A high-sensitivity stretchable fiber sensor and a preparation method thereof

Abstract

The application discloses a high-sensitivity stretchable fiber sensor and a preparation method thereof. The high-sensitivity stretchable fiber sensor comprises at least a soft section fiber and a hard section fiber. The Young's modulus of the hard section fiber is less than or equal to 100 Ga, the Young's modulus of the soft section fiber is less than or equal to 10 GPa, and the Young's modulus of the hard section fiber is more than twice the Young's modulus of the soft section fiber. Different from a fiber sensor prepared by a conventional method, the stretchable fiber sensor can amplify local strain when uniformly stretched, and can realize electric signal collection of a small strain. The high-sensitivity stretchable fiber sensor can be knitted into a fabric to realize real-time detection of human body movement due to high sensitivity, flexibility and cyclic stability, and provides a new idea for manufacturing an intelligent fabric for health protection of human body movement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a high-sensitivity stretchable fiber sensor and a preparation method thereof. BACKGROUND

[0002] With the advent of the 5G information age and the vigorous development of electronic devices, it is possible to monitor human movement and health behavior in real time through electronic signal collection. Due to the increasing demand for fabrics, compared with traditional fiber fabrics for cold resistance and warmth, stretchable fiber sensors can record human movement patterns and strain degrees by detecting changes in electrical signals under strain such as stretching and bending, and are expected to realize real-time monitoring of human movement. However, this puts higher requirements on the performance of stretchable fiber sensors. Most importantly, fiber sensors need to have a very high sensitivity factor to ensure that the fiber has a significant change in electrical signals under very small strain, thereby enabling the detection of some small movement behaviors of the human body. At the same time, the fiber needs to have a certain elongation to meet some strain behaviors in human movement.

[0003] Currently, the design of flexible and lightweight fiber sensors mainly uses conductive carbon materials or conductive material / polymer composite materials. However, there are serious limitations. Pure conductive carbon material fibers usually have obvious brittleness and very low elongation, which cannot meet the detection of some large strain in human movement. Although the conductive material / polymer composite system significantly optimizes the elongation of the fiber, considering its poor conductivity, the sensing sensitivity is low, and it is difficult to detect some small strain signals.

[0004] Therefore, how to design the structure of the fiber sensor and optimize its sensitivity to realize a high-sensitivity stretchable fiber sensor has great significance. SUMMARY

[0005] In view of this, the present application provides a high-sensitivity stretchable fiber sensor and a preparation method thereof. The present application is different from general fiber sensors. The stretchable fiber sensor has high sensitivity and can realize the detection of small strain. At the same time, it has good conductivity and cyclic stretching stability, and can be applied to woven sensing fabrics to detect human movement signals.

[0006] According to a first aspect of the present application, a high-sensitivity stretchable fiber sensor is provided, which at least includes a soft segment fiber and a hard segment fiber, the Young's modulus of the hard segment fiber is 100 Ga or less, the Young's modulus of the soft segment fiber is 10 GPa or less, and the Young's modulus of the hard segment fiber is more than twice the Young's modulus of the soft segment fiber.

[0007] Optionally, the soft segment fiber and the hard segment fiber are conductive fibers or insulating fibers with a conductive coating on the surface.

[0008] The soft segment fibers and the hard segment fibers are both composed of stretchable insulating pure materials or mixtures;

[0009] Optionally, the conductive fibers and conductive coating are conductive and stretchable pure materials or mixtures.

[0010] Optionally, the materials of the soft segment fibers and the hard segment fibers are selected from one or more of polyurethane (PU), thermoplastic olefin (TPO), vulcanized rubber (TPV), thermoplastic rubber (TPR), polystyrene elastomer (TPS), polyamide elastomer (TPA), polyether ester elastomer (TPEE), polydimethylsiloxane (PDMS), and hydrogel materials.

[0011] Optionally, the soft segment fibers can be modified by a mechanical modifier. Further, the mechanical modifier is one or more of graphene oxide, silicate nanoplate, silica, insulating metal oxide, boron nitride.

[0012] Optionally, the material of the conductive coating is a conductive material or a mixture of a conductive material and a mechanical modifier. Further, the conductive material is selected from one or more of graphene, rGO, carbon nanotube, carbon black, conductive metal, liquid metal, Mxene, PEDOT, polyaniline, and ion conductive salt materials. The mechanical modifier is selected from one or more of polyurethane (PU), thermoplastic olefin (TPO), vulcanized rubber (TPV), thermoplastic rubber (TPR), polystyrene elastomer (TPS), polyamide elastomer (TPA), polyether ester elastomer (TPEE), polydimethylsiloxane (PDMS), and hydrogel materials.

[0013] Optionally, the material of the conductive fibers or the conductive coating is a mixture of a stretchable material and a conductive modifier. Further, the stretchable material is selected from one or more of polyurethane (PU), thermoplastic olefin (TPO), vulcanized rubber (TPV), thermoplastic rubber (TPR), polystyrene elastomer (TPS), polyamide elastomer (TPA), polyether ester elastomer (TPEE), polydimethylsiloxane (PDMS), and hydrogel materials. The conductive modifier material is selected from one or more of graphene, rGO, carbon nanotube, carbon black, conductive metal, liquid metal, Mxene, PEDOT, polyaniline, and ion conductive salt materials.

[0014] Optionally, the conductive fibers or the conductive coating can be modified by a mechanical modifier. Further, the mechanical modifier is one or more of graphene, graphene oxide, carbon nanotube, carbon black, graphite, silicate nanoplate, silica, metal oxide, and boron nitride.

[0015] The second aspect of the embodiment of the application provides a preparation method of the high-sensitivity stretchable fiber sensor.

[0016] The two conductive material spinning solutions are injected into two inlets of the three-way pipe in sequence, the soft segment fiber spinning solution and the hard segment fiber spinning solution are alternately extruded to form continuous alternating conductive fiber blocks;

[0017] The alternating insulating fiber blocks are subjected to immersion or magnetron sputtering treatment to form a uniform conductive coating layer with a thickness of 0.1-100 mu m, and a high-sensitivity stretchable fiber sensor is prepared.

[0018] Optionally, the length of the fiber block is controlled by controlling the injection amount of the spinning solution.

[0019] The thickness of the conductive fiber or the uniform conductive coating layer is controlled by controlling the addition amount of the conductive material.

[0020] The technical scheme provided by the embodiment of the application can include the following beneficial effects:

[0021] As can be seen from the above embodiment, the high-sensitivity stretchable fiber sensor prepared by the application is different from the stretchable fiber sensor prepared by the conventional method, and the local strain can be amplified when the fiber is uniformly stretched by the design of the local microstructure, and the electrical signal of the micro strain can be collected. The high-sensitivity stretchable fiber sensor has high sensitivity, flexibility and cyclic stability, and can be woven into a fabric to detect human motion in real time, which provides a new idea for manufacturing intelligent fabrics for human motion health protection.

[0022] The alternating wet spinning technology is adopted to prepare fibers with different axial blocks of Young's modulus, and then the local strain is controlled in the uniform stretching state. Based on the significant strain amplification effect of the soft segment area (compared with the uniform fiber), a sensitive resistance signal change of the micro strain can be generated, and the design and preparation of the high-sensitivity stretchable fiber sensor are realized. It should be understood that the above general description and the detailed description below are only exemplary and explanatory, and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings incorporated into the specification and forming a part of the specification, show embodiments consistent with the application, and together with the specification, serve to explain the principles of the application.

[0024] Figure 1 The three-way pipe diagram for the preparation process of Example 1.

[0025] Figure 2 The alternating insulating block fiber and the high-sensitivity stretchable fiber sensor prepared in Example 1 are shown in the morphology diagram.

[0026] Figure 3A topography of the stretched state of the high-sensitivity stretchable fiber sensor prepared in Example 1.

[0027] Figure 4 A plot of the cyclic stability of the resistance of the high-sensitivity stretchable fiber sensor prepared in Example 1 at 35% strain. DETAILED DESCRIPTION

[0028] The exemplary embodiments will be described in detail herein with reference to the accompanying drawings.

[0029] Example 1:

[0030] TPU1170A (Young's modulus ~ 0.02 GPa) and TPU3072D (Young's modulus ~ 0.2 GPa) were chosen as two kinds of fiber insulating block materials with different Young's modulus. The above materials were dissolved in DMF respectively, heated to 120°C and stirred for 2h to prepare 20wt% solution, and marked with commercially available oil-soluble pigment.

[0031] As shown in Figure 1 , two kinds of insulating block material spinning solution were connected to two inlets of a tee, and by alternately extruding the two kinds of spinning solution, continuous alternating insulating fiber blocks were formed in the coagulation bath water from the outlet. Figure 2

[0032] The alternating insulating fiber blocks were sputtered for 30 seconds under a magnetron sputtering instrument using a gold target as the target material to form a conductive gold layer. As shown in Figure 3 , a high-sensitivity stretchable fiber sensor was prepared. The resistance change of the obtained fiber stretchable sensor showed a linear relationship with the strain, and the sensitivity factor was as high as 240. And it had good cyclic characteristics under 35% strain and 5000 cycles of cycling conditions Figure 4

[0033] Example 2:

[0034] TPU1170A (Young's modulus ~ 0.02 GPa) and TPU3072D (Young's modulus ~ 0.2 GPa) were chosen as two kinds of fiber insulating block materials with different Young's modulus. The above materials were dissolved in DMF respectively, heated to 120°C and stirred for 2h to prepare 20wt% solution, and marked with commercially available oil-soluble pigment.

[0035] Two kinds of insulating block material spinning solution were connected to two inlets of a tee, and by alternately extruding the two kinds of spinning solution, continuous alternating insulating fiber blocks were formed in the coagulation bath water from the outlet.

[0036] The alternating insulating fiber blocks were immersed in a commercially available 10% MWCNT dispersion for 30 seconds to form a conductive MWCNT coating. A high-sensitivity stretchable fiber sensor was prepared. ​​

[0037] Example 3:

[0038] TPU1170A (Young's modulus ~ 0.02 GPa) and TPU3072D (Young's modulus ~ 0.2 GPa) were chosen as two kinds of fiber insulation block raw materials with different Young's modulus. The above raw materials were dissolved in DMF respectively, heated to 120°C and stirred for 2h to prepare 20wt% solution, and marked with commercially available oil-soluble pigment.

[0039] The two kinds of insulation block material spinning solution were connected to the two inlets of the tee joint, and the two kinds of spinning solution were alternately extruded to form continuous alternating insulation fiber blocks in the coagulation bath water from the outlet.

[0040] The alternating insulation fiber blocks were immersed in commercially available graphene / polyurethane emulsion for 30 seconds to form a conductive graphene / polyurethane coating. A high-sensitivity stretchable fiber sensor was prepared. The prepared stretchable fiber sensor has good cycle characteristics, and the sensitivity factor can be as high as 25 under 0-20% strain and as high as 1100 under 20-80% strain.

[0041] Example 4:

[0042] TPU1170A (Young's modulus ~ 0.02 GPa) and TPU3072D / aluminum nanosheet (Young's modulus ~ 0.5 GPa) were chosen as two kinds of fiber insulation block raw materials with different Young's modulus. Among them, the aluminum nanosheet is a mechanical reinforcing modifier. The above raw materials were dissolved in DMF respectively, heated to 120°C and stirred for 2h to prepare 20wt% solution, and marked with commercially available oil-soluble pigment.

[0043] The two kinds of insulation block material spinning solution were connected to the two inlets of the tee joint, and the two kinds of spinning solution were alternately extruded to form continuous alternating insulation fiber blocks in the coagulation bath water from the outlet.

[0044] The alternating insulation fiber blocks were sputtered for 30 seconds under a magnetron sputtering instrument using a gold target as a target material to form a conductive gold layer. A high-sensitivity stretchable fiber sensor was prepared.

[0045] Example 5:

[0046] TPU1170A / MWCNT (Young's modulus ~ 0.02 GPa) and TPU3072D / MWCNT (Young's modulus ~ 0.2 GPa) were chosen as two kinds of fiber conductive block raw materials with different Young's modulus. Among them, MWCNT is a conductive modifier. The above raw materials were dissolved in DMF respectively, heated to 120°C and stirred for 2h to prepare 25wt% solution (20wt% TPU, 5wt% MWCNT), and marked with commercially available oil-soluble pigment.

[0047] Two conductive block material spinning solutions are connected to two inlets of a tee, and two spinning solutions are extruded alternately to form continuous alternating conductive fiber blocks in a coagulation bath. A high-sensitivity stretchable fiber sensor is prepared.

[0048] Example 6:

[0049] Acrylamide / 2959 / BIS (Young's modulus ~ 0.1 MPa) and acrylamide / GO / 2959 / BIS (Young's modulus ~ 4 MPa) are selected as two fiber insulating block raw materials with different Young's moduli. Among them, acrylamide is a hydrogel monomer, 2959 is a photoinitiator, BIS is a crosslinking agent, and GO is a mechanical enhancement modifier. The above raw materials are dissolved in water respectively, stirred for 1 h to prepare a solution (20wt% acrylamide, 0.2wt% 2959, 0.02wt% BIS, 1wt% GO).

[0050] Two insulating block material spinning solutions are connected to two inlets of a tee, and two spinning solutions are extruded alternately. In the outlet tube, crosslinking is initiated by nitrogen atmosphere and 365 nm ultraviolet light to form continuous alternating insulating fiber blocks. The alternating insulating fiber blocks are sputtered for 30 seconds under a magnetron sputtering instrument using a gold target as a target material to form a conductive gold layer. A high-sensitivity stretchable fiber sensor is prepared.

[0051] Example 7:

[0052] Acrylamide / 2959 / BIS / MWCNT (Young's modulus ~ 0.1 MPa) and acrylamide / GO / 2959 / BIS / MWCNT (Young's modulus ~ 4 MPa) are selected as two fiber conductive block raw materials with different Young's moduli. Among them, acrylamide is a hydrogel monomer, 2959 is a photoinitiator, BIS is a crosslinking agent, GO is a mechanical enhancement modifier, and MWCNT is a conductive modifier. The above raw materials are dissolved in water respectively, stirred for 1 h to prepare a solution (20wt% acrylamide, 0.2wt% 2959, 0.02wt% BIS, 10wt% MWCNT, 1wt% GO).

[0053] Two conductive block material spinning solutions are connected to two inlets of a tee, and two spinning solutions are extruded alternately. In the outlet tube, crosslinking is initiated by nitrogen atmosphere and 365 nm ultraviolet light to form continuous alternating conductive fiber blocks. A high-sensitivity stretchable fiber sensor is prepared.

[0054] Example 8:

[0055] Acrylamide / 2959 / BIS / NaCl (Young's modulus ~ 0.1 MPa) and acrylamide / GO / 2959 / BIS / NaCl (Young's modulus ~ 4 MPa) were chosen as two kinds of fiber conductive block raw materials with different Young's modulus. Among them, acrylamide is a hydrogel monomer, 2959 is a photoinitiator, BIS is a crosslinking agent, GO is a mechanical enhancement modifier, and NaCl is a conductive modifier. The above raw materials were dissolved in water respectively, stirred for 1 h to prepare a solution (20 wt% acrylamide, 0.2 wt% 2959, 0.02 wt% BIS, 10 wt% NaCl, 1 wt% GO).

[0056] The two conductive block material spinning solutions were connected to two inlets of a three-way pipe, and the two spinning solutions were extruded alternately. In the outlet pipe, crosslinking was initiated by nitrogen atmosphere and 365 nm ultraviolet light to form a continuous alternating conductive fiber block. A high-sensitivity stretchable fiber sensor was prepared.

[0057] Example 9:

[0058] Large piece graphene oxide (100 μm, Young's modulus ~ 100 GPa) and small piece graphene oxide (1 μm, Young's modulus ~ 10 GPa) were chosen as two kinds of fiber conductive block raw materials with different Young's modulus. The above raw materials were dispersed in DMF respectively, and ultrasonic treatment was performed for 2 h to prepare a 2 wt% dispersion.

[0059] The two material spinning solutions were connected to two inlets of a three-way pipe, and the two spinning solutions were extruded alternately to form a continuous alternating fiber block in the coagulation bath water. Then the obtained fiber was reduced in HI / EtOH for 24 h (95 °C) to obtain a block-reduced large piece graphene oxide / reduced small piece graphene oxide colloidal conductive fiber block. A high-sensitivity fiber sensor was prepared.

[0060] Comparative Example 1:

[0061] TPU3072D fiber raw material was chosen. The above raw material was dissolved in DMF, heated to 120 °C and stirred for 2 h to prepare a 20 wt% spinning solution. The spinning solution was extruded into the coagulation bath water to form a polyurethane fiber.

[0062] The polyurethane fiber was sputtered for 30 seconds under a magnetron sputtering instrument using a gold target as the target material to form a conductive gold layer. A stretchable fiber sensor was obtained. The sensitivity factor of the obtained fiber was only 25.

[0063] Since the comparative example selects the fiber as a traditional homogeneous fiber, the strain is uniformly distributed under stretching, without amplification. The fiber structure with soft and hard block alternating arrangement prepared in the application can be amplified in a local area, improving the sensitivity of the fiber sensor. Compared with the comparative example, the high-sensitivity stretchable fiber sensor prepared in Example 1 of the application has a sensitivity factor as high as 240.

[0064] Comparative Example 2

[0065] TPU1170A (Young's modulus ~ 0.02 MPa) and TPU1175AW (Young's modulus ~ 0.03 MPa) fiber raw materials were selected as two kinds of fiber insulation block raw materials with different Young's moduli. The above raw materials were dissolved in DMF, heated to 120°C and stirred for 2h to prepare a 20wt% solution, and marked with a commercially available oil-soluble pigment. The two insulation block material spinning solutions were connected to two inlets of a three-way tube, and by alternately extruding the two spinning solutions, a continuous alternating insulation fiber block was formed in the coagulation bath water. The alternating insulation fiber block was sputtered for 30 seconds under a magnetron sputtering instrument using a gold target as the target material to form a conductive gold layer, obtaining a stretchable fiber sensor. Since the difference between the two Young's moduli is less than 2 times, the sensitivity factor of the obtained fiber is only 29, without obvious improvement.

[0066] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the application be limited only by the scope of the claims, appropriately interpreted in light of the specification. The specification and examples are to be construed as merely illustrative of the presently preferred embodiments of the application and not limitative of the scope of the application in any way.

[0067] It should be understood that the application is not limited to the precise construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application should only be limited by the appended claims.

Claims

1. A high-sensitivity stretchable fiber sensor, characterized by: At least one soft segment fiber and one hard segment fiber, the Young's modulus of the hard segment fiber is 100 Ga or less, the Young's modulus of the soft segment fiber is 10 GPa or less, and the Young's modulus of the hard segment fiber is more than twice the Young's modulus of the soft segment fiber.

2. The high-sensitivity stretchable fiber sensor of claim 1, wherein, The soft segment fiber and the hard segment fiber are electrically conductive fibers or insulating fibers with electrically conductive coatings.

3. The high-sensitivity stretchable fiber sensor of claim 2, wherein, Both the soft segment fiber and the hard segment fiber are composed of stretchable insulating pure substances or mixtures.

4. The high-sensitivity stretchable fiber sensor of claim 2, wherein, The electrically conductive fiber and the electrically conductive coating are electrically conductive and stretchable pure substances or mixtures.

5. The high-sensitivity stretchable fiber sensor of claim 1, wherein, The materials of the soft segment fiber and the hard segment fiber are selected from one or more of the following: polyurethane (PU), polyolefin elastomer (TPO), thermoplastic rubber (TPR), polystyrene elastomer (TPS), polyamide elastomer (TPA), polyether ester elastomer (TPEE), polydimethylsiloxane (PDMS), and hydrogel materials.

6. The high-sensitivity stretchable fiber sensor of claim 1, wherein, The soft segment fiber is modified with a mechanical modifier.

7. The high-sensitivity stretchable fiber sensor of claim 2, wherein, The material of the electrically conductive coating is an electrically conductive material or a mixture of an electrically conductive material and a mechanical modifier.

8. The high-sensitivity stretchable fiber sensor of claim 2, wherein, The electrically conductive fiber or the electrically conductive coating material is a mixture of a stretchable material and an electrically conductive modifier.

9. The high-sensitivity stretchable fiber sensor of claim 2, wherein, The electrically conductive fiber or the electrically conductive coating is modified with a mechanical modifier.

10. The method of claim 1, wherein the high-sensitivity stretchable fiber sensor is prepared by the steps of: The method comprises: Two electrically conductive material spinning solutions are injected into two inlets of a three-way pipe in sequence, and the soft segment fiber spinning solution and the hard segment fiber spinning solution are alternately extruded to form a continuous alternating electrically conductive fiber block; The alternating electrically conductive fiber block is subjected to immersion or magnetron sputtering treatment to form a uniform electrically conductive coating with a thickness of 0.1-100 μm, thereby preparing a high-sensitivity stretchable fiber sensor.

11. The production method according to claim 10, wherein: The length of the fiber block is controlled by controlling the injection amount of the spinning solution.

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