Heterogeneous fiber sensor

Abstract

The application relates to a heterogeneous fiber sensor, which comprises at least one sensing fiber and at least one sensing fiber, the sensing fiber and the sensing fiber are prepared by using different materials, a matching structure is formed between the at least one sensing fiber and the at least one sensing fiber, and when the sensing fiber is deformed along with the change of a detection environment, the sensing fiber drives the sensing fiber to be deformed to generate a signal change. The application realizes the synchronous response between the functions of the fibers by matching the fibers made of different materials through a mechanical structure, and has more sensitive detection and sensing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a heterogeneous fiber sensor. BACKGROUND

[0002] Most of the current fiber sensors are stretchable and deformable flexible sensors made of homogeneous materials. Most fiber sensors generate electrical signals through overall deformation or sensor devices mounted on the surface of the material. The structure design of fiber sensors is not much. Moreover, most of the existing materials generally cannot have good conductivity and good deformation performance at the same time, so that the fiber sensors made of homogeneous materials cannot simultaneously consider conductivity and deformation characteristics in performance. As a result, the sensitivity and detection accuracy of the existing fiber sensors are low, which limits the application of fiber sensors in the wearable field. SUMMARY

[0003] In view of the above technical problems, the present application provides a heterogeneous fiber sensor with more sensitive detection and sensing performance.

[0004] To solve the above technical problems, the present application provides a heterogeneous fiber sensor, which includes at least one sensing fiber and at least one sensing fiber. The sensing fiber and the sensing fiber are made of different materials. The sensing fiber and the sensing fiber form a matching structure. When the sensing fiber deforms with the change of the detection environment, the sensing fiber deforms to generate a signal change.

[0005] Among them, the sensing fiber is one of shape memory polymer fiber, hydrogel fiber and shape memory polymer doped fiber. The sensing fiber contains an electrical material, and the electrical material is one of liquid metal, piezoelectric material and piezoresistive material.

[0006] Among them, the sensing fiber and the sensing fiber form one of the matching structures of spiral structure, winding structure and planar weaving structure.

[0007] Among them, the sensing fiber and the sensing fiber are independently encapsulated.

[0008] Among them, the number of sensing fibers and sensing fibers is one, the sensing fiber and the sensing fiber form a spiral structure, and when the sensing fiber stretches with the change of the detection environment, the sensing fiber is stretched to change the cross section of the sensing fiber to generate an electrical signal change.

[0009] The number of the sensing fibers is greater than or equal to two, the sensing fibers and the sensing fibers are alternately wound on the surface of the columnar body that can be locally heated to form a spiral structure, and the sensing fibers are pushed to move and deform to change the distance between the sensing fibers to generate a capacitance change when the sensing fibers stretch and shrink with the change of the temperature of the surface of the columnar body.

[0010] The number of the sensing fibers is greater than or equal to two, the sensing fibers and the sensing fibers are alternately wound on the surface of the columnar body that can be locally heated to form a spiral structure, and the sensing fibers are pushed to move and deform to change the distance between the sensing fibers to generate a capacitance change when the sensing fibers stretch and shrink with the change of the temperature of the surface of the columnar body.

[0011] The sensing fiber is a temperature-controlled shape memory polymer fiber, the cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter, and the sensing fiber is a polydimethylsiloxane fiber with liquid metal inside, and the cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter.

[0012] The sensing fiber is a temperature-controlled shape memory polymer fiber, the cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter, and the sensing fiber is a polydimethylsiloxane fiber with liquid metal inside, and the cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter.

[0013] The sensing fiber is a temperature-controlled shape memory polymer fiber, the cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter, and the sensing fiber is a polydimethylsiloxane fiber with liquid metal inside, and the cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter.

[0014] The application relates to a heterogeneous fiber sensor, which comprises at least one sensing fiber and at least one sensing fiber, the sensing fiber and the sensing fiber are made of different materials, the sensing fiber and the sensing fiber form a matching structure, and the sensing fiber deforms to drive the sensing fiber to deform to generate a signal change when the sensing fiber deforms with the change of the detection environment. The fibers of different materials are matched through mechanical structure to realize the synchronous response of the functions of the fibers, and the detection and sensing performance is more sensitive. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a side view of the heterogeneous fiber sensor according to the first embodiment;

[0016] Figure 2 is a side view of the heterogeneous fiber sensor according to the second embodiment;

[0017] Figure 3 is a cross-sectional view of the heterogeneous fiber sensor according to the second embodiment;

[0018] Figure 4 is a side view of a heterogeneous fiber sensor according to a third embodiment;

[0019] Figure 5 is a side view of a heterogeneous fiber sensor according to a fourth embodiment. DETAILED DESCRIPTION

[0020] The following detailed description is presented to enable any person skilled in the art to make and use the application. Various modifications to the embodiments described herein will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments described herein but is to be accorded the widest scope consistent with the claims.

[0021] In the following description, reference is made to the accompanying drawings which form a part hereof, and which is shown by way of illustration of several embodiments of the present application. It is understood that other embodiments can be used and structural, electrical, and operational changes can be made without departing from the spirit and scope of the present application. The following detailed description is, therefore, not to be taken in a limiting sense, as the scope of the present application is defined by the appended claims.

[0022] While in some examples the terms first, second, etc. are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0023] Also, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", as used herein, specify the presence of stated features, steps, operations, elements, components, items, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, items, and / or groups thereof. As used herein the terms "or" and "and / or" are to be interpreted as inclusive, i.e., as meaning one or more of the stated items is present. Therefore, "A, B or C" or "A, B and / or C" means any of the following: A; B; C; A and B; A and C; B and C; A, B and C. An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.

[0024] The heterogeneous fiber sensor of the present application comprises at least one sensing fiber and at least one sensing fiber, the sensing fiber and the sensing fiber are made of different materials, the at least one sensing fiber and the at least one sensing fiber form a mechanical cooperation structure, when the sensing fiber deforms with the change of the detection environment, the sensing fiber is driven to deform to generate a signal change through the mechanical cooperation structure between the sensing fiber and the sensing fiber.

[0025] Because the sensing fibers and the sensor fibers are made from different materials, the appropriate materials can be selected to fabricate fibers according to their functions, resulting in a wider range and richer variety of materials to choose from, and allowing each fiber's function to be optimized to its maximum extent. Furthermore, by forming a mating structure between the sensing and sensor fibers, the deformation of the sensing fiber can be fed back as the deformation of the sensor fiber, synchronously converting changes in the detection environment into signal changes in the sensor fiber, achieving synchronous response between fiber functions. Thus, through the separation of fiber materials and the structural maturation of the fibers, more sensitive detection and sensing performance is achieved.

[0026] Sensing fibers are environmental sensing materials, including but not limited to shape memory polymer fibers, hydrogel fibers, shape memory polymer-doped fibers, and other sensitive deformation materials and doped materials. Sensing fibers contain electrical materials, including but not limited to liquid metals, piezoelectric materials, piezoresistive materials, and other materials or devices that can generate electrical signals with deformation. Due to the separation of fiber materials, sensing fibers and sensor fibers can be independently packaged, which facilitates the use of sensors in complex environments. In practical implementation, the fibers can be packaged or not depending on the materials used in the sensing and sensor fibers and the operating environment. Sensing fibers can be packaged using flexible and insulating materials such as polydimethylsiloxane (PDMS) without affecting the electrical properties of the internal materials.

[0027] The mating structure formed between the sensing fibers and the cooperating fibers includes, but is not limited to, linear structures, planar structures, or combinations of linear and planar structures such as helical structures, winding structures, and planar braided structures. The specific structure can be selected based on the detection target, the detection environment, and the type of signal to be detected. The detection target can be environmental humidity, environmental temperature, environmental deformation, etc.; the detection environment can be a specific space or a specific surface; and the signal type includes, but is not limited to, resistance signals, current signals, capacitance signals, and pressure signals. By forming a mating structure between the sensing fibers and the cooperating fibers, the deformation of the sensing fibers can be sensitively and accurately fed back as the deformation of the cooperating fibers, thereby synchronously converting changes in the detection environment into changes in the signal of the cooperating fibers, achieving synchronous response between fiber functions.

[0028] In practice, sensing fibers and fibrous fibers can be prepared using a spinning process. The spinning process utilizes polymer solutions or melts under the influence of an electric field to prepare submicron or nanofibers. Therefore, spun nanofibers have advantages such as large specific surface area, high porosity, and small fiber diameter and pore size. It is understandable that, depending on the different application requirements of the sensor, sensing fibers and fibrous fibers can also be prepared using other processes.

[0029] This application assembles different materials together through a mechanical structure, resulting in a separation of sensing and perception functions after the mechanical interaction of the different materials. This enables synchronous response between fiber functions, forming a highly sensitive, multifunctional, and multi-mode sensor combination. Furthermore, the separation of materials allows for better sealing of the sensor, facilitating its use in complex environments.

[0030] The sensor structures of different embodiments are described in detail below.

[0031] First Embodiment

[0032] Figure 1 This is a side view of the heterogeneous fiber sensor shown according to the first embodiment. Figure 1 As shown, the heterogeneous fiber sensor in this embodiment includes a sensing fiber 11 and a sensing fiber 12. There is one sensing fiber 11 and one sensing fiber 12. The sensing fiber 11 and the sensing fiber 12 form a spiral structure. When the sensing fiber 11 stretches and contracts with the change of the detection environment, it drives the sensing fiber 12 to stretch, causing the cross-section of the sensing fiber 12 to change and generate a change in electrical signal.

[0033] In this embodiment, the sensing fiber 11 is a temperature-controlled shape memory polymer fiber, which can expand and contract according to temperature changes in the detection environment. The cross-sectional diameter of the sensing fiber 11 is 50 micrometers to 1 millimeter. The sensing fiber 12 is a polydimethylsiloxane fiber containing liquid metal inside. That is, the liquid metal is encapsulated in polydimethylsiloxane. When the polydimethylsiloxane deforms under the stretching of the temperature-controlled shape memory polymer fiber, the cross-sectional size of the polydimethylsiloxane changes, causing the cross-sectional size of the internal liquid metal to change, thus generating a change in resistance. The cross-sectional diameter of the sensing fiber 12 is 50 micrometers to 1 millimeter, which is comparable to the size of the sensing fiber 11.

[0034] In fabricating the heterogeneous fiber sensor of this embodiment, a temperature-controlled shape memory polymer based on polyethylene glycol (PEG) and doped with tin is prepared, with a shape memory deformation temperature of, for example, 50 degrees Celsius. The polymer is then spun into fibers with a cross-sectional diameter of 50 micrometers to 1 millimeter using a mold, and the shape memory is imparted to it, forming a helical shape. Furthermore, after curing liquid metal at a low temperature, polydimethylsiloxane (PDMS) is coated onto the surface, and after curing, a fiber material is formed, thus preparing a PDMS material containing liquid metal, with a controlled cross-sectional diameter of 50 micrometers to 1 millimeter.

[0035] Next, the two fibers are spirally wound together and the ends of the two fibers are fixed so that friction is generated between the wound fibers and no relative displacement occurs. During the extension and contraction process, the length change of the entire fiber sensor on a macroscopic scale is controlled by tightening and loosening the spiral.

[0036] In use, when the ambient temperature is below 50 degrees Celsius, the shape memory polymer is in a contracted state. When the ambient temperature rises to 50 degrees Celsius, the shape memory polymer undergoes a shape change, stretching in length, which in turn causes the PDMS fibers containing liquid metal to stretch elastically. At this time, the liquid metal deforms due to the change in the length of the PDMS, and the cross-section of the liquid metal within the fibers changes, resulting in a change in resistance. This change in resistance, in turn, generates a change in electrical signal due to the temperature change, thus enabling the detection of ambient temperature.

[0037] Second Embodiment

[0038] Figure 2 This is a side view of a heterogeneous fiber sensor according to a second embodiment. Figure 3 This is a schematic cross-sectional view of a heterogeneous fiber sensor according to the second embodiment. Figure 2 and Figure 3 As shown, the heterogeneous fiber sensor in this embodiment includes a sensing fiber 21 and two sensing fibers, namely a first sensing fiber 22 and a second sensing fiber 23. In actual implementation, the number of sensing fibers can be greater than two. The sensing fiber 21, the first sensing fiber 22, and the second sensing fiber 23 are alternately wound around the surface of a locally heatable columnar body 20 to form a helical structure. When the sensing fiber 21 expands and contracts with the temperature change of the surface of the columnar body 20, it pushes the first sensing fiber 22 and the second sensing fiber 23 to move and deform, thereby changing the distance between the first sensing fiber 22 and the second sensing fiber 23 and generating a change in capacitance.

[0039] In this embodiment, the sensing fiber 21 is a temperature-controlled shape memory polymer fiber, which can expand and contract according to temperature changes in the detection environment. The cross-sectional diameter of the sensing fiber 21 is 50 micrometers to 1 millimeter. The first sensing fiber 22 and the second sensing fiber 23 are polydimethylsiloxane fibers containing liquid metal inside. That is, the liquid metal is encapsulated by polydimethylsiloxane. When the polydimethylsiloxane deforms under the stretching of the temperature-controlled shape memory polymer fiber, it changes the distance between two adjacent segments of liquid metal, thereby generating a change in capacitance. The cross-sectional diameter of the first sensing fiber 22 and the second sensing fiber 23 is 50 micrometers to 1 millimeter, which is comparable to the size of the sensing fiber 21.

[0040] In fabricating the heterogeneous fiber sensor of this embodiment, a temperature-controlled shape memory polymer based on polyethylene glycol (PEG) and doped with tin is prepared, with a shape memory deformation temperature of, for example, 50 degrees Celsius. The polymer is spun into fibers with a cross-sectional diameter of 50 micrometers to 1 millimeter using a mold, and then shaped into a helical shape by imparting shape memory. After curing liquid metal at a low temperature, polydimethylsiloxane (PDMS) is coated onto the surface, and after curing, a fiber material is formed, resulting in two segments of PDMS material containing liquid metal, with a controlled cross-sectional diameter of 50 micrometers to 1 millimeter. Next, the three fiber segments are repeatedly and alternately spirally wound onto a locally heated columnar body 20, and the ends of the three fiber segments are fixed.

[0041] In use, when the local temperature of the columnar body 20 is below 50 degrees Celsius, the shape memory polymer is in a contracted state. When the local temperature of the columnar body 20 rises to 50 degrees Celsius, the shape memory polymer undergoes a shape change, stretching in length, which in turn causes the PDMS fibers containing liquid metal to stretch elastically. Specifically, when the local temperature of the columnar body 20 exceeds 50 degrees Celsius, the shape memory polymer stretches, increasing the distance between two adjacent sensing fibers, thus reducing the capacitance between the sensing fibers and the adhesion to the ground / other surfaces. When the temperature of other parts of the columnar body 20 is below 50 degrees Celsius, the shape memory polymer contracts, the distance between two adjacent sensing fibers decreases, the capacitance increases, and the adhesion to the ground / other surfaces increases. By alternating the temperature changes of the columnar body 20, the local ground adhesion and geometry of the heterogeneous fiber sensor can be changed, enabling the crawling function of the fiber sensor, which is suitable for the field of biomimetic soft robots.

[0042] Third Embodiment

[0043] Figure 4 This is a side view of a heterogeneous fiber sensor according to a third embodiment. Figure 4 As shown, the heterogeneous fiber sensor in this embodiment includes a sensing fiber 31 and a sensing fiber 32. The number of sensing fibers 31 and 32 is one. The sensing fibers 31 and 32 are alternately stacked to form a planar woven structure. The sensing fiber 31 bends when it stretches and contracts with the change of the detection environment. The stretched sensing fiber 32 bends and deforms to generate capacitance changes.

[0044] In this embodiment, the sensing fiber 31 is a temperature-controlled shape memory polymer fiber that can expand and contract according to temperature changes in the detection environment. The cross-sectional diameter of the sensing fiber 31 is 50 micrometers to 1 millimeter. The sensing fiber 32 is a polydimethylsiloxane fiber containing liquid metal inside. That is, the liquid metal is encapsulated in polydimethylsiloxane. When the polydimethylsiloxane deforms under the stretching of the temperature-controlled shape memory polymer fiber, it changes the distance and angle between two adjacent segments of liquid metal, thereby generating a change in capacitance. The cross-sectional diameter of the sensing fiber 32 is 50 micrometers to 1 millimeter, which is comparable to the size of the sensing fiber 31.

[0045] In fabricating the heterogeneous fiber sensor of this embodiment, a temperature-controlled shape memory polymer based on polyethylene glycol (PEG) and doped with tin is prepared, with a shape memory temperature of, for example, 50 degrees Celsius. Fibers with a cross-sectional diameter of 50 micrometers to 1 millimeter are prepared using a mold and given bending shape memory. Then, after low-temperature curing of liquid metal, polydimethylsiloxane (PDMS) is coated onto the surface, and after curing, a fiber material is formed, thus preparing a PDMS material containing liquid metal, with a controlled cross-sectional diameter of 50 micrometers to 1 millimeter. Next, the two types of fibers are woven together to form a large-area woven sensing unit.

[0046] In use, when the local temperature is below 50 degrees Celsius, the shape memory polymer is in a stretched state. When the local temperature rises to 50 degrees Celsius, the shape memory polymer undergoes a shape change, bending under the constraint of the PDMS fibers, which in turn simultaneously causes the PDMS fibers containing liquid metal to bend as well. By testing the capacitance changes between different sensing fibers, the bending changes between large-area woven sensing units can be determined through electrical signals, making it suitable for muscle stretching or heart rate / pulse detection.

[0047] Fourth embodiment

[0048] Figure 5 This is a side view of a heterogeneous fiber sensor according to the fourth embodiment. Figure 5 As shown, the heterogeneous fiber sensor in this embodiment includes a sensing fiber 51 and a sensing fiber 52. There is one sensing fiber 51 and one sensing fiber 52. The sensing fiber 52 is wound around the surface of the sensing fiber 51 to form a winding structure. When the sensing fiber 51 expands or contracts with the change of the detection environment, it squeezes or releases the sensing fiber 52, causing the surface of the sensing fiber 52 to deform and generate a change in pressure signal.

[0049] In this embodiment, the sensing fiber 51 is a rod-shaped, multi-arm thiolized polyethylene glycol hydrogel fiber that can absorb water and swell or lose water and shrink. The cross-sectional diameter of the sensing fiber 51 is 5 mm to 10 mm. The sensing fiber 52 includes an encapsulation layer 521 and an internal material 522. Specifically, it can be a polydimethylsiloxane fiber with piezoelectric material inside. That is, the encapsulation layer 521 is polydimethylsiloxane, and the internal material 522 is a piezoelectric material. The piezoelectric material 522 includes, but is not limited to, piezoelectric ceramics, polyvinyl fluoride, and doped materials of the above. When the polydimethylsiloxane is deformed under the compression of the multi-arm thiolized polyethylene glycol hydrogel fiber, it further compresses the internal piezoelectric material, thereby generating a change in pressure signal. The cross-sectional diameter of the sensing fiber 52 is 50 micrometers to 1 mm, which is smaller than the cross-sectional size of the sensing fiber 51.

[0050] In fabricating the heterogeneous fiber sensor of this embodiment, a multi-arm thiolized polyethylene glycol (SH-PEG) hydrogel is prepared, and the rod-shaped hydrogel is spun into fibers with a cross-section of 5 mm to 10 mm using a mold. Additionally, a PDMS material containing piezoelectric material is prepared, with a cross-section ranging from 50 μm to 1 mm. Next, the rod-shaped hydrogel is allowed to absorb water and swell, and the piezoelectric material fibers are wound around the hydrogel fibers. The ends of the two types of fibers are fixed, so that friction is generated between the wound fibers without relative displacement.

[0051] In use, the pressure exerted on the piezoelectric material is controlled by the shape changes that occur during the absorption and loss of water by the hydrogel material. When the ambient humidity or moisture content is higher than that of the hydrogel material, the hydrogel material absorbs water and expands, generating a gradually increasing pressure on the piezoelectric material and producing an increased pressure signal. The change in this pressure signal allows for quantitative measurement of the ambient humidity or moisture content. Conversely, when the ambient humidity or moisture content is lower than that of the hydrogel material, the hydrogel material loses water and shrinks, gradually decreasing the pressure on the piezoelectric material and producing a decreased pressure signal. This change in pressure signal also allows for quantitative measurement of the ambient humidity or moisture content.

[0052] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A heterogeneous fiber sensor, characterized in that, The sensing fiber and the sensing fiber are made of different materials, and the sensing fiber and the sensing fiber form a matching structure. When the sensing fiber deforms with the change of the detection environment, it drives the sensing fiber to deform to generate a signal change. The sensing fiber contains a material that generates an electrical signal with deformation. The sensing fiber is one of a shape memory polymer fiber, a hydrogel fiber, and a shape memory polymer doped fiber. The sensing fiber contains an electrical material, which is one of a liquid metal, a piezoelectric material, and a piezoresistive material. The number of sensing fibers is greater than or equal to two. The sensing fiber and the sensing fiber are alternately wound on the surface of the locally heatable columnar body to form a spiral structure. When the sensing fiber expands and contracts with the change of the temperature of the columnar body surface, it pushes the sensing fiber to move and deform to change the distance between the sensing fibers, generating a capacitance change. Alternatively, the number of sensing fibers and sensing fibers is one. The sensing fiber and the sensing fiber are alternately superimposed to form a planar woven structure. When the sensing fiber expands and contracts with the change of the temperature of the detection environment, it bends and stretches the sensing fiber to deform to generate a capacitance change.

2. The heterogeneous fiber sensor of claim 1, wherein, The sensing fiber and the sensing fiber are independently encapsulated.

3. The heterogeneous fiber sensor of claim 1, wherein, The sensing fiber is a temperature-controlled shape memory polymer fiber, the cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter, and the sensing fiber is a polydimethylsiloxane fiber with a liquid metal inside. The cross-sectional diameter of the sensing fiber is 50 microns to 1 millimeter.

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