A coaxial liquid-jet spun structured colored fiber membrane and its preparation method

Abstract

This invention discloses a coaxial liquid-jet spun structural color fiber membrane and its preparation method. The structural color fiber membrane is obtained through coaxial liquid-jet spinning of a shell solution and a core solution. The shell solution is a SiO2 microsphere dispersion, and the core solution is a PEO polymer solution. The polymer solution is refined into fibers under the traction and stretching of a high-speed airflow. During this process, the microsphere dispersion adheres to the fibers. Under the action of capillary force generated by solvent evaporation within the microsphere dispersion, the microspheres self-assemble and arrange themselves in an orderly manner on the fiber surface. This invention employs coaxial liquid-jet spinning. When the shell microsphere dispersion is stretched by a high-speed airflow, strong shear stress is generated at the interface between the inner and outer solutions. Under the action of shear stress, the core PEO spinning solution moves coaxially along the shell, allowing the microspheres to better arrange themselves on the fiber surface, thus exhibiting structural color. The preparation method is simple, portable, and highly operable; the fiber receiving surface is diversified and flexible.

Description

Technical Field

[0001] This invention belongs to the field of nanofibers, and particularly relates to a coaxial liquid-jet spun structured colored fiber membrane and its preparation method. Background Technology

[0002] Structural color is an optical effect caused by the submicroscopic structure of organisms, also known as physical color. It is mainly produced through optical phenomena, including light interference, diffraction, dispersion, scattering and their combined effects. Currently, the main methods for directly preparing structural color fibers include electrospinning, microfluidics, and extrusion curing.

[0003] Chinese patent application CN111101214A discloses a method for preparing coaxial core-shell structured color fibers using microfluidic control. The method includes: injecting a skin solution and a core solution into a microfluidic chip device through two separate inlets; performing microfluidic spinning, causing the skin solution to coat the core solution and flow into a coagulation bath through the outlet of the microfluidic chip device to continuously prepare coaxial core-shell structured color fibers; and finally, placing the obtained wet structured color fibers in a fume hood to dry, resulting in the final state of the structured color fibers. The skin solution comprises a colorless and transparent polymer solution, and the core solution comprises a microsphere dispersion, including nanospheres capable of producing structural color, or nanospheres capable of producing structural color, and carbon black nanospheres. When using microfluidic control to prepare core-shell structured color fibers, the skin solution can only be selected from colorless and transparent polymers, which greatly limits the selection of raw materials for the skin solution. Furthermore, post-treatment such as drying is unavoidable to achieve the desired color in the structured color fibers or fiber membranes.

[0004] Chinese patent application CN116180331A discloses a method for preparing structural color fiber membranes by colloidal electrospinning. The structural color fiber membrane uses responsive soft microgels as colloidal particles and linear polymers as templates. It is prepared by colloidal electrospinning technology in five steps: responsive microgel synthesis, linear template polymer solution synthesis, microgel composite spinning solution preparation, colloidal electrospinning to prepare microgel composite nanofiber membranes, and structural color nanofiber membrane color development. The key feature is that a solution is sprayed onto the surface of the fiber membrane to exhibit structural color. In the preparation of structural color fibers by electrospinning, the spinning solution is prepared by mixing nanospheres with polymers, then the fiber membrane is electrospinned, and finally the obtained fiber membrane is sprayed to exhibit structural color.

[0005] Therefore, it is essential to develop a method that can be used to directly prepare structural color fibers using a wide variety of polymer materials without any post-processing. Summary of the Invention

[0006] The main objective of this invention is to provide a method for preparing coaxial liquid-jet spun structured color fiber membranes, based on coaxial liquid-jet spinning, to solve the problems of cumbersome and time-consuming preparation processes in the prior art.

[0007] Another objective of this invention is to provide a coaxial liquid-jet spun structural color fiber membrane, which is prepared by the same method. The microsphere particle size is controlled between 170 nm and 350 nm, and the resulting structural color fiber membrane can cover the entire visible light spectrum. The relationship between color and particle size follows Bragg's diffraction law: silica particles with a diameter between 167 and 192 nm exhibit purple; those between 193 and 209 nm exhibit cyan and blue; and those between 210 and 250 nm exhibit green.

[0008] The above-mentioned objective of the present invention is achieved through the following technical methods:

[0009] This invention provides a method for preparing a coaxial liquid-jet spun structured colored fiber membrane, comprising the following steps:

[0010] Step 1: Weigh a certain amount of PEO powder and ink, dissolve them in a water-soluble polymer, and heat and stir in a water bath until the PEO is completely dissolved to obtain the core layer solution; weigh a certain amount of SiO2 powder and disperse it in water or ethanol, and ultrasonically stir until the spheres are evenly dispersed to obtain the shell layer solution.

[0011] Step 2: Pour the shell layer solution and core layer solution into the coaxial liquid jet spinning portable device, set the feed speed, connect the spray gun interface to the pressure regulating valve through an air pipe, and connect the pressure regulating valve to the air compressor through an air pipe. A detachable coaxial needle is built into the nozzle. Adjust the distance between the receiving net and the nozzle; wherein:

[0012] The portable coaxial liquid jet spinning device includes independent and parallel shell solution channels and core solution channels, and also includes a spray gun interface, air pipe a, air pipe b, pressure regulating valve, air compressor, nozzle, feed inlet, and receiving net; the spray gun interface is connected to the pressure regulating valve through the air pipe a, the pressure regulating valve is connected to the air compressor through the air pipe b, the nozzle has a built-in detachable coaxial needle, and the distance between the receiving net and the nozzle is adjustable;

[0013] Step 3: Turn on the air compressor, open the pressure regulating valve, set the air pressure, and open the feed port. The solution is pushed into the nozzle and flows out from the coaxial spinning needle. Then, it is blown by a high-speed airflow. Under the action of traction and stretching, the spinning solution forms fibers and deposits on the receiving net. The shell solution generates capillary force when the solvent evaporates, which induces the microspheres to self-assemble on the fiber, thereby forming structural color fibers.

[0014] Preferably, in step 1, the PEO has a molecular weight of 600,000 and a mass fraction of 6% to 9%, with a preferred dosage of 7%.

[0015] Preferably, in step 1, the mass fraction of the SiO2 powder is 2% to 4%, and the preferred amount is 3%.

[0016] The particle size of the SiO2 powder is 170–350 nm, preferably 180–250 nm.

[0017] Preferably, in step 2, the feed rate of the core layer solution is 0.2 to 0.4 mL / min, preferably 0.2 mL / min;

[0018] The feed rate of the shell solution is 0.4 to 0.6 mL / min, preferably 0.6 mL / min;

[0019] Preferably, in step 2, the nozzle has a built-in detachable coaxial needle with a specification of 17G+23G.

[0020] Preferably, in step 3, the air pressure is 0.06 to 0.15 MPa, and more preferably 0.1 MPa.

[0021] In the above-mentioned preparation method of the present invention, the shell solution and the core solution are injected into the coaxial liquid-jet spinning portable device from two inlets to perform coaxial liquid-jet spinning. The principle is that the solutions of the core layer and the shell layer materials are separately packaged into two different syringes. Under the action of a high-speed airflow field, the shell liquid is stretched at high frequency. When the high-speed jet is applied, a strong shear stress is generated at the interface between the inner and outer layer solutions. Under the action of shear stress, the core layer solution moves coaxially along the shell layer, bends and deforms, and solidifies into ultrafine coaxial composite nanofibers. The shell solution is a microsphere dispersion, and the core solution is a polymer solution. The core polymer is refined into fibers under the traction and stretching of the high-speed airflow. The microsphere dispersion of the shell layer adheres to the fibers in this process. Then, due to the evaporation of the solvent, a capillary force is generated, which induces the self-assembly of the microspheres, which are arranged in an orderly manner on the fiber surface.

[0022] The present invention also provides a coaxial liquid-jet spun structural color fiber membrane, which is prepared by the method of preparing the coaxial liquid-jet spun structural color fiber membrane.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] ①This invention employs coaxial liquid-jet spinning, with PEO spinning solution as the core layer and microsphere dispersion as the shell layer. When the shell layer microsphere dispersion is stretched by high-speed airflow, strong shear stress is generated at the interface between the inner and outer layer solutions. Under the action of shear stress, the core layer PEO spinning solution moves coaxially along the shell layer, which allows the microspheres to be better arranged on the fiber surface, thereby exhibiting structural color.

[0025] ② This invention uses a handheld spray gun, which is simple and portable to operate. The fiber receiving surface can be diversified. For example, a wall can be selected as the fiber receiving surface, or it can be curved, such as on a cylindrical thermos cup. It is flexible and highly operable. Attached Figure Description

[0026] Figure 1 The following is a process flow diagram of the preparation of the coaxial liquid-jet spun structured colored fiber membrane in the embodiment; wherein: 1 shell layer solution channel; 2 core layer solution channel; 3 nozzle; 4 spray gun interface; 5 air pipe a; 6 pressure regulating valve; 7 air pipe b; 8 receiving net; 9 feed port.

[0027] Figure 2 This is a schematic diagram of the detachable coaxial needle structure at the nozzle in the embodiment.

[0028] Figure 3 This is an optical photograph (dark green) of the coaxial liquid-jet spun structured colored fiber membrane in Example 1.

[0029] Figure 4 This is an optical photograph (purple) of the coaxial liquid-jet spun structured colored fiber membrane in Example 2.

[0030] Figure 5 This is a SEM image of the coaxial liquid-jet spun structured colored fiber membrane in Example 2.

[0031] Figure 6 The image shows the reflectance spectrum of the coaxial liquid-jet spun structured colored fiber membrane in Example 1. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to examples and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0033] The portable coaxial liquid jet spinning device used in the following embodiments is as follows: Figure 1 and 2 As shown, it includes an independent and parallel shell solution channel 1 and a core solution channel 2, as well as a spray gun interface 4, an air pipe a 5, an air pipe b 7, a pressure regulating valve 6, a nozzle 3, a feed inlet 9, and a receiving net 8; it also includes an air compressor; wherein: the spray gun interface 4 is connected to the pressure regulating valve 6 through the air pipe a 5, the pressure regulating valve 6 is connected to the air compressor through the air pipe b 7, the nozzle 3 has a built-in detachable coaxial needle, and the distance between the receiving net 8 and the nozzle 3 is adjustable.

[0034] The following examples illustrate the preparation of coaxial liquid-jet spun structural color fiber membranes, including the following steps:

[0035] Step 1: Weigh a certain amount of PEO powder and ink, dissolve them in a water-soluble polymer, and heat and stir in a water bath until the PEO is completely dissolved to obtain the core layer solution; weigh a certain amount of SiO2 powder and disperse it in water or ethanol, and ultrasonically stir until the spheres are evenly dispersed to obtain the shell layer solution.

[0036] Step 2: Pour the shell solution and core solution into the coaxial liquid jet spinning portable device, set the feed speed, connect the spray gun interface to the pressure regulating valve through the air pipe, connect the pressure regulating valve to the air compressor through the air pipe, and the nozzle has a built-in detachable coaxial needle. Adjust the distance between the receiving net and the nozzle.

[0037] Step 3: Turn on the air compressor, open the pressure regulating valve, set the air pressure, and open the feed port. The solution is pushed into the nozzle and flows out from the coaxial spinning needle. Then, it is blown by a high-speed airflow. Under the action of traction and stretching, the spinning solution forms fibers and deposits on the receiving net. The shell solution generates capillary force when the solvent evaporates, which induces the microspheres to self-assemble on the fiber, thereby forming structural color fibers.

[0038] In the above preparation method, the process parameters can be adjusted as follows:

[0039] In step 1, the PEO has a molecular weight of 600,000 and a mass fraction of 6%–9%, ​​preferably 7%; the SiO2 powder has a mass fraction of 2%–4%, preferably 3%; the SiO2 powder has a particle size of 170–350 nm, preferably 180–250 nm. Different concentrations of solutions can be prepared by changing the mass of PEO powder or ink to obtain fiber membranes with different properties. Furthermore, different colors of fiber membranes can be obtained by changing the particle size of the SiO2 microspheres. When the average particle size of the silica microspheres is 220 nm, the prepared structural color fiber membrane is dark green; when the average particle size of the silica microspheres is 182 nm, the prepared structural color fiber membrane is purple.

[0040] In step 2, the feed rate of the core layer solution is 0.2–0.4 mL / min, preferably 0.2 mL / min; the feed rate of the shell layer solution is 0.4–0.6 mL / min, preferably 0.6 mL / min; and the nozzle has a built-in detachable coaxial needle with a specification of 17G+23G. During this process, by adjusting the spray width, feed rate, air pressure, the distance between the receiving net and the needle, and changing the coaxial needle specification, structural color fiber membranes with different properties or deposition structures can be obtained.

[0041] In step 3, the air pressure is 0.06 to 0.15 MPa, preferably 0.1 MPa.

[0042] Example 1

[0043] This embodiment prepares a coaxial liquid-jet spun structured colored fiber membrane, with the following process parameters:

[0044] ① Spinning solution preparation parameters: PEO mass fraction is 7%, SiO2 mass fraction is 2%, and particle size is 220nm.

[0045] ② Spinning parameters: coaxial needles are 16G+21G, core solution feed rate is 0.3mL / min, shell solution feed rate is 0.6mL / min, and the distance between the receiving net and the coaxial needles is set to 60cm.

[0046] Figure 3 This is an optical image of the dark green structural color fiber membrane obtained in this embodiment. Figure 6 This is an example. Figure 3 The spectrum of the structural color fiber shows a peak at 500 nm, further proving that the obtained fiber membrane is dark green.

[0047] Example 2

[0048] This embodiment prepares a coaxial liquid-jet spun structured colored fiber membrane, with the following process parameters:

[0049] ① Spinning solution preparation parameters: PEO mass fraction is 7%, SiO2 mass fraction is 3%, and particle size is 182nm.

[0050] ② Spraying parameters: coaxial needle is 17G+23G, core layer solution feed rate is 0.2mL / min, shell layer solution feed rate is 0.5mL / min, and the distance between the receiving net and the coaxial needle is set to 60cm.

[0051] Figure 4 This is an optical image of the purple structural color fiber membrane obtained in this embodiment. Figure 5 for Figure 4 Scanning electron microscope images of the structured color fiber surface clearly show the distribution of silica microspheres on the fiber surface, which is an amorphous photonic crystal structure with long-range disorder and short-range order.

[0052] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A coaxial liquid-jet spun structural colored fiber membrane, characterized in that, The fiber is obtained by coaxial liquid-jet spinning of a shell solution and a core solution. The shell solution is a microsphere dispersion and the core solution is a polymer solution. The polymer solution is refined into fibers under the traction and stretching of a high-speed airflow. During this process, the microsphere dispersion adheres to the fibers. Under the action of capillary force generated by solvent evaporation in the microsphere dispersion, the microspheres are induced to self-assemble and arrange themselves in an orderly manner on the surface of the fibers. The shell solution is a SiO2 microsphere dispersion, and the core solution is a polymer solution formed by dissolving PEO powder and ink in a water-soluble polymer. The method for preparing the coaxial liquid-jet spun structured colored fiber membrane includes the following steps: Step 1: Weigh a certain amount of PEO powder and ink, dissolve them in a water-soluble polymer, and heat and stir in a water bath until the PEO is completely dissolved to obtain the core layer solution. Weigh a certain amount of SiO2 powder and disperse it in water or ethanol. Stir it ultrasonically until the small balls are evenly dispersed to prepare the shell solution. The PEO has a molecular weight of 600,000 and a mass fraction of 6% to 9%. The mass fraction of the SiO2 powder is 2% to 4%; The particle size of the SiO2 powder is 170–350 nm; Step 2: Pour the shell layer solution and core layer solution into the coaxial liquid jet spinning portable device, set the feed speed, connect the spray gun interface to the pressure regulating valve through an air pipe, and connect the pressure regulating valve to the air compressor through an air pipe. A detachable coaxial needle is built into the nozzle. Adjust the distance between the receiving net and the nozzle; wherein: The portable coaxial liquid jet spinning device includes independent and parallel shell solution channels and core solution channels, and also includes a spray gun interface, air pipe a, air pipe b, pressure regulating valve, air compressor, nozzle, feed inlet, and receiving net; the spray gun interface is connected to the pressure regulating valve through the air pipe a, the pressure regulating valve is connected to the air compressor through the air pipe b, the nozzle has a built-in detachable coaxial needle, and the distance between the receiving net and the nozzle is adjustable; The feed rate of the core layer solution is 0.2–0.4 mL / min; The feed rate of the shell solution is 0.4–0.6 mL / min; The nozzle has a built-in detachable coaxial needle with a specification of 17G+23G; Step 3: Turn on the air compressor, open the pressure regulating valve, set the air pressure to 0.06~0.15MPa, open the feed port, the solution is pushed into the nozzle and flows out from the coaxial spinning needle, and then is blown by a high-speed airflow. The coaxial liquid-jet spinning solution forms fibers and deposits on the receiving net under the action of traction and stretching. The shell solution generates capillary force when the solvent evaporates, which induces microspheres to self-assemble on the fiber, thereby forming structural color fibers.

2. The method for preparing the coaxial liquid-jet spun structured colored fiber membrane according to claim 1, characterized in that, The PEO has a molecular weight of 600,000 and a mass fraction of 7%. And / or the mass fraction of the SiO2 powder is 3%; And / or the particle size of the SiO2 powder is 180–250 nm.

3. The method for preparing the coaxial liquid-jet spun structured colored fiber membrane according to claim 1, characterized in that, The feed rate of the core solution is 0.2 mL / min; and / or the feed rate of the shell solution is 0.6 mL / min.

4. The method for preparing the coaxial liquid-jet spun structured colored fiber membrane according to claim 1, characterized in that, In step 3, the air pressure is 0.1 MPa.

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