Fiber-based torsional actuator with stimuli responsiveness to light heat and humidity, preparation method and application thereof

Abstract

The present invention discloses a fiber-based torsional actuator with photothermal and humidity stimulus responsiveness, its preparation method and application, belonging to the technical field of functional materials. The fiber-based torsional actuator is obtained by mixing graphene oxide powder, sodium alginate powder and deionized water with a mass ratio of (0.05-0.2):1:(25-40), followed by spinning and twisting processes. Among them, the fiber-based torsional actuator exhibits a reversible rotational driving behavior under the irradiation of near-infrared light with a wavelength of 780 nm to 1100 nm and a light intensity of 100 to 500 mW / cm<supgt;2< / supgt>, with the number of rotation cycles being 30 to 125 cycles and the rotational speed being 90 to 520 rpm / m; the fiber-based torsional actuator exhibits a reversible rotational driving behavior in an external environment with a relative humidity of 40% to 80%, with the number of rotation cycles being 250 to 330 cycles and the rotational speed being 4000 to 10000 rpm / m. In the fiber-based torsional actuator designed by the present invention, sodium alginate and graphene oxide work together, enabling it to have good application prospects in photothermal stimulus-responsive intelligent driving materials or humidity stimulus-responsive intelligent driving materials.

Description

Technical Field

[0001] The present invention relates to a torsional actuator, belonging to the technical field of functional materials, and particularly relates to a fiber-based torsional actuator having photo-thermal and humidity stimulus responsiveness, a preparation method thereof, and an application thereof. Background Art

[0002] Intelligent materials are a new type of functional materials that can sense external stimuli, judge and make appropriate processing, such as accompanying some self-responsive behaviors. Intelligent materials originated from functional materials, but their performance and application prospects are much higher than those of functional materials. As a new type of functional material, flexible actuators are an important and indispensable part of intelligent materials.

[0003] Flexible drive materials include one-dimensional fiber-based drive materials, two-dimensional film-based drive materials, and three-dimensional gel-based drive materials. Among them, one-dimensional fiber-based drive materials have become a new type of intelligent material due to their light weight, large-scale deformability, and weavability. The drive device can make a stimulative response to external environmental stimuli, thereby generating macroscopic motion during the driving process, that is, generating mechanical energy, and mechanical energy is one of the energy forms that we can directly utilize, so it will have a great impact on our production and life.

[0004] In current research, fiber-based drive materials having stimulus responsiveness to solvents, humidity, and heat have been reported. For example, the inventor of the present application has also applied for a patent for an invention on a preparation method and an application of a sodium alginate fiber-based torsional actuator. This application utilizes the hygroscopicity of sodium alginate to make sodium alginate into a sodium alginate gel fiber, and then through a twisting process, a sodium alginate fiber-based torsional actuator with high energy carriers is prepared. This actuator absorbs water and swells in an aqueous environment, and the volume change during the water absorption and swelling process is converted into a mechanical driving behavior, thereby generating a spontaneous, high-speed, and reversible torsional driving behavior.

[0005] For another example, a Chinese invention patent application (publication number: CN105003405, publication date: October 28, 2015) discloses a coiled and uncoiled twisted nanofiber yarn and a polymer fiber torsion and tension actuator, which includes a drive (artificial muscle) for twisting nanofiber yarns or inserting twisted polymer fibers that generates torsion and / or tension drive when energized by electricity, light, chemistry, heat, absorption, or other means. In Example 17 of this invention patent, it is described that a paraffin-impregnated carbon nanotube yarn generates a torsional drive through light heating, and in Examples 10 and 11, it is described that temperature changes can also provide a torsional drive for pure carbon nanotube yarns. That is, this invention patent application elaborates in detail on the twisted nanofiber yarns or inserted twisted polymer fibers that have a stimulatory response to temperature changes in the external environment, but does not mention flexible actuators that generate a torsional response to water stimulation in the external environment.

[0006] Therefore, there is currently no flexible actuator fiber material that can simultaneously generate a torsional response to both photothermal and humidity changes in the environment. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a torsional actuator that can simultaneously generate a spontaneous and reversible response to both photothermal and humidity changes in the environment, and a preparation method thereof. The preparation method is simple and fast, and can achieve large-scale production in batches.

[0008] To achieve the above object, the present invention discloses a fiber-based torsional actuator that is responsive to photothermal and humidity stimuli. It is obtained by mixing graphene oxide powder, sodium alginate powder, and deionized water in a mass ratio of (0.05 - 0.2):1:(25 - 40), followed by spinning and twisting processes. The fiber-based torsional actuator exhibits a reversible rotational drive behavior when irradiated with near-infrared light with a wavelength of 780 nm to 1100 nm and an optical intensity of 100 - 500 mW / cm 2 The number of rotation cycles is 30 - 125 cycles, and the rotational speed is 90 - 520 rpm / m. The fiber-based torsional actuator exhibits a reversible rotational drive behavior in an external environment with a relative humidity of 40% - 80%. The number of rotation cycles is 250 - 330 cycles, and the rotational speed is 4000 - 10000 rpm / m.

[0009] If the near-infrared light irradiation and the relative humidity of the environment are superimposed, both the number of rotation cycles and the rotational speed of the fiber-based torsional actuator increase compared to the single case.

[0010] Further, the fiber-based torsional actuator is responsive to near-infrared light with a wavelength of 900 nm to 1000 nm and an optical intensity of 200 - 400 mW / cm 2Reversible rotational driving behavior occurs under near-infrared light irradiation, with the number of rotation cycles being 40 - 120 cycles and the rotational speed being 95 - 500 rpm / m.

[0011] Furthermore, the fiber-based torsional actuator exhibits reversible rotational driving behavior in an external environment with a relative humidity of 55% - 80%, with the number of rotation cycles being 280 - 330 cycles and the rotational speed being 6000 - 10000 rpm / m.

[0012] Optimally, under the condition of controlling the environmental humidity RH = 30%, under the irradiation of near-infrared light with a wavelength of 808 nm and an intensity of 100 mW / cm 2 using an infrared stroboscope to measure its rotational speed, the maximum rotational speed is measured to be 90 rpm / m and the number of rotation cycles is 30 cycles.

[0013] Optimally, under the condition of controlling the environmental humidity RH = 30%, under the irradiation of near-infrared light with a wavelength of 808 nm and an intensity of 500 mW / cm 2 using an infrared stroboscope to measure its rotational speed, the maximum rotational speed is measured to be 520 rpm / m, the number of rotation cycles is 125 cycles, and at the same time, the length expansion and contraction amount of the sodium alginate fiber-based torsional actuator is 3.4%.

[0014] Optimally, in an environmental humidity of RH = 50%, using an infrared stroboscope to measure its rotational speed, the maximum rotational speed is measured to be 5500 rpm / m, the number of rotation cycles is 270 cycles, and at the same time, the length expansion and contraction amount of the sodium alginate fiber-based torsional actuator is 6%.

[0015] Optimally, in an environmental humidity of RH = 60%, using an infrared stroboscope to measure its rotational speed, the maximum rotational speed is measured to be 7500 rpm / m, the number of rotation cycles is 300 cycles, and at the same time, the length expansion and contraction amount of the sodium alginate fiber-based torsional actuator is 9%.

[0016] Preferably, the sodium alginate has high water absorbency, dissolves in an aqueous solution to form an aqueous solution with a relatively high viscosity, and graphene oxide can be stably dispersed in this solution for a long time.

[0017] Preferably, the graphene oxide has a unique lamellar structure and a large number of oxygen-containing functional groups, making it extremely easy to have reversible adsorption - desorption behavior with water molecules in the air, so that the fiber-based torsional actuator is easy to interact with water molecules in the air.

[0018] Furthermore, in the twisting process, the number of twists is 5000 - 6000 turns / meter, and the fiber diameter in the obtained fiber-based torsional actuator is 70 - 80 μm, and the fiber length is 15 - 20 cm.

[0019] Preferably, the number of twists in the twisting process is one of 5000 turns / m, 5200 turns / m, 5400 turns / m, 5600 turns / m, 5800 turns / m or 6000 turns / m.

[0020] Preferably, the fiber diameter of the obtained fiber-based torsional actuator is one of 70μm, 71μm, 72μm, 73μm, 74μm, 75μm, 76μm, 77μm, 78μm, 79μm or 80μm, and the fiber length is one of 15cm, 16cm, 17cm, 18cm, 19cm or 20cm.

[0021] To better achieve the object of the present invention, the present invention also discloses a preparation method of the above-mentioned fiber-based torsional actuator with photo-thermal and humidity stimulus responsiveness, which includes preparing a gel-like sodium alginate / graphene oxide colloidal spinning solution, preparing sodium alginate gel fibers from the sodium alginate / graphene oxide colloidal spinning solution through a wet spinning process, and performing a twisting process on the sodium alginate gel fibers to prepare a sodium alginate fiber-based torsional actuator.

[0022] Furthermore, the twisting process includes the following specific steps:

[0023] Take 1 prepared sodium alginate gel fiber, fix its two ends on a twisting machine, with the number of twists being 5000 - 6000 turns / m, and the fiber diameter of the obtained fiber-based torsional actuator is 70 - 80μm, and the fiber length is 15 - 20cm.

[0024] Furthermore, the wet spinning process includes the following specific steps: continuously injecting the sodium alginate / graphene oxide colloidal spinning solution into a calcium chloride coagulation bath with a mass percentage of 3wt% - 4wt% through a spinneret to prepare sodium alginate gel fibers with a fiber diameter of 0.2 - 0.3mm.

[0025] Furthermore, the preparation of the gel-like sodium alginate / graphene oxide colloidal spinning solution includes the following specific steps:

[0026] Add graphene oxide powder to deionized water and obtain a graphene oxide aqueous solution through ultrasonic pulverization, then add sodium alginate powder to the graphene oxide aqueous solution, stir at room temperature for 4 - 6h, stop stirring, and let it stand at room temperature for 20 - 28h to prepare a uniformly mixed sodium alginate / graphene oxide colloidal spinning solution.

[0027] Optimally, add graphene oxide powder to deionized water, and perform ultrasonic pulverization in an ultrasonic pulverizer for 30 - 45min to obtain a graphene oxide aqueous solution.

[0028] In addition, the present invention also discloses the application of the fiber-based torsional actuator prepared above in photothermal stimulus responsive intelligent driving materials or humidity stimulus responsive intelligent driving materials.

[0029] The principle of the preparation method of the present invention is:

[0030] The preparation method designed in the present invention uses sodium alginate and graphene oxide as main raw materials, mixes sodium alginate and graphene oxide (GO) to prepare sodium alginate / graphene oxide (GO) gel fibers, and then uses twisting treatment to squeeze out moisture in the sodium alginate / graphene oxide (GO) gel fibers and achieve shaping. The twisting treatment process is equivalent to an energy storage process. In addition, the sodium alginate / graphene oxide (GO) composite fibers obtained after twisting have a rough structure and excellent hygroscopicity.

[0031] The principle of the torsional actuator designed by the present invention to respond to light, heat and humidity is as follows: when the fiber-based torsional actuator is subjected to light with a wavelength of 780nm to 1100nm and an intensity of 100 to 500mW / cm 2 When exposed to near-infrared light, the photothermal stimulation causes water molecules between the graphene oxide sheets in the fiber to evaporate continuously, reducing the spacing between the graphene oxide layers. The entire fiber contracts and produces a twisting rotational motion, which in turn reduces the length of the torsional actuator. When the near-infrared light is removed, the excellent adsorption behavior between the graphene oxide sheets and water molecules in the environment causes water molecules in the environment to continuously enter between the graphene oxide sheets, causing the entire fiber to expand and produce an untwisting rotational motion, which in turn increases the length of the torsional actuator. When the torsional actuator is stimulated by an ambient humidity of 30% to 80%, due to the excellent water absorption of the sodium alginate / GO composite fiber and the high surface roughness of the twisted fiber, the torsional fiber-based actuator can undergo rapid water absorption and swelling at high humidity, causing the entire fiber to expand and produce an untwisting rotational motion, which in turn increases the length of the torsional actuator. When the ambient humidity decreases, the water molecules in the torsional fiber-based actuator rapidly diffuse from the inside of the fiber into the low-humidity environment under the action of the humidity gradient. The entire fiber undergoes deswelling behavior, shrinks in volume and produces twisting rotational motion, and the length of the fiber-based torsional actuator decreases accordingly. Figure 1 Schematic diagram of the principle of torsional actuator's ability to respond to light, heat and humidity.

[0032] The process of the torsional actuator designed in the present invention responding to light, heat and humidity is carried out in a coordinated manner, ultimately achieving spontaneous, rapid and reversible torsional driving behavior of the torsional actuator.

[0033] The beneficial effects of the present invention are mainly reflected in the following aspects:

[0034] 1. The fiber-based torsional actuator designed in the present invention uses sodium alginate and graphene oxide as the main raw materials. On the one hand, sodium alginate has a certain hygroscopicity. On the other hand, the addition of sodium alginate helps to prepare fibers by electrospinning graphene oxide. The addition of graphene oxide makes the torsional composite fiber loose and wrinkled from the inside out, with a larger contact area with water molecules in the environment. Combining the adsorption-desorption process between the graphene oxide sheets themselves and water molecules, the torsional actuator exhibits fast and reversible rotational driving behavior;

[0035] 2. The fiber-based torsional actuator designed in the present invention realizes the process of directly converting photothermal and humidity stimuli into kinetic energy, effectively achieving the conversion and direct utilization of energy;

[0036] 3. The preparation method of the fiber-based torsional actuator designed in the present invention is simple, the raw materials are widely available, and large-scale production can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the principle that the fiber-based torsional actuator of the present invention has responsiveness to photothermal and humidity;

[0038] Figure 2 It is a scanning electron microscope image of the fiber-based torsional actuator prepared in the present invention;

[0039] Figure 3 For Figure 1 It is a curve graph of the driving strain and the number of rotation cycles of the fiber-based torsional actuator in

[0040] Figure 4 For Figure 1 It is a curve graph of the rotational speed of the fiber-based torsional actuator in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] To better explain the present invention, the main content of the present invention is further clarified below in conjunction with specific embodiments, but the content of the present invention is not limited to the following embodiments.

[0042] Example 1

[0043] A preparation method of a fiber-based torsional actuator with responsiveness to photothermal and humidity is prepared according to the following steps:

[0044] 1) Prepare a colloidal spinning solution of sodium alginate and graphene oxide (GO): According to the mass ratio, the mass ratio of GO to sodium alginate powder is 0.05:1. Weigh GO powder, sodium alginate powder and deionized water. Add GO powder into deionized water, and ultrasonically crush it in an ultrasonic crusher for 30 min to obtain a GO aqueous solution. Then add sodium alginate powder into the GO aqueous solution, and the mass percentage of sodium alginate in the mixed solution is 2.5 wt%. Continuously stir with a mechanical stirring device at room temperature for 5 hours to obtain a gel-like sodium alginate / GO colloidal spinning solution. Let the prepared sodium alginate / GO colloidal spinning solution stand at room temperature for 24 h to naturally remove the air bubbles in it;

[0045] 2) Prepare a calcium chloride coagulation bath: Prepare a 4 wt% calcium chloride aqueous solution as the sodium alginate coagulation bath, and fully stir to make anhydrous calcium chloride fully dissolve in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0046] 3) Prepare sodium alginate / GO gel fibers: Continuously inject the sodium alginate / GO colloidal spinning solution into the calcium chloride coagulation bath through a spinneret, and use the wet spinning process to prepare sodium alginate gel fibers.

[0047] 4) Twisting treatment of sodium alginate / GO gel fibers: Take a sodium alginate / GO gel fiber, fix its two ends on a twisting machine, and perform twisting treatment. The twist number is 6000 turns / m, and the diameter is 70 μm.

[0048] The test experiment on the stimulus response behavior of the fiber-based torsional actuator with photothermal and humidity stimulus responsiveness prepared in Example 1 is as follows;

[0049] Test method: Cut a 15 cm long sodium alginate / GO fiber-based torsional drive fiber, fix one end and hang it up, and load a 50 mg weight at the other end, and perform a reciprocating drive behavior under near-infrared light irradiation. During this rotation drive process, use an infrared stroboscope, a digital display electronic revolution counter and a high-speed camera to measure the rotation speed of the sodium alginate fiber-based torsional actuator, the total number of rotation circles in the whole process, and the length change amount during the movement of the sodium alginate fiber-based torsional actuator. And the test methods for the stimulus response behaviors of the sodium alginate fiber-based torsional actuators obtained in Examples 2-8 below all adopt the above methods, which will not be elaborated below.

[0050] Test results: Under the condition of controlling the environmental humidity RH = 30%, under the irradiation of near-infrared light with a wavelength of 808 nm and an intensity of 100 mW / cm 2 When measuring its rotation speed with an infrared stroboscope, the maximum rotation speed is measured to be 90 rpm / m, the number of rotation circles is 30, and at the same time, the length expansion and contraction amount of the sodium alginate fiber-based torsional actuator is 1%.

[0051] Example 2

[0052] A preparation method of a fiber-based torsional actuator with photothermal and humidity stimulus responsiveness is prepared according to the following steps:

[0053] 1) Prepare a mixed spinning solution of sodium alginate and graphene oxide (GO) colloid: By mass ratio, the mass ratio of GO to sodium alginate powder is 0.1:1. Weigh GO powder, sodium alginate powder and deionized water. Add the GO powder into the deionized water, and ultrasonically crush it in an ultrasonic crusher for 35 min to obtain a GO aqueous solution. Then add the sodium alginate powder into the GO aqueous solution, and the mass percentage of sodium alginate in the mixed solution is 2.5 wt%. Continuously stir with a mechanical stirring device at room temperature for 5 hours to obtain a gel-like sodium alginate / GO colloid spinning solution. Let the prepared sodium alginate / GO colloid spinning solution stand at room temperature for 24 h to naturally remove the bubbles in it;

[0054] 2) Prepare a calcium chloride coagulation bath: Prepare a 4 wt% calcium chloride aqueous solution as the sodium alginate coagulation bath, and fully stir to make anhydrous calcium chloride fully dissolve in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0055] 3) Prepare sodium alginate / GO gel fibers: Continuously inject the sodium alginate / GO colloid spinning solution into the calcium chloride coagulation bath through a spinneret, and use the wet spinning process to prepare sodium alginate gel fibers.

[0056] 4) Twisting treatment of sodium alginate / GO gel fibers: Take a sodium alginate / GO gel fiber, fix its two ends on a twisting machine, and perform twisting treatment. The number of twists is 6000 turns / m, and the diameter is 74 μm.

[0057] The stimulus response behavior test experiment of the fiber-based torsional actuator with photothermal and humidity stimulus responsiveness prepared in Example 2 is as follows;

[0058] Test results: Under the condition of controlling the environmental humidity RH = 30%, under the irradiation of near-infrared light with a wavelength of 808 nm and a light intensity of 200 mW / cm 2 , use an infrared stroboscope to measure its rotational speed, and the maximum rotational speed is measured to be 150 rpm / m, the number of rotation circles is 60 circles. At the same time, the length expansion amount of the sodium alginate fiber-based torsional actuator is 1.5%.

[0059] Example 3

[0060] A preparation method of a fiber-based torsional actuator with photothermal and humidity stimulus responsiveness is prepared according to the following steps:

[0061] 1) Prepare the alginate and graphene oxide (GO) colloidal spinning solution: According to the mass ratio, the mass ratio of GO to sodium alginate powder is 0.15:1. Weigh the GO powder, sodium alginate powder and deionized water. Add the GO powder to the deionized water and ultrasonically crush it in an ultrasonic crusher for 40 min to obtain a GO aqueous solution. Then add the sodium alginate powder to the GO aqueous solution. The mass percentage of sodium alginate in the mixed solution is 2.5 wt%. Continuously stir with a mechanical stirring device at room temperature for 5 hours to obtain a gel-like sodium alginate / GO colloidal spinning solution. Let the prepared sodium alginate / GO colloidal spinning solution stand at room temperature for 24 h to naturally remove the air bubbles in it;

[0062] 2) Prepare the calcium chloride coagulation bath: Prepare a 4 wt% calcium chloride aqueous solution as the sodium alginate coagulation bath, and fully stir to dissolve anhydrous calcium chloride in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0063] 3) Prepare the sodium alginate / GO gel fiber: Continuously inject the sodium alginate / GO colloidal spinning solution into the calcium chloride coagulation bath through a spinneret, and use the wet spinning process to prepare sodium alginate gel fibers.

[0064] 4) Twisting treatment of the sodium alginate / GO gel fiber: Take a sodium alginate / GO gel fiber, fix its two ends on a twisting machine, and perform twisting treatment. The twist number is 6000 turns / m, and the diameter is 77 μm.

[0065] The test experiment on the stimulus response behavior of the fiber-based torsional actuator with photothermal and humidity stimulus responsiveness prepared in Example 3 is as follows;

[0066] Test results: Under the condition of controlling the environmental humidity RH = 30%, under the irradiation of near-infrared light with a wavelength of 808 nm and a light intensity of 300 mW / cm 2 Measure its rotational speed using an infrared stroboscope. The maximum rotational speed measured is 400 rpm / m, the number of rotation cycles is 90, and at the same time, the length expansion amount of the sodium alginate fiber-based torsional actuator is 2.25%.

[0067] Example 4

[0068] A preparation method of a fiber-based torsional actuator with photothermal and humidity stimulus responsiveness is prepared according to the following steps:

[0069] 1) Prepare a colloidal spinning solution of sodium alginate and graphene oxide (GO): By mass ratio, the mass ratio of GO to sodium alginate powder is 0.2:1. Weigh GO powder, sodium alginate powder, and deionized water. Add the GO powder into deionized water and ultrasonically crush it in an ultrasonic crusher for 45 min to obtain a GO aqueous solution. Then add the sodium alginate powder into the GO aqueous solution, and the mass percentage of sodium alginate in the mixed solution is 3 wt%. Continuously stir it with a mechanical stirring device at room temperature for 5 hours to obtain a gel-like sodium alginate / GO colloidal spinning solution. Let the prepared sodium alginate / GO colloidal spinning solution stand at room temperature for 24 h to naturally remove the air bubbles in it;

[0070] 2) Prepare a calcium chloride coagulation bath: Prepare a 4 wt% calcium chloride aqueous solution as the sodium alginate coagulation bath, and fully stir it to make anhydrous calcium chloride fully dissolve in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0071] 3) Prepare sodium alginate / GO gel fibers: Continuously inject the sodium alginate / GO colloidal spinning solution into the calcium chloride coagulation bath through a spinneret, and use the wet spinning process to prepare sodium alginate gel fibers.

[0072] 4) Twisting treatment of sodium alginate / GO gel fibers: Take a sodium alginate / GO gel fiber, fix its two ends on a twisting machine, and conduct twisting treatment. The number of twists is 6000 turns / m, and the diameter is 80 μm.

[0073] The stimulation response behavior test experiment of the fiber-based torsional actuator with photothermal and humidity stimulation responsiveness prepared in Example 4 is as follows;

[0074] Test results: Under the condition of controlling the environmental humidity RH = 30%, under the irradiation of near-infrared light with a wavelength of 808 nm and a light intensity of 500 mW / cm 2 Using an infrared stroboscope to measure its rotation speed, the maximum rotation speed is measured to be 520 rpm / m, the number of rotation circles is 125 circles, and at the same time, the length expansion and contraction amount of the sodium alginate fiber-based torsional actuator is 3.4%.

[0075] In addition, the scanning electron microscope image of the fiber-based torsional actuator prepared in this example is as Figure 1 shown. Combining Figure 2 it can be seen that after the fiber is twisted, a torsional structure with a certain twist direction and twist angle is formed on the surface, its surface roughness is greatly increased, and this torsional structure is fixed as the initial form of the fiber.

[0076] Example 5

[0077] A preparation method of a fiber-based torsional actuator with photothermal and humidity stimulation responsiveness is prepared according to the following steps:

[0078] 1) Preparing a sodium alginate and graphene oxide (GO) colloidal mixed spinning solution: The mass ratio of GO to sodium alginate powder is 0.2:1. GO powder, sodium alginate powder, and deionized water are weighed. GO powder is added to deionized water and ultrasonically pulverized in an ultrasonic mill for 45 minutes to obtain a GO aqueous solution. Sodium alginate powder is added to the GO aqueous solution, with the mass percentage of sodium alginate in the mixed solution being 3 wt%. The mixture is stirred continuously at room temperature for 5 hours using a mechanical stirrer to obtain a gel-like sodium alginate / GO colloidal spinning solution. The prepared sodium alginate / GO colloidal spinning solution is allowed to stand at room temperature for 24 hours to allow bubbles therein to naturally dissipate.

[0079] 2) Preparing a calcium chloride coagulation bath: preparing a 4 wt % calcium chloride aqueous solution as a sodium alginate coagulation bath, and stirring thoroughly to fully dissolve anhydrous calcium chloride in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0080] 3) Preparation of sodium alginate / GO gel fibers: Sodium alginate / GO colloid spinning solution was continuously injected into a calcium chloride coagulation bath through a spinning head, and sodium alginate gel fibers were prepared by a wet spinning process.

[0081] 4) Twisting treatment of sodium alginate / GO gel fiber: A sodium alginate / GO gel fiber was taken, and its two ends were fixed on a twisting machine for twisting treatment. The twist number was 6000 turns / m and the diameter was 80 μm.

[0082] The stimulus response behavior test experiment of the fiber-based torsional actuator with stimulus response to light, heat and humidity prepared in Example 5 is as follows;

[0083] Test results: Under an ambient humidity of RH = 40%, the rotation speed was measured using an infrared stroboscope, and the maximum rotation speed was measured to be 4000 rpm / m, the number of rotations was 250, and the length expansion and contraction of the sodium alginate fiber-based torsional actuator was 3%.

[0084] Example 6

[0085] A fiber-based torsional actuator responsive to light, heat, and humidity is prepared by the following steps:

[0086] 1) Preparing a sodium alginate and graphene oxide (GO) colloidal mixed spinning solution: The mass ratio of GO to sodium alginate powder is 0.2:1. GO powder, sodium alginate powder, and deionized water are weighed. GO powder is added to deionized water and ultrasonically pulverized in an ultrasonic mill for 45 minutes to obtain a GO aqueous solution. Sodium alginate powder is added to the GO aqueous solution, with the mass percentage of sodium alginate in the mixed solution being 3 wt%. The mixture is stirred continuously at room temperature for 5 hours using a mechanical stirrer to obtain a gel-like sodium alginate / GO colloidal spinning solution. The prepared sodium alginate / GO colloidal spinning solution is allowed to stand at room temperature for 24 hours to allow bubbles therein to naturally dissipate.

[0087] 2) Preparing a calcium chloride coagulation bath: preparing a 4 wt % calcium chloride aqueous solution as a sodium alginate coagulation bath, and stirring thoroughly to fully dissolve anhydrous calcium chloride in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0088] 3) Preparation of sodium alginate / GO gel fibers: Sodium alginate / GO colloid spinning solution was continuously injected into a calcium chloride coagulation bath through a spinning head, and sodium alginate gel fibers were prepared by a wet spinning process.

[0089] 4) Twisting treatment of sodium alginate / GO gel fiber: A sodium alginate / GO gel fiber was taken, and its two ends were fixed on a twisting machine for twisting treatment. The twist number was 6000 turns / m and the diameter was 80 μm.

[0090] The stimulus response behavior test experiment of the fiber-based torsional actuator with stimulus response to light, heat and humidity prepared in Example 6 is as follows;

[0091] Test results: Under an ambient humidity of RH = 50%, the rotation speed was measured using an infrared stroboscope, and the maximum rotation speed was measured to be 5500 rpm / m, the number of rotations was 270, and the length expansion and contraction of the sodium alginate fiber-based torsional actuator was 6%.

[0092] Example 7

[0093] A fiber-based torsional actuator responsive to light, heat, and humidity is prepared by the following steps:

[0094] 1) Prepare the alginate and graphene oxide (GO) colloidal spinning solution: By mass ratio, the mass ratio of GO to sodium alginate powder is 0.2:1. Weigh GO powder, sodium alginate powder and deionized water. Add the GO powder into deionized water and ultrasonically crush it in an ultrasonic crusher for 45 min to obtain a GO aqueous solution. Then add the sodium alginate powder into the GO aqueous solution. The mass percentage of sodium alginate in the mixed solution is 3 wt%. Continuously stir it with a mechanical stirring device at room temperature for 5 hours to obtain a gel-like sodium alginate / GO colloidal spinning solution. Let the prepared sodium alginate / GO colloidal spinning solution stand at room temperature for 24 h to naturally remove the bubbles in it;

[0095] 2) Prepare the calcium chloride coagulation bath: Prepare a 4 wt% calcium chloride aqueous solution as the sodium alginate coagulation bath. Stir it well to fully dissolve anhydrous calcium chloride in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0096] 3) Prepare the sodium alginate / GO gel fiber: Continuously inject the sodium alginate / GO colloidal spinning solution into the calcium chloride coagulation bath through a spinneret, and use the wet spinning process to prepare the sodium alginate gel fiber.

[0097] 4) Twisting treatment of the sodium alginate / GO gel fiber: Take a sodium alginate / GO gel fiber, fix its two ends on a twister, and perform twisting treatment. The number of twists is 6000 turns / m, and the diameter is 80 μm.

[0098] The test experiment on the stimulus response behavior of the fiber-based torsional actuator with photothermal and humidity stimulus responsiveness prepared in Example 7 is as follows;

[0099] Test results: In an environmental humidity of RH = 60%, use an infrared stroboscope to measure its rotation speed. The measured maximum rotation speed is 7500 rpm / m, the number of rotation circles is 300, and at the same time, the length expansion and contraction amount of the sodium alginate fiber-based torsional actuator is 9%.

[0100] Example 8

[0101] A preparation method of a fiber-based torsional actuator with photothermal and humidity stimulus responsiveness is prepared according to the following steps:

[0102] 1) Prepare the alginate and graphene oxide (GO) colloidal spinning solution: By mass ratio, the mass ratio of GO to sodium alginate powder is 0.2:1. Weigh the GO powder, sodium alginate powder, and deionized water. Add the GO powder to the deionized water and ultrasonically crush it in an ultrasonic crusher for 45 minutes to obtain a GO aqueous solution. Then add the sodium alginate powder to the GO aqueous solution, and the mass percentage of sodium alginate in the mixed solution is 3 wt%. Continuously stir with a mechanical stirring device at room temperature for 5 hours to obtain a gel-like sodium alginate / GO colloidal spinning solution. Let the prepared sodium alginate / GO colloidal spinning solution stand at room temperature for 24 hours to naturally remove the air bubbles in it;

[0103] 2) Prepare the calcium chloride coagulation bath: Prepare a 4 wt% calcium chloride aqueous solution as the sodium alginate coagulation bath, and stir well to fully dissolve anhydrous calcium chloride in deionized water to obtain an anhydrous calcium chloride aqueous solution;

[0104] 3) Prepare sodium alginate / GO gel fibers: Continuously inject the sodium alginate / GO colloidal spinning solution into the calcium chloride coagulation bath through a spinneret, and use the wet spinning process to prepare sodium alginate gel fibers.

[0105] 4) Twist treatment of sodium alginate / GO gel fibers: Take a sodium alginate / GO gel fiber, fix its two ends on a twisting machine, and perform twisting treatment. The twist number is 6000 turns / meter, and the diameter is 80 μm.

[0106] The test experiment on the stimulus response behavior of the fiber-based torsional actuator with photothermal and humidity stimulus response prepared in Example 8 is as follows;

[0107] Test results: Under the environmental humidity of RH = 80%, use an infrared stroboscope to measure its rotation speed. The measured maximum rotation speed is 10000 rpm / m, the number of rotation circles is 330, and at the same time, the length expansion and contraction amount of the sodium alginate fiber-based torsional actuator is 12%.

[0108] As can be seen from the above Examples 1-8, the fiber-based torsional actuator prepared by the present invention has a reversible rotational drive behavior for near-infrared light with a wavelength of 808 nm and an illumination intensity of 100-500 mW / cm 2 and an external environment with a relative humidity of 40%-80%, and the number of rotation circles and the rotation speed continuously increase with the increase of the illumination intensity, the content of graphene oxide, and the environmental humidity.

[0109] Combined with Figure 3 it can be seen that at a wavelength of 808 nm and an illumination intensity of 500 mW / cm 2Under the irradiation of near-infrared light, as the GO content in the twisted fiber increases, the length elongation and the number of rotation cycles of the twisted fiber during the rotation drive continuously increase.

[0110] Combined with Figure 4 it can be seen that under the irradiation of near-infrared light with a wavelength of 808 nm and an illumination intensity of 500 mW / cm 2 as the GO content in the twisted fiber increases, the rotation speed of the twisted fiber continuously increases, and the response sensitivity to humidity continuously improves.

[0111] Application Example 1

[0112] Apply the sodium alginate / GO fiber-based torsional actuator prepared in the above Example 4 to the drive motor under near-infrared light irradiation, so as to drive the trolley forward or backward.

[0113] Specifically: Cut the sodium alginate / GO fiber-based torsional actuator into 25 cm in length, fix one end firmly so that it cannot move freely, and fix the other end on a simple prepared model trolley that can move freely. When applying near-infrared light irradiation stimulation to the sodium alginate / GO twisted fiber, due to the desorption behavior of water molecules in the GO lamellae, the fiber shrinks to generate a twisting-type rotational motion, thereby driving the trolley backward; when removing the near-infrared light irradiation stimulation, water molecules in the environment re-enter the fiber, causing an increase in the GO layer spacing, and the fiber elongates to generate an untwisting-type rotational motion, thereby driving the trolley backward.

[0114] Application Example 2

[0115] Apply the sodium alginate / GO fiber-based torsional actuator prepared in Example 4 to the humidity control switch, so as to control the on-off process of the light bulb.

[0116] Specifically: Cut the sodium alginate / GO fiber-based torsional actuator into 15 cm in length, fix one end firmly so that it cannot move freely, and fix the other end to one end of a wire that can move freely. When applying a humidity stimulation with a relative humidity of 70% to the sodium alginate / GO twisted fiber, the fiber absorbs water and swells by itself, and an untwisting driving behavior occurs. The fiber elongation drives the wire to connect the closed circuit where the light bulb is located, and the light bulb is lit; when the environmental humidity drops to 30%, the water molecules on the fiber diffuse from the inside to the outside, the fiber loses water and shrinks by itself, and a twisting driving behavior occurs. The fiber length shortens, thereby driving the wire to disconnect the closed circuit where the light bulb is located, and the light bulb is extinguished.

[0117] The above embodiments are only the best examples and are not intended to limit the implementation manners of the present invention. In addition to the above embodiments, the present invention has other implementation manners. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. Preparation method of a fiber-based torsional actuator with photothermal and humidity stimulus responsiveness, characterized in that: The preparation method of the fiber-based torsional actuator includes the following specific processes: Adding graphene oxide powder into deionized water, and obtaining graphene oxide aqueous solution through ultrasonic comminution. Then adding sodium alginate powder into the graphene oxide aqueous solution, stirring at room temperature for 4 - 6 h, stopping stirring, and standing at room temperature for 20 - 28 h to prepare a uniformly mixed sodium alginate / graphene oxide colloidal spinning solution; wherein, the mass ratio among the graphene oxide powder, sodium alginate powder and deionized water is (0.05 - 0.2):1:(25 - 40); Continuously injecting the sodium alginate / graphene oxide colloidal spinning solution into a calcium chloride coagulation bath with a mass percentage of 3 wt% - 4 wt% through a spinneret to prepare sodium alginate gel fibers with a fiber diameter of 0.2 - 0.3 mm; Taking 1 prepared sodium alginate gel fiber, fixing its two ends on a twisting machine, with a twist number of 5000 - 6000 turns / meter, and the fiber diameter in the obtained fiber-based torsional actuator is 70 - 80 μm, and the fiber length is 15 - 20 cm; The fiber-based torsional actuator exhibits reversible rotational driving behavior under irradiation with near-infrared light having a wavelength of 780 - 1100 nm and an optical intensity of 100 - 500 mW / cm 2 . The number of rotation cycles is 30 - 125 cycles, and the rotational speed is 90 - 520 rpm / m. The fiber-based torsional actuator also exhibits reversible rotational driving behavior in an external environment with a relative humidity of 40% - 80%. The number of rotation cycles is 250 - 330 cycles, and the rotational speed is 4000 - 10000 rpm / m.

2. Application of the fiber-based torsional actuator prepared by the preparation method according to claim 1 in photothermal stimulus-responsive intelligent driving materials or humidity stimulus-responsive intelligent driving materials.

Images