Preparation method and application of conductive fiber material with tensile negative resistance response

Abstract

The invention discloses a preparation method and application of a conductive fiber material with tensile negative resistance response. The preparation method comprises the following steps: S1, performing melt spinning on polyester to obtain polyester filaments; s2, performing drafting, false twisting and heat setting on the polyester filament yarns to form polyester tensile deformation grid yarns; s3, immersing the polyester tensile deformation grid yarns in a Tris buffer solution, and adding dopamine to polymerize the polyester tensile deformation grid yarns to form a polydopamine layer; s4, the polyester grid yarn with the polydopamine layer is soaked in a solution containing silver ions, and the silver ions are chelated with amino and phenolic hydroxyl groups in polydopamine; and S5, reducing silver ions on the surface of the fiber into silver nanoparticles through an in-situ reduction reaction, and uniformly loading the silver nanoparticles on the surface of the polyester mesh yarn by utilizing the adsorption effect of polydopamine. The conductive fiber prepared by the method disclosed by the invention has negative resistance response, and is suitable for the fields of intelligent wearable textile equipment, medical monitoring equipment and textile materials needing conductive and antibacterial properties at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of conductive fibers, in particular to a method for preparing a conductive fiber material with a stretched negative resistance response. Background Art

[0002] Wearable devices have shown great potential in many fields such as healthcare sensors, soft robots, and smart clothing due to their lightness, flexibility, and comfort. In recent years, the rapid development of wearable devices has greatly promoted the research of functional fiber materials. Among them, conductive fibers, as key materials for wearable devices, have attracted widespread attention because of their ability to sense and respond to external stimuli (such as stretching, pressure, and temperature).

[0003] Existing conductive fibers face many challenges in the application process, especially the problem of increased resistance and bacterial growth during the stretching process. The increase in resistance directly leads to a decrease in conductivity, which affects the real-time data transmission and function execution of wearable devices, causing signal instability and increased energy consumption, and shortening the battery life. In addition, over time, fluctuations in resistance may cause material fatigue and reduce the durability of the device. At the same time, conductive fibers are prone to breeding bacteria because they fit the skin, which may cause health risks such as skin infections and allergic reactions. In addition, bacterial metabolites will form a dirt layer on the fiber surface, further affecting the conductivity and mechanical properties and reducing the service life. For a long time, bacterial growth may also cause odor and irritation, affecting the user experience. Therefore, the development of a conductive fiber that can maintain low resistance and has antibacterial properties during the stretching process is crucial to improving the overall performance, safety and user experience of wearable devices. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a conductive fiber material with a negative resistance response under tension and its application, so as to solve the problems in the prior art.

[0005] In a first aspect, the present invention provides a method for preparing a conductive fiber material having a negative resistance response when stretched, comprising the following steps:

[0006] S1: melt spinning polyester to obtain polyester filaments;

[0007] S2: drawing, false twisting and heat setting the polyester filaments to form polyester stretched and deformed mesh yarns;

[0008] S3: immersing the polyester stretched mesh in a Tris buffer solution, adding dopamine to polymerize it to form a polydopamine layer;

[0009] S4: The polyester mesh with the polydopamine layer is immersed in a silver nitrate solution, and the silver ions chelate with the amino and phenolic hydroxyl groups in the polydopamine;

[0010] S5: The silver ions on the fiber surface are reduced to silver nanoparticles through an in-situ reduction reaction, and the silver nanoparticles are evenly loaded on the surface of the polyester mesh fiber by the adsorption effect of polydopamine.

[0011] A method for preparing a conductive fiber material with a stretched negative resistance response as described above, wherein, preferably, in step S2, the polyester filament drawing speed is 300-500 m / min, the drawing ratio is 1.5-2.5 times, the false twist speed is 800-1200 rpm, the twist range is 50-70 twists / m, the heat setting temperature is 160-180°C, and the setting time is 30-60 seconds.

[0012] The method for preparing a conductive fiber material with a stretched negative resistance response as described above, wherein preferably, the pH value of the tris buffer in step S3 is 8.5-9.0, the reaction temperature of the polyester stretched deformed mesh yarn immersed in the Tris buffer solution is 30-45°C, and the reaction time is 6-12 hours.

[0013] In the method for preparing a conductive fiber material with a stretched negative resistance response as described above, preferably, the concentration of the silver nitrate in step S4 is 0.05-0.10 mol / L.

[0014] The method for preparing a conductive fiber material with a stretched negative resistance response as described above, wherein preferably, the reducing agent of the in-situ reduction reaction is a glucose solution, the concentration of the glucose solution is 0.2-0.4 mol / L, the reaction temperature of the in-situ reduction reaction is 30-40°C, and the reaction time is 20-40 minutes.

[0015] In the second aspect, the present invention provides an application of a conductive fiber material with a negative resistance response when stretched, and the conductive fiber material with a negative resistance response when stretched prepared by the aforementioned method for preparing the conductive fiber material with a negative resistance response when stretched is used in strain sensing and antibacterial textiles.

[0016] Compared with the prior art, the conductive fiber prepared by the method of the present invention is based on polyester stretched and deformed mesh yarn. Polydopamine is grown on the polyester mesh yarn through a tris solution, and its good adhesion is utilized to form a uniform coating on the fiber surface. Then, silver nanoparticles are plated on the fiber surface through a reduction reaction-adsorption synergistic effect, giving the fiber good conductivity and antibacterial properties. The conductive fiber of the present invention exhibits a negative resistance response under tension, that is, when the fiber is stretched, its resistance decreases with the increase in the degree of stretching. This phenomenon is due to the special structure of the polyester mesh yarn. During the stretching process, the fiber shrinks due to the fluffy structure, which increases the contact area between the fibers, thereby enhancing the connection of the conductive network and reducing the overall resistance. In addition, the silver particles are plated on the fiber surface, giving the fiber antibacterial properties, effectively inhibiting the growth of bacteria, so that the conductive fiber can maintain good performance and safety during long-term use.

[0017] The preparation method of the present invention is simple, and the process flow is easy for industrial production. The prepared conductive fiber not only has a negative resistance response, but also has antibacterial properties. It is suitable for smart wearable textile devices, medical monitoring equipment, and textile materials that need to have both conductive and antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a physical picture of a conductive fiber material with a negative resistance response when stretched, which is prepared by the present invention;

[0019] Figure 2 This is a scanning electron microscope image of a conductive fiber material with a stretched negative resistance response obtained by the present invention;

[0020] Figure 3 This is a resistance effect diagram of a conductive fiber material with a negative resistance response when stretched, which is prepared by the present invention;

[0021] Figure 4 This is a diagram showing the antibacterial effect of a conductive fiber material with a stretched negative resistance response prepared by the present invention;

[0022] Figure 5 This is a diagram showing the resistance change of a conductive fiber material with a negative resistance response under stress loading and unloading conditions obtained by the present invention.

[0023] Figure 6 It is a resistance change rate diagram of a conductive fiber material with a stretched negative resistance response prepared by the present invention under different strain conditions;

[0024] Figure 7 It is a resistance change rate diagram of a conductive fiber material with a stretched negative resistance response prepared by the present invention under different frequency conditions;

[0025] Figure 8The figure is a resistance change rate diagram of a conductive fiber material with a negative resistance response when stretched, which is prepared by the present invention, on a model's arm. DETAILED DESCRIPTION

[0026] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but should not be construed as limiting the present invention.

[0027] The present invention provides a method for preparing a conductive fiber material with a tensile negative resistance response, which comprises the following steps:

[0028] S1: Preparation of polyester mesh yarn

[0029] The polyester pre-oriented yarn is prepared by melt spinning process and has high initial strength and good stretchability.

[0030] S2: The pre-oriented yarn is drawn, false-twisted, and heat-set to form a polyester stretched and deformed mesh yarn.

[0031] The drafting ratio is set to 1.8 times and the drafting speed is 400 m / min. This drafting ratio ensures that the fiber has appropriate tensile strength and elastic recovery. This drafting condition can form a stable grid-like fluffy structure, providing a basis for the subsequent tensile negative resistance effect.

[0032] The false twist speed is set at 1000 rpm and the twist is 60 twists / m. This speed and twist can ensure that the fiber has moderate curl and fluffiness while maintaining good mechanical properties. The optimization of the false twist process helps the conductive fiber to produce uniform stress distribution during the strain process, so that it can stably exhibit negative resistance response characteristics.

[0033] The false-twisted fiber was heat-set at a temperature of 170°C for 45 seconds. The heat-setting process can eliminate the residual stress inside the fiber and stabilize the curling structure of the fiber.

[0034] S3: Dopamine polymerization

[0035] Dopamine was added to the tris buffer and the polyester mesh was immersed in the solution.

[0036] The pH value of the dopamine-tris solution is controlled at 8.5, the reaction temperature is 40°C, and the immersion time is 8 hours, so that dopamine can be evenly deposited on the surface of the mesh wire to form a stable polydopamine coating.

[0037] After the polymerization is completed, the fiber surface is cleaned with deionized water to remove unreacted dopamine. After cleaning, the fiber is dried at 50°C.

[0038] S4: Silver particle deposition process

[0039] An ammoniacal silver nitrate solution is prepared, the concentration of the silver nitrate is 0.08 mol / L, and the fiber is immersed in the reaction solution, and the silver ions chelate with the amino groups and phenolic hydroxyl groups in the polydopamine.

[0040] S5: The silver ions on the fiber surface are reduced to silver nanoparticles by an in-situ reduction reaction, and the silver nanoparticles are uniformly loaded on the surface of the polyester mesh by the adsorption of polydopamine. The in-situ reduction reaction uses a 0.3 mol / L glucose solution as a reducing agent.

[0041] The reaction temperature was 35°C and the reaction time was 30 minutes. In this process, silver ions were deposited to form silver particles under the reduction of glucose and fixed on the fiber surface through the chelation and adhesion of the polydopamine layer. Figure 1 As shown, a conductive fiber material with a negative resistance response upon stretching is obtained.

[0042] 1. Use an electron microscope to detect the stretched negative resistance responsive conductive fiber material provided in Example 1. Figure 2 As shown in the figure, silver ions (Ag+) are reduced to silver particles in situ on the fiber surface, which are evenly distributed to form a conductive layer. This conductive layer significantly improves the conductivity of the fiber. Figure 3 As shown in the figure, by measuring the resistivity during the stretching process to evaluate its conductivity, it can be seen that the resistance of the fiber continues to decrease during the stretching process. This is mainly because the polyester mesh is made of multi-layered curved fiber bundles interwoven with each other. This structure provides a large number of gaps, allowing the fiber to stretch while maintaining its conductivity during stretching. This fluffy structure can ensure good elasticity and flexibility while maintaining conductivity. As the stretching progresses, the fibers gradually arrange in an orderly manner. In this process, the contact between the conductive particles increases, forming a new conductive path.

[0043] Second, the conductive fiber material in Example 1 was subjected to an antibacterial experiment. Figure 4 As shown, the prepared fiber was placed in a culture medium containing Staphylococcus aureus, and a decrease in the number of colonies was observed after 24 hours. The experimental results show that the silver particles on the fiber surface have a significant antibacterial effect and effectively inhibit the growth of bacteria.

[0044] 3. Perform motion monitoring test on the strain sensor assembled with the stretched negative resistance responsive conductive fiber material obtained in Example 1. Figure 5The figure is a graph of the relative resistance change of the stretched negative resistance responsive conductive fiber material under stress loading and unloading. As the strain increases, the relative resistance change of the fiber continues to decrease. The fiber strain sensor exhibits negligible electrical hysteresis during the loading and unloading cycles. The above results confirm that the relationship between the relative resistance change and the tensile strain of the stretched negative resistance responsive conductive fiber material shows good monotonicity in the absence of other interference factors, and has good signal accuracy and reliability. The resistance change of the fiber was tested in the strain range of 0-40%. Figure 6 As shown in the figure, as the strain increases, the resistance of the fiber gradually decreases, showing a typical strain negative resistance response characteristic. This phenomenon is attributed to the change in the fiber arrangement, which leads to an increase in the number of conductive contact points, thereby causing a decrease in resistance. Figure 7 The change curve of relative resistance under 40% strain at different frequencies (0.02Hz-0.10Hz) is shown. The results show that within this frequency range, the fiber exhibits a negative strain resistance response, which makes it have good application prospects in wearable devices. In addition, Figure 8 As shown in the figure, the sensor is attached to the surface of the arm and tensile strain occurs during bending. From the relative resistance change curve, it can be seen that the sensor can quickly identify the bending posture of the index finger and convert it into a stable resistance change signal.

[0045] Therefore, a conductive fiber material with a stretched negative resistance response has excellent sensing performance and reliable antibacterial properties as a wearable sensor, which has great prospects in the field of smart wearable textiles such as personal health monitoring.

[0046] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made according to the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present invention.

Claims

1. A method for preparing a conductive fiber material with a tensile negative resistance response, characterized in that: The following steps are involved: S1: melt spinning polyester to obtain polyester filaments; S2: drawing, false twisting and heat setting the polyester filaments to form polyester stretched and deformed mesh yarns; S3: immersing the polyester stretched mesh in a Tris buffer solution, adding dopamine to polymerize it to form a polydopamine layer; S4: The polyester mesh with the polydopamine layer is immersed in a silver nitrate solution, and the silver ions chelate with the amino and phenolic hydroxyl groups in the polydopamine; S5: The silver ions on the fiber surface are reduced to silver nanoparticles through an in-situ reduction reaction, and the silver nanoparticles are evenly loaded on the surface of the polyester mesh fiber by the adsorption effect of polydopamine.

2. The method for preparing a conductive fiber material with a stretched negative resistance response according to claim 1, characterized in that: In step S2, the polyester filament drawing speed is 300-500 m / min, the drawing ratio is 1.5-2.5 times, the false twist speed is 800-1200 rpm, the twist range is 50-70 twists / m, the heat setting temperature is 160-180°C, and the setting time is 30-60 seconds.

3. The method for preparing a conductive fiber material with a stretched negative resistance response according to claim 1, characterized in that: The pH value of the tris buffer in step S3 is 8.5-9.0, the reaction temperature of the polyester stretched deformed mesh yarn immersed in the tris buffer solution is 30-45° C., and the reaction time is 6-12 hours.

4. The method for preparing a conductive fiber material with a stretched negative resistance response according to claim 1, characterized in that: The concentration of silver nitrate in step S4 is 0.05-0.10 mol / L.

5. The method for preparing a conductive fiber material with a stretched negative resistance response according to claim 1, characterized in that: The reducing agent of the in-situ reduction reaction is a glucose solution, the concentration of the glucose solution is 0.2-0.4 mol / L, the reaction temperature of the in-situ reduction reaction is 30-40° C., and the reaction time is 20-40 minutes.

6. An application of a conductive fiber material with a tensile negative resistance response, characterized in that: The conductive fiber material with a stretched negative resistance response prepared by the method for preparing the conductive fiber material with a stretched negative resistance response according to any one of claims 1 to 5 is used in strain sensing and antibacterial textiles.

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