A solvent-free ion conductive fiber, a preparation method and application thereof

Abstract

The application provides a solvent-free ion conductive fiber and a preparation method and application thereof, and comprises the following steps: mixing dimethylsiloxane and a catalyst as a skin layer spinning solution; mixing methoxy polyethylene glycol acrylate, N,N-dimethyl acrylamide, lithium bistrifluoromethanesulfonimide and 2,2-diethoxyphenylacetone to obtain a core layer spinning solution; extruding the skin layer spinning solution and the core layer spinning solution into an oil bath through coaxial needles to obtain an initial fiber; and drying the initial fiber to obtain the solvent-free ion conductive fiber. The skin layer of the solvent-free ion conductive fiber is polydimethylsiloxane, which endows the fiber with hydrophobicity and mechanical protection; the core layer is a solvent-free ion conductive elastomer, and lithium ions are combined in the polydimethylsiloxane network through coordination bonds, which endows the fiber with intrinsic ion conductivity. The solvent-free ion conductive fiber maintains excellent stretchability and stable strain sensing response in the range of-50 DEG C to 50 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of flexible materials technology, specifically relating to a solvent-free ion-conductive fiber, its preparation method, and its application. Background Technology

[0002] As human activities continue to expand into extreme environments such as polar glaciers, high-altitude snowfields, and even outer space, developing sensing materials capable of operating stably under ultra-low temperature conditions has become a key requirement for exploring the unknown. Especially in scenarios such as aerospace exploration, polar scientific expeditions, and high-altitude sports, temperatures can drop below -70°C, where traditional sensing materials often fail due to low-temperature embrittlement and decreased conductivity. Therefore, developing flexible sensing materials capable of real-time and precise monitoring of human activity or equipment deformation in ultra-low temperature regions not only has significant scientific research value but also holds broad application prospects.

[0003] Most existing low-temperature resistant materials exist in thin film or bulk form, which suffers from poor air permeability and inability to be cut, severely limiting their application in wearable devices. Currently reported solvent-free ionic conductors are mostly limited to bulk or thin film forms and have not yet been prepared into fibers, which greatly restricts their application in the wearable field. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to obtain solvent-free ion-conductive fibers.

[0005] The present invention solves the above-mentioned technical problems through the following technical means:

[0006] This invention provides a method for preparing solvent-free ion-conductive fibers, comprising the following steps: mixing dimethylsiloxane emulsion with a curing agent as a sheath spinning solution; mixing methoxy polyethylene glycol acrylate, N,N-dimethylacrylamide, lithium bis(trifluoromethanesulfonyl)imide, and 2,2-diethoxyacetophenone to prepare a core spinning solution; extruding the sheath spinning solution and the core spinning solution into an oil bath through a coaxial needle to form a preliminary fiber; and drying the preliminary fiber to obtain solvent-free ion-conductive fibers.

[0007] Beneficial Effects: The solvent-free ion-conductive fiber of this invention has a sheath of polydimethylsiloxane, which imparts hydrophobicity and mechanical protection to the fiber. The core layer is a solvent-free ion-conductive elastomer, in which lithium ions are bound to the polydimethylsiloxane network through coordination bonds, giving the fiber intrinsic ion conductivity. The solvent-free ion-conductive fiber maintains excellent stretchability and stable strain sensing response within a temperature range of -50℃ to 50℃. It can be woven into fabric and can accurately and in real time detect externally applied deformations. This invention solves the problems of traditional low-temperature resistant materials being difficult to fiberize and having poor environmental stability, providing a new solution for wearable sensing, smart fabrics, and human motion monitoring in extreme environments.

[0008] Preferably, the mass ratio of dimethylsiloxane to curing agent is 100:8~12.

[0009] Preferably, the mass ratio of methoxy polyethylene glycol acrylate, N,N-dimethylacrylamide, lithium bis(trifluoromethanesulfonylimide) and 2,2-diethoxyacetophenone is 3~5:3~5:1~3:0.05~0.2.

[0010] Preferably, the extrusion rate of the sheath spinning solution is 350~450 uL / min.

[0011] Preferably, the core layer spinning solution extrusion rate is 150~250 uL / min.

[0012] Preferably, the extrusion rate ratio of the sheath spinning solution to the core spinning solution is 1.5~2.5:1.

[0013] Beneficial effects: The present invention aims to facilitate the preferential forming of the skin layer and increase the skin layer thickness by controlling the extrusion rate and extrusion rate ratio; it also facilitates the extrusion of the core layer without breaking the skin layer.

[0014] Preferably, the temperature of the oil bath is 160~200℃.

[0015] More preferably, the oil in the oil bath is dimethoxysilicone oil.

[0016] Preferably, the drying temperature is 180~220℃ and the time is 1~3h.

[0017] The second aspect of the present invention provides a method for preparing the above-mentioned solvent-free ion-conductive fiber to obtain solvent-free ion-conductive fiber.

[0018] The third aspect of the present invention provides the application of the above-mentioned solvent-free ion-conductive fiber in -50~50°C.

[0019] Beneficial effects: The solvent-free ion-conductive fiber of the present invention generates a stable resistance response signal in the range of -50~50℃ to 0-100% applied strain.

[0020] The fourth aspect of the present invention provides the application of the above-mentioned solvent-free ion-conductive fibers in wearable electronic devices, smart fabrics or extreme environment monitoring devices.

[0021] Beneficial effects: The solvent-free ion-conductive fiber of the present invention can be attached to the surface of the object being tested or into the fabric, and can monitor the change of sensor resistance in the range of -50~50℃ to identify and quantify the deformation of the object in real time.

[0022] This invention involves thermally polymerizing polydimethylsiloxane with a solvent-free ion-conductive elastomer and then coaxially spinning it to obtain solvent-free ion-conductive fibers. The solvent-free ion-conductive fibers maintain stretchability within a temperature range of -50℃ to 50℃, with an elongation at break of not less than 200%. After repeated stretching, the core-skin interface of the solvent-free ion-conductive fibers exhibits good bonding without core-skin delamination. After 1000 tensile cycles at 100% strain, the surface and cross-sectional microstructure remain intact. Attached Figure Description

[0023] Figure 1 This is an image showing the appearance of the solvent-free ion-conductive fiber formed into a filament in an oil bath in Embodiment 1 of the present invention; Figure 2 This is an image of the initial yarn before drying in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the solvent-free ion-conductive fiber stretchable according to Embodiment 1 of the present invention; Figure 4 This is a surface microstructure diagram of the solvent-free ion-conductive fiber of Embodiment 1 of the present invention; Figure 5 This is a cross-sectional microstructure diagram of the solvent-free ion-conductive fiber of Embodiment 1 of the present invention; Figure 6 This is a graph showing the resistance signal versus time variation of the solvent-free ion-conductive fiber in Application Example 1 of this invention. Figure 7 This is a stretching diagram of the fabric made of solvent-free ion-conductive fibers in Application Example 2 of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0026] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0027] Dimethylsiloxane is SYLGARD TM184 Silicone Elastomer Base; Curing agent is 184 Silicone Elastomer Curing Agent.

[0028] Example 1 This embodiment provides a method for preparing solvent-free ion-conductive fibers, including the following steps: S1 mixes 100g of dimethylsiloxane with 10g of curing agent as a skin spinning solution.

[0029] S2 prepares a core spinning solution by mixing 4g of methoxy polyethylene glycol acrylate, 4g of N,N-dimethylacrylamide, 2g of lithium bis(trifluoromethanesulfonyl)imide and 0.1g of 2,2-diethoxyacetophenone.

[0030] S3 uses a syringe to extract the sheath spinning solution and the core spinning solution. The sheath spinning solution is injected from the syringe into a 23G coaxial needle using a syringe pump, and the core spinning solution is injected from the syringe into a 16G coaxial needle using the same pump. The sheath spinning solution from the coaxial needle is then extruded into a 180°C dimethoxysilicone oil bath at a rate of 350 μL / min, while the core spinning solution from the coaxial needle is extruded into the same bath at a rate of 150 μL / min. The mixture is then molded in the dimethoxysilicone oil bath for 15 minutes to obtain the initial filament. The initial filament is as follows... Figure 1 As shown.

[0031] according to Figure 1 It is evident that because the polydimethylsiloxane in the sheath spinning solution is not fully cross-linked, the initial filament has low mechanical strength and cannot be directly removed. The polymerization reaction in the core spinning solution is not yet fully complete, and the core spinning solution still possesses a certain degree of fluidity. Therefore, the synthesized initial filament still needs to be heated in a 180℃ dimethoxysilicone oil bath to promote its formation and increase its mechanical strength until it can be removed as a whole.

[0032] S4 places the raw yarn in an oven at 200℃ for 2 hours to dry it, thus obtaining solvent-free ion-conductive fibers.

[0033] The raw yarn, before drying treatment, is as follows: Figure 2 As shown. According to Figure 2 It is known that although the initial filament treated in a 180℃ dimethoxysilicone oil bath has good mechanical strength and can be extracted as a whole, the polydimethylsiloxane in the sheath spinning solution is not fully cross-linked at this time, resulting in lower mechanical strength. The polymerization reaction in the core spinning solution is not fully completed, leading to poor mechanical resilience. At this point, stretching the fiber will cause stress concentration due to the poor resilience of the core spinning solution, causing the middle part of the initial filament to bend and fail to rebound.

[0034] The initial filament is dried to obtain solvent-free ion-conductive fiber, such as... Figure 3 As shown. According to Figure 3 It is known that the catalyst in the sheath spinning solution continuously promotes the sheath cross-linking reaction of the initial filament, improving the mechanical strength of the sheath and ensuring that the core layer does not leak. The cross-linking of the core layer also occurs simultaneously, increasing its resilience. After drying, the initial filament is transformed into a solvent-free ionic conductive fiber. When the stress is removed after stretching the solvent-free ionic conductive fiber, it can return to its original length.

[0035] The performance of solvent-free ion-conductive fibers was tested. The specific procedure was as follows: the solvent-free ion-conductive fibers were stretched to 100% and repeated 1000 times to obtain G1; G1 was then cut into several equal segments to obtain G2. The surface microstructure of G2 was imaged using a scanning electron microscope. Figure 4 As shown, the cross-sectional microstructure of G2 was captured using a scanning electron microscope. Figure 5 As shown.

[0036] according to Figure 4 It can be seen that the surface of the solvent-free ion-conductive fiber is smooth and without cracks. This indicates that the solvent-free ion-conductive fiber has good mechanical resilience and structural stability.

[0037] according to Figure 5 It is evident that the solvent-free ion-conductive fiber possesses a clear core-sheath structure, with the core layer of solvent-free ion-conductive material tightly encapsulated by the PDMS sheath. Furthermore, there are no gaps between the sheath and the core layer, indicating a strong bond between them and no mechanical mismatch between them.

[0038] Application Example 1 This application example demonstrates the use of the solvent-free ion-conductive fiber from Example 1 at -50 to 50°C, including the following steps: S1 Cut the solvent-free ion-conductive fiber to a length of 10cm and denote it as G3; connect the two ends of G3 to silver electrode wires and fix the wires with conductive silver paste and epoxy adhesive and denote it as G4; S2 connects G4 to an electronic universal testing machine with an environmental control box, and connects two silver electrode wires to a digital source meter. The controlled temperatures are -50℃, -25℃, 0℃, 25℃, and 50℃, the tensile rate is 50 mm / min, and the tensile strain is 100%, resulting in the following... Figure 6 The graph shows the resistance signal versus time.

[0039] according to Figure 6 It is known that the solvent-free ion-conductive fiber of the present invention has good and stable response performance to deformation applied by the external environment in the range of -50~50℃; in particular, it has good and stable response performance to deformation applied by the external environment at -50℃.

[0040] Application Example 2 This application example provides the application of the solvent-free ion-conductive fiber fabric of Example 1, including the following steps: S1 woven solvent-free ion-conductive fibers into fabric G5; G5 was then cooled to -50°C for 24 hours and stretched to obtain G6. The ambient temperature and the stretched state of G6 were recorded using an infrared thermal imaging camera. Figure 7 As shown.

[0041] according to Figure 7 It was found that a fabric woven from solvent-free ion-conductive fibers was tested, and its tensile properties at -50°C were examined to investigate the effect of temperature on the solvent-free ion-conductive fibers and their fabric. Observation using an infrared thermal imaging camera showed that the fabric made from solvent-free ion-conductive fibers could still be stretched at -50°C. This ability to be stretched at -50°C is attributed to the excellent freeze-thaw resistance of the PDMS sheath layer and the solvent-free ion-conductive core layer in the solvent-free ion-conductive fibers. Therefore, the solvent-free ion-conductive fiber-based fabric of this invention exhibits excellent mechanical tensile properties at -50°C. This lays the foundation for using solvent-free ion-conductive fibers as sensing materials at ultra-low temperatures.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing solvent-free ion-conductive fibers, characterized in that, Includes the following steps: Dimethylsiloxane is mixed with a curing agent to form a skin spinning solution; a core spinning solution is prepared by mixing methoxy polyethylene glycol acrylate, N,N-dimethylacrylamide, lithium bis(trifluoromethanesulfonyl)imide and 2,2-diethoxyacetophenone; the skin spinning solution and the core spinning solution are extruded into an oil bath through a coaxial needle to form a preliminary fiber; the preliminary fiber is dried to obtain solvent-free ion-conductive fiber.

2. The method for preparing solvent-free ion-conductive fibers according to claim 1, characterized in that, The mass ratio of dimethylsiloxane to curing agent is 100:8~12.

3. The method for preparing solvent-free ion-conductive fibers according to claim 1, characterized in that, The mass ratio of methoxy polyethylene glycol acrylate, N,N-dimethylacrylamide, lithium bis(trifluoromethanesulfonylimide) and 2,2-diethoxyacetophenone is 3~5:3~5:1~3:0.05~0.

2.

4. The method for preparing solvent-free ion-conductive fibers according to claim 1, characterized in that, The extrusion rate of the cortex spinning solution is 350~450 uL / min; the extrusion rate of the core spinning solution is 150~250 uL / min.

5. The method for preparing solvent-free ion-conductive fibers according to claim 4, characterized in that, The extrusion rate ratio of the cortex spinning solution to the core spinning solution is 1.5~2.5:

1.

6. The method for preparing solvent-free ion-conductive fibers according to claim 1, characterized in that, The temperature of the oil bath is 160~200℃.

7. The method for preparing solvent-free ion-conductive fibers according to claim 1, characterized in that, The drying temperature is 180~220℃, and the time is 1~3h.

8. A method for preparing solvent-free ion-conductive fibers as described in any one of claims 1-7 yields solvent-free ion-conductive fibers.

9. The application of the solvent-free ion-conductive fiber as described in claim 8 at -50~50°C.

10. The application of the solvent-free ion-conductive fiber as described in claim 8 in wearable electronic devices, smart fabrics, or extreme environment monitoring devices.

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