A preparation method of 3D printed organic nanofiber aerogel

Abstract

The present invention relates to a method for preparing a 3D printed organic nanofiber aerogel, comprising the following steps: after the shredded organic electrospun nanofiber membrane is mixed with a polyelectrolyte solution and homogenously dispersed to obtain an organic nanofiber dispersion, a photosensitive monomer and a photoinitiator are added thereto and heated with stirring to obtain a photosensitive ink, which is added to the printing cartridge of a laser direct writing type 3D printing device and printed according to the G code of a preset printing model to obtain a 3D printed nanofiber hydrogel, which is freeze-dried to obtain an uncrosslinked 3D printed nanofiber aerogel, and then the uncrosslinked 3D printed nanofiber aerogel is subjected to thermal crosslinking treatment to obtain a 3D printed organic nanofiber aerogel. Compared with the prior art, the preparation method of the present invention has a simple process, and the prepared and used photosensitive ink has a low viscosity and good formability, and can prepare a 3D printed nanofiber aerogel with high precision and complex structure.

Description

Technical Field

[0001] The present invention relates to the technical field of organic nanofiber aerogels, and particularly to a preparation method of 3D printed organic nanofiber aerogels. Background Art

[0002] Aerogels have characteristics such as ultra-light weight, high porosity, and high specific surface area, and have been widely used in the fields of environmental governance, biomedicine, sound absorption and heat insulation, etc., and are one of the key research contents in the field of new materials at present. Aerogel materials can be divided into three categories according to the different skeleton constituent substances: inorganic aerogels, organic aerogels, and carbon aerogels. At present, aerogels are generally prepared by the sol-gel method, and the materials obtained by this method have high uniformity and simple preparation processes. The sol-gel method mainly includes three types: (1) the condensation method, in which polymer monomers in the solution polymerize or copolymerize to form a gel; (2) the gelation of colloidal powder sols; (3) the hydrolysis or polycondensation of salt precursors to form a gel. The preparation of organic aerogels generally adopts the condensation method, and the gel structure is controlled by adjusting the ratio parameters of the precursors in the reaction system. The preparation of the gel by the condensation method goes through three processes: one is the formation of primary particles, the second is the further growth and branching of the particles, and the third is the cross-linking between the particles to form a three-dimensional network structure. The organic aerogels prepared by this method have high tunability of structure and properties, but a large amount of organic solvents are used during preparation, and there are deficiencies such as high thermal shrinkage rate, high brittleness, and low elasticity, which limit their application in fields with higher elasticity requirements.

[0003] Electrospun nanofibers, as a new type of fiber material, have reduced the diameter from the micron order of traditional fibers to the nanometer order. The resulting structural characteristics such as high specific surface area, small pore diameter, and high pore connectivity, etc., but it is difficult to achieve effective penetration and interlacing of the fibers in the vertical direction, making the material exhibit an anisotropic layered structure feature, resulting in low porosity of the material and easy delamination between layers, seriously restricting the improvement of the application performance of the material and hindering the development of the electrospun fiber industry. Therefore, using nanofibers as building blocks, a three-dimensional fiber gel aggregate is obtained through homogeneous emulsification dispersion and cryogelation, combined with the gas-liquid non-destructive replacement in the critical drying process, to prepare nanofiber aerogels, which have characteristics such as good compression resilience, low density, and high porosity. However, at present, the preparation of nanofiber aerogels is by mold forming or cutting forming, and the nanofiber aerogels prepared by this method have low dimensional accuracy and are difficult to prepare complex and diverse shapes (such as hollow, grid, multi-curved surfaces, etc.).

[0004] To overcome these problems, researchers have successively conducted a large number of experimental explorations. CN110982111A discloses a 3D printed aramid aerogel, its preparation method and application. The preparation method includes: at least uniformly mixing aramid nanofibers and a solvent to form an aramid nanofiber dispersion, and obtaining a 3D printed aramid aerogel through a freeze-direct writing molding method, sol-gel conversion, and drying treatment. The preparation method of the 3D printed aramid aerogel of this invention has a wider dispersibility, a simple process, and a designable structure. However, the aramid nanofiber dispersion of this invention has a high viscosity, is prone to clogging the nozzle, resulting in discontinuous printing and low dimensional accuracy.

[0005] Therefore, there is an urgent need to develop a preparation method for a photosensitive ink with a simple preparation process, low viscosity, good formability, and a 3D printed nanofiber aerogel with high precision and a complex structure. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a preparation method for a 3D printed organic nanofiber aerogel. In the preparation method of this method, the prepared and used photosensitive ink has a low viscosity, shear-thinning characteristics, and good formability, and a laser-direct writing 3D printing molding technology is adopted, which can prepare a 3D printed organic nanofiber aerogel with high precision and a complex structure.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] The purpose of the present invention is to protect a preparation method for a 3D printed organic nanofiber aerogel, including the following steps:

[0009] First step: Add the shredded organic electrospun nanofiber membrane to a polyelectrolyte solution to obtain a mixture, and homogenize and disperse the obtained mixture to obtain an organic nanofiber dispersion;

[0010] Second step: Add a photosensitive monomer and a photoinitiator to the organic nanofiber dispersion obtained in the first step, heat and stir to obtain a photosensitive ink, and the obtained photosensitive ink has non-Newtonian fluid characteristics;

[0011] Third step: Add the photosensitive ink obtained in the second step to the printing cartridge of a laser-direct writing 3D printing device, and the laser-direct writing 3D printing device prints according to the G code of a preset printing model to obtain a 3D printed nanofiber wet gel;

[0012] Fourth step: Freeze-dry the 3D printed nanofiber wet gel obtained in the third step to obtain an uncrosslinked 3D printed nanofiber aerogel, and then perform thermal crosslinking treatment on the obtained uncrosslinked 3D printed nanofiber aerogel to obtain an organic nanofiber aerogel, and the organic nanofiber aerogel is stable and has a multi-scale three-dimensional network structure.

[0013] In one embodiment of the present invention, in the first step, the organic electrospun nanofiber membrane is prepared by high-voltage electrostatic traction curing; the material selected for preparing the organic electrospun nanofiber membrane is one of polylactic acid, polycaprolactone, polyvinylidene fluoride, polysulfone, polystyrene, polyester, polyamide, etc.

[0014] In one embodiment of the present invention, in the first step, the polyelectrolyte solution is a solution obtained by adding a polyelectrolyte dispersant to a solvent and stirring, and the stirring time is 30 - 240 min; the polyelectrolyte dispersant is one of polyacrylamide, ammonium polyacrylate, sodium polymethacrylate, sodium polystyrene sulfonate, polyethyleneimine; the solvent is a mixed solvent of deionized water and tert-butanol, wherein the mass ratio of water to tert-butanol is 1:(0.01 - 0.25).

[0015] In one embodiment of the present invention, in the first step, the mass ratio of the polyelectrolyte dispersant to the solvent is (0.05 - 1):100; the mass ratio of the organic electrospun nanofiber membrane to the polyelectrolyte solution is (1 - 4):100.

[0016] In one embodiment of the present invention, in the first step, a homogenizer is used to homogenize and disperse the obtained mixture, the stirring speed is 5000 - 12000 rad / min; the stirring time is 1 - 10 min; the length of the organic nanofibers in the organic nanofiber dispersion is 100 - 800 μm, and the diameter of the organic nanofibers is 100 - 800 nm.

[0017] In one embodiment of the present invention, in the second step, the photosensitive monomer is one or a combination of more than one of 2-phenoxyethyl acrylate (PHEA), dipropylene glycol diacrylate (DPGDA), 1,6-hexanediol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA), lauryl methacrylate (LMA), diethylene glycol dimethacrylate (DEGDMA), etc.; the photoinitiator is one or a combination of more than one of 2,2-dimethoxybenzophenone ketal, 2,2-diethoxyacetophenone (DEAP), diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphinate (TEPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO), α-hydroxy ketone compounds (such as Darocur1173, Irgacure184, Darocur2959, etc.), α-amino ketone compounds (such as Irgacure907, Irgacure369, etc.), etc.

[0018] In one embodiment of the present invention, in the second step, the photosensitive monomer accounts for 5-15 wt% of the organic nanofiber dispersion; the photoinitiator accounts for 0.1-1.2 wt% of the organic nanofiber dispersion.

[0019] In one embodiment of the present invention, in the second step, the conditions for heating and stirring are that the heating temperature is 25-80 °C and the heating and stirring time is 10-180 min; the fact that the obtained photosensitive ink has non-Newtonian fluid characteristics means that the viscosity of the photosensitive ink decreases as the shear rate increases.

[0020] In one embodiment of the present invention, in the third step, the printing speed of the laser-direct writing 3D printing device is 6-30 mm / s, the nozzle diameter is 30-400 um, and the extrusion pressure is 0.1-0.6 MPa. Among them, the light source for photocuring is selected as an ultraviolet laser and the brightness is adjustable, and the light source is a laser with a wavelength of 250-400 nm.

[0021] In one embodiment of the present invention, in the third step, the preset printing model is one of a honeycomb structure model, a hollow frame structure model, a grid-like array model, a three-dimensional frame structure model, etc.

[0022] In one embodiment of the present invention, in the fourth step, the conditions for freeze-drying are that the freezing temperature is -60 to -30 °C, the drying temperature is 40-80, and the time is 24-72 h;

[0023] In one embodiment of the present invention, in the fourth step, the thermal cross-linking treatment means putting the uncrosslinked 3D printed nanofiber aerogel into a vacuum oven, the temperature of the vacuum oven is 80-200 °C, the vacuum degree condition is -1 to -0.01 MPa, and the thermal cross-linking time is 1-5 h.

[0024] The mechanism of the present invention is as follows:

[0025] In the preparation method of the present invention, the photosensitive ink prepared and used has the characteristics of low viscosity and shear thinning. When the photosensitive ink is subjected to an external force in the cartridge and nozzle, the entanglement between fibers, between polymer molecular chains and fibers, and between polymer molecular chains is untangled, the viscosity of the photosensitive ink decreases, and it is smoothly extruded from the nozzle. After the external force on the photosensitive ink is removed, the fibers are entangled with each other, the polymer molecular chains are entangled with the fibers, and the polymer molecular chains are entangled with each other, and the viscosity of the ink increases, but it is difficult to maintain instant shaping of the shape after extrusion. Therefore, after the photosensitive ink is extruded from the nozzle, it will immediately be irradiated by ultraviolet laser. The photoinitiator absorbs radiant energy of a certain wavelength, undergoes a chemical change after excitation, and generates active intermediates (free radicals or cations) with the ability to initiate polymerization. The active intermediates excite the photosensitive monomers through energy transfer, and a condensation polymerization reaction occurs to form cross-linked molecular chains, ensuring that the photosensitive ink can be instantaneously shaped after being extruded from the nozzle. After layer-by-layer printing, a 3D printed nanofiber hydrogel with high dimensional accuracy, complex structure and adjustable properties is obtained. Then, using the freeze-drying technology, the ice in the hydrogel is directly sublimated from the liquid state to the gaseous state, leaving porous channels with openings in the aerogel. Finally, by heating the aerogel, the heating temperature is near the softening point of the nanofibers, so that the fibers are cross-linked with each other to prepare a 3D printed organic nanofiber aerogel with excellent mechanical properties.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1) The existing nanofiber aerogels are limited by the forming mold and cutting process, resulting in a single shape and low dimensional accuracy of the aerogels. However, a preparation method of a 3D printed organic nanofiber aerogel provided by the present invention can prepare a 3D printed organic nanofiber aerogel with a complex shape and high dimensional accuracy by using a laser-direct writing 3D printing forming method.

[0028] 2) The existing 3D printing forming is usually used to print high-viscosity solutions, which are prone to nozzle blockage during the printing process, resulting in low accuracy and poor structural integrity of the printed objects. However, a preparation method of a 3D printed organic nanofiber aerogel provided by the present invention prepares a low-viscosity, homogeneous and stable photosensitive ink by regulating the fiber content, solvent ratio, photosensitive monomer and initiator content, homogeneous dispersion parameters, etc., and uses the instant cross-linking technology to realize the preparation of an organic nanofiber aerogel with high mechanical properties from a low-viscosity organic nanofiber photosensitive ink, which can be applied to emerging fields such as electronic devices, biological engineering, and electromagnetic shielding. Description of the Drawings

[0029] Figure 1 It is a preparation flow chart of the preparation method of the 3D printed organic nanofiber aerogel in the present invention.

[0030] Figure 2Schematic diagram when the preset printing model in the present invention is a three-dimensional frame structure model.

[0031] Figure 3 Schematic diagram when the preset printing model in the present invention is a grid-like array model.

[0032] Figure 4 Fiber length distribution diagram of the polyamide nanofiber dispersion liquid in Example 1 of the present invention.

[0033] Figure 5 SEM image of the microstructure of the 3D-printed polyamide nanofiber aerogel in Example 1 of the present invention. Detailed implementation manners

[0034] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. In this technical solution, features such as preparation means, materials, structures, or composition ratios that are not clearly described are regarded as common technical features disclosed in the prior art.

[0035] As Figure 1 shown, it is the preparation flow chart of the preparation method of the 3D-printed organic nanofiber aerogel in the present invention.

[0036] Example 1

[0037] This example provides a preparation method of a 3D-printed organic nanofiber aerogel, including the following steps:

[0038] First step: Add 1.1022 g of electrospun polyamide nanofiber membrane after being cut into small pieces to 50.11 g of polyacrylamide solution to obtain a mixed solution, and homogenize and disperse the obtained mixed solution to obtain a polyamide nanofiber dispersion liquid. Among them, the polyacrylamide solution is prepared by adding 0.25 g of polyacrylamide dispersant to a solvent and stirring for 120 min. The mass of water in the solvent is 50 g, and the mass of tert-butanol is 5 g. The conditions for homogenizing and dispersing are a stirring speed of 6000 rad / min and a stirring time of 3 min.

[0039] Second step: Add 3.3727 g of dipropylene glycol diacrylate and 0.1686 g of ethyl 2,4,6-trimethylbenzoyl phenylphosphinate to the polyamide nanofiber dispersion liquid obtained in the first step, and heat and stir to obtain a photosensitive ink. The obtained photosensitive ink has non-Newtonian fluid characteristics. Among them, the heating temperature is 50 °C, and the heating and stirring time is 90 min.

[0040] Third step: Add the photosensitive ink obtained in the second step to the printing cartridge of a laser direct writing type 3D printing device. The laser direct writing type 3D printing device is based on a preset three-dimensional frame structure model (such as Figure 2Print using the G-code (as shown), and obtain a 3D printed nanofiber hydrogel. Among them, the printing speed of the laser direct writing type 3D printing device is 8 mm / s, the nozzle diameter is 200 μm, the extrusion pressure is 0.5 MPa, and the light source is a laser with a wavelength of 273 nm.

[0041] Step 4: Freeze-dry the 3D printed nanofiber hydrogel obtained in the third step to obtain an uncrosslinked 3D printed nanofiber aerogel. Subsequently, perform thermal crosslinking treatment on the obtained uncrosslinked 3D printed nanofiber aerogel to obtain an organic nanofiber aerogel. The organic nanofiber aerogel is stable and has a multi-scale three-dimensional network structure. Among them, the freeze-drying time is 48 h, the freezing temperature is -40 °C, the drying temperature is 60 °C. The uncrosslinked 3D printed nanofiber aerogel is placed in a vacuum oven, the temperature of the vacuum oven is 180 °C, the vacuum degree is -0.08 MPa, and the thermal crosslinking time is 3 h.

[0042] As Figure 4 shown, it is the fiber length distribution diagram of the polyamide nanofiber dispersion liquid in this embodiment. It can be seen from the figure that the length of the polyamide nanofibers is distributed between 100 and 800 μm, and the average length is 345 μm. By adjusting the process parameters of the homogenizer, the average length of the fibers is 350 μm. The purpose is to ensure that the fibers can be connected to each other, and it is not that the fibers are overly entangled resulting in uneven fiber dispersion.

[0043] As Figure 5 shown, it is the electron microscopy image of the microstructure of the 3D printed polyamide nanofiber aerogel in this embodiment. It can be seen from the figure that the obtained 3D printed polyamide nanofiber aerogel has a multi-scale three-dimensional network structure, making the polyamide nanofiber aerogel have excellent properties such as ultra-light, super-elastic, and low thermal conductivity.

[0044] Example 2

[0045] This embodiment provides a preparation method of a 3D printed organic nanofiber aerogel, including the following steps:

[0046] Step 1: Add 1.7452 g of electrostatically spun polyester nanofiber membrane after being cut into pieces to 58.174 g of sodium polystyrene sulfonate solution to obtain a mixed solution. Homogeneously disperse the obtained mixed solution to obtain a polyester nanofiber dispersion liquid. Among them, the preparation of the sodium polystyrene sulfonate solution is to add 0.4 g of sodium polystyrene sulfonate dispersant to the solvent and stir for 90 min. The mass of water in the solvent is 50 g, and the mass of tert-butanol is 8 g. The conditions for homogeneous dispersion are a stirring speed of 8000 rad / min and a stirring time of 2.5 min.

[0047] Step 2: Add 5.9919 g of dipropylene glycol diacrylate and 0.3 g of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide to the polyester nanofiber dispersion obtained in the first step, heat and stir to obtain a photosensitive ink. The obtained photosensitive ink has non-Newtonian fluid characteristics. Among them, the heating temperature is 55 °C, and the heating and stirring time is 70 min.

[0048] Step 3: Add the photosensitive ink obtained in the second step to the printing cartridge of a laser-direct writing 3D printing device. The laser-direct writing 3D printing device prints according to the G code of a preset grid array model (as Figure 3 shown) to obtain a 3D printed nanofiber hydrogel. Among them, the printing speed of the laser-direct writing 3D printing device is 10 mm / s, the nozzle diameter is 300 μm, the extrusion pressure is 0.3 MPa, and the light source is a laser with a wavelength of 299 nm.

[0049] Step 4: Freeze-dry the 3D printed nanofiber hydrogel obtained in the third step to obtain an uncrosslinked 3D printed nanofiber aerogel. Subsequently, perform thermal crosslinking treatment on the obtained uncrosslinked 3D printed nanofiber aerogel to obtain an organic nanofiber aerogel. The organic nanofiber aerogel is stable and has a multi-scale three-dimensional network structure. Among them, the freeze-drying time is 48 h, the freezing temperature is -60 °C, the drying temperature is 60 °C, the uncrosslinked 3D printed nanofiber aerogel is placed in a vacuum oven, the temperature of the vacuum oven is 200 °C, the vacuum degree is -0.5 MPa, and the thermal crosslinking time is 4 h.

[0050] Example 3

[0051] This example provides a method for preparing a 3D printed organic nanofiber aerogel, including the following steps:

[0052] Step 1: Add 1.7895 g of electrospun polystyrene nanofiber membrane after being cut into pieces to 51.1275 g of polyacrylamide solution to obtain a mixed solution. Homogenize and disperse the obtained mixed solution to obtain a polystyrene nanofiber dispersion. Among them, the polyacrylamide solution is prepared by adding 0.15 g of polyacrylamide dispersant to the solvent and stirring for 90 min. The mass of water in the solvent is 50 g, the mass of tert-butanol is 1 g, and the conditions for homogenization and dispersion are a stirring speed of 10000 rad / min and a stirring time of 1 min.

[0053] Step 2: Add 4.2334 g of trimethylolpropane triacrylate and 0.2117 g of 2,2-diethoxyacetophenone to the polystyrene nanofiber dispersion obtained in the first step, heat and stir to obtain a photosensitive ink. The obtained photosensitive ink has non-Newtonian fluid characteristics. Among them, the heating temperature is 60 °C, and the heating and stirring time is 80 min.

[0054] Step 3: Add the photosensitive ink obtained in Step 2 into the printing cartridge of the laser direct writing type 3D printing device, and the laser direct writing type 3D printing device prints according to the G code of the preset honeycomb structure model (such as Figure 3 shown) to obtain a 3D printed nanofiber wet gel. Among them, the printing speed of the laser direct writing type 3D printing device is 15 mm / s, the nozzle diameter is 400 μm, the extrusion pressure is 0.5 MPa, and the light source is a laser with a wavelength of 270 nm.

[0055] Step 4: Freeze-dry the 3D printed nanofiber wet gel obtained in Step 3 to obtain an uncrosslinked 3D printed nanofiber aerogel, and then perform thermal crosslinking treatment on the obtained uncrosslinked 3D printed nanofiber aerogel to obtain an organic nanofiber aerogel. The organic nanofiber aerogel is stable and has a multi-scale three-dimensional network structure. Among them, the freeze-drying time is 48 h, the freezing temperature is -50 °C, the drying temperature is 70 °C, the uncrosslinked 3D printed nanofiber aerogel is placed in a vacuum oven, the temperature of the vacuum oven is 200 °C, the vacuum degree is -0.1 MPa, and the thermal crosslinking time is 4 h.

[0056] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention as disclosed should be within the protection scope of the present invention.

Claims

1. A preparation method of 3D printed organic nanofiber aerogel, characterized in that, it comprises the following steps: First step, adding the shredded organic electrospun nanofiber membrane into a polyelectrolyte solution to obtain a mixture, and subjecting the obtained mixture to homogenizing dispersion to obtain an organic nanofiber dispersion; Second step, adding a photosensitive monomer and a photoinitiator into the organic nanofiber dispersion obtained in the first step, heating and stirring to obtain a photosensitive ink, and the obtained photosensitive ink has non-Newtonian fluid characteristics; Third step, adding the photosensitive ink obtained in the second step into the printing cartridge of a laser direct writing type 3D printing device, and the laser direct writing type 3D printing device prints according to the G code of a preset printing model to obtain a 3D printed nanofiber wet gel; Fourth step, subjecting the 3D printed nanofiber wet gel obtained in the third step to freeze-drying to obtain an uncrosslinked 3D printed nanofiber aerogel, and then subjecting the obtained uncrosslinked 3D printed nanofiber aerogel to thermal crosslinking treatment to obtain an organic nanofiber aerogel, and the organic nanofiber aerogel is stable and has a multi-scale three-dimensional network structure; In the first step, the organic electrospun nanofiber membrane is prepared by high-voltage electrostatic traction curing; The material selected for preparing the organic electrospun nanofiber membrane is one of polyvinylidene fluoride, polysulfone, polystyrene, polyester, and polyamide; In the first step, the polyelectrolyte solution is a solution obtained by adding a polyelectrolyte dispersant into a solvent and stirring, and the stirring time is 30 - 240 min; The polyelectrolyte dispersant is one of polyacrylamide, ammonium polyacrylate, sodium polymethacrylate, sodium polystyrene sulfonate, and polyethyleneimine; The solvent is a mixed solvent of deionized water and tert-butanol, wherein the mass ratio of water to tert-butanol is 1:(0.01 - 0.25); The mass ratio of the polyelectrolyte dispersant to the solvent is (0.05 - 1):100; In the second step, the photosensitive monomer is one or a combination of more than one of dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, diethylene glycol dimethacrylate; The photoinitiator is one or a combination of more than one of 2,2-dimethoxybenzil ketal, 2,2-diethoxyacetophenone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoyl phenylphosphinate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, α-hydroxy ketone compounds, and α-amino ketone compounds; The photosensitive monomer accounts for 5 - 15 wt% of the organic nanofiber dispersion; The photoinitiator accounts for 0.1 - 1.2 wt% of the organic nanofiber dispersion.

2. The preparation method of a 3D printed organic nanofiber aerogel according to claim 1, characterized in that, in the first step, the mass ratio of the organic electrospun nanofiber membrane to the polyelectrolyte solution is (1 - 4):

100.

3. The preparation method of a 3D printed organic nanofiber aerogel according to claim 1, characterized in that, In the first step, a homogenizer is used to homogenize and disperse the obtained mixture. The stirring speed is 5000 - 12000 rad / min, and the stirring time is 1 - 10 min. The length of the organic nanofibers in the organic nanofiber dispersion is 100 - 800 μm, and the diameter of the organic nanofibers is 100 - 800 nm.

4. A method for preparing a 3D printed organic nanofiber aerogel according to claim 1, characterized in that, In the second step, the conditions for heating and stirring are that the heating temperature is 25 - 80 °C, and the heating and stirring time is 10 - 180 min. The fact that the obtained photosensitive ink has non-Newtonian fluid characteristics means that the viscosity of the photosensitive ink decreases as the shear rate increases.

5. A method for preparing a 3D printed organic nanofiber aerogel according to claim 1, characterized in that, In the third step, the printing speed of the laser-direct writing type 3D printing device is 6 - 30 mm / s, the nozzle diameter is 30 - 400 μm, and the extrusion pressure is 0.1 - 0.6 MPa.

6. A method for preparing a 3D printed organic nanofiber aerogel according to claim 1, characterized in that, In the third step, the preset printing model is one of a honeycomb structure model, a hollow frame structure model, a grid-like array model, and a three-dimensional frame structure model.

7. A method for preparing a 3D printed organic nanofiber aerogel according to claim 1, characterized in that, In the fourth step, the conditions for freeze-drying are that the freezing temperature is -60 - -30 °C, the drying temperature is 40 - 80 °C, and the time is 24 - 72 h. The thermal cross-linking treatment refers to putting the uncross-linked 3D printed nanofiber aerogel into a vacuum oven. The temperature of the vacuum oven is 80 - 200 °C, the vacuum degree condition is -0.1 - -0.01 MPa, and the thermal cross-linking time is 1 - 5 h.

Images