Wet response fiber as well as preparation method and application thereof

Abstract

The invention relates to a wet response fiber and a preparation method and application thereof. The wet response fiber is a double-component parallel type composite fiber. Wherein the first component comprises a wet response factor and a polymer; the second component includes a hydrophobic polymer. The two components in the two-component wet response fiber material are controllable and adjustable, the driving effect is obvious, the spinning process is simple, continuous preparation can be achieved, various textile processes can be easily matched, and customized wet response textured fabric is achieved. The wet response fiber disclosed by the invention is expected to be used in the fields of intelligent wearing, sports health, medical assistance, high-end equipment, environmental perception, information acquisition, artificial muscles, soft robots and the like.

Description

Technical Field

[0001] The present invention belongs to the field of functional fibers, and in particular relates to a moisture-responsive fiber and a preparation method and application thereof. Background Art

[0002] The development of artificial intelligence and human-machine-environment interaction technologies has created multiple application demands for intelligent response, autonomous control, and motion perception in complex environments. Smart deformable materials play a key role in these technologies and are crucial for advancing this field. Moisture-responsive deformable materials, with their diverse energy sources and unique responsiveness to environmental moisture, chemical vapors, and other factors, represent a class of smart materials with significant application potential.

[0003] Traditional moisture-based actuators are mostly composed of dense structural blocks or thin film driving materials. The preparation process is complex, and the structural design and deformation behavior are simple, which limits their application. The one-dimensional properties of fiber materials allow their components and structures to be precisely controlled, making it easy to achieve controllable actuation. Combining weaving and other methods can better achieve specific actuation. At present, the main forms of moisture-responsive fiber actuators are fiber membranes and single fibers. Due to their structural limitations, fiber membrane actuators are difficult to achieve diverse and complex deformations. Current single-fiber actuators are mostly achieved through two-step / multi-step twisting. The preparation process is complex and time-consuming, and the production cost is high. At the same time, this type of fiber can usually only achieve torsional and contraction movements in one dimension, and requires the help of multiple stimuli to achieve bending deformation, which greatly limits its application. Therefore, it is of great significance to develop a class of moisture-responsive fiber materials with high response deformation capabilities through simple integrated molding technology. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a moisture-responsive fiber and a preparation method and application thereof.

[0005] The present invention provides a wet-responsive fiber, which is a two-component side-by-side composite fiber; wherein the first component includes a wet-responsive factor and a polymer; and the second component includes a hydrophobic polymer;

[0006] wherein the polymer in the first component is a mixture of a hydrophilic polymer and a hydrophobic polymer;

[0007] The hydrophilic polymer in the first component includes one or more of cellulose material, chitosan, and sodium alginate; the cellulose material includes one or more of bacterial nanocellulose, methyl cellulose, carboxymethyl cellulose, cellulose acetate, carboxyethyl cellulose, and hydroxyethyl cellulose; the hydrophobic polymer includes one or more of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, styrene-butadiene-styrene block copolymer, polylactic acid, polyacrylate, phenyl silicone rubber, polyvinylidene fluoride, polychlorotrifluoroethylene, polycarbonate, polyether ketone, polyurethane, chlorinated rubber, and polyacrylonitrile;

[0008] The hydrophobic polymer in the second component includes one or more of polyurethane, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, styrene-butadiene-styrene block copolymer, polylactic acid, polyacrylate, phenyl silicone rubber, polyvinylidene fluoride, polychlorotrifluoroethylene, polycarbonate, polyether ketone, chlorinated rubber, and polyacrylonitrile.

[0009] Preferably, the mass ratio of the wet response factor to the polymer in the first component is 1:9 to 5:5.

[0010] Preferably, the mass ratio of the first component to the second component is 10:1 to 1:10, and more preferably, the mass ratio of the first component to the second component is 3:1 to 1:3.

[0011] Preferably, the wet response factor includes one or more of bentonite, titanium dioxide, starch, silicon dioxide, aluminum hydroxide, hydroxyapatite, aluminum oxide, calcium carbonate, barium sulfate, talc, montmorillonite, gelatin, collagen, and graphene oxide.

[0012] The bentonite is one or more of sodium bentonite, calcium bentonite, hydrogen bentonite and organic bentonite.

[0013] Further preferably, the wet response factor is bentonite.

[0014] Preferably, the hydrophobic polymer in the first component is the same as the hydrophobic polymer in the second component.

[0015] Furthermore, the polymer in the first component is a mixture of a hydrophilic polymer and a hydrophobic polymer, wherein the mass ratio of the hydrophilic polymer to the hydrophobic polymer is 5:5 to 9:1.

[0016] Preferably, the hydrophilic polymer is a cellulosic material.

[0017] Cellulose molecular chains are rich in hydroxyl groups (-OH), while bentonite's silica tetrahedrons and interlayer water molecules also contain hydroxyl groups or proton acceptors. The two can hydrogen bond, enhancing the stability of the composite material. The high specific surface area of bentonite and the synergistic moisture absorption of cellulose effectively enhance the reaction rate of the moisture-responsive layer and the change in the macroscopic curvature of the fiber membrane under external stimuli.

[0018] More preferably, the cellulose material is hydroxyethyl cellulose. Adding a small amount of hydroxyethyl cellulose can take into account both mechanical properties and driving performance.

[0019] Preferably, the hydrophobic polymer in the second component is polyurethane.

[0020] The diameter of the wet-responsive fiber is 0.2-3 mm;

[0021] The cross section of the moisture-responsive fiber is circular;

[0022] The moisture-responsive fiber has a rough surface.

[0023] The present invention provides a textile comprising yarn or fabric integrated with the moisture-responsive fibers.

[0024] The present invention provides a method for preparing a moisture-responsive fiber, comprising:

[0025] Step (1) mixing the wet response factor, the polymer, and the solvent to obtain a first spinning solution;

[0026] Step (2) mixing a hydrophobic polymer and a solvent to obtain a second spinning solution;

[0027] Step (3) The first spinning solution and the second spinning solution are extruded and spun in parallel through a double channel, passed through a confluence zone, and solidified into fibers by phase exchange in a coagulation bath, and then drawn to obtain wet-responsive fibers.

[0028] The preferred embodiment of the above preparation method is as follows:

[0029] The first spinning solution in step (1) further contains a dissolving agent; the dissolving agent is lithium chloride.

[0030] In the step (1), the polymer concentration in the first spinning solution is 1 wt% to 60 wt%; and the concentration of the wet response factor in the spinning solution is 1 wt% to 40 wt%.

[0031] The concentration of the hydrophobic polymer in the second spinning solution in step (2) is 1 wt% to 60 wt%.

[0032] The solvent in steps (1) and (2) includes one or more of deionized water, ethanol, methanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, chloroform, acetone, toluene, and thionyl chloride. The first spinning solution and the second spinning solution use the same solvent.

[0033] In the step (1), the mixture is stirred after mixing at a temperature of 20 to 80° C. for a time of 1 to 24 h.

[0034] In the step (2), the mixture is stirred after mixing at a temperature of 20 to 80° C. for a time of 1 to 24 h.

[0035] In step (3), the extrusion rate of the first spinning solution is 5 mL / h~30 mL / h, and the extrusion rate of the second spinning solution is 5 mL / h~30 mL / h.

[0036] In step (3), the coagulation bath comprises deionized water and a solvent, and the volume ratio of deionized water to the solvent is 1:9 to 9:1. The solvent comprises one or more of ethanol, methanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, chloroform, acetone, toluene, thionyl chloride, and N-methylpyrrolidone.

[0037] The drafting ratio in the step (3) is 1:1.05 to 1:1.3.

[0038] After stretching in step (3), drying is performed.

[0039] In step (3), the spinning speeds of the two components are controlled to achieve different thickness ratios of the humidity responsive layer and the inert layer formed subsequently.

[0040] The present invention discloses an apparatus for producing wet-responsive fibers, comprising a parallel extrusion section, a confluence zone for first and second spinning solutions, and a phase exchange fiber-forming zone. The extrusion section comprises a dual-channel extrusion pump, wherein the first and second spinning solutions are extruded in parallel within a polytetrafluoroethylene tube and converge through a dual-needle channel. In the convergence zone, the first and second spinning solutions are fully contacted and extruded, then pass through a spinneret into a coagulation bath, where they undergo phase exchange to form bicomponent fibers.

[0041] The present invention provides an application of the moisture-responsive fiber in the fields of smart wearables, sports health, medical assistance, high-end equipment, environmental perception, information collection, artificial muscles, and soft robots.

[0042] In the method for preparing wet-responsive fibers of the present invention, a two-component spinning solution is extruded in parallel through two channels, passes through a small confluence area to form two-component parallel fibers, and undergoes phase exchange and solidification into fibers in a coagulation bath. Due to the cohesive force between the components and the constraints of the straight spinning channel, the two components do not mix at the intersection, the interface of the two-component fiber is clear, and the difference in the hygroscopicity of the two components is large, thereby achieving high responsive deformation capability; at the same time, by adopting the strategy of mutual doping of the base polymer and the same solvent treatment of the two-component polymer, the two-component fibers have strong compatibility, and the van der Waals force gives them good interfacial bonding fastness, giving the fiber actuator excellent cyclic stability. By precisely controlling the ratio and composition of the two components and utilizing the difference in the response of the two components to humidity, not only can the controllable deformation of a single fiber be achieved, but also the specific response of the fabric actuator to moisture can be achieved by combining weaving, knitting, braiding and other methods.

[0043] The present invention provides a universal solution, which uses a low-cost wet spinning process to spin two-component fibers in parallel, adopts a mutual doping strategy to improve the interfacial adhesion of the two-component polymers, and utilizes the asymmetric response of the two components to moisture to achieve differentiated driving of the fibers to moisture.

[0044] Beneficial effects

[0045] (1) The wet-responsive fiber of the present invention comprises a wet-responsive layer of a first component and an inert layer of a second component, and the rough fiber surface can expose more polar groups. The synergistic moisture absorption effect of the wet-responsive factor and the hydrophilic polymer in the wet-responsive layer can expand the difference in moisture absorption and expansion between the wet-responsive layer and the inert layer, thereby macroscopically increasing the fiber bending deformation and improving the fiber response speed.

[0046] (2) The present invention adopts a polymer interdoping strategy to improve the interfacial stability of the two components. By doping a small amount of the two-component polymer base and selecting the same solvent during the spinning solution preparation process, the intermolecular force between the two components can be enhanced, thereby improving the cyclic stability of the two-component fiber.

[0047] (3) The present invention starts from the design of one-dimensional materials, has strong controllability, and can reasonably design the surface roughness of the fiber. The spinning solution ratio is controllable, the amount of wet response factor added is controllable, the fiber material stretching ratio is controllable, etc. The entire strategy has a wide range of material choices, flexible design, and a certain degree of universality. From the application perspective, by selecting a suitable base material and optimizing the diameter of the two-component fiber, extrusion speed, wet response factor, etc., a wet response deformation fiber material with excellent mechanical properties, fast response, and large deformation can be designed;

[0048] (4) The present invention utilizes spinning technology to realize an integrated wet-responsive fiber material with high responsiveness and deformation capability. The fiber can be further used as a driving unit and combined with modern knitting, weaving, braiding and other technologies to develop fabric-type drivers, which are expected to be used in smart wearables, sports health, medical assistance, high-end equipment, environmental perception, information collection and artificial muscles. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a diagram of the production process and formation mechanism of the integrated wet-responsive deformation fiber material of the present invention;

[0050] Figure 2 is a schematic diagram of a wet-responsive deformable fiber material according to Example 8 of the present invention;

[0051] Figure 3 This is a physical picture of the wet-responsive deformable fiber material of Example 4 of the present invention, with a clear boundary between the two components;

[0052] Figure 4 is a schematic diagram of the calculation of the bending angle for measuring the fiber driving effect in all embodiments of the present invention;

[0053] Figure 5 is the tensile strain mechanical property of the polyurethane / hydroxyethyl cellulose-calcium bentonite moisture-responsive fiber in Example 1 of the present invention;

[0054] Figure 6 is the tensile strain mechanical property of the polyurethane / polyurethane-polyacrylonitrile-calcium bentonite moisture-responsive fiber in Example 2 of the present invention;

[0055] Figure 7 is the maximum bending angle of the fibers in the polyurethane / polyurethane-calcium bentonite parallel fibers of Example 3 of the present invention;

[0056] Figure 8 is the maximum bending angle of the polyurethane / polyurethane-hydroxyethyl cellulose-titanium dioxide parallel fibers of Example 4 of the present invention;

[0057] Figure 9 is the maximum bending angle of the polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers (mass ratio of the wet response layer to the inert layer is 1:2) of Example 5 of the present invention;

[0058] Figure 10 is the maximum bending angle of the polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers (mass ratio of the wet response layer to the inert layer is 2:1) of Example 6 of the present invention;

[0059] Figure 11 This is a graph showing the driving effect of the polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers as a function of humidity in Example 8 of the present invention;

[0060] Figure 12 The cyclic deformation stability of the polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers of Example 7 of the present invention;

[0061] Figure 13 This is a diagram of a wet-responsive fabric and its driving effect, which is demonstrated by the polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fiber weaving technology in Example 9 of the present invention; (1) is the wet-responsive layer of the woven fabric; (2) is the inert layer of the woven fabric; (3) is a diagram of the driving effect of the fabric in a humid environment;

[0062] Figure 14 This is an electron microscope image of the fiber surface of the polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers in Example 8 of the present invention. DETAILED DESCRIPTION

[0063] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0064] The main reagents involved in the present invention are all of analytical grade and are used directly.

[0065] Polyacrylonitrile (PAN, Mw=4000, Yuanye); thermoplastic polyurethane (TPU, Mw=150,000, Mairui); calcium bentonite (CaO / Al2O3 / SiO2, Xiangyuan Bentonite Co., Ltd.); N,N-dimethylformamide (DMF, AR, Aladdin); hydroxyethyl cellulose (HEC, RG, Titan); anhydrous lithium chloride (LiCl, AR, Aladdin); titanium dioxide (TiO2, ≥99%, Aladdin); 100% cotton yarn (40S / 2, 3000 yards, Diguan Garment Accessories Co., Ltd.)

[0066] Test standards and methods:

[0067] Mechanical properties test: According to GB / T 14337-2022 standard, the test was carried out using a 3365 universal material testing machine from Instron, USA, with a tensile speed of 10 mm / min. -1 .

[0068] Bending performance test: Place a 3 cm long fiber vertically on a binder clip, humidify the sample at a distance of 10 cm from the humidifier, record the ambient humidity with an electronic tester, and record the humidification time with a stopwatch. Figure 4As shown, a tangent line is drawn from the bent end of the fiber, and the angle between the tangent line and the normal line of the horizontal plane is recorded as the bending angle.

[0069] Example 1

[0070] In this embodiment, a fiber capable of moisture-responsive deformation is provided, and the preparation method is as follows:

[0071] Inert layer spinning solution: Dissolve polyurethane in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20wt% as the inert layer, and add a small amount of black pigment for color development;

[0072] Wet response layer spinning solution: Hydroxyethyl cellulose is dissolved in N,N-dimethylformamide, lithium chloride is added to promote dissolution, and calcium-based bentonite is added as a wet response factor to obtain a spinning solution; wherein the wet response factor content in the spinning solution is 5wt%, the hydroxyethyl cellulose content is 15wt%; and the mass of lithium chloride is 6% of the hydroxyethyl cellulose.

[0073] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0074] The spinning solutions of the inert layer and the wet-responsive layer were extruded into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 15 mL / h, with a draft ratio of 1:1.2. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then placed in a 30°C forced air oven to dry for 24 hours to obtain wet-responsive deformable fiber materials polyurethane / hydroxyethyl cellulose-calcium bentonite parallel fibers.

[0075] The diameter of the parallel fibers is about 0.3 mm, the mass ratio of the two components is 1:1, and the interface between the components is clear and no separation occurs.

[0076] As the humidity increases from 30% to 95%, the moisture absorption and expansion of the wet response layer of the parallel fiber increases significantly, showing a bending deformation phenomenon toward the inert layer. The parallel fiber shows the maximum bending phenomenon at a humidity of 95%, and the bending curvature reaches the maximum within 18 seconds, with a maximum bending angle of 30°. The mechanical properties of the parallel fiber are as follows: Figure 5 As shown in the figure, the maximum tensile strain is 760% and the maximum tensile strength is 14.9 MPa. From the stress-strain curve, it can be seen that there is a stress drop point, which is caused by the insufficient strength of the two-component interface.

[0077] Example 2

[0078] Inert layer spinning solution: Dissolve polyurethane in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20wt%, and add a small amount of black pigment for color development;

[0079] Wet response layer spinning solution: Polyacrylonitrile and polyurethane are dissolved in N,N-dimethylformamide in a mass ratio of 5:5, and calcium-based bentonite is added as a wet response factor to obtain a spinning solution; wherein the total content of polyacrylonitrile and polyurethane in the spinning solution is 15wt%, and the content of the wet response factor is 5wt%.

[0080] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0081] The spinning solutions of the inert layer and the wet-responsive layer were extruded into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 15 mL / h, with a draft ratio of 1:1.2. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then placed in a 30°C forced air oven to dry for 24 hours to obtain wet-responsive deformable fiber materials polyurethane / polyurethane-polyacrylonitrile-calcium-based bentonite parallel fibers.

[0082] The diameter of the parallel fibers is about 0.3 mm, the mass ratio of the two components is 1:1, and the interface between the components is clear and no separation occurs.

[0083] As the humidity increases from 30% to 95%, the moisture absorption and expansion of the wet response layer of the parallel fiber increases significantly, showing a bending deformation phenomenon toward the inert layer. The parallel fiber shows the maximum bending phenomenon at a humidity of 95%, and the bending curvature reaches the maximum within 20 seconds, with a maximum bending angle of 52°. The stress-strain curve of the parallel fiber is shown in Figure 6 As shown in Figure 1, the maximum tensile strain is 720% and the maximum tensile strength is 27.2 MPa. The stress-strain curve rises evenly, which, compared with Example 1, shows that the polymer intermixing strategy in the spinning process can effectively enhance the adhesion between the two interfaces.

[0084] Example 3

[0085] Inert layer spinning solution: Polyurethane was dissolved in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20 wt% as the inert layer;

[0086] Wet response layer spinning solution: polyurethane is dissolved in N,N-dimethylformamide, and calcium-based bentonite is added as a wet response factor to obtain a spinning solution; wherein the polyurethane content in the spinning solution is 15wt%, and the wet response factor is 5wt%.

[0087] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0088] The spinning solutions of the inert layer and the wet-responsive layer were extruded into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 15 mL / h, with a draft ratio of 1:1.2. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then placed in a 30°C forced air oven to dry for 24 hours to obtain wet-responsive deformable fiber materials polyurethane / polyurethane-calcium-based bentonite parallel fibers.

[0089] The diameter of the parallel fibers is about 0.3 mm, the mass of the two components is 1:1, and the interface between the components is clear and no separation occurs.

[0090] As the humidity increases from 30% to 95%, the moisture absorption and expansion of the wet response layer of the parallel fiber increases significantly, showing a phenomenon of bending deformation toward the inert layer. The parallel fiber shows the maximum bending phenomenon at a humidity of 95%, as shown in FIG. Figure 7 The parallel fibers exhibited obvious bending behavior at a humidity of 95%, with the bending curvature reaching a maximum within 25 s and a maximum bending angle of 40°. The composite fibers exhibited excellent response stability, with no significant change in the driving amplitude after 50 cycles.

[0091] Example 4

[0092] Inert layer spinning solution: Dissolve polyurethane in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20 wt% as the inert layer, and add a small amount of black pigment for color development;

[0093] Wet response layer spinning solution: hydroxyethyl cellulose and polyurethane are first dissolved in N,N-dimethylformamide in a mass ratio of 5:5, lithium chloride is added to promote dissolution, and then titanium dioxide is added as a wet response factor to obtain a spinning solution; the total content of hydroxyethyl cellulose and polyurethane in the spinning solution is 15wt%, and the wet response factor is 5wt%; the mass of the lithium chloride is 6% of the hydroxyethyl cellulose.

[0094] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0095] The spinning solutions of the inert layer and the wet response layer were squeezed into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 15 mL / h, with a draft ratio of 1:1.2. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then placed in a 30°C forced air oven for 24 hours to obtain wet response deformation fiber materials polyurethane / polyurethane-hydroxyethyl cellulose-titanium dioxide parallel fibers. The actual picture is as follows Figure 3 shown.

[0096] The diameter of the parallel fibers is about 0.3 mm, the mass ratio of the two components is 1:1, and the interface between the components is clear and no separation occurs.

[0097] As the humidity increases from 30% to 95%, the moisture absorption and expansion of the wet response layer of the parallel fiber increases significantly, showing a phenomenon of bending deformation toward the inert layer. The parallel fiber shows the maximum bending phenomenon at a humidity of 95%, as shown in FIG. Figure 8 As shown in Figure 3, the bending curvature reaches its maximum within 30 s, and the maximum bending angle is 80°. The parallel fibers exhibit excellent response stability, and the driving amplitude does not change after 50 cycles.

[0098] Example 5

[0099] Inert layer spinning solution: Dissolve polyurethane in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20wt% as the inert layer, and add a small amount of black pigment for color development;

[0100] Wet response layer spinning solution: hydroxyethyl cellulose and polyurethane are first dissolved in N,N-dimethylformamide in a mass ratio of 5:5, lithium chloride is added to promote dissolution, and then calcium-based bentonite is added as a wet response factor to obtain a spinning solution, wherein the total content of hydroxyethyl cellulose and polyurethane in the spinning solution is 15wt%, and the wet response factor is 5wt%; the mass of lithium chloride is 6% of that of hydroxyethyl cellulose.

[0101] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0102] The spinning solutions of the inert layer and the wet-responsive layer were extruded into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 20 mL / h and 10 mL / h, respectively, with a draft ratio of 1:1.2. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then dried in a 30°C forced air oven for 24 hours to obtain wet-responsive deformable fiber materials polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers.

[0103] The diameter of the parallel fiber is about 0.3 mm, the mass ratio of the two components is 2:1, and the interface of the components is clear and no separation occurs. As the humidity increases from 30% to 95%, the moisture absorption and expansion of the wet response layer of the parallel fiber increases significantly, showing a phenomenon of bending deformation toward the inert layer. The parallel fiber shows the maximum bending phenomenon at a humidity of 95%, as shown in FIG. Figure 9 As shown in Figure 3, the bending curvature reaches its maximum within 28 s, and the maximum bending angle is 60°. The composite fiber exhibits excellent response stability, and the actuation amplitude does not change after 50 cycles.

[0104] Example 6

[0105] Inert layer spinning solution: Polyurethane was dissolved in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20 wt% as the inert layer;

[0106] Wet response layer spinning solution: Hydroxyethyl cellulose and polyurethane are dissolved in N,N-dimethylformamide in a mass ratio of 5:5, lithium chloride is added to promote dissolution, and then calcium-based bentonite is added as a wet response factor to obtain a spinning solution; the total content of hydroxyethyl cellulose and polyurethane in the spinning solution is 15wt%, the wet response factor is 5wt%, and the mass of lithium chloride is 6% of the hydroxyethyl cellulose.

[0107] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0108] The spinning solutions of the inert layer and the wet-responsive layer were extruded into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 10 mL / h and 20 mL / h, respectively, with a draft ratio of 1:1.2. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then placed in a 30°C forced air oven to dry for 24 hours to obtain wet-responsive deformable fiber materials polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers.

[0109] The diameter of the parallel fibers is about 0.3 mm, the mass ratio of the two components is 1:2, and the interface between the components is clear and no separation occurs.

[0110] As the humidity increases from 30% to 95%, the moisture absorption and expansion of the wet response layer of the parallel fiber increases significantly, showing a phenomenon of bending deformation toward the inert layer. The parallel fiber shows the maximum bending phenomenon at a humidity of 95%, as shown in FIG. Figure 10 As shown in Figure 3, the bending curvature reaches its maximum within 32 s, and the maximum bending angle is 62°. The composite fiber exhibits excellent response stability, and the actuation amplitude does not change after 50 cycles.

[0111] Example 7

[0112] Inert layer spinning solution: Dissolve polyurethane in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20 wt% as the inert layer, and add a small amount of black pigment for color development;

[0113] Wet response layer spinning solution: Hydroxyethyl cellulose and polyurethane are dissolved in N,N-dimethylformamide in a mass ratio of 5:5, lithium chloride is added to promote dissolution, and then calcium-based bentonite is added as a wet response factor to obtain a spinning solution; the total content of hydroxyethyl cellulose and polyurethane in the spinning solution is 15wt%, and the wet response factor is 5wt%; the mass of lithium chloride is 6% of the hydroxyethyl cellulose.

[0114] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0115] The spinning solutions of the inert layer and the wet-responsive layer were extruded into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 15 mL / h, with a draft ratio of 1:1.1. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then placed in a 30°C forced air oven to dry for 24 hours to obtain wet-responsive deformable fiber materials polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers.

[0116] The diameter of the parallel fibers is about 0.7 mm, the mass ratio of the two components is 1:1, and the interface between the components is clear and no separation occurs. As the humidity increases from 30% to 95%, the moisture absorption and expansion of the wet response layer of the parallel fibers increases significantly, showing a bending deformation phenomenon toward the inert layer. The parallel fibers show the maximum bending phenomenon at a humidity of 95%, and the bending curvature reaches the maximum within 35 seconds, with a maximum bending angle of 82°. Figure 12 As shown, the composite fiber exhibited excellent response stability, with no change in the actuation amplitude after 50 cycles.

[0117] Example 8

[0118] Inert layer spinning solution: Dissolve polyurethane in N, N-dimethylformamide to prepare a spinning solution with a mass fraction of 20 wt% as the inert layer, and add a small amount of black pigment for color development;

[0119] Wet response layer spinning solution: Hydroxyethyl cellulose and polyurethane are dissolved in N,N-dimethylformamide in a mass ratio of 5:5, lithium chloride is added to promote dissolution, and then calcium-based bentonite is added as a wet response factor to obtain a spinning solution; wherein the total content of hydroxyethyl cellulose and polyurethane in the spinning solution is 15wt%, the wet response factor is 5wt%, and the mass of lithium chloride is 6% of the hydroxyethyl cellulose.

[0120] The two groups of spinning solutions were stirred at 60 °C for 24 hours in preparation for subsequent spinning.

[0121] Both the inert layer and the wet-responsive layer were extruded into a 40°C N, N-dimethylformamide / deionized water (volume ratio 5:15) coagulation bath at a rate of 15 mL / h, with a draw ratio of 1:1.2. After the fibers were formed, they were washed twice in deionized water to remove impurities, and then placed in a 30°C forced air oven to dry for 24 hours to obtain wet-responsive deformable fiber materials polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers.

[0122] The diameter of the parallel fiber is about 0.3 mm, the ratio of the two components is 1:1, and the black and white interface of the two components is clear and no separation occurs. As the humidity increases from 30% to 95%, the moisture absorption and expansion degree of the wet response layer of the parallel fiber increases significantly, showing a bending deformation phenomenon toward the inert layer. The parallel fiber shows the maximum bending phenomenon at a humidity of 95%, and the bending curvature reaches the maximum within 50 s, with a maximum bending angle of 135°. The fiber bending process is as follows Figure 11 The composite fiber exhibited excellent response stability, with no change in the actuation amplitude after 50 cycles.

[0123] like Figure 2 Shown is a schematic diagram of a wet-responsive deformable fiber material.

[0124] Examples 5, 6 and 8 illustrate that the driving effect of the parallel bicomponent fibers is best when the ratio of the two components is 1:1, at which point the difference in hygroscopicity between the two components is the greatest.

[0125] like Figure 14 Shown is the fiber surface image of polyurethane / polyurethane-hydroxyethyl cellulose-calcium bentonite parallel fibers under an electron microscope.

[0126] Example 9

[0127] In this embodiment, a wet-responsive smart deformable fabric is provided, and the preparation method is as follows:

[0128] The wet-responsive smart deformable fiber and cotton thread in Example 8 were integrated into a fabric with a size of 3 cm × 0.8 cm × 0.3 cm by crochet. The cotton thread was used as the fabric as a whole to fix the smart fiber units. During the weaving process, all the wet-responsive layers of the two-component fiber were ensured to be on the same side. Finally, a small amount of glue was applied to both sides of the fabric to fix it. The wet-responsive smart deformable fabric was obtained. Figure 13 (1) is the wet response side of the fabric, Figure 13 (2) is the inert layer side of the fabric. The wet response drive test is basically the same as the fiber test.

[0129] As the humidity increases from 30% to 95%, the moisture-responsive layer of the moisture-responsive smart deformable fabric significantly increases its moisture absorption and expansion, showing a bending deformation phenomenon toward the inert layer. The moisture-responsive smart deformable fabric shows the maximum bending phenomenon at a humidity of 95%, and the bending curvature reaches the maximum within 180 seconds, with a maximum bending angle of 115°. The moisture-responsive smart deformable fabric bends as follows Figure 13 As shown in (3).

[0130] Comparative Example 1

[0131] In this comparative example, compared with Example 6, a heat-moisture responsive fiber with photothermal conversion and antibacterial properties is provided. The fiber is prepared by spinning a parallel spinning assembly to obtain a parallel composite fiber composed of a hydrophilic antibacterial fiber and a hydrophobic photothermal conversion fiber. The fiber is prepared as follows:

[0132] Nanosilver and a copolymer of terephthalic acid, ethylene glycol, polyethylene glycol, and 1,2-butylene glycol are melt-blended in a twin-screw extruder to produce a hydrophilic spinning component. Far-infrared ceramic powder is melt-blended with polyethylene terephthalate in a twin-screw extruder to produce a hydrophobic spinning component. The mass of nanosilver is 0.5% of the mass of the copolymer of terephthalic acid, ethylene glycol, polyethylene glycol, and 1,2-butylene glycol, and the mass of far-infrared ceramic powder is 0.5% of the mass of the polyethylene terephthalate.

[0133] The hydrophilic and hydrophobic spinning components were placed in a parallel bicomponent spinning machine for melt spinning, drawing, and winding to produce a heat-moisture responsive fiber with photothermal conversion and antibacterial properties. The fiber was a "peanut-shaped" parallel composite fiber with a bicomponent diameter ratio of 1:1 and a diameter of approximately 35 μm.

[0134] The fiber actuator adjusts the diameter ratio of the two components of the fiber. When the diameter ratio is 1:1, the maximum bending angle is 69°. Compared with Example 6, the deformation performance of the fiber is reduced; the cross-section is irregularly circular, and the "peanut-shaped" cross-section will cause stress concentration in the actuator during frequent bending or friction use, reducing the service life of the device; the response stability is not mentioned; the process flow is complicated and requires polymer modification, and the universality is weak.

Claims

1. A wet responsive fiber, characterized in that The wet responsive fiber is a two-component side-by-side composite fiber; wherein the first component comprises a wet responsive factor and a polymer; the second component comprises a hydrophobic polymer; wherein the polymer in the first component is a mixture of a hydrophilic polymer and a hydrophobic polymer; The hydrophilic polymer in the first component includes one or more of cellulose material, chitosan, and sodium alginate; the cellulose material includes one or more of bacterial nanocellulose, methyl cellulose, carboxymethyl cellulose, cellulose acetate, carboxyethyl cellulose, and hydroxyethyl cellulose; the hydrophobic polymer includes one or more of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, styrene-butadiene-styrene block copolymer, polylactic acid, polyacrylate, phenyl silicone rubber, polyvinylidene fluoride, polychlorotrifluoroethylene, polycarbonate, polyether ketone, polyurethane, chlorinated rubber, and polyacrylonitrile; The hydrophobic polymer in the second component includes one or more of polyurethane, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, styrene-butadiene-styrene block copolymer, polylactic acid, polyacrylate, phenyl silicone rubber, polyvinylidene fluoride, polychlorotrifluoroethylene, polycarbonate, polyether ketone, chlorinated rubber, and polyacrylonitrile.

2. The wet responsive fiber according to claim 1, characterized in that The mass ratio of the first component to the second component is 10:1 to 1:

10.

3. The wet responsive fiber according to claim 1, characterized in that The wet response factor includes one or more of bentonite, titanium dioxide, starch, silicon dioxide, aluminum hydroxide, hydroxyapatite, aluminum oxide, calcium carbonate, barium sulfate, talc, montmorillonite, gelatin, collagen, and graphene oxide.

4. The wet responsive fiber according to claim 1, characterized in that The diameter of the wet-responsive fiber is 0.2-3 mm; The cross section of the wet-responsive fiber is circular; The moisture-responsive fiber has a rough surface.

5. A textile, characterized in that: The textile comprises yarn or fabric integrated with the moisture-responsive fiber according to claim 1.

6. A method for preparing the moisture-responsive fiber according to any one of claims 1 to 4, characterized in that: include: Step (1) mixing the wet response factor, the polymer, and the solvent to obtain a first spinning solution; Step (2) mixing a hydrophobic polymer and a solvent to obtain a second spinning solution; Step (3) The first spinning solution and the second spinning solution are extruded and spun in parallel through a double channel, passed through a confluence zone, and solidified into fibers by phase exchange in a coagulation bath, and then drawn to obtain wet-responsive fibers.

7. The preparation method according to claim 6, characterized in that: In step (1), the polymer concentration in the first spinning solution is 1 wt% to 60 wt%; the wet response factor concentration in the spinning solution is 1 wt% to 40 wt%; In the step (2), the concentration of the hydrophobic polymer in the second spinning solution is 1 wt% to 60 wt%; The solvent in steps (1) and (2) includes one or more of deionized water, ethanol, methanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, chloroform, acetone, toluene, thionyl chloride, and N-methylpyrrolidone; the first spinning solution and the second spinning solution use the same solvent; In step (3), the extrusion rate of the first spinning solution is 5 mL / h to 30 mL / h; the extrusion rate of the second spinning solution is 5 mL / h to 30 mL / h; In step (3), the coagulation bath comprises deionized water and a solvent, and the volume ratio of deionized water to the solvent is 1:9 to 9:1, wherein the solvent comprises one or more of ethanol, methanol, isopropanol, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, chloroform, acetone, toluene, thionyl chloride, and N-methylpyrrolidone; The drafting ratio in the step (3) is 1:1.05 to 1:1.

3.

8. An application of the moisture-responsive fiber according to any one of claims 1 to 4 and the textile according to claim 5 in the fields of smart wearables, sports health, medical assistance, high-end equipment, environmental perception, information collection, artificial muscles, and soft robots.

Images