CN111227812A - All-fiber-based flexible sensor and preparation method and application thereof - Google Patents

Abstract

The invention discloses an all-fiber-based flexible sensor and a preparation method and application thereof. The invention adopts elastic conductive yarn, wraps the electrode layer of the stress sensor in the sensing layer by a rope knitting method to prepare the 'skin-core structure' linear sensing material which integrates sensing and electrode compounding, can be further directly mixed with common yarn or linear elastomer to be woven into a piece to be used as a flexible pressure sensing electronic device, is applied to the fields of detecting human body physiological health (pulse) and full range motion (facial expression, sound production, joint motion) and the like, and has the characteristics of simple structure, high stability, simple preparation process, good reproducibility, high detection sensitivity and the like.

Description

An all-fiber-based flexible sensor and its preparation method and application

technical field

The invention relates to the technical field of flexible sensors, in particular to an all-fiber-based flexible sensor and a preparation method and application thereof.

Background technique

With the rapid development of artificial intelligence and the popularization of smart terminals, wearable electronic devices present a huge market prospect. As the core part of artificial flexible electronic devices, flexible stress sensors have great application potential in the fields of human clinical diagnosis, health assessment, health monitoring, virtual electronics, flexible touch screens, flexible electronic skins, and even industrial robots. Whether it can achieve high resolution, high sensitivity, fast response, low-cost manufacturing and complex signal detection is the key to whether flexible wearable electronic devices can be widely promoted. The traditional flexible sensing materials are mostly polymer-based flexible films. Due to the limitations of the materials themselves, they can only achieve partial flexibility, which limits their development and application. Therefore, the development of fully flexible sensing materials has important research significance.

At present, the mainstream way to manufacture flexible stress sensors is to convert the deformation of the sensor into a change in resistance value, that is, a piezoresistive stress sensor. One of the more commonly used preparation methods is to embed or cover a layer of conductive material on the surface of the flexible substrate to obtain a multi-layered strain sensor. The conductive material can be a metal film or a conductive nanomaterial assembled through various processes to obtain a conductive thin film. The uniformity of such conductive films is not high, and the reproducibility of the obtained pressure sensor is poor. In addition, the traditional pressure sensing device needs a three-layer structure (sensing layer, electrode layer, sensing layer) to realize the sensing effect, and its composition structure is relatively complex, so the repeatability is poor, which limits the promotion of diversified pressure sensors. and application.

In addition, the base material of the traditional flexible stress sensor is an elastic film with a flat surface, such as polymethylvinylsiloxane (PDMS), Ecoflex, Dragon skin, rubber, etc., and the conductive layers embedded or covered on its surface are all flat structures . The sensors with such a planar structure generally have the shortcomings that the sensitivity is not high enough and it is difficult to detect small deformations, which limits its development and application. Therefore, a novel stress sensor with high sensitivity and simple fabrication process is urgently needed.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a full-fiber-based flexible sensor and a preparation method and application thereof in view of the problems existing in the prior art, using elastic conductive yarn, and wrapping the electrode layer of the stress sensor in the sensing layer by the braiding method , in order to prepare a "skin-core structure" linear sensing material that integrates sensing and electrodes, and it can be further directly mixed with ordinary yarn or linear elastomer into sheets as flexible pressure sensing electronics The device is used to detect human physiological health (pulse) and full-range motion (facial expression, vocalization, joint movement), etc., and the linear sensing material has simple structure, high stability, simple preparation process and good reproducibility , High detection sensitivity.

For achieving the above object, the technical scheme adopted in the present invention is:

An all-fiber-based flexible sensor, the all-fiber-based flexible sensor includes an elastic conductive rope core and a sensing layer woven by conductive yarns and wrapped around the outer periphery of the elastic conductive rope core, the elastic conductive rope core has low resistance on the sensing layer resistance.

As a further limitation of the above solution, the elastic conductive rope core is formed by twisting and weaving a plurality of conductive yarns, and the resistance of the elastic conductive rope core is lower than 2-8% of the resistance of the sensing layer.

As a further limitation of the above solution, the diameter of the elastic conductive rope core is 100-1000 μm, and the elongation is greater than or equal to 0.01%.

As a further limitation of the above solution, the length of the all-fiber-based flexible sensor is greater than or equal to 5 cm, the diameter is 0.1-5 mm, the elongation is greater than or equal to 0.01%, and the diameter of the conductive yarn in the all-fiber-based flexible sensor is 100～ 1500μm.

As a further limitation of the above solution, the conductive yarns include, but are not limited to, one or a combination of blended yarns or plated yarns.

As a further limitation of the above scheme, the blended yarn is prepared by blending common fibers with conductive fibers; the common fibers are one of natural fibers, synthetic fibers, regenerated fibers, inorganic fibers and man-made fibers; the conductive fibers The fibers include one or more of metal-based conductive fibers, inorganic-based conductive fibers, organic-based conductive fibers, composite-based conductive fibers, doped-based composite fibers, or coating-based composite fibers.

As a further limitation of the above scheme, the natural fibers include, but are not limited to, one or more of cotton fibers, hemp fibers, and silk fibers; the synthetic fibers include, but are not limited to, polyester, spandex, vinylon, and polypropylene fibers. One or more; the regenerated fibers include but are not limited to one or more of viscose fiber and soybean fiber; the inorganic fibers include but are not limited to glass fibers.

As a further limitation of the above solution, the metal-based conductive fibers include but are not limited to metal fibers formed by any one or more of gold, silver, copper, iron, aluminum, and stainless steel; the inorganic-based conductive fibers include but are not limited to Not limited to any one or more of graphite fibers, carbon fibers, silicon fibers, and carbon nanotube fibers; the organic conductive fibers include ordinary fibers and conductive polymers supported on the ordinary fibers; the composite Conductive fibers include but are not limited to fibers made of any two or more of the metal fibers, inorganic conductive fibers, organic conductive fibers and ordinary fibers; the doped composite fibers are made of thermoplastic materials and composite fibers. After the conductive materials are blended, they are prepared by melt spinning, wet spinning, dry spinning or electrospinning; the plated composite fibers are prepared by coating the surface of thermoplastic fibers with conductive materials.

As a further limitation of the above solution, the thermoplastic material includes, but is not limited to, one of polyurethane (PU), polycarbonate (PC), nylon (PA), polyethylene terephthalate (PET) or A variety of; the thermoplastic fiber is obtained by melt spinning or wet spinning of the thermoplastic material.

As a further limitation of the above solution, the coated yarn includes a common yarn and a conductive material loaded on the common yarn after coating.

As a further limitation of the above scheme, the conductive material is selected from single-wall/multi-wall carbon nanotubes, graphene, graphene oxide, carbon black, graphite microplates, metal nanoparticles, metal nanowires/sheets, liquid metal, metal One of oxide powder, conductive titanium dioxide, ionic liquid or conductive polymer; the conductive polymer is selected from polyaniline, polythiophene, polypyrrole, polyacetylene, polyphenylene sulfide, polyparaphenylene, polyphenylene One or more of aniline derivatives, polythiophene derivatives and polypyrrole derivatives.

Another object of the present invention is to provide the described preparation method of a full-fiber-based flexible sensor, comprising the following steps:

S1. Wind the conductive yarn for the sensing layer on the braided bobbin respectively with a bobbin winding machine to obtain the braided rope strand bobbin for the sensing layer;

S2, twist and weave a plurality of conductive yarns into a bundle of rope cores, and then wind the rope cores with conductive yarns on the braided bobbin through a bobbin winding machine, thereby obtaining a braided rope core bobbin;

S3. Insert the braided rope strand bobbin for the sensing layer on the spindle rod of the 2-20-spindle rope braiding machine; and the rope core bobbin is placed on the iron ingot at the lower part of the rope braiding machine, and the conductive wire on the rope core bobbin The yarn is introduced from the central hole in the lower part of the braiding machine, drawn out from the braided yarn guide hole, and collected with the braided rope strands for the sensing layer;

S4. Shake the hand wheel, the spindle rotates to weave into the beginning of the mixed braid of the linear sensing material; wrap the beginning of the mixed braid of the linear sensing material 5 to 7 times around the traction plate, close the clutch, and start the braiding to process the thread. Shape sensing material mixed braid.

As a further limitation of the above scheme, in step S4, the tension balance between the strands is maintained during weaving, and the braided rope strands for the sensing layer are cross-braided to form a linear sensing material mixed braided surface. The elastic conductive rope core of the sensing material is filled in the center of the linear sensing material mixed braided rope; finally, the braided linear sensing material mixed braided rope is drawn out from the rope braiding machine, and wound on the winding roller to be processed into a Wire-like sensing material mixed braid.

Another object of the present invention is to provide the application of the all-fiber-based flexible sensor, and the all-fiber-based flexible sensor is mixed with ordinary yarn or linear elastomer into a sheet to make a large-area flexible pressure sensing electronic device.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention uses elastic conductive yarn, and wraps the electrode layer of the stress sensor in the sensing layer by the braiding method to prepare a "skin-core structure" linear sensing material that integrates sensing and electrodes. , and can be further blended with ordinary yarn or linear elastomer into a sheet as a flexible pressure sensing electronic device, which can be used to detect human physiological health (pulse) and full range of motion (facial expression, vocalization, joint movement) ) and other fields, and the linear sensing material has the characteristics of simple structure, high stability, simple preparation process, good reproducibility, and high detection sensitivity.

(2) The present invention adopts the rope knitting method to realize the regulation of the pressure sensing performance by adjusting the variables such as yarn type, yarn fineness, yarn twist and yarn content, so as to realize the fast sensing performance according to the required pressure. The wire-like sensing materials with excellent performance are prepared, which will help to promote the development of smart wearable electronic devices.

(3) The principle of realizing the pressure sensing performance of the all-fiber flexible sensor provided by the present invention and the preparation method thereof is that when the sensing layer of the linear sensing material is subjected to pressure, the deformation occurs, and the thickness of the sensing area changes accordingly. The resistance changes, and the resistance changes, which can be converted into a pressure signal by testing the resistance. The performance of the linear sensing material of the invention is stable, reliable and easy to control, thereby providing an effective way for the preparation of pressure sensors with diversified performances.

Description of drawings

FIG. 1 is a schematic structural diagram of an all-fiber flexible sensor and a preparation method thereof of the present invention.

Figure 2 shows the pressure-resistance curves obtained by cross-superimposing two full-fiber-based flexible sensors prepared in Example 1 under different pressures.

FIG. 3 is a graph showing the pressure distribution presented by the all-fiber-based flexible sensing pad obtained in Example 38 to detect the force-bearing point of the human foot.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention, and are not intended to limit the present invention. ; Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

In the following specific embodiments of the present invention, the sensing performance test method of the prepared full-fiber-based flexible sensor is:

Connect the electrode layer of the "skin-core structure" linear sensing material prepared by the braiding method to the working electrode of the electrochemical workstation, apply a voltage of 0.5V to the linear sensing material, and use mark-10 to Different pressures were applied, and the corresponding pressure-current curves were obtained from the test.

The present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings.

Example 1

Referring to FIG. 1 , this embodiment provides an all-fiber-based flexible sensor, the all-fiber-based flexible sensor includes an elastic conductive rope core 1 and a sensing layer woven by conductive yarns and wrapped around the outer periphery of the elastic conductive rope core 1 2. The resistance of the elastic conductive rope core 1 is lower than 5% of the resistance of the sensing layer 2 .

The elastic conductive rope core is formed by twisting and weaving a plurality of conductive yarns, the diameter of the elastic conductive rope core is 600 μm, and the elongation rate is greater than or equal to 0.01%.

The length of the all-fiber-based flexible sensor is 5 cm, the diameter is 2 mm, the elongation is greater than or equal to 0.01%, and the diameter of the conductive yarn in the all-fiber-based flexible sensor is 300 μm.

The conductive yarn is a blended yarn, which is prepared by blending polyester fiber and stainless steel fiber at a ratio of 5:1.

The above-mentioned preparation method of an all-fiber-based flexible sensor comprises the following steps:

S1. Wind the conductive yarn for the sensing layer on the braided bobbin respectively with a bobbin winding machine to obtain the braided rope strand bobbin for the sensing layer;

S2, twist and weave a plurality of conductive yarns into a bundle of rope cores, and then wind the rope cores with conductive yarns on the braided bobbin through a bobbin winding machine, thereby obtaining a braided rope core bobbin;

S3. Insert the braided rope strand bobbin for the sensing layer on the spindle of the 16-spindle braiding machine; and the rope core bobbin is placed on the iron ingot at the lower part of the rope braiding machine, and the conductive yarn on the rope core bobbin Lead in from the central hole at the lower part of the braiding machine, lead out from the braided yarn guide hole, and gather with the braided rope strands for the sensing layer;

S4. Shake the hand wheel, the spindle rotates to weave into the beginning of the mixed braid of the linear sensing material; wrap the beginning of the mixed braid of the linear sensing material around the traction plate for 5 to 7 times, close the clutch, start the braiding, and keep it during braiding. The tension between the strands is balanced. The sensing layer is made of braided rope strands that are crossed to form a hybrid braided surface of linear sensing material, and the elastic conductive rope core of the linear sensing material is filled with the linear sensing material. The center of the material mixed braided rope; finally, the braided linear sensing material mixed braided rope is drawn out from the braiding machine, and wound on the winding roller to process the linear sensing material mixed braided rope.

The all-fiber-based flexible sensors prepared in the two basic examples are cross-superimposed, and the pressure-resistance curves obtained by testing under different pressures are shown in Fig. 2 . It can be seen from the results in the figure that with the increase of pressure, the resistance of the prepared sensing material decreases.

Example 2-5

Embodiments 2-5 provide an all-fiber-based flexible sensor. Compared with Embodiment 1, the difference is that the diameter of the elastic conductive rope core is changed to test the breaking strength of a single sensing material, and other operations are the same. , which will not be repeated here, the specific experimental conditions, parameters and performance test results are shown in the following table.

It can be seen from the results in the above table that the diameter of the elastic conductive rope core in the linear sensing material affects the breaking strength and the sensing performance of the obtained coating linear sensing material. Based on the data in the table, it can be seen that under the condition that other conditions remain unchanged, with the increase of the diameter of the yarn core, the breaking strength of the obtained full-fiber flexible sensor and its preparation method increases, and the detection range value (detection upper limit) increases. Sensitivity increases.

Examples 6-9

Embodiments 6-9 provide an all-fiber-based flexible sensor. Compared with Embodiment 1, the difference is that the diameter of the conductive yarn in the all-fiber-based flexible sensor is changed, and other operations are the same, which will not be repeated here. To repeat, the specific experimental conditions parameters and performance test results are shown in the following table.

It can be seen from the results in the above table that the diameter of the conductive yarn in the linear sensing material directly affects the breaking strength and the sensing performance of the obtained coated linear sensing material. Based on the data in the table, it can be seen that under the condition that other conditions remain unchanged, with the increase of the diameter of the conductive yarn, the breaking strength of the prepared full-fiber flexible sensor increases, the detection range value (detection upper limit) increases, and the sensitivity increases with the conductivity. The increase of yarn diameter showed a trend of first increase and then decrease.

Examples 10-13

Embodiments 10-13 provide an all-fiber-based flexible sensor. Compared with Embodiment 1, the difference is that the diameter of the all-fiber-based flexible sensor is changed, and other operations are the same, which will not be repeated here. The condition parameters and performance test results are shown in the table below.

It can be seen from the results in the above table that the diameter of the all-fiber-based flexible sensor in the linear sensing material directly affects the breaking strength and sensing performance of the obtained linear sensing material with a coated structure. Based on the data in the table, it can be seen that under the condition that other conditions remain unchanged, with the increase of the diameter of the linear sensing material, the fracture strength of the obtained all-fiber-based flexible sensor increases, the detection range value (detection upper limit) increases, and the sensitivity increases with the increase of the sensitivity. The increase of the rope diameter showed a trend of increasing first and then decreasing. Therefore, in the actual application process, the diameter of the wire-shaped sensing material can be adjusted according to the requirements to obtain a wire-shaped full-fiber-based flexible sensor with different breaking strength and pressure sensing performance.

Examples 14-29

Embodiments 14-29 provide an all-fiber-based flexible sensor. Compared with Embodiment 1, the difference lies in the type of the conductive yarn in the all-fiber-based flexible sensor, and other operations are the same. To repeat, the specific experimental conditions parameters and performance test results are shown in the following table.

It can be seen from the results in the above table that when the diameter of the braided rope is constant, linear sensing materials with different detection upper limit ranges and sensitivities are obtained by adjusting the yarn types. At the same time, by comparing the results in the above table, it can be seen that the materials used in the core and the conductive yarn in the sensing layer have a significant impact on the pressure sensing performance of the prepared all-fiber-based flexible sensor. Therefore, different kinds of conductive yarns can be compounded or the yarns can be coated to prepare linear sensing materials with different detection limits and sensitivities. Therefore, in practical applications, flexible pressure sensing devices with different pressure sensing performances can be obtained by adjusting the yarn types to meet different stress sensing performance requirements.

Examples 30-37

Embodiments 30-37 provide an all-fiber-based flexible sensor. Compared with Embodiment 1, the difference is that the elastic conductive rope core in the all-fiber-based flexible sensor and the conductive wire in the sensing layer are changed. The type of yarn and other operations are the same, and will not be repeated here. The specific experimental parameters and performance test results are shown in the following table.

Among them, the metal conductive yarns are all gold yarns, the inorganic conductive yarns are carbon fiber yarns, the organic conductive yarns are cotton yarns with polypyrrole attached to the surface, and the composite conductive yarns are all polypyrrole attached to the surface. Cotton fiber and carbon fiber blended yarn, ordinary yarn are polyester yarn.

Example rope core sensing layer Detection upper limit (kPa) Sensitivity kPa^-1 30 Metallic Conductive Yarn Organic conductive yarn 400 18.25 31 Inorganic conductive yarn Organic conductive yarn 200 16.23 32 Organic conductive yarn Organic conductive yarn 200 10.25 33 Composite conductive yarn Organic conductive yarn 100 9.23 34 Inorganic conductive yarn Inorganic conductive yarn 200 9.65 35 Organic conductive yarn Composite conductive yarn 150 11.42 36 Inorganic conductive yarn Composite conductive yarn 300 17.22 37 Composite conductive yarn Composite conductive yarn 100 8.36

It can be seen from the above table that when the diameter of the all-fiber-based flexible sensor is constant, linear sensing materials with different detection upper limit ranges and sensitivities are obtained by adjusting the composition of the conductive yarns in the rope core and the sensing layer. Comparing the results of the various examples, it can be seen that the composition of the conductive yarns in the rope core and the sensing layer has a significant impact on the pressure sensing performance of the fabricated all-fiber-based flexible sensing device. Therefore, in the actual application process, the yarn types of the rope core and the sensing layer can be adjusted to obtain a linear all-fiber-based flexible sensor with different sensing properties, so as to meet different stress sensing performance requirements. The promotion and application of chemical pressure sensors provide new directions.

Example 38

Embodiment 38 provides a large-area pressure sensing pad woven from the all-fiber-based flexible sensor obtained in Embodiment 1, and the weaving method is as follows:

Using the woven plain weave structure, the full-fiber-based flexible sensing material prepared in Example 1 and the ordinary yarn (polyester yarn) were periodically fed into the loom at a ratio of 1:5 to form a fabric warp, and the same The proportions of are periodically fed into the loom to form the weft of the fabric, thus constituting a typical plain weave weave up and down. Each warp and weft yarn interweaving point in the plain weave fabric thus prepared is a signal acquisition point, and the electrodes in each full-fiber-based flexible sensor are connected to the acquisition circuit for detecting the force point of the human foot.

Figure 3 shows the result of the pressure distribution map presented by the all-fiber-based flexible sensing pad obtained in this embodiment to detect the force-bearing point of the human foot. From the results presented in the figure, it can be seen that when the human foot presses on the upper part of the sensing pad, the outline of the foot is clearly visible, and it can be clearly seen that the signals collected by the forefoot and heel are more significant. The focus is mainly on the forefoot and heel. This shows that the all-fiber-based flexible sensor prepared by the present invention can be applied to the fields of human clinical diagnosis, health assessment, health monitoring, flexible electronic skin, and even industrial robots, so as to achieve high resolution, high sensitivity, fast response and low cost. performance in manufacturing and complex signal detection.

To sum up, the linear full-fiber-based flexible sensor with a covered structure prepared by the present invention is based on the large specific surface area of the elastic conductive yarn and the excellent performance characteristics of the material. When stimulated by external force, the flexible and highly stretchable nanofiber yarn is The line stress sensor exhibits ultra-high sensitivity and a wide sensing range. In the human body monitoring system, it can be realized from the heart rate monitoring of weak pressure to the limb movement monitoring of high pressure. In addition, the manufacturing process of the present invention is simple and low in cost, which is beneficial to the development of the large-scale commercialized fully flexible stress sensor.

The above are only illustrative examples of the present invention, and are not intended to limit the present invention in any form or substance. It should be pointed out that for those skilled in the art, without departing from the method of the present invention, Several improvements and additions should also be regarded as the protection scope of the present invention; all those skilled in the art, without departing from the spirit and scope of the present invention, make use of the above disclosed technical content to make some changes, modifications and evolutions The equivalent changes of the present invention are all equivalent embodiments of the present invention; meanwhile, any modification, modification and evolution of any equivalent changes made to the above-mentioned embodiments according to the essential technology of the present invention still belong to the protection scope of the present invention.

Claims (14)

1. An all-fiber-based flexible sensor, characterized in that the all-fiber-based flexible sensor comprises an elastic conductive rope core and a sensing layer woven by conductive yarns and wrapped around the periphery of the elastic conductive rope core, and the rope The resistance of the core is lower than the resistance of the sensing layer. 2 . The all-fiber-based flexible sensor according to claim 1 , wherein the elastic conductive rope core is twisted and braided by a plurality of conductive yarns, and the resistance of the elastic conductive rope core is lower than 1-10% of the resistance of the sensing layer. 3 . The all-fiber-based flexible sensor according to claim 1 or 2 , wherein the elastic conductive rope core has a diameter of 100-1000 μm, and an elongation rate of 0.01% or more. 4 . The full-fiber-based flexible sensor according to any one of claims 1-3, characterized in that the full-fiber-based flexible sensor has a length of 5 cm or more, a diameter of 0.1 to 5 mm, and an elongation of greater than or equal to 5 cm. 0.01%, the diameter of the conductive yarn in the all-fiber-based flexible sensor is 100-1500 μm. 5 . The all-fiber-based flexible sensor according to claim 4 , wherein the conductive yarns include but are not limited to one or a combination of blended yarns or plated yarns. 6 . 6 . The all-fiber-based flexible sensor according to claim 5 , wherein the blended yarn is obtained by blending common fibers with conductive fibers; the common fibers are natural fibers, synthetic fibers, regenerated fibers, One of inorganic fibers and man-made fibers; the conductive fibers include metal conductive fibers, inorganic conductive fibers, organic conductive fibers, composite conductive fibers, doped composite fibers or coating composite fibers. variety. 7. A full-fiber-based flexible sensor according to claim 6, wherein the natural fibers include but are not limited to one or more of cotton fibers, hemp fibers, and silk fibers; the synthetic fibers Including but not limited to one or more of polyester, spandex, vinylon, polypropylene; the regenerated fiber includes but not limited to one or more of viscose fiber and soybean fiber; the inorganic fiber includes but not limited to Limited to fiberglass. 8 . The all-fiber-based flexible sensor according to claim 6 , wherein the metal-based conductive fibers include but are not limited to any one or more of gold, silver, copper, iron, aluminum, and stainless steel. 9 . The metal fibers formed by seed; the inorganic conductive fibers include but are not limited to any one or more of graphite fibers, carbon fibers, silicon fibers, and carbon nanotube fibers; the organic conductive fibers include ordinary fibers and The conductive polymer on the common fiber; the composite conductive fiber includes but is not limited to the composite made of any two or more fibers of the metal fiber, inorganic conductive fiber, organic conductive fiber and common fiber fiber; the doped composite fiber is prepared by melt spinning, wet spinning, dry spinning or electrospinning after blending thermoplastic material and conductive material; the coating composite fiber is made of conductive material in The thermoplastic fiber surface is made by coating. 9. An all-fiber-based flexible sensor according to claim 8, wherein the thermoplastic material includes but is not limited to polyurethane (PU), polycarbonate (PC), nylon (PA), polyparaphenylene One or more of ethylene dicarboxylate (PET); the thermoplastic fiber is obtained by melt spinning or wet spinning of the thermoplastic material. 10 . The all-fiber-based flexible sensor according to claim 5 , wherein the coated yarns comprise common yarns and conductive materials loaded on the common yarns after coating. 11 . 11. The all-fiber-based flexible sensor according to claim 8, wherein the conductive material is selected from the group consisting of single-wall/multi-wall carbon nanotubes, graphene, graphene oxide, carbon black, graphite microplates, One of metal nanoparticle, metal nanowire/sheet, liquid metal, metal oxide powder, conductive titanium dioxide, ionic liquid or conductive polymer; the conductive polymer is selected from polyaniline, polythiophene, polypyrrole, One or more of polyacetylene, polyphenylene sulfide, polyparaphenylene, polyaniline derivatives, polythiophene derivatives and polypyrrole derivatives. 12. The preparation method of a full-fiber-based flexible sensor according to any one of claims 1 to 11, characterized in that it comprises the following steps: S1. Wind the conductive yarn for the sensing layer on the braided bobbin respectively with a bobbin winding machine to obtain the braided rope strand bobbin for the sensing layer; S2, twist and weave a plurality of conductive yarns into a bundle of rope cores, and then wind the rope cores with conductive yarns on the braided bobbin through a bobbin winding machine, thereby obtaining a braided rope core bobbin; S3. Insert the braided rope strand bobbin for the sensing layer on the spindle rod of the 2-20-spindle rope braiding machine; and the rope core bobbin is placed on the iron ingot at the lower part of the rope braiding machine, and the conductive wire on the rope core bobbin The yarn is introduced from the central hole in the lower part of the braiding machine, drawn out from the braided yarn guide hole, and collected with the braided rope strands for the sensing layer; S4. Shake the hand wheel, the spindle rotates to weave into the beginning of the mixed braid of the linear sensing material; wrap the beginning of the mixed braid of the linear sensing material 5 to 7 times around the traction plate, close the clutch, and start the braiding to process the thread. Shape sensing material mixed braid. 13. The preparation method of an all-fiber-based flexible sensor according to claim 12, wherein in step S4, the tension balance between the strands is maintained during weaving, and the sensing layer is made of braided strands. The wire-shaped sensing material mixed braided surface is crossed and braided, and the elastic conductive rope core of the linear sensing material is filled in the center of the linear sensing material mixed braid; finally, the braided wire-shaped sensing material is mixed. The rope is drawn out from the rope braiding machine and wound on the take-up roller to be processed into a linear sensor material mixed braided rope. 14. An application of an all-fiber-based flexible sensor, characterized in that, the all-fiber-based flexible sensor according to any one of claims 1-11 or the preparation method according to any one of claims 12-13 is prepared All-fiber-based flexible sensors are mixed with common yarns or linear elastomers to form large-area flexible pressure sensing electronic devices.

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