Acetylene black is filled into PDMS through an efficient and low-cost process to increase the number of conductive particles inside the sensor to increase the sensitivity of the sensor. Its sensitivity is almost 5 times that of pure PDMS within a certain pressure range, greatly improving the sensitivity of the PDMS sensor.

[0057] In some embodiments, the first electrode plate and the second electrode plate are both copper foils; and the first insulating layer and the second insulating layer are both polyimide films.

[0058] The present invention is further described below with reference to the following examples. It should also be understood that the following examples are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above contents of the present invention fall within the scope of protection of the present invention.

[0059] Example 1

[0060] like Figure 2 As shown, preparing capacitive pressure sensors with different acetylene black contents and different curing times specifically includes the following steps:

[0061] First, PDMS prepolymer and curing agent are mixed in a weight ratio of 10:1 to obtain a PDMS solution, so that it has a smaller shrinkage rate in the subsequent curing step;

[0062] The prepared PDMS solution was then fully blended with acetylene black having concentrations of 0.0 (control), 2, and 2.5 wt % (the concentration here refers to the mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution) to obtain uniformly dispersed acetylene black / PDMS mixed solutions of different concentrations;

[0063] The acetylene black / PDMS mixed solution was then poured into a circular mold with a diameter of 15 mm and a height of 1.5 mm and cured for 10, 15, 20, 25, and 30 minutes, respectively, to obtain intermediate dielectric layers with different elastic moduli. Finally, Kapton tape (PI film) and copper foil were attached to the upper and lower surfaces of the sensor to obtain 15 acetylene black / PDMS capacitive pressure sensors with different acetylene black contents and elastic moduli, and the sensors were electrically tested.

[0064] The copper foil in the acetylene black / PDMS capacitive pressure sensor prepared in this embodiment can be regarded as a parallel plate capacitor, so the capacitance between the copper foils is expressed as

[0065]

[0066] where ε0 is the dielectric constant of vacuum, ε ris the relative dielectric constant, A is the area of ​​the electrode plate, and d is the distance between the two parallel electrode plates. When pressure is applied to the sensor, the spacing between each two adjacent conductive particles will decrease, resulting in ε r Therefore, the intermediate dielectric layer in the uncured state prepared in this embodiment can make a positive contribution to the performance of the sensor.

[0067] The following data is tested on 15 acetylene black / PDMS capacitive pressure sensors with different acetylene black contents and elastic moduli, as follows:

[0068] 1. The influence of different parameters on the sensor capacitance response

[0069] Fifteen prepared acetylene black / PDMS capacitive pressure sensors with different elastic moduli (different acetylene black concentrations and different curing times) were installed on a force measuring device for testing; four pressure ranges were applied to the prepared sensors, namely 0-5.6kPa with a step of 1.13kPa, 5.67-22.65kPa with a step of 2.83kPa, 22.65-73.6kPa with a step of 6.37kPa and 39.63-243.45kPa with a step of 28.31kPa; at the same time, the capacitance changes of the sensor were continuously monitored by an LCR meter.

[0070] Figure 3 The results in Figure 2 show the relationship between acetylene black concentration, sensor capacitance, and sensitivity at different pressures. Figure 3 As shown in (a), when the pressure is less than 4 kPa, the sensitivity test results of pressure sensors with different acetylene black concentrations are very similar, which may be due to the accuracy limitations of the equipment. Due to the low dielectric constant, the sensitivity of the pure PDMS capacitive sensor is lower than that of other samples. By introducing a certain amount of acetylene black into the PDMS layer (for example, acetylene black with a mass concentration of 2 and 2.5 wt%), the sensitivity is significantly improved. However, when the acetylene black is excessive, the sensitivity decreases. This may be due to the adhesion of excessive conductive particles, which reduces the number of microcapacitors and causes a decrease in the dielectric constant. In addition, due to the elastic limit of PDMS, the sensitivity of the sensor in the relatively low pressure range of 4-50 kPa is higher than that in the pressure range of 50-250 kPa.

[0071] Figure 4 The results in Figure 2 show the relationship between the capacitance response and sensitivity of the sensor at different curing times. For the pure PDMS capacitive sensor, a shorter curing time showed higher sensitivity, while for the acetylene black / PDMS sensor, the best sensor performance was observed when the curing time was 20 minutes, with a sensitivity of 0.248 kPa. -1 (like Figure 4 The reason for this phenomenon is that a short curing time makes the sensor soft and easy to compress, which may cause particle adhesion, while a long curing time makes the sensor difficult to compress and the change in capacitance is small (as shown in (b)-(c) in the figure). Figure 5 shown).

[0072] 2. Sensor stability characterization

[0073] Figure 6 The results show that the acetylene black / PDMS capacitive pressure sensor developed by the present invention has good stability and reliability in real-time response in loading and unloading tests under various pressures. Figure 6 As shown in (a) of the figure, the sensor is alternately loaded and unloaded with pressures ranging from 1 kPa to 250 kPa by increasing the fixed load and observing the effects of different pressure conditions on the sensor. The results show that the sensor can deform and recover under different loading and unloading pressures without causing any structural damage. Figure 6 As shown in (b), when tested under an external pressure of 1.6 kPa, the fast response and recovery time is 250 ms.

[0074] Compared with the existing technology, the acetylene black / PDMS capacitive pressure sensor proposed in the present invention is based on the percolation principle. Acetylene black is filled into PDMS through an efficient and low-cost process to increase the number of conductive particles inside the sensor to increase the sensitivity of the sensor. Its sensitivity is almost 5 times that of pure PDMS within a certain pressure range, greatly improving the sensitivity of the PDMS sensor.

[0075] This example systematically studies 15 sensors to explore the effects of acetylene black / PDMS mass concentration ratio and curing time on sensor performance. A 20-minute curing time and a 2 wt% acetylene black / PDMS concentration are optimal parameters for achieving high sensitivity. The sensor achieves a sensitivity of 0.248 kPa within a pressure range of 4-50 kPa. -1 and 0.025kPa in the pressure range of 50-250kPa -1 , and has good stability and a fast response time of 250ms, and has broad application prospects in many fields such as wearable devices, industrial / environmental monitoring and consumer electronics.

[0076] In summary, the present invention provides an acetylene black flexible pressure sensor based on the seepage principle and a preparation method thereof, the preparation method comprising the steps of: providing a PDMS solution; adding acetylene black powder to the PDMS solution, stirring to obtain an acetylene black / PDMS mixed solution; pouring the acetylene black / PDMS mixed solution into a mold, and curing it to obtain an intermediate dielectric layer in a non-completely cured state; and sequentially stacking an insulating layer and a plate on the two end faces of the intermediate dielectric layer to obtain an acetylene black flexible pressure sensor. The present invention uses acetylene black and PDMS materials as the intermediate dielectric layer of the sensor. Based on the seepage principle, the spacing between the conductive particles (acetylene black) that is closely related to the sensing performance is adjusted by controlling the proportion of acetylene black and the curing time of PDMS, so that a microcapacitor is formed between every two conductive particles, and the spacing between the conductive particles affects the electrical properties of the microcapacitor, thereby preparing a new capacitive pressure sensor with higher sensitivity, and achieving 0.248kPa in the range of 4-50kPa. -1 The sensitivity is 5 times that of pure PDMS sensors, and the response time is 250ms. That is, the present invention has the characteristics of high sensitivity, fast response time and good stability, and has broad application prospects in wearable and real-time detection.

[0077] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing an acetylene black flexible pressure sensor based on the seepage principle, characterized in that: Including steps: Providing PDMS solution; Adding acetylene black powder to the PDMS solution and stirring to obtain an acetylene black / PDMS mixed solution; The acetylene black / PDMS mixed solution is poured into a mold and cured to obtain an intermediate dielectric layer in a partially cured state; A first insulating layer and a first electrode are sequentially stacked on a first surface of the intermediate dielectric layer, and a second insulating layer and a second electrode are sequentially stacked on a second surface of the intermediate dielectric layer to obtain an acetylene black flexible pressure sensor; wherein the first surface and the second surface are opposite surfaces of the intermediate dielectric layer; The mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is 1.0wt%-2.5wt%; the curing treatment is carried out in a vacuum drying oven at 70-90°C, and the curing time is 10-30 minutes.

2. The method for preparing the acetylene black flexible pressure sensor based on the seepage principle according to claim 1, characterized in that: The preparation method of the PDMS solution comprises the steps of: The PDMS prepolymer and the curing agent were mixed in a weight ratio of (8-12):1 to obtain a PDMS solution.

3. The method for preparing the acetylene black flexible pressure sensor based on the seepage principle according to claim 1, characterized in that: The material of the first insulating layer and the material of the second insulating layer are independently selected from one of silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, polyimide, polyethylene, polyvinylidene fluoride, and polytetrafluoroethylene.

4. The method for preparing the acetylene black flexible pressure sensor based on the seepage principle according to claim 1, characterized in that: The first electrode plate and the second electrode plate are independently selected from one of copper foil and silicon carbide conductive electrode plates.

5. The method for preparing the acetylene black flexible pressure sensor based on the seepage principle according to claim 1, characterized in that: The mass percentage of the acetylene black powder in the acetylene black / PDMS mixed solution is 2.0 wt %. The curing treatment is carried out in a vacuum drying oven at 80° C. for 20 minutes.

6. The method for preparing the acetylene black flexible pressure sensor based on the seepage principle according to claim 1, characterized in that: The mold is a cylindrical mold with a diameter of 15 mm and a height of 1.5 mm.

7. An acetylene black flexible pressure sensor based on the seepage principle, characterized in that: The acetylene black flexible pressure sensor based on the seepage principle is manufactured using the preparation method of the acetylene black flexible pressure sensor based on the seepage principle as described in any one of claims 1 to 6; the acetylene black flexible pressure sensor based on the seepage principle includes a first electrode plate, a first insulating layer, an intermediate dielectric layer, a second insulating layer, and a second electrode plate stacked in sequence.

8. The acetylene black flexible pressure sensor based on the seepage principle according to claim 7 is characterized in that: The first electrode plate and the second electrode plate are both copper foils; the first insulating layer and the second insulating layer are both polyimide films.

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