CN112729628A - Hypersensitive flexible sensor and preparation method thereof - Google Patents

Abstract

Translated fromChinese

本发明涉及一种超敏柔性传感器及其制备方法，所述超敏柔性传感器包括柔性基底层以及柔性压敏层；所述柔性基底层具有导电性，用于传输压力响应信号；所述柔性压敏层用于放大并传输所述压力响应信号；所述柔性压敏层包括微纳结构阵列，所述柔性基底层叠设在所述微纳结构阵列上。通过在柔性基底层和柔性压敏层之间设置微纳阵列结构，利用微纳结构具有微小压力下易变形的特点，柔性基底层和柔性压敏层在压力作用下的接触面积显著增加，降低了接触电阻，从而获得较大电阻变化率，从而使得超敏柔性传感器的灵敏度较高，具有较短的响应时间。

The invention relates to an ultra-sensitive flexible sensor and a preparation method thereof. The ultra-sensitive flexible sensor comprises a flexible base layer and a flexible pressure-sensitive layer; the flexible base layer has conductivity and is used for transmitting pressure response signals; the flexible pressure The sensitive layer is used for amplifying and transmitting the pressure response signal; the flexible pressure sensitive layer includes a micro-nano structure array, and the flexible substrate is stacked on the micro-nano structure array. By arranging a micro-nano array structure between the flexible base layer and the flexible pressure-sensitive layer, the micro-nano structure is easily deformed under small pressure, and the contact area between the flexible base layer and the flexible pressure-sensitive layer under pressure is significantly increased and reduced. Therefore, the contact resistance is improved, so that a larger resistance change rate can be obtained, so that the ultrasensitive flexible sensor has a higher sensitivity and a shorter response time.

Description

Hypersensitive flexible sensor and preparation method thereof

Technical Field

The invention relates to the technical field of bionic sensing, in particular to a hypersensitive flexible sensor and a preparation method thereof.

Background

The flexible pressure sensor is used as a sensing device which is most widely applied, can sense or monitor the change of the external pressure, has the characteristics of simple preparation process, high sensitivity, flexible deformation and the like, and has wide and important application in the emerging fields of software robots, wearable electronic products, health medical treatment, human-computer interaction and the like.

The flexible sensor is also widely used for monitoring various functional data of a human body, and has higher requirements on the performance of the flexible sensor, the sensitivity of the piezoresistive flexible pressure sensor is generally lower at present, the sensing working range is smaller, the sensor is insensitive to tiny vibration such as heartbeat and pulse, and the response time is generally longer.

Therefore, the prior art is still subject to further improvement.

Disclosure of Invention

In view of the above-mentioned deficiencies of the prior art, the present invention aims to provide a hypersensitive flexible sensor and a method for manufacturing the same, which aims to solve the problems of low sensitivity and long response time of the conventional piezoresistive flexible pressure sensor.

In a first aspect of the embodiments of the present invention, there is provided a hypersensitive flexible sensor, including: a flexible substrate layer and a flexible pressure sensitive layer; the flexible substrate layer has electrical conductivity for transmitting a pressure response signal; the flexible pressure-sensitive layer is used for amplifying and transmitting the pressure response signal; the flexible pressure-sensitive layer comprises a micro-nano structure array, and the flexible substrate is arranged on the micro-nano structure array in a laminated mode.

Optionally, the hypersensitive flexible sensor further comprises a conductive wire, wherein the conductive wire comprises a first conductive wire electrically connected to the flexible substrate layer and a second conductive wire electrically connected to the flexible pressure-sensitive layer.

Optionally, the hypersensitive flexible sensor, wherein the material of the flexible substrate layer is selected from one of polyvinyl alcohol, polyester, polyimide, polyethylene naphthalate and polydimethylsiloxane having conductivity.

Optionally, the hypersensitive flexible sensor, wherein the micro-nano structure array is a pyramid-shaped micro-nano structure array.

Optionally, the hypersensitive flexible sensor, wherein each pyramid-shaped micro-nano structure in the pyramid-shaped micro-nano structure array comprises a honeycomb-shaped substructure.

Optionally, in the hypersensitive flexible sensor, in the pyramid-shaped micro-nano structure array, the length of the bottom edge of each pyramid-shaped micro-nano structure is 10 to 100um, and the height of each pyramid-shaped micro-nano structure is 10 to 100 um.

Optionally, in the hypersensitive flexible sensor, in the pyramid-shaped micro-nano structure array, a distance between adjacent pyramid-shaped micro-nano structures is 10 to 100 um.

Optionally, the hypersensitive flexible sensor, wherein the voids of the honeycomb substructure are between 100nm and 1 um.

In a second aspect, a method for preparing a hypersensitive flexible sensor comprises:

providing a flexible substrate layer, the flexible substrate layer having electrical conductivity;

preparing a negative mould structure, and pouring a flexible material into the negative mould structure for film pouring to obtain a semi-finished product;

dissolving the negative mold structure in the semi-finished product to obtain a flexible pressure-sensitive layer, wherein the flexible pressure-sensitive layer comprises a micro-nano structure;

and laminating the flexible substrate on the micro-nano structure to obtain the hypersensitive flexible sensor.

Optionally, the preparation method of the hypersensitive flexible sensor, wherein the preparing of the negative mold structure, and the pouring of the flexible material into the negative mold structure to obtain a semi-finished product specifically include:

establishing a positive mode structure of the pyramid three-dimensional model, and establishing a negative mode structure of the pyramid three-dimensional model through Boolean operation of modeling software;

carrying out micro-nano processing on the pyramid three-dimensional model negative structure to obtain a micro-nano pyramid three-dimensional model negative structure;

and injecting a flexible material into the micro-nano pyramid three-dimensional model negative structure for film inversion to obtain a semi-finished product.

Has the advantages that: the invention provides a hypersensitive flexible sensor, which is characterized in that a micro-nano array structure is arranged between a flexible substrate layer and a flexible pressure-sensitive layer, the micro-nano structure has the characteristic of easy deformation under micro pressure, the contact area of the flexible substrate layer and the flexible pressure-sensitive layer under the action of pressure is obviously increased, the contact resistance is reduced, and therefore a larger resistance change rate is obtained, the sensitivity of the hypersensitive flexible sensor is higher, and the response time is shorter.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without any inventive work.

FIG. 1 is a schematic structural diagram of a hypersensitive flexible sensor provided by an embodiment of the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is a perspective view of a flexible pressure sensitive layer provided by an embodiment of the present invention;

FIG. 4 is a front view of a flexible pressure sensitive layer provided by an embodiment of the present invention;

FIG. 5 is a top view of a flexible pressure sensitive layer provided by an embodiment of the present invention;

FIG. 6 is a perspective view of a flexible substrate layer provided by an embodiment of the present invention;

FIG. 7 is a perspective view of a pyramid structure provided in an embodiment of the present invention;

FIG. 8 is a front view of a pyramid structure provided by an embodiment of the present invention;

FIG. 9 is a 45 degree offset view of the pyramid structure of FIG. 7;

fig. 10 is a top view of a pyramid structure according to an embodiment of the present invention.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

At present, the sensitivity of the piezoresistive flexible pressure sensor is generally low, the sensing working range is small, the sensor is insensitive to tiny vibration such as heartbeat and pulse, the response time is generally long, and the flexible sensor still has a huge development space in the aspect of light weight design at present.

The inventor researches and discovers that the lightweight characteristic of the bird feather shaft is derived from the core of the medullary in the bird feather shaft, the medullary is composed of cellular cavities, the walls of the cavities are connected with each other through collagen fibers to jointly construct a spatial polygonal latticed structure, and the cavities are filled with extremely light foam. When the plume is subjected to external wind load, one part of stress is absorbed through foam compression, the other part of stress is transmitted between the chamber walls, the stress area is increased through the compression deformation of the chamber walls, and finally stress homogenization is realized. The scheme of the space grid-shaped structure for realizing the uniform stress distribution and the light weight of organisms provides a good idea for realizing the ultra-light design of the flexible wearable hypersensitive sensor in the technical field of sensing.

In the embodiment of the application, the inventor adopts a bionics technology, the flexible pressure-sensitive layer in the piezoresistive flexible pressure sensor is designed to be the flexible pressure-sensitive layer comprising the micro-nano structure array, the micro-nano structure is utilized to deform easily under micro pressure, so that the contact area of the flexible substrate layer and the flexible pressure-sensitive layer is increased obviously under the action of pressure, the contact resistance is reduced, the characteristic of large resistance change rate is obtained, and the hypersensitive flexible sensor is prepared. The hypersensitive flexible sensor has high sensing sensitivity and a wide sensing working range.

The present disclosure will be further explained by the following description of embodiments with reference to the attached drawings.

Referring to fig. 1, fig. 1 is a perspective view of a hypersensitivity flexible sensor according to an embodiment of the present invention, as shown in the figure, the hypersensitivity flexible sensor includes: the flexible pressure-sensitive adhesive comprises aflexible base layer 10 and a flexible pressure-sensitive layer 20, wherein theflexible base layer 10 is overlapped on the flexible pressure-sensitive layer 20.

In this embodiment, theflexible substrate layer 10 is mainly used for transmitting the pressure response signal, and the flexible pressure-sensitive layer is used for amplifying and transmitting the pressure response signal transmitted by the flexible substrate layer. The flexible pressure-sensitive layer 20 comprises amicro-nano structure array 21, and the characteristic that themicro-nano structure array 21 is easy to deform under micro pressure is utilized, so that the hypersensitive flexible sensor has high detection sensitivity.

In this embodiment, the material of theflexible substrate layer 10 may be polyvinyl alcohol (PVA), Polyester (PET), Polyimide (PI), polyethylene naphthalate (PEN), Polydimethylsiloxane (PDMS), etc., and it should be noted that, since the flexible substrate layer is used for transmitting a pressure response signal, it is required to have conductivity, and the conductivity may be processed by conductivity, so that the material for preparing the flexible substrate layer has conductivity, wherein the method for making the flexible material conductive includes mixing the conductive material before molding, and making the flexible material conductive by chemical vapor deposition, ion sputtering, physical vapor deposition, etc. after molding. The thickness of the flexible substrate layer can be set according to actual needs, and for example, the thickness of the flexible substrate layer is 20-40 um.

In an implementation manner of this embodiment, with reference to fig. 2 to fig. 7, themicro-nano structure array 21 is a pyramid-shaped micro-nano structure array.

Specifically, in the pyramid-shaped micro-nano structure array, each pyramid-shaped micro-nano structure comprises a honeycomb-shaped substructure. In other words, the flexible pressure-sensitive layer is a flexible pressure-sensitive layer with a pyramid-shaped micro-structure array, and the pyramid-shaped micro-nano structure array is integrally formed on the flexible material, wherein each pyramid has a honeycomb structure. Wherein, each pyramid-shaped main body is built by a space hexagonal grid structure. By adopting the pyramid-shaped main body built by the space hexagonal grid structure, more obvious contact area increment can be obtained under the same pressure, and higher resistance change rate under the same pressure condition is realized, so that the sensing sensitivity of the hypersensitive flexible sensor can be improved.

In this embodiment, the voids of the honeycomb structure (also referred to as a honeycomb substructure) may be 100nm to 200nm, 200nm to 300nm, 300nm to 400nm, 400nm to 500nm, 500nm to 600nm, 600nm to 700nm, 700nm to 800nm, 800nm to 900nm, 900nm to 1 um.

In an implementation manner of the embodiment, the bottom edge length of the pyramid can be 10um to 20um, 20um to 30um, 30um to 40um, 40um to 50um, 50um to 60um, 60um to 70um, 70um to 80um, 80um to 90um, 90um to 100 um. The pyramid height of each pyramid can be 10um to 40um, 40um to 70um, 70um to 100 um.

Further, the distance between any two adjacent pyramid-shaped micro-nano structures can be 10um to 15um, 15um to 20um, 20um to 25um, 25um to 30um, 30um to 35um, 35um to 40um, 40um to 45um, 45um to 50um, 50um to 55um, 55um to 60um, 60um to 65um, 65um to 70um, 70um to 75um, 75um to 80um, 80um to 85um, 85um to 90um, 90um to 95um, 95um to 100 um.

In one implementation of this embodiment, the hypersensitive flexible sensor further comprises a lead 30, it being understood that the lead is provided with two wires, namely the first lead and the second lead, electrically connecting the first lead and the second lead with the flexible substrate layer and the flexible pressure sensitive layer, respectively. The hypersensitive flexible sensor is powered by an external power supply.

Based on the above-mentioned hypersensitivity flexible sensor, in combination with the specific embodiment of the present invention, there is also provided a preparation method of the hypersensitivity flexible sensor, wherein the preparation method comprises the following steps:

s10, providing a flexible substrate layer, wherein the flexible substrate layer has conductivity;

s20, preparing a negative mould structure, and pouring a flexible material into the negative mould structure for film pouring to obtain a semi-finished product;

s30, dissolving the negative mode structure in the semi-finished product to obtain a flexible pressure-sensitive layer, wherein the flexible pressure-sensitive layer comprises a micro-nano structure;

and S40, stacking the flexible substrate on the micro-nano structure to obtain the hypersensitive flexible sensor.

Specifically, when the hypersensitive flexible sensor shown in fig. 1 is prepared, the material of the flexible substrate layer is selected from polyvinyl alcohol (PVA), Polyester (PET), Polyimide (PI), polyethylene naphthalate (PEN), Polydimethylsiloxane (PDMS), which have conductivity. Illustratively, the conductive material-doped PET particles can be dissolved in an organic solvent to prepare a PET slurry, and the PET slurry is coated on a substrate by coating, and dried to obtain the conductive PET flexible film.

In this embodiment, the step S20 specifically includes: establishing a micro-nano lightweight pyramid three-dimensional model positive model structure, and establishing a lightweight pyramid three-dimensional model negative model structure through Boolean operation of modeling software (such as UG software, Solidworks and the like). And preparing a micro-nano lightweight pyramid three-dimensional model negative mode structure by micro-nano processing technologies such as 3D printing and laser etching. Pouring a flexible material into the negative mold structure of the micro-nano level lightweight pyramid three-dimensional model by utilizing the castability of the flexible material for film pouring, dissolving the negative mold structure through a solvent or heating after curing, simultaneously ensuring that the cured flexible material is not damaged, and finally obtaining the integrally molded pyramid-shaped micro-nano structure array on the flexible material. The structure of the pyramid-shaped micro-nano structure array is shown in fig. 7 to 10. The material of the flexible pressure-sensitive layer may be selected from polyvinyl alcohol (PVA), Polyester (PET), Polyimide (PI), polyethylene naphthalate (PEN), and Polydimethylsiloxane (PDMS), which have conductivity.

In an implementation manner of the present embodiment, after step S40, the method further includes: and (4) connecting the flexible substrate layer and the flexible pressure-sensitive layer to an enameled wire, buckling the flexible pressure-sensitive layer on the flexible substrate layer and packaging to obtain the hypersensitive flexible sensor. It is easy to understand that after the flexible pressure-sensitive layer is buckled on the flexible substrate layer, the obtained hypersensitive flexible sensor can be encapsulated by adopting sealant, and the damage of foreign matters to the micro-nano structure array can be prevented through encapsulation. Namely, the hypersensitive flexible device is protected by adding an encapsulation layer.

In summary, the present invention provides a hypersensitive flexible sensor and a method for preparing the same, wherein the hypersensitive flexible sensor comprises a flexible substrate layer and a flexible pressure-sensitive layer; the flexible substrate layer has electrical conductivity for transmitting a pressure response signal; the flexible pressure-sensitive layer is used for amplifying and transmitting the pressure response signal; the flexible pressure-sensitive layer comprises a micro-nano structure array, and the flexible substrate is arranged on the micro-nano structure array in a laminated mode.

From the aspect of sensing function, the bionic ultralight hypersensitive flexible wearable sensing device provided by the embodiment of the invention can realize hypersensitive sensing of micro vibration such as pulse and heartbeat, and the sensing working range and mechanical sensitivity of the sensor are greatly increased. Particularly, when the traditional pyramid is processed into the pyramid-shaped main body built by the space hexagonal grid structure, under the same pressure, more obvious contact area increment can be obtained, and higher resistance change rate under the same pressure condition is realized, so that the sensing sensitivity is improved.

Compared with the known porous flexible material processing technology, the light-weight honeycomb structure provided by the embodiment of the invention has controllable size and quantity, and realizes great weight reduction of the micro-nano level flexible sensing device.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.

Claims (10)

Translated fromChinese

1.一种超敏柔性传感器，其特征在于，包括：柔性基底层以及柔性压敏层；所述柔性基底层具有导电性，用于传输压力响应信号；所述柔性压敏层用于放大并传输所述压力响应信号；所述柔性压敏层包括微纳结构阵列，所述柔性基底层叠设在所述微纳结构阵列上。1. An ultrasensitive flexible sensor, characterized in that it comprises: a flexible base layer and a flexible pressure-sensitive layer; the flexible base layer has conductivity and is used for transmitting pressure response signals; the flexible pressure-sensitive layer is used for amplifying and The pressure response signal is transmitted; the flexible pressure-sensitive layer includes an array of micro-nano structures, and the flexible substrate is stacked on the array of micro-nano structures.2.如权利要求1所述的超敏柔性传感器，其特征在于，还包括导线，所述导线包括与所述柔性基底层电连接的第一导线，与所述柔性压敏层电连接的第二导线。2 . The ultra-sensitive flexible sensor according to claim 1 , further comprising a wire, the wire comprises a first wire electrically connected to the flexible base layer, and a second wire electrically connected to the flexible pressure-sensitive layer. 3 . Two wires.3.如权利要求1所述的超敏柔性传感器，其特征在于，所述柔性基底层的材料选自具有导电性的聚乙烯醇、聚酯、聚酰亚胺、聚萘二甲酯乙二醇酯、聚二甲基硅氧烷中的一种。3. The supersensitive flexible sensor according to claim 1, wherein the material of the flexible base layer is selected from the group consisting of conductive polyvinyl alcohol, polyester, polyimide, polyethylene naphthalene A kind of alcohol ester and polydimethylsiloxane.4.如权利要求1所述的超敏柔性传感器，其特征在于，所述微纳结构阵列为具有金字塔状的微纳结构阵列。4 . The ultrasensitive flexible sensor according to claim 1 , wherein the micro-nano structure array is a pyramid-shaped micro-nano structure array. 5 .5.如权利要求4所述的超敏柔性传感器，其特征在于，所述金字塔状的微纳结构阵列中，每一所述金字塔状的微纳结构均包括蜂窝状子结构。5 . The ultra-sensitive flexible sensor according to claim 4 , wherein, in the pyramid-shaped micro-nano structure array, each of the pyramid-shaped micro-nano structures comprises a honeycomb-shaped substructure. 6 .6.如权利要求4所述的超敏柔性传感器，其特征在于，所述金字塔状微纳结构阵列中，每一所述金字塔状的微纳结构的底边长度为10-100um，每一所述金字塔状的微纳结构的塔高为10-100um。6 . The ultrasensitive flexible sensor according to claim 4 , wherein in the pyramid-shaped micro-nano structure array, the base length of each of the pyramid-shaped micro-nano structures is 10-100 μm, and each The tower height of the pyramid-shaped micro-nano structure is 10-100um.7.如权利要求4所述的超敏柔性传感器，其特征在于，所述金字塔状微纳结构阵列中，相邻所述金字塔状的微纳结构的间距为10-100um。7 . The ultra-sensitive flexible sensor according to claim 4 , wherein, in the pyramid-shaped micro-nano structure array, the spacing between the adjacent pyramid-shaped micro-nano structures is 10-100 um. 8 .8.如权利要求5所述的超敏柔性传感器，其特征在于，所述蜂窝状子结构的空隙为100nm-1um。8 . The ultra-sensitive flexible sensor according to claim 5 , wherein the gap of the honeycomb substructure is 100 nm-1 um. 9 .9.一种权利要求1所述的超敏柔性传感器的制备方法，其特征在于，包括：9. a preparation method of the supersensitive flexible sensor of claim 1, is characterized in that, comprising:提供柔性基底层，所述柔性基底层具有导电性；providing a flexible base layer, the flexible base layer having electrical conductivity;制备负模结构，向所述负模结构中加注柔性材料进行倒膜，得到半成品；preparing a negative mold structure, and pouring a flexible material into the negative mold structure to perform film pouring to obtain a semi-finished product;对所述半成品中的所述负模结构进行溶解，得到柔性压敏层，所述柔性压敏层包括微纳结构；dissolving the negative mold structure in the semi-finished product to obtain a flexible pressure-sensitive layer, and the flexible pressure-sensitive layer includes a micro-nano structure;将所述柔性基底层叠设在所述微纳结构上，得到超敏柔性传感器。The flexible substrate is laminated on the micro-nano structure to obtain an ultra-sensitive flexible sensor.10.如权利要求9所述的超敏柔性传感器的制备方法，其特征在于，所述制备负模结构，向所述负模结构中加注柔性材料进行倒膜，得到半成品，具体包括：10 . The method for preparing a supersensitive flexible sensor according to claim 9 , wherein, in the preparation of the negative mold structure, the negative mold structure is filled with a flexible material to perform film pouring to obtain a semi-finished product, specifically comprising: 10 .建立金字塔三维模型正模结构，通过建模软件布尔操作，建立金字塔三维模型负模结构；Establish the positive model structure of the three-dimensional pyramid model, and establish the negative model structure of the three-dimensional pyramid model through the Boolean operation of the modeling software;对所述金字塔三维模型负结构进行微纳加工，得到微纳级金字塔三维模型负结构；Micro-nano processing is performed on the negative structure of the pyramid three-dimensional model to obtain the negative structure of the three-dimensional pyramid model at the micro-nano level;向所述微纳级金字塔三维模型负结构中加注柔性材料进行倒膜，得到半成品。A flexible material is poured into the negative structure of the micro-nano-level pyramid three-dimensional model to perform film pouring to obtain a semi-finished product.

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