CN107881768B - Stretchable strain sensor based on polyurethane fibers and preparation method thereof - Google Patents

Stretchable strain sensor based on polyurethane fibers and preparation method thereof Download PDF

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CN107881768B
CN107881768B CN201711229196.1A CN201711229196A CN107881768B CN 107881768 B CN107881768 B CN 107881768B CN 201711229196 A CN201711229196 A CN 201711229196A CN 107881768 B CN107881768 B CN 107881768B
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strain sensor
polyethylene glycol
polyurethane fiber
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polyurethane
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CN107881768A (en
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黄英
赵雨农
王志强
郭小辉
刘平
刘彩霞
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Hefei University of Technology
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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
    • D06M11/73—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with carbon or compounds thereof
    • D06M11/74—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with carbon or compounds thereof with carbon or graphite; with carbides; with graphitic acids or their salts
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/227—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of hydrocarbons, or reaction products thereof, e.g. afterhalogenated or sulfochlorinated
    • D06M15/233—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of hydrocarbons, or reaction products thereof, e.g. afterhalogenated or sulfochlorinated aromatic, e.g. styrene
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/53—Polyethers
    • D—TEXTILES; PAPER
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    • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
    • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
    • D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M15/643—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds containing silicon in the main chain
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
    • G01B7/18—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
    • D06M2101/16—Synthetic fibres, other than mineral fibres
    • D06M2101/30—Synthetic polymers consisting of macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D06M2101/38—Polyurethanes
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M2200/00—Functionality of the treatment composition and/or properties imparted to the textile material
    • D06M2200/50—Modified hand or grip properties; Softening compositions

Abstract

The invention discloses a stretchable strain sensor based on polyurethane fibers and a preparation method thereof. The strain sensor obtained by the invention has good light flexibility, tensile property and large-scale integration property, and can be used as a wearable device compatible with skin.

Description

Stretchable strain sensor based on polyurethane fibers and preparation method thereof
Technical Field
The invention belongs to the field of sensors, and particularly relates to a stretchable strain sensor based on polyurethane fibers and a preparation method thereof.
Background
The wearable strain sensor has wide application prospect in the fields of artificial intelligence, bioelectronics, medical treatment and man-machine interaction as an artificial flexible electronic device which has high flexibility and stretchability, has sensing sensitivity similar to the human skin touch function and can realize the external environment information sensing function. Strain sensors conceived, designed and prepared for human motion detection, vital sign monitoring and acoustic signal or gesture recognition have recently attracted considerable attention, and have become a research hotspot in the fields of flexible electronics, artificial skin, medical care and the like. The sensors used based on the above applications must have high stretchability, flexibility and good sensitivity. Metallic and rigid semiconductor materials with only limited stretchability are incompatible with the skin surface of a human body and are also incompatible biologically, for example, JL Tanner et al have prepared a strain sensor based on platinum nanoparticles, but the strain sensor has high rigidity and cannot be applied to the preparation of wearable devices. At present, the existing wearable strain sensor has low ductility and poor durability, and the application of the wearable strain sensor is limited. Therefore, new flexible substrates and sensitive materials and corresponding methods of preparation are considerable and exploratory.
For the tensile strain sensor, from the aspects of substrate material, filler selection, preparation process and the like, researchers at home and abroad recently carry out extensive research to develop various strain sensors. For general elastomer or polymer substrates, metal nanoparticles or nanowires (e.g., silver, copper) and carbon nanomaterials (e.g., carbon black, carbon nanotubes, and graphene) are widely used by being dispersed in a polymer matrix or coated on the surface of the substrate. Xiaohui Guo et al designs a strain sensor with a sandwich structure based on a spin coating process and a polymer substrate, and can be used for gesture recognition and monitoring of activity at joints of a human body, but the method has certain problems: on one hand, the high-concentration conductive material added into the matrix not only reduces the flexibility, but also limits the stretchability of the synthesized composite material; on the other hand, when strain is applied, the uniform microscopic mechanism and morphology in the film or coating of the strain sensor changes toward a non-uniform state, resulting in a non-linear response to the change in resistance as the strain changes continuously. Xiao Li et al prepared a graphene fabric strain sensor based on CVD process, although the sensitivity was very high, the microstructure of the film in the stretched state changed to a non-uniform morphology, resulting in a non-linear resistance response. MortezaAmjadi et al designed a strain sensor based on a copolyester and carbon nanotube nanocomposite, with a maximum tensile limit of 500%, but the problem of low sensitivity limited its application in the field of wearable devices. Better linearity indicates that the sensor is able to detect and quantify the change in resistance with applied strain. Nevertheless, simultaneous consideration of stretchability, linearity, and sensitivity remains a challenge for most strain sensors.
Due to their excellent characteristic properties such as extensibility, elasticity, portability, and large-scale integration, while considering environmental protection and cost efficiency, fabrics, fibers, and yarns have attracted increasing attention as new base materials for strain sensors. The modified fiber or fabric is combined and integrated with a sensitive material and a sensing part, and can be prepared into an intelligent fabric sensor sensitive to physical quantities such as stress, tensile strain and temperature change. While lacking uniform standards and guidelines, which have led to their lack of widespread use, this class of materials provides an alternative to wearable electronics. Recently, polyurethane-based materials have been applied in various forms, such as thermoplastic polyurethane, polyurethane sponge, polyurethane fiber, and the like. Sensors made from the above materials have improved stretchability or enhanced sensitivity, and are expected to address issues associated with wearable strain sensors.
Disclosure of Invention
The invention provides a stretchable strain sensor based on polyurethane fibers and a preparation method thereof based on a dipping-coating method, and aims to solve the problems of low ductility, low linearity, poor flexibility, difficulty in skin compatibility and poor durability of the conventional strain sensor and improve the capability of the strain sensor as a wearable device.
The invention solves the technical problem and adopts the following technical scheme:
the invention relates to a stretchable strain sensor based on polyurethane fibers, which is characterized in that: the stretchable strain sensor takes polyurethane fiber as a substrate, and an inner-layer conductive structure and an outer-layer conductive structure are sequentially wrapped on the surface of the substrate; the inner layer conductive structure is a graphene nano-sheet layer, and the outer layer conductive structure is a synergetic conductive network layer of carbon black and single-walled carbon nano-tubes.
The tensile strain sensor has a dual mode cooperative conduction mechanism: on one hand, the carbon black and the single-walled carbon nanotube in the outer layer conductive structure are in a cooperative conductive mechanism; on the other hand, the structure is a synergistic conduction mechanism between an inner double-layer conduction structure and an outer double-layer conduction structure in the laminated structure, namely the synergistic effect between the carbon black and the single-walled carbon nanotube composite filler in the outer layer conduction structure and the graphene in the inner layer conduction structure.
The breaking strength of the polyurethane fiber is 0.03-0.09N/tex, and the breaking elongation is 450-800%. The elongation at break of the polyurethane fiber is high compared with other common textile fibers, but has a relatively low strength at break, indicating that the polyurethane fiber has excellent flexibility and stretchability.
The tensile strain sensor has the elongation at break of 350 percent, and the linear fitting goodness of fit value of the strain resistance change curve in the 0-100 percent tensile range is between 0.990 and 1.
A method of making a stretchable strain sensor, comprising the steps of:
step 1, preparing polyethylene glycol aqueous solution
Weighing 0.03-0.06 g of polyethylene glycol, adding the polyethylene glycol into 15mL of deionized water, magnetically stirring at 60-80 ℃ until the polyethylene glycol is dissolved, and then ultrasonically dispersing for 0.5-1 h to obtain a polyethylene glycol aqueous solution with the concentration of 2-4 mg/mL;
step 2, surface modification of polyurethane fiber
Washing polyurethane fibers with deionized water to remove surface impurities, then drying in the air at normal temperature, soaking in the aqueous solution of polyethylene glycol prepared in the step 1 for 5-10 min, taking out, washing with deionized water again, and drying in the air at normal temperature to obtain polyethylene glycol modified polyurethane fibers;
step 3, preparing a composite aqueous solution of graphene and sodium poly (p-styrene sulfonate)
0.03-0.06 g of graphene nanosheet and 0.03-0.06 g of sodium poly-p-styrene sulfonate are mixed according to the mass ratio of 1: 1, adding the mixture into 15mL of deionized water, mixing and uniformly stirring, ultrasonically dispersing the obtained mixed solution for 2-3 h, and then magnetically stirring for 0.5-1 h to obtain a composite aqueous solution of graphene and sodium poly-p-styrene sulfonate;
step 4, wrapping the inner layer conductive structure
Soaking the polyurethane fiber modified by polyethylene glycol in the composite aqueous solution prepared in the step (3) for 5-10 min, taking out, placing in air, drying at normal temperature, repeatedly soaking and drying for 3-4 times, and passingSulfonic acid group-SO in sodium poly (p-styrene) sulfonate3H and hydroxyl-OH in polyethylene glycol form hydrogen bonding, namely the surface of the polyurethane fiber is uniformly coated with a graphene nanosheet layer;
step 5, preparation of carbon black/single-walled carbon nanotube/silicone rubber composite conductive solution
Mixing 0.1g of carbon black and 0.05g of single-walled carbon nanotubes in a mass ratio of 2: dissolving 1 in 15mL solvent naphtha, stirring uniformly, then performing ultrasonic dispersion for 1-2 h, performing magnetic stirring for 0.5-1 h, then adding 1.0-1.5 g of silicon rubber, and continuing to perform magnetic stirring for 1-2 h to obtain a carbon black/single-walled carbon nanotube/silicon rubber composite conductive solution with the conductive filler mass fraction of 10-15%;
step 6, wrapping the outer layer conductive structure
And (3) soaking the polyurethane fiber wrapped with the inner graphene nanosheet layer in the composite conductive solution prepared in the step (5) for 5-10 min, and then placing the polyurethane fiber in a vacuum drying oven to dry for 2-3 h at the temperature of 50-70 ℃ to obtain the tensile strain sensor based on the polyurethane fiber.
In the outer layer conductive structure, the total mass fraction of the conductive filler, namely the single-walled carbon nanotube and the carbon black, in the silicon rubber needs to be controlled. Too low a mass fraction can result in too low a percolation threshold or breakage of the conductive path of the polymer filler during stretching; an excessive mass fraction of conductive filler may limit not only the flexibility of the sensor but also the stretchability of the composite material, and in addition, when the sensor is subjected to a large magnitude of strain, the film or coating in the sensor structure may have a uniform microstructure or surface morphology that changes towards a non-uniform state, resulting in a non-linear response of the sensor to continuous strain.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention is based on the combination mode of hydrogen bond theory, and leads the conductive filler to be attached on the polyurethane fiber substrate by a method of forming hydrogen bond between two molecules, namely, by sulfonic acid group (-SO) in sodium poly (styrene sulfonate)3H) The function mechanism of hydrogen bond formed between the hydroxyl (-OH) in the polyethylene glycol is utilized, so that the polyurethane fiber substrate is coated to form an inner layer conductive junctionA graphene nanosheet layer; the hydrogen bonding promotes the adhesion between the interfaces of the filler substrates to be enhanced, so that the conductive filler is uniformly and tightly bonded on the flexible and superfine polyurethane fiber substrate.
2. The invention adopts a dual-mode cooperative conduction mechanism: on one hand, a stable two-dimensional conductive network is formed by the carbon black and the single-walled carbon nanotube in the outer layer conductive structure in a point-line connection and line-line connection mode, and a good synergetic conductive mechanism is realized by the combined action of the carbon black and the single-walled carbon nanotube; on the other hand, the synergistic conduction between the inner and outer double-layer conductive structures in the laminated structure is the synergistic effect between the carbon black/single-walled carbon nanotube composite filler in the outer layer conductive structure and the graphene in the inner layer conductive structure. The double-mode synergistic conduction effect enables a good conduction path to be continued under a slightly large amplitude strain, and the conductivity and the ductility of the sensor are improved and the linear fitting degree of the sensor is improved by combining the inherent excellent characteristics of the polyurethane fiber substrate material.
3. The strain sensor has high stretchability, and can be applied to the strain range with larger amplitude, such as parts with large curvature, such as palms, joints and the like; meanwhile, the method has better sensitivity, and can be used for monitoring deformation in a small-amplitude strain range, such as fingertip movement, swallowing movement, breathing and the like; the linearity of a strain-resistance change curve is excellent, and the linear fitting degree is excellent; the durability is good, and the paint is suitable for repeated use for a long time.
4. The invention adopts a dipping-coating method to realize the compounding of the conductive filler layer and the polyurethane fiber, does not need to use a large amount of chemical reagents, and compared with the existing chemical method, the process method of the invention has the advantages of environmental protection, simple operation and low cost. Compared with rigid material sensors such as metal and semiconductor, the strain sensor has the advantages that the polyurethane fiber is used as the substrate, so that the strain sensor has good light flexibility and tensile property and large-scale integration property, and can be widely applied to wearable devices.
Drawings
FIG. 1 is a schematic diagram of the external structure of a polyurethane fiber based tensile strain sensor of the present invention;
FIG. 2 is a schematic cross-sectional view of a stretchable strain sensor based on polyurethane fibers according to the present invention;
FIG. 3 is a schematic perspective view of the hydrogen bonding principle of the stretchable strain sensor based on urethane fibers according to the present invention;
FIG. 4 is an electronic photograph of a stretchable strain sensor based on polyurethane fibers according to the present invention;
FIG. 5 is a scanning electron microscope image of a polyurethane fiber based tensile strain sensor of the present invention;
FIG. 6 is a stress-strain characteristic of a tensile strain sensor of polyurethane fibers of the present invention;
FIG. 7 is a graph of the stretch-conductivity characteristic of a polyurethane fiber-based stretchable strain sensor of the present invention over a small magnitude strain range;
FIG. 8 is a graph of the hysteresis response of a polyurethane fiber based stretchable strain sensor of the present invention during stretch-release;
FIG. 9 is a graph of tensile-conductivity characteristics of a polyurethane fiber based tensile strain sensor of the present invention over a 100% strain range and its goodness of fit value corresponding to a linear fit;
FIG. 10 is a graph of the electrical stability of a stretchable strain sensor based on polyurethane fibers in accordance with the present invention;
reference numbers in the figures: 1 is polyurethane fiber, 2 is an inner layer conductive structure, 3 is an outer layer conductive structure, 4 graphene nanosheets, 5 is a single-walled carbon nanotube, 6 is carbon black, 7 is polyethylene glycol, 8 is sodium poly (styrene sulfonate) and 9 is a hydrogen bond.
Detailed Description
The following embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are provided for implementing the technical solution of the present invention, and provide detailed embodiments and specific procedures, but the scope of the present invention is not limited to the following embodiments.
As shown in fig. 1, the structure of the tensile strain sensor based on polyurethane fiber of the present invention is: the polyurethane fiber 1 is used as a matrix, and the surface of the matrix is sequentially wrapped with an inner-layer conductive structure 2 and an outer-layer conductive structure 3; the inner layer conductive structure is a graphene nanosheet layer, and the outer layer conductive structure is a synergetic conductive network layer of carbon black and single-walled carbon nanotubes. In the figure, for the purpose of making the illustration clearer, two ends are stripped, and in practice, the three-layer structure is equal in length, namely the inner layer conductive structure and the outer layer conductive structure completely cover the polyurethane fiber.
The preparation steps of the stretchable strain sensor are as follows:
step 1, preparing polyethylene glycol aqueous solution
Weighing 0.03g of polyethylene glycol, adding the polyethylene glycol into 15mL of deionized water, magnetically stirring the mixture at 70 ℃ until the polyethylene glycol is dissolved, and then ultrasonically dispersing the mixture for 30min to obtain a polyethylene glycol aqueous solution with the concentration of 2 mg/mL;
step 2, surface modification of polyurethane fiber
Washing polyurethane fibers with deionized water to remove surface impurities, then drying in the air at normal temperature, then soaking in the aqueous solution of polyethylene glycol prepared in the step 1 for 5min, taking out, washing with deionized water again, and drying in the air at normal temperature to obtain polyethylene glycol modified polyurethane fibers;
step 3, preparing a composite aqueous solution of graphene and sodium poly (p-styrene sulfonate)
Adding 0.03g of graphene nanosheet and 0.03g of sodium poly-p-styrene sulfonate into 15mL of deionized water, mixing and uniformly stirring, ultrasonically dispersing the obtained mixed solution for 2 hours, and then magnetically stirring for 30 minutes to obtain a composite aqueous solution of graphene and sodium poly-p-styrene sulfonate;
step 4, wrapping the inner layer conductive structure
Soaking the polyurethane fiber modified by polyethylene glycol in the composite aqueous solution prepared in the step (3) for 5min, taking out, placing in the air, drying at normal temperature, repeatedly soaking and drying for 3-4 times, and passing through sulfonic group-SO in sodium poly (styrene sulfonate)3H and hydroxyl-OH in polyethylene glycol form hydrogen bonding, namely the surface of the polyurethane fiber is uniformly coated with a graphene nanosheet layer;
step 5, preparation of carbon black/single-walled carbon nanotube/silicone rubber composite conductive solution
Dissolving 0.1g of carbon black and 0.05g of single-walled carbon nanotube in 15mL of solvent naphtha, stirring uniformly, then performing ultrasonic dispersion for 1h, performing magnetic stirring for 30min, then adding 1.5g of silicon rubber, and continuing to perform magnetic stirring for 1h to obtain a carbon black/single-walled carbon nanotube/silicon rubber composite conductive solution;
step 6, wrapping the outer layer conductive structure
And (3) soaking the polyurethane fiber wrapped with the inner graphene nanosheet layer in the composite conductive solution prepared in the step (5) for 5min, and then drying in a vacuum drying oven at 50 ℃ for 3 hours to obtain the stretchable strain sensor based on the polyurethane fiber.
As shown in FIG. 2, the tensile strain sensor has a dual mode cooperative conduction mechanism: on the one hand, the synergistic conduction mechanism between the carbon black 6 and the single-walled carbon nanotube 5 in the outer-layer conductive structure 3 is adopted; on the other hand, the composite material is a synergistic conduction mechanism between an inner double-layer conduction structure and an outer double-layer conduction structure in a laminated structure, namely the synergistic effect between carbon black and single-walled carbon nanotube composite filler in the outer layer conduction structure and graphene nanosheets in the inner layer conduction structure.
Wherein, as shown in the hydrogen bonding principle diagram of FIG. 3, the invention is based on the bonding mode of hydrogen bonding theory, and sulfonic acid group (-SO) in the sodium poly (p-styrene sulfonate) 8 is passed through3H) And a hydrogen bond 9 is formed between the graphene nano sheet and hydroxyl (-OH) in polyethylene glycol 7, so that the graphene nano sheet 4 serving as an inner layer conductive structure is wrapped on the polyurethane fiber substrate.
An electronic photograph of the tensile strain sensor prepared by the invention is shown in fig. 4, and 3 products in the drawing sequentially comprise polyurethane fibers, polyurethane fibers wrapped with an inner-layer conductive structure and an outer-layer conductive structure (namely, the tensile strain sensor of the invention). It can be seen from the figure that the prepared sensor has good flexibility and ductility, and can be used for further design and manufacture of wearable devices.
Fig. 5 is a scanning electron microscope image of the stretchable strain sensor based on polyurethane fiber according to the present invention, wherein (a) and (b) are polyurethane fibers wrapping graphene nanoplatelets with inner conductive structures, it can be seen that graphene is uniformly dense and dispersed around the substrate material; (c) and (d) the surface of the sensor, namely the polyurethane fiber wrapped with an inner and an outer double-layer conductive structures, and the figure shows that the single-walled carbon nanotube and the carbon black are well dispersed in the silicon rubber matrix and uniformly and tightly wrap the substrate and the inner layer structure.
In order to test the maximum stretchable limit of the stretchable strain sensor obtained in the present invention, stress-strain tests were performed on the pure polyurethane fiber substrate and the sensor sample, respectively, and the results are shown in fig. 6, it can be seen that the elongation at break of the polyurethane fiber substrate and the sensor sample are 740% and 350%, respectively, which indicates that the substrate material has excellent flexibility and stretchability, and the prepared sensor also has excellent stretchability.
Fig. 7 is a graph of the monitoring of the change in sensor resistance during cyclic loading and release at different strains, showing the dynamic behavior of the device. No excessive change and no significant drift were found for different strains under continuous loading, demonstrating outstanding flexibility and repeatability at various strains.
Fig. 8 illustrates the hysteretic response of the sensor under dynamic loading, and it can be seen that the sensor of the present invention has a substantially negligible hysteretic response.
In order to characterize the linearity performance of the tensile strain sensor obtained by the invention, the strain resistance curves of the obtained sensor under 10%, 30%, 50% and 100% strains are respectively subjected to linear fitting, and the result is shown in fig. 9, and it can be seen that the goodness-of-fit value of the sensor under 10% -100% strains is more than 0.990, which shows that the linearity is excellent.
FIG. 10 is the stability of the sensor with the number of stretches at 25% tensile strain strength. As can be seen from the figure, the resistance was substantially stable in the 25% stretch range after the sensor was stretched 2400 times, indicating that the sensor of the present invention has excellent reproducibility and durability.

Claims (4)

1. A preparation method of a stretchable strain sensor based on polyurethane fibers is characterized by comprising the following steps: the stretchable strain sensor takes polyurethane fiber as a substrate, and an inner-layer conductive structure and an outer-layer conductive structure are sequentially wrapped on the surface of the substrate; the inner layer conductive structure is a graphene nanosheet layer, and the outer layer conductive structure is a synergistic conductive network layer of carbon black and a single-walled carbon nanotube;
the preparation method of the stretchable strain sensor comprises the following steps:
step 1, preparing aqueous solution of polyethylene glycol
Weighing 0.03-0.06 g of polyethylene glycol, adding the polyethylene glycol into 15mL of deionized water, magnetically stirring at 60-80 ℃ until the polyethylene glycol is dissolved, and then ultrasonically dispersing for 0.5-1 h to obtain a polyethylene glycol aqueous solution with the concentration of 2-4 mg/mL;
step 2, surface modification of polyurethane fiber
Washing polyurethane fibers with deionized water to remove surface impurities, then drying in the air at normal temperature, soaking in the aqueous solution of polyethylene glycol prepared in the step 1 for 5-10 min, taking out, washing with deionized water again, and drying in the air at normal temperature to obtain polyethylene glycol modified polyurethane fibers;
step 3, preparing a composite aqueous solution of graphene and sodium poly (p-styrene sulfonate)
0.03-0.06 g of graphene nanosheet and 0.03-0.06 g of sodium poly-p-styrene sulfonate are mixed according to the mass ratio of 1: 1, adding the mixture into 15mL of deionized water, mixing and uniformly stirring, ultrasonically dispersing the obtained mixed solution for 2-3 h, and then magnetically stirring for 0.5-1 h to obtain a composite aqueous solution of graphene and sodium poly-p-styrene sulfonate;
step 4, wrapping the inner layer conductive structure
Soaking the polyurethane fiber modified by polyethylene glycol in the composite aqueous solution prepared in the step (3) for 5-10 min, taking out, placing in the air, drying at normal temperature, repeatedly soaking and drying for 3-4 times, and passing through sulfonic group-SO in poly (p-styrene) sodium sulfonate3H and hydroxyl-OH in polyethylene glycol form hydrogen bonding, namely the surface of the polyurethane fiber is uniformly coated with a graphene nanosheet layer;
step 5, preparation of carbon black/single-walled carbon nanotube/silicone rubber composite conductive solution
Mixing 0.1g of carbon black and 0.05g of single-walled carbon nanotubes in a mass ratio of 2: dissolving 1 in 15mL solvent naphtha, stirring uniformly, then performing ultrasonic dispersion for 1-2 h, performing magnetic stirring for 0.5-1 h, then adding 1.0-1.5 g of silicon rubber, and continuing to perform magnetic stirring for 1-2 h to obtain a carbon black/single-walled carbon nanotube/silicon rubber composite conductive solution with the conductive filler mass fraction of 10-15%;
step 6, wrapping the outer layer conductive structure
And (3) soaking the polyurethane fiber wrapped with the inner graphene nanosheet layer in the composite conductive solution prepared in the step (5) for 5-10 min, and then placing the polyurethane fiber in a vacuum drying oven to dry for 2-3 h at the temperature of 50-70 ℃ to obtain the tensile strain sensor based on the polyurethane fiber.
2. The method of claim 1, wherein: the tensile strain sensor has a dual mode cooperative conduction mechanism: on one hand, the carbon black and the single-walled carbon nanotube in the outer layer conductive structure are in a cooperative conductive mechanism; on the other hand, the structure is a synergistic conduction mechanism between an inner double-layer conduction structure and an outer double-layer conduction structure in the laminated structure, namely the synergistic effect between the carbon black and the single-walled carbon nanotube composite filler in the outer layer conduction structure and the graphene in the inner layer conduction structure.
3. The method of claim 1, wherein: the breaking strength of the polyurethane fiber is 0.03-0.09N/tex, and the breaking elongation is 450-800%.
4. The method of claim 1, wherein: the tensile strain sensor has an elongation at break of 350% and a linear fit goodness of fit value of 0.990-1 for strain resistance change curves in the 0-100% tensile range.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106052544A (en) * 2016-05-18 2016-10-26 郑州大学 Flexible wearable strain sensor and preparation method thereof
CN106609396A (en) * 2016-09-30 2017-05-03 郑州大学 Elastic electric-conductive nano-fiber yarns and preparation method for same

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EP1313900A4 (en) * 2000-08-24 2011-12-07 Univ Rice William M Polymer-wrapped single wall carbon nanotubes

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106052544A (en) * 2016-05-18 2016-10-26 郑州大学 Flexible wearable strain sensor and preparation method thereof
CN106609396A (en) * 2016-09-30 2017-05-03 郑州大学 Elastic electric-conductive nano-fiber yarns and preparation method for same

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