Preparation method of temperature-responsive controllable liquid-guiding functional yarn

Abstract

The application relates to the field of intelligent textiles, and discloses a preparation method of temperature-responsive controllable liquid-guiding functional yarn, which comprises the following steps: (1) preparing a temperature-sensitive polymer; (2) sequentially electrospinning a temperature-sensitive polymer spinning solution and a hydrophobic polyurethane spinning solution on the surface of a hydrophilic cotton yarn through conjugate electrospinning technology to obtain a micro-nano composite yarn with a core layer of the hydrophilic cotton yarn, an intermediate layer of a temperature-sensitive nanofiber layer and a shell layer of a hydrophobic polyurethane nanofiber layer; and (3) heat treating and crosslinking the yarn to obtain a finished product. The composite yarn prepared by the application has temperature responsiveness, can be switched through the wettability of the temperature-sensitive nanofiber layer, can control the thickness of the hydrophobic layer in the composite yarn through the wettability of the intermediate temperature-sensitive nanofiber, and can further realize accurate control of the liquid transmission direction, thereby achieving the effect of efficient and intelligent management of body fluids.

Description

Technical Field

[0001] This invention relates to the field of smart textiles, and more particularly to a method for preparing a temperature-responsive, controllable liquid-wicking functional yarn. Background Technology

[0002] Smart textiles have shown broad application prospects in fields such as human body thermal and humidity comfort management, physiological signal monitoring, and precise microenvironment regulation. Among them, the directional and controllable management of liquid water (such as sweat, environmental condensation, etc.) is the key to achieving wearing comfort, inhibiting microbial growth, and ensuring the stable operation of the sensing system. However, traditional liquid-conducting textile materials are mostly based on fabric or membrane structures, using wettability gradients or pore size differences to achieve unidirectional liquid transmission. These materials mainly have the following shortcomings: (1) During the process of liquid transmission from the hydrophobic side to the hydrophilic side, local liquid accumulation is easily generated at the interface; (2) The liquid conduction behavior is continuously activated, and it is difficult to switch on or off or adjust the flow rate according to actual needs (such as dynamic changes in the amount of liquid discharged); (3) There is a lack of active response mechanism, and it is impossible to make intelligent feedback to external environmental stimuli (such as temperature and humidity).

[0003] Temperature-responsive polymer materials exhibit reversible wettability transitions around specific temperature thresholds, displaying a hydrophobic or hypowetting state below the critical temperature and a hydrophilic state above the critical temperature. Combining these materials with textiles holds promise for temperature-gated control of liquid transport behavior. However, current research primarily focuses on two-dimensional fabrics or nanofiber membrane structures, lacking the technology to construct temperature-gated liquid-conducting functions at the scale of yarn, the fundamental building block of textiles. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for preparing a temperature-responsive, controllable fluid-conducting functional yarn. First, using conjugate electrospinning technology, a temperature-sensitive polymer nanofiber layer and a hydrophobic polyurethane nanofiber layer are sequentially deposited on the surface of a hydrophilic cotton yarn to form a micro-nano composite structure yarn. Subsequently, a simple heat treatment causes moderate cross-linking of the temperature-sensitive polymer nanofibers, maintaining the fiber morphology in a hydrophilic state while enhancing its mechanical properties. This composite yarn exhibits temperature responsiveness; by utilizing the wettability switching of the intermediate temperature-sensitive polymer nanofibers with temperature changes, the effective thickness of the outer hydrophobic layer can be effectively controlled, thereby achieving precise control of the liquid transport direction and achieving efficient and intelligent management of body fluids.

[0005] The specific technical solution of this invention is: a method for preparing a temperature-responsive, controllable liquid-wicking functional yarn, such as... Figure 1 As shown, it includes the following steps:

[0006] (1) Preparation of thermosensitive polymer: Acrylamide, acrylonitrile and N-hydroxymethylacrylamide are dissolved in an organic solvent (preferably dimethyl sulfoxide), and free radical polymerization is carried out under the conditions of initiation by an initiator (preferably azobisisobutyronitrile) and deoxygenation by an inert gas. After the reaction is completed, the mixture is cooled, dialyzed and freeze-dried to obtain a thermosensitive polymer with a temperature transition point of 38-45℃.

[0007] (2) Preparation of micro-nano composite yarn: Using hydrophilic yarn as the core layer, the conjugate electrospinning technology is used to electrospin a temperature-sensitive polymer spinning solution and a hydrophobic polyurethane spinning solution on the surface of the hydrophilic yarn in sequence to form an intermediate layer and a shell layer, respectively, thus preparing a micro-nano composite yarn with a hydrophilic yarn core layer, a temperature-sensitive polymer nanofiber layer in the intermediate layer, and a hydrophobic polyurethane nanofiber layer in the shell layer.

[0008] (3) Crosslinking treatment: The micro-nano composite yarn obtained in step (2) is heat-treated to cause the temperature-sensitive polymer nanofibers to undergo appropriate crosslinking, and the finished product is obtained.

[0009] As described in the background section of this application, traditional liquid-wicking textile materials are mostly based on fabric or membrane structures. During the transport of liquid from the hydrophobic side to the hydrophilic side, localized liquid accumulation easily occurs at the interface, and there is a lack of active response mechanism. Therefore, this invention provides a method for preparing a temperature-responsive, controllable liquid-wicking functional yarn. This invention sequentially deposits a temperature-sensitive nanofiber layer and a hydrophobic polyurethane nanofiber layer on the surface of a hydrophilic yarn using conjugate electrospinning technology. By controlling the wettability of the temperature-sensitive nanofiber surface through temperature changes, the effective thickness of the hydrophobic layer in the composite yarn is altered, thereby achieving precise control over the direction of liquid transport and achieving efficient and intelligent management of body fluids. Specifically, the hydrophobic polyurethane nanofiber layer has fixed hydrophobicity, while the wettability of the temperature-sensitive nanofiber layer changes reversibly with temperature—exhibiting hydrophilicity above the critical temperature and hydrophobicity below the critical temperature. At room temperature, the temperature-sensitive nanofibers are in a hydrophobic state, forming a composite hydrophobic layer together with the hydrophobic polyurethane nanofiber layer, preventing liquid from penetrating from the yarn shell to the core layer. However, at high temperatures, the temperature-sensitive nanofibers transform into a hydrophilic state, reducing the effective thickness of the composite hydrophobic layer to the thickness of the hydrophobic polyurethane nanofiber layer. Liquid can then penetrate from the yarn shell to the yarn core layer and achieve directional transport and targeted drainage along the hydrophilic yarn core layer.

[0010] Preferably, in step (1), the molar percentage of each monomer in the thermosensitive polymer is: acrylamide 59-61%, acrylonitrile 16-22%, and N-hydroxymethylacrylamide 16-22%.

[0011] The temperature transition point of a thermosensitive polymer is determined by its monomer ratio. The above ratio allows the temperature transition point of the thermosensitive polymer to be controlled within the range of 38-45℃: when the ambient temperature is higher than this transition point, the thermosensitive nanofibers exhibit hydrophilicity; when it is lower than this transition point, they exhibit hydrophobicity. This transition point should not be too high (it should be below 50℃ to avoid thermal damage to human skin) nor too low (otherwise, the thermosensitive properties cannot be effectively exerted). Therefore, the monomer ratio of the thermosensitive polymer must be limited to the above range.

[0012] Preferably, in step (1), the total concentration of monomer in the reaction solution is 1.0-2 mM; the molar ratio of azobisisobutyronitrile to monomer is 0.5-2%.

[0013] Preferably, in step (1), the inert gas is at least one of nitrogen and argon.

[0014] Preferably, in step (2), the hydrophilic yarn is cotton yarn.

[0015] The choice of the core layer is crucial to the controllable liquid-conducting performance of the composite yarn. The yarn core layer consists of multiple bundles of fine fibers, forming a continuous capillary channel structure with excellent hydrophilicity and liquid absorption capacity. After liquid enters the yarn, it can achieve effective capillary drive and directional transport along the axial direction, thus ensuring the rapid and directional outflow of liquid in the controllable liquid-conducting yarn of this invention when in the open state. Comparative studies have found that cotton yarn has superior liquid-conducting performance compared to bamboo yarn. This is mainly due to two factors: first, bamboo fiber contains more lignin, and its natural hydrophilicity is not as good as cotton yarn; second, bamboo fiber has lower porosity, resulting in limited water absorption rate and moisture retention capacity. Therefore, choosing cotton yarn as the core layer is one of the key technical features ensuring the controllable liquid-conducting function of the composite yarn of this invention.

[0016] Preferably, in step (2), the hydrophilic yarn has a count of 20-30S and a yarn structure of single or double strands.

[0017] The selection of yarn structure parameters plays a crucial role in constructing a multi-level capillary network. This invention uses 20-30S yarn as the base material, a range designed to balance capillary dynamics and fabric adaptability. If the yarn count is too low (too coarse), the thickness of the finished textile will increase, reducing its skin-friendliness; if the count is too high, it can lead to insufficient liquid transport cross-section, affecting liquid wicking efficiency. This invention discovers that a 20-30S yarn count range can maintain yarn fineness, improve wearing comfort, and create suitable porosity, thus balancing liquid wicking performance and user experience.

[0018] Regarding the yarn structure, this invention further employs a single / double-strand helical structure. This structure, while ensuring fineness, utilizes micro-level "liquid reservoirs" at the fiber intersections to generate a strong Laplace pressure differential, driving the exudate to overcome viscous resistance. Both single-strand and double-strand yarns can achieve liquid-guiding functions, allowing for flexible selection based on specific application scenarios. Double-strand yarns, due to their enhanced capillary action, can transport liquid more quickly and evenly, offering significant advantages in applications requiring efficient liquid guidance or long-term liquid management. While single-strand yarns have a relatively slower liquid-guiding speed, they are suitable for scenarios with higher comfort requirements and lower liquid-guiding speed requirements.

[0019] Preferably, in step (2), the hydrophilic yarn needs to be pretreated with a pretreatment solution, which includes 5-20 g / L sodium hydroxide and 1-5 g / L sodium silicate; the pretreatment bath ratio is 1:20-1:50, the treatment temperature is 70-100℃, and the treatment time is 2-6 h.

[0020] Pretreatment of hydrophilic yarns is crucial for achieving the controllable liquid-wicking function of this invention. Untreated yarn surfaces typically retain sizing agents, oils, and some natural impurities, resulting in low surface energy and insufficient wettability, thus weakening the ability of liquids to penetrate the capillary channels within the yarn. Pretreatment of the yarn with a pretreatment solution effectively removes surface impurities and increases the polar groups on the fiber surface, improving the overall hydrophilicity and liquid absorption properties of the yarn. Simultaneously, pretreatment also improves the openness of the yarn's internal pore structure, enhances the capillary driving force, and significantly improves the liquid transport efficiency along the yarn axis.

[0021] Preferably, in step (2), the solvent of the temperature-sensitive polymer spinning solution is N,N-dimethylformamide, and the concentration of the spinning solution is 15-20 wt%; the solvent of the hydrophobic polyurethane spinning solution is N,N-dimethylformamide, and the concentration of the spinning solution is 18-22 wt%.

[0022] The concentration of the spinning solution has a significant impact on the formation of nanofibers. This invention employs conjugate electrospinning technology, which results in a shorter spinning distance compared to conventional electrospinning. When the spinning solution concentration is too low and the positive and negative voltages are too high, the triangular pyramidal structure formed on the surface of the metal disk is easily damaged, thus affecting the uniformity of nanofiber deposition on the cotton yarn surface and the control of layer thickness. When the spinning solution concentration is too high, it is difficult to form a stable jet, making continuous spinning impossible. Therefore, the spinning solution concentration needs to be controlled within a suitable range to ensure stable nanofiber formation and uniform deposition on the core yarn surface.

[0023] Preferably, in step (2), the conjugate electrospinning parameters of the temperature-sensitive nanofiber layer are: pump flow rate 0.01-0.02 mm / s, needle 20-22 G, nozzle-to-metal disc distance 5.5-8.5 cm, conjugate spinning positive voltage 3-5 kV, conjugate spinning negative voltage 3-5 kV, ambient temperature 35-45%, and ambient humidity 40-50%; the conjugate electrospinning parameters of the hydrophobic polyurethane nanofiber layer are: pump flow rate 0.01-0.02 mm / s, needle 20-22 G, nozzle-to-metal disc distance 5.5-8.5 cm, conjugate spinning positive voltage 4-6 kV, conjugate spinning negative voltage 4-6 kV, ambient temperature 35-45%, and ambient humidity 40-50%.

[0024] Conjugate spinning parameters have a significant impact on the formation and structural uniformity of nanofibers. The flow rate of the injection pump, the distance between the nozzle and the collector, and the applied voltage jointly determine the stability of the jet flow and the fiber formation state: if the jet is unstable, it will affect the triangular pyramidal surface constructed by the nanofibers on the metal disk, thus resulting in the inability to uniformly coat the core yarn.

[0025] Preferably, in step (2), the rotation speed of the metal disk of the temperature-sensitive nanofiber is 30-100 rpm; the rotation speed of the metal disk of the hydrophobic polyurethane nanofiber layer is 30-100 rpm.

[0026] The rotational speed of the metal disc directly affects the uniformity of fiber deposition and the density of coating on the yarn surface. Within the above rotational speed range, the fiber jetting stably forms a triangular pyramidal surface, which can uniformly coat the core layer. If the disc speed is too fast, the formed triangular pyramidal surface is easily damaged, thus affecting the uniformity of nanofiber deposition on the core layer yarn surface.

[0027] Preferably, in step (2), the winding speed of the temperature-sensitive nanofiber layer is 0.5-1.5 mm / s, and its thickness is 60-150 μm; the winding speed of the hydrophobic polyurethane nanofiber layer is 0.5-1.5 mm / s, and its thickness is 60-150 μm.

[0028] The thickness of the hydrophobic polyurethane nanofiber layer and the temperature-sensitive nanofiber layer has a crucial impact on the controllable liquid-conducting properties of the composite yarn. This invention achieves precise control over the thickness of these two nanofiber layers by adjusting the take-up speed. If the take-up speed is too slow, the hydrophobic polyurethane nanofibers deposit too thickly, hindering liquid penetration from the outer shell to the core of the composite yarn; if the take-up speed is too fast, the deposited layer is too thin, increasing the risk of liquid backflow from the core to the shell, easily causing overall yarn wetting. For the temperature-sensitive nanofibers, under normal temperature conditions, the temperature-sensitive nanofiber layer and the polyurethane nanofiber layer together form a sufficiently thick composite hydrophobic layer to effectively prevent liquid penetration from the yarn shell to the yarn core. Under high temperature conditions, the temperature-sensitive layer transforms into a hydrophilic state. At this point, the composite hydrophobic nanofibers consist only of the hydrophobic polyurethane shell layer, allowing liquid to penetrate from the shell to the core and drain at specific points along the hydrophilic yarn core. Therefore, adjusting the take-up speed and precisely controlling the thickness of the hydrophilic and hydrophobic layers are key process steps to ensure that the temperature-responsive controllable liquid-conducting yarn of this invention achieves stable gating function.

[0029] Preferably, in step (3), the heat treatment process is performed with a pressure of 5-20 N, a temperature of 100-130 °C, and a time of 8-10 h.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] (1) This invention imparts excellent temperature responsiveness to the composite yarn by introducing a temperature-sensitive nanofiber interlayer into the hydrophilic yarn structure. When the ambient temperature changes, the wettability of the temperature-sensitive nanofiber can reversibly switch between a hydrophobic state and a hydrophilic state, thereby adjusting the effective thickness of the hydrophobic layer and the liquid penetration path in the composite yarn, achieving precise control of liquid flow. Under this temperature gating mechanism, liquid can be efficiently collected along the yarn axis and discharged from both ends, avoiding liquid retention or leakage on the fabric surface, and improving the efficiency and reliability of intelligent body fluid management.

[0032] (2) The yarn of this invention can be used as warp and weft yarns or functional filling, and integrated into a three-dimensional fabric structure through weaving, knitting or braiding processes. Utilizing its unique temperature response characteristics, an "intelligent hydraulic valve" system can be constructed in the direction perpendicular to the skin to achieve active fluid delivery and self-regulation of the humidity of the human body's microenvironment. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the preparation process of the temperature-responsive hydrophobic layer thickness controllable liquid-conducting yarn of the present invention.

[0034] Figure 2 The contact angle diagrams for the sample in Example 1 at room temperature and high temperature are shown.

[0035] Figure 3 Contact angle diagrams of the sample in Example 2 at room temperature and high temperature;

[0036] Figure 4 The contact angle diagrams for the sample in Example 3 at room temperature and high temperature are shown.

[0037] Figure 5 The contact angle diagrams for the sample in Example 4 at room temperature and high temperature are shown.

[0038] Figure 6 The contact angle diagrams for the sample in Comparative Example 1 at room temperature and high temperature are shown.

[0039] Figure 7 The contact angle diagrams for the sample in Comparative Example 2 at room temperature and high temperature are shown.

[0040] Figure 8 The contact angle diagrams for Comparative Example 3 sample at room temperature and high temperature are shown.

[0041] Figure 9 The contact angle diagrams for Comparative Example 4 sample at room temperature and high temperature are shown.

[0042] Figure 10 The contact angle diagrams for Comparative Example 5 sample at room temperature and high temperature are shown.

[0043] Figure 11 The contact angle diagrams for Comparative Example 6 sample at room temperature and high temperature are shown.

[0044] Figure 12 The contact angle diagrams for Comparative Example 7 sample at room temperature and high temperature are shown.

[0045] Figure 13 The contact angle diagrams for Comparative Example 8 sample at room temperature and high temperature are shown.

[0046] Figure 14 The contact angle diagrams for Comparative Example 9 sample at room temperature and high temperature are shown.

[0047] Figure 15 Contact angle diagrams of Comparative Example 10 sample at room temperature and high temperature;

[0048] Figure 16 The following are the liquid conduction effect diagrams for Example 1; wherein: (a) Fluorescent liquid conduction diagrams of Example 1 at room temperature and high temperature; (b) Thermal infrared imaging diagrams of Example 1 at room temperature and high temperature. Detailed Implementation

[0049] The present invention will be further described below with reference to the embodiments. The polyurethane used is manufactured by BASF AG, Germany, and is model 1180A.

[0050] Example 1

[0051] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0052] (2) Place the cotton yarn in a solution containing 15 g / L sodium hydroxide and 3 g / L sodium silicate, with a bath ratio of 1:30, a treatment temperature of 100 °C, and a treatment time of 6 h, and set aside for later use.

[0053] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 106.6 μm) and hydrophobic polyurethane nanofiber layer (110.9 μm) are sequentially deposited on cotton yarn (20S, double strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s. The parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0054] (4) Heat-treat the composite yarn in step (2) in an oven at 130°C for 10 hours to obtain cross-linked temperature-responsive hydrophobic layer thickness controllable liquid-conducting yarn.

[0055] Example 2

[0056] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0057] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 3 g / L sodium silicate, with a bath ratio of 1:30, a treatment temperature of 100 °C, and a treatment time of 5 h, and set aside for later use.

[0058] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 55 μm) and hydrophobic polyurethane nanofiber layer (thickness: 107.0 μm) are sequentially deposited on cotton yarn (20S, double strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 60 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1.5 mm / s; the parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 60 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0059] (4) Heat-treat the composite yarn in step (2) in an oven at 120°C for 10 hours to obtain cross-linked temperature-responsive hydrophobic layer thickness controllable liquid-conducting yarn.

[0060] Example 3

[0061] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 2 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0062] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 2 g / L sodium silicate, with a bath ratio of 1:40, a treatment temperature of 90 °C, and a treatment time of 4 h, and set aside for later use.

[0063] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (161.8μm) and hydrophobic polyurethane nanofiber layer (159.9 μm) are sequentially deposited on cotton yarn (30S, single strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01mm / s, needle: 22G, distance: 5.5cm, positive and negative voltage: 4.0kv, turntable speed: 100rpm, temperature: 40℃, humidity: 35%, and take-up speed: 0.5mm / s; the parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01mm / s, needle: 22G, distance: 5.5cm, positive and negative voltage: 5.4kv, turntable speed: 100rpm, temperature: 40℃, humidity: 35%, and take-up speed: 0.5mm / s.

[0064] (4) Heat-treat the composite yarn in step (2) in an oven at 120°C for 10 hours to obtain cross-linked temperature-responsive hydrophobic layer thickness controllable liquid-conducting yarn.

[0065] Example 4

[0066] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0067] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 3 g / L sodium silicate, with a bath ratio of 1:40, a treatment temperature of 80 °C, and a treatment time of 5 h, and set aside for later use.

[0068] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. A thermosensitive nanofiber layer (thickness: 108.1 μm) and a hydrophobic polyurethane nanofiber layer (thickness: 111.6 μm) were sequentially deposited on cotton yarn (30S, double strand) via conjugate electrospinning. The parameters for the thermosensitive nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 20 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 0.5 mm / s. The parameters for the polyurethane nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 20 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 0.5 mm / s.

[0069] (4) Heat-treat the composite yarn in step (2) in an oven at 120°C for 12 hours to obtain cross-linked temperature-responsive hydrophobic layer thickness controllable liquid-conducting yarn.

[0070] Comparative Example 1 (Polyester yarn as the core layer)

[0071] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0072] (2) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 105.9 μm) and hydrophobic polyurethane nanofiber layer (108.1 μm) are sequentially deposited on polyester yarn (20S, double strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s. The parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0073] (3) Heat-treat the composite yarn in step (2) in an oven at 130°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0074] Comparative Example 2 (Bamboo yarn as the core layer)

[0075] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0076] (2) Place the bamboo yarn in a solution containing 30 g / L sodium hydroxide and 2 g / L sodium silicate, with a bath ratio of 1:30, a treatment temperature of 80 °C, and a treatment time of 4 h, and set aside for later use.

[0077] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 107.1 μm) and hydrophobic polyurethane nanofiber layer (thickness: 107.5 μm) are sequentially deposited on bamboo yarn (20S, single strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s. The parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0078] (4) Heat-treat the composite yarn in step (2) in an oven at 130°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0079] Comparative Example 3 (Triangular Cone Surface Destruction: Instability of Conjugate Spinning Parameters)

[0080] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0081] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 3 g / L sodium silicate, with a bath ratio of 1:40, a treatment temperature of 100 °C, and a treatment time of 6 h, and set aside for later use.

[0082] (3) Using N,N-dimethylformamide as a solvent, prepare 10wt% thermosensitive polymer solution and 10wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 27.1μm) and hydrophobic polyurethane nanofiber layer (thickness: 30.1μm) are sequentially deposited on cotton yarn (20S, double strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01mm / s, needle: 22G, distance: 8.5cm, positive and negative voltage: 5.0kv, turntable speed: 100rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1mm / s. The parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01mm / s, needle: 22G, distance: 8.5cm, positive and negative voltage: 6.4kv, turntable speed: 100rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1mm / s.

[0083] (4) Heat-treat the composite yarn in step (2) in an oven at 130°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0084] Comparative Example 4 (Destruction of the triangular pyramid surface: excessive turntable speed)

[0085] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0086] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 2 g / L sodium silicate, with a bath ratio of 1:30, a treatment temperature of 90 °C, and a treatment time of 6 h, and set aside.

[0087] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 33.4 μm) and hydrophobic polyurethane nanofiber layer (thickness: 31 μm) are sequentially deposited on cotton yarn (20S, double strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 300 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s. The parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 300 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0088] (4) Heat-treat the composite yarn in step (2) in an oven at 130°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0089] Comparative Example 5 (The thickness of the temperature-sensitive nanofiber layer is too thin)

[0090] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0091] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 3 g / L sodium silicate, with a bath ratio of 1:40, a treatment temperature of 90 °C, and a treatment time of 4 h, and set aside for later use.

[0092] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. A temperature-sensitive nanofiber layer (thickness: 17.1 μm) and a hydrophobic polyurethane nanofiber layer (thickness: 109.6 μm) were sequentially deposited on cotton yarn (20S, double strand) via conjugate electrospinning. The parameters for the temperature-sensitive nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 3.5 mm / s. The parameters for the polyurethane nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0093] (4) Heat-treat the composite yarn in step (2) in an oven at 110°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0094] Comparative Example 6 (The thickness of the temperature-sensitive nanofiber layer is too thick)

[0095] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0096] (2) Place the cotton yarn in a solution containing 15 g / L sodium hydroxide and 2 g / L sodium silicate, with a bath ratio of 1:30, a treatment temperature of 100 °C, and a treatment time of 5 h, and set aside for later use.

[0097] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. A thermosensitive nanofiber layer (thickness: 189.2 μm) and a hydrophobic polyurethane nanofiber layer (thickness: 107.8 μm) were sequentially deposited on cotton yarn (20S, double strand) via conjugate electrospinning. The parameters for the thermosensitive nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 0.1 mm / s. The parameters for the polyurethane nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0098] (4) Heat-treat the composite yarn in step (2) in an oven at 110°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0099] Comparative Example 7 (The polyurethane nanofiber layer is too thick)

[0100] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0101] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 2 g / L sodium silicate, with a bath ratio of 1:40, a treatment temperature of 100 °C, and a treatment time of 6 h, and set aside for later use.

[0102] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. A thermosensitive nanofiber layer (thickness: 60.1 μm) and a hydrophobic polyurethane nanofiber layer (thickness: 190.3 μm) were sequentially deposited on cotton yarn (30S, double strand) via conjugate electrospinning. The parameters for the thermosensitive nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1.5 mm / s. The parameters for the polyurethane nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 0.1 mm / s.

[0103] (4) Heat-treat the composite yarn in step (2) in an oven at 110°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0104] Comparative Example 8 (The thickness of the polyurethane nanofiber layer is too thin)

[0105] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0106] (2) Place the cotton yarn in a solution containing 15 g / L sodium hydroxide and 2 g / L sodium silicate, with a bath ratio of 1:30, a treatment temperature of 100 °C, and a treatment time of 6 h, and set aside for later use.

[0107] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. A thermosensitive nanofiber layer (thickness: 105.1 μm) and a hydrophobic polyurethane nanofiber layer (thickness: 20.1 μm) were sequentially deposited on cotton yarn (20S, single strand) via conjugate electrospinning. The parameters for the thermosensitive nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1.0 mm / s. The parameters for the polyurethane nanofiber conjugate spinning were: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 3.5 mm / s.

[0108] (4) Heat-treat the composite yarn in step (2) in an oven at 110°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0109] Comparative Example 9 (The inversion point of the thermosensitive polymer is too low)

[0110] (1) 75% acrylamide, 10% acrylonitrile, and 5% N-hydroxymethylacrylamide (total concentration 1 mM) were added to a round-bottom flask by molar ratio. Azobisisobutyronitrile (1% of the monomer molar ratio) was added to a dimethyl sulfoxide solution. After deoxygenation under nitrogen, the reaction was carried out at 55 °C. After the reaction was completed, the solution was cooled to room temperature and then dialyzed in deionized water for 40 h. The target product was obtained by freeze drying and set aside for later use.

[0111] (2) Place the cotton yarn in a solution containing 20 g / L sodium hydroxide and 3 g / L sodium silicate, with a bath ratio of 1:40, a treatment temperature of 90 °C, and a treatment time of 5.5 h, and set aside for later use.

[0112] (3) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 106.8 μm) and hydrophobic polyurethane nanofiber layer (thickness: 106.1 μm) are sequentially deposited on cotton yarn (20S, single strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 4.0 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s. The parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01 mm / s, needle: 22G, distance: 5.5 cm, positive and negative voltage: 5.4 kV, turntable speed: 100 rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1 mm / s.

[0113] (4) Heat-treat the composite yarn in step (2) in an oven at 130°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0114] Comparative Example 10 (Cotton yarn without pretreatment)

[0115] (1) Add 60% acrylamide, 20% acrylonitrile, and 20% N-hydroxymethylacrylamide (total concentration 1 mM) to a round-bottom flask by molar ratio. Add 1% azobisisobutyronitrile (DIBN) to a dimethyl sulfoxide solution. After deoxygenation with nitrogen, react at 55°C. After the reaction is complete, allow the solution to cool to room temperature and then dialyze it in deionized water for 40 h. After freeze-drying, obtain the target product for later use.

[0116] (2) Using N,N-dimethylformamide as a solvent, prepare 20wt% thermosensitive polymer solution and 20wt% polyurethane solution respectively. Thermosensitive nanofiber layer (thickness: 108.1μm) and hydrophobic polyurethane nanofiber layer (thickness: 108.4μm) are sequentially deposited on cotton yarn (20S, double strand) by conjugated electrospinning. The parameters of the thermosensitive nanofiber conjugated spinning are: feed flow rate: 0.01mm / s, needle: 22G, distance: 5.5cm, positive and negative voltage: 4.0kv, turntable speed: 100rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1mm / s. The parameters of the polyurethane nanofiber conjugated spinning are: feed flow rate: 0.01mm / s, needle: 22G, distance: 5.5cm, positive and negative voltage: 5.4kv, turntable speed: 100rpm, temperature: 40℃, humidity: 35%, and take-up speed: 1mm / s.

[0117] (3) Heat-treat the composite yarn in step (2) in an oven at 130°C for 10 hours to obtain the cross-linked liquid-conducting yarn.

[0118] Performance testing of liquid-wicking yarn

[0119] The temperature transition point of the thermosensitive polymer was determined using UV-Vis light. The hydrophilicity / hydrophobicity of the core yarn was determined by video contact angle. The thickness of each layer was analyzed and measured using SEM of different layers in the composite yarn cross-section, with the core layer having a diameter of 0.3 mm. The liquid penetration performance from the outside to the inside of the yarn was determined as follows: 5 μL of blue liquid was dropped onto the outside of the composite yarn, and the penetration time was recorded at both room temperature (25℃) and high temperature (45℃). The results are shown in the table below.

[0120]

[0121]

[0122] From the above results, we can conclude that:

[0123] The temperature transition point of the thermosensitive polymer has a certain impact on the liquid-wicking yarn. If the transition temperature of the thermosensitive polymer is too low (Comparative Example 9), the temperature responsiveness of the composite yarn is not applicable, and it has water absorption properties under both room temperature and high temperature conditions.

[0124] The thickness of the temperature-sensitive nanofiber layer and the polyurethane nanofiber layer have a significant impact on the controllable liquid conduction performance of the yarn. If the thickness of the temperature-sensitive nanofiber layer and the polyurethane nanofiber layer is too thin (Comparative Example 5 and Comparative Example 8, respectively), the yarn can transport liquid from the outer layer to the core layer at both room temperature and high temperature, and does not have the ability to conduct liquid in a controlled manner. If the thickness of the temperature-sensitive nanofiber layer is too thick (Comparative Example 6), the yarn has the ability to conduct liquid in a controlled manner, but the efficiency of liquid transport from the outside to the inside of the composite yarn decreases at high temperatures. If the thickness of the polyurethane nanofiber layer is too thick (Comparative Example 7), the yarn cannot transport liquid at both room temperature and high temperature, and does not have the ability to conduct liquid in a controlled manner.

[0125] Furthermore, spinning parameters affect the thickness of the deposited temperature-sensitive nanofiber layer and polyurethane nanofiber layer, thus affecting the controllable liquid conduction performance of the yarn. If the spinning parameters are unstable (Comparative Example 3 and Comparative Example 4), the triangular pyramidal surface of the nanofibers constructed on the metal disk is easily damaged, resulting in uneven thickness of the nanofibers deposited on the surface of the cotton yarn or a decrease in the deposition thickness. Liquid can be transported from the outside to the inside of the composite yarn at both room temperature and high temperature, and it does not have the controllable liquid conduction performance.

[0126] The hydrophilicity of the core layer is directly related to its water-conducting performance. If hydrophobic yarn (Comparative Example 1) or untreated cotton yarn (Comparative Example 10) is selected, the capillary force of the core layer will decrease, and it will be unable to transport liquids at both room temperature and high temperature. If the core layer has a certain degree of hydrophilicity (Comparative Example 2, bamboo yarn), it can still achieve controllable liquid-conducting performance, but it may lead to a decrease in liquid-conducting efficiency.

[0127] In addition, such as Figure 2-15 As shown, based on the contact angle test results, the present invention analyzed different embodiments:

[0128] Example 1 ( Figure 2 This indicates that the yarn remains hydrophobic at room temperature; however, at high temperatures, the droplet permeates after 8 seconds, demonstrating that temperature changes can trigger liquid permeation. Further research revealed that altering the transition speed (i.e., changing the tightness between the nanofibers and the yarn) affects the liquid conduction efficiency. For example, in Example 2 (rotary speed 60), Figure 3 ) and Example 4 (turntable speed 20, Figure 5 As shown in the figure, at room temperature, the droplets remain hydrophobic; however, at high temperatures, the droplets disappear, exhibiting liquid-conducting behavior, but the liquid-conducting efficiency decreases. This phenomenon is due to the fact that the decrease in rotational speed causes more air layers to form between the nanofibers and the yarn, thereby reducing the liquid-conducting efficiency.

[0129] In Example 3, by changing the thickness of the hydrophobic nanofibers and the thermosensitive nanofibers, it was found that when the thickness of the hydrophobic nanofibers increased, the droplets remained spherical at room temperature, while at high temperature, the droplets disappeared after 50 seconds. Figure 4 This indicates that increasing the thickness of the nanofibers leads to a longer liquid wetting path, thus affecting the liquid conduction efficiency.

[0130] The capillary forces in the core layer also significantly influence liquid conduction behavior. As shown in Comparative Example 1, when the core layer is made of hydrophobic polyester yarn, it maintains hydrophobicity at both room temperature and high temperature, and no liquid conduction behavior occurs. Figure 6 In Comparative Example 2, when bamboo yarn with weaker capillary force than cotton yarn was used, the droplets remained spherical at room temperature but disappeared at high temperature, exhibiting liquid-conducting behavior. However, its liquid-conducting efficiency was lower than that of Example 1. Figure 7 ).

[0131] If the triangular pyramidal surface deposited on the cotton yarn surface is disrupted, for example by changing the conjugate spinning parameters (Comparative Example 3), Figure 8 Or increase the turntable speed (Comparative Example 4, Figure 9 This results in a thinner nanofiber layer on the surface of the cotton yarn, allowing liquids to quickly penetrate at both room and high temperatures, thus losing its gating properties.

[0132] The thickness of the temperature-sensitive nanofibers has a certain influence on the gated liquid conduction behavior. For example, Comparative Example 5 ( Figure 10 As shown in Comparative Example 6, if the temperature-sensitive nanofibers are too thin, liquid permeation can occur at both room temperature and high temperature, thus losing their gated liquid conduction function; while in Comparative Example 6 ( Figure 11 In the case of thermosensitive nanofibers, when the thickness is too thick, the droplets remain hydrophobic at room temperature, but disappear after 12 seconds at high temperature, exhibiting gated liquid conduction performance.

[0133] The thickness of the hydrophobic polyurethane nanofibers also affects the gated liquid conduction behavior. For example, Comparative Example 7 (… Figure 12 As shown in Comparative Example 8, when the hydrophobic polyurethane nanofibers are too thick, liquid permeation cannot occur at either room temperature or high temperature; while Comparative Example 8 ( Figure 13 In this process, if the hydrophobic polyurethane nanofibers are too thin, liquids will permeate at both room temperature and high temperature.

[0134] The transition temperature of thermosensitive polymers also has a significant impact on gated liquid conduction behavior. For example, Comparative Example 9 ( Figure 14 As shown in the figure, the thermosensitive polymer can induce liquid permeation at both room temperature and high temperature; while Comparative Example 10 ( Figure 15 In this process, if the cotton yarn in the core layer is not treated, it will not be able to conduct liquid at either room temperature or high temperature.

[0135] In summary, this invention provides a controllable liquid-conducting yarn whose liquid-conducting behavior is influenced by multiple factors, including the rotary table speed, nanofiber layer thickness, capillary force in the core layer, and the transition temperature of the temperature-sensitive polymer. By adjusting these parameters, precise control over the yarn's liquid-conducting efficiency and gating performance can be achieved to meet different application requirements.

[0136] Example 1 is the best case, and its fluid conductivity analysis is as follows:

[0137] Analysis of controllable liquid-conducting yarn using thermal infrared imaging (TIR) Figure 16 a) Experimental results show that at room temperature, the state of the droplet hardly changes significantly over time (0 seconds to 90 seconds), indicating that the droplet remains stable at room temperature and does not undergo penetration or diffusion. At high temperature, the liquid expands rapidly and orderly along the axial arrangement of the gated yarn, exhibiting significant anisotropy and gated liquid conduction characteristics, and the droplet's penetration behavior changes significantly over time.

[0138] To further intuitively and in real-time verify the liquid-wicking performance of the controllable liquid-wicking yarn after it is woven into the fabric, this invention performs real-time visualization analysis by dripping dyeing liquid onto the fabric surface. Figure 16b). Experimental results show that the droplets mainly remain in the local area at the initial moment (0 seconds) without significant diffusion; as heating starts (5 to 30 seconds), the liquid migrates rapidly and orderly along the axial arrangement of the gated yarn, forming a continuous liquid flow channel; from 60 to 120 seconds, the liquid front continues to advance towards the other end of the fabric, and the liquid guiding direction is clear.

Claims

1. A method for preparing a temperature-responsive, controllable liquid-wicking functional yarn, characterized in that... include: (1) Acrylamide, acrylonitrile, and N-hydroxymethylacrylamide were added to an organic solvent and subjected to free radical polymerization under inert atmosphere protection, initiation by an initiator and heating conditions. The reaction product was dialyzed and dried to obtain a thermosensitive polymer with a temperature transition point of 38-45℃. (2) The hydrophilic cotton yarn is pretreated to remove impurities on the surface of the hydrophilic cotton yarn and improve its hydrophilicity and expand its internal pores. Then, the hydrophilic cotton yarn is electrospun with a concentration of 15-20wt% of thermosensitive polymer spinning solution and a concentration of 18-22wt% of hydrophobic polyurethane spinning solution on the surface of the hydrophilic cotton yarn by conjugate electrospinning technology. This results in a micro-nano composite yarn with a core layer of hydrophilic cotton yarn, a middle layer of 60-150μm thick thermosensitive nanofiber layer and a shell layer of 60-150μm thick hydrophobic polyurethane nanofiber layer. The conjugate electrospinning parameters for the temperature-sensitive nanofiber layer are as follows: pump flow rate 0.01-0.02 mm / s, nozzle-to-metal disc distance 5.5-8.5 cm, positive conjugate spinning voltage 3-5 kV, negative conjugate spinning voltage 3-5 kV, and metal disc rotation speed 30-100 rpm; the conjugate electrospinning parameters for the hydrophobic polyurethane nanofiber layer are as follows: pump flow rate 0.01-0.02 mm / s, nozzle-to-metal disc distance 5.5-8.5 cm, positive conjugate spinning voltage 4-6 kV, negative conjugate spinning voltage 4-6 kV, and metal disc rotation speed 30-100 rpm. (3) Crosslinking of micro-nano composite yarns by heat treatment.

2. The preparation method according to claim 1, characterized in that, In step (1), the molar percentages of each monomer in the thermosensitive polymer are: acrylamide 59-61%, acrylonitrile 16-22%, and N-hydroxymethylacrylamide 16-22%.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), The total concentration of monomers in the reaction system is 1.0-2 mM; The initiator accounts for 0.5-2 mol of the total monomer.

4. The preparation method according to claim 1 or 2, characterized in that, In step (1), The organic solvent is dimethyl sulfoxide; The initiator is azobisisobutyronitrile; The inert gas is at least one of nitrogen and argon.

5. The preparation method according to claim 1, characterized in that, In step (2), the count of the hydrophilic cotton yarn is 20-30S, and the yarn structure is single-ply or double-ply yarn.

6. The preparation method according to claim 1, characterized in that, In step (2), the pretreatment involves immersing the hydrophilic cotton yarn in a pretreatment solution for soaking. The pretreatment solution contains 10-20 g / L sodium hydroxide and 2-3 g / L sodium silicate. The pretreatment bath ratio is 1:30-1:50, the treatment temperature is 70-100℃, and the treatment time is 2-6h.

7. The preparation method according to claim 1, characterized in that: In step (2), the solvent of the temperature-sensitive polymer spinning solution is N,N-dimethylformamide; the solvent of the hydrophobic polyurethane spinning solution is N,N-dimethylformamide.

8. The preparation method according to claim 1, characterized in that: In step (2), The conjugate electrospinning parameters for the temperature-sensitive nanofiber layer are as follows: injection pump flow rate 0.01-0.02 mm / s, needle size 20-22 G, nozzle-to-metal disc distance 5.5-8.5 cm, conjugate spinning positive voltage 3-5 kV, conjugate spinning negative voltage 3-5 kV, ambient temperature 35-45%, and ambient humidity 40-50%. The conjugate electrospinning parameters of the hydrophobic polyurethane nanofiber layer are as follows: injection pump flow rate 0.01-0.02 mm / s, needle 20-22 G, nozzle-to-metal disc distance 5.5-8.5 cm, conjugate spinning positive voltage 4-6 kV, conjugate spinning negative voltage 4-6 kV, ambient temperature 35-45%, and ambient humidity 40-50%.

9. The preparation method according to claim 1 or 8, characterized in that: In step (2), the winding speed of the temperature-sensitive nanofiber layer is 0.5-1.5 mm / s; the winding speed of the hydrophobic polyurethane nanofiber layer is 0.5-1.5 mm / s.

10. The preparation method according to claim 1, characterized in that: In step (3), the heat treatment conditions are: pressure 5-20N, temperature 100-130℃, and time 8-10h.

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