Preparation method of transparent nanoporous glass ink and method for additive manufacturing of transparent nanoporous glass material

Abstract

A method for preparing a transparent nanoporous glass ink and a method for additive manufacturing a transparent nanoporous glass material. By hydrolyzing metal alkoxide and introducing a photocurable monomer and an initiator, a highly transparent and low-viscosity prepolymer photocurable transparent nanoporous glass ink is prepared. According to the usage scenario, a 3D model of the device is freely designed using computer-aided design software, and after slicing processing, a data set is formed and transferred to the printer, and then printing is carried out. By precisely controlling the ink ratio, printing parameters, and heat treatment process, a transparent nanoporous glass with excellent optical properties and a high specific surface area can be printed. The preparation of a multifunctional material platform based on the printed transparent nanoporous glass is realized, which greatly saves the preparation cost of the transparent nanoporous glass and improves the production efficiency. It solves the problems of the existing manufacturing methods, such as the forming relying on molds, long preparation cycle, low efficiency, and difficulty in forming transparent nanoporous glass devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of transparent nanoporous glass, and particularly relates to the preparation of a 3D printing transparent nanoporous glass ink and the additive manufacturing of transparent nanoporous glass, and its application, wherein the application is to prepare a complex structure transparent nanoporous glass device by using additive manufacturing (3D printing) technology and the transparent nanoporous glass ink. Background Art

[0002] Transparent nanoporous glass is a promising optical material. It inherits the excellent physical and chemical stability of inorganic glass and has a high specific surface area and pore structure. Due to its unique properties, transparent nanoporous glass has been widely used in the manufacture of nanofilters, biological agent substrates, nano-encapsulated optical matrices for luminescent nanocrystals or rare earth ions, photonic crystal fiber lasers, and the production of micro-optical elements. The most typical transparent nanoporous glass is Vycor glass produced by Corning Inc., and its manufacturing method is to carry out spinodal decomposition in a multi-component oxide glass and leach out one of the decomposed phases with an acid solution. However, the heat treatment phase separation technology is not compatible with 3D printing technology due to the cumbersome post-treatment process. Therefore, directly printing transparent nanoporous glass is currently impossible to achieve. The sol-gel process forms nanopores through the hydrolysis and condensation reactions of metal salts, providing a unique way to manufacture transparent nanoporous glass with high affinity for 3D printing technology. The sol-gel process can obtain a particle-free transparent composition, which is very beneficial to the photopolymerization process.

[0003] Additive manufacturing (3D printing) is a revolutionary technology in the manufacturing field. It provides new possibilities for manufacturing objects with complex shapes in a fully digital design process, and thus has attracted more and more attention globally. In the field of glass, 3D printing technology has made many breakthroughs in manufacturing complex-shaped glass objects ranging from millimeters to 100 nanometers. For example, three-dimensional ultraviolet curing printing (digital light process, DLP or stereolithography, SLA) by directly extruding quartz glass slurry or sol-gel precursor in a molten state, selective laser melting (SLM) using glass powder, and direct ink writing (DIW) using glass slurry. Recently, it has been reported that 3D printing of nanoscale silica glass has been achieved through two-photon polymerization (TPP) technology. 3D printing of glass still faces many challenges, including limited printable glass systems, complex and time-consuming printing processes, limited precision, and relatively low optical quality. So far, the printable glass systems are mainly limited to the silica glass system. Therefore, broadening the glass type and composition design space at high printing resolution is the key to promoting the development of 3D printing glass technology.

[0004] However, on the one hand, there are no relevant literature reports on transparent nanoporous glass for 3D printing and its preparation method; on the other hand, compared with the prior art, for example, CN111018321A discloses a method for preparing dense glass by 3D printing photocuring forming, which belongs to the field of preparing traditional glass. Using the sol-gel method and applied to the manufacturing process of dense silicon-based glass, the added organic resin will significantly reduce the transparency of the ink, reduce the printing accuracy, and the addition of the resin will also increase the viscosity of the ink, which is not conducive to 3D printing; secondly, the process of removing the organic resin will cause a large number of macropores to appear and damage the integrity of the glass, and the prepared glass green body does not have high transparency. To prepare transparent glass for optical devices, high-temperature sintering is required, and transparent nanoporous glass with a high specific surface area and high transparency cannot be prepared, so it has no reference significance. Summary of the Invention

[0005] In view of the above problems, the present invention provides an additive manufacturing (3D printing) method for transparent nanoporous glass. By taking advantage of digital light processing (DLP) and sol-gel processes for 3D printing, this process can form 3D transparent nanoporous glass devices with inherent uniform porosity and multi-oxide chemical compositions. A template-free sol-gel route using metal chelates has been developed, which can form transparent nanoporous glass in a variety of compositional systems. In this sol-gel route, organic chelating ligands result in a prepolymer gel with a three-dimensional continuous structure, which pyrolyzes to form transparent nanoporous glass. Compared with non-porous glass, nanoporous glass has great advantages in designing functional devices by adsorbing and loading target molecules and ions. The present invention can improve the forming ability of optical functional devices with complex structures.

[0006] The specific solutions are as follows:

[0007] The present invention provides a transparent nanoporous glass ink and its additive manufacturing method.

[0008] The technical solution of the present invention is realized as follows:

[0009] On the one hand, the present invention protects a transparent nanoporous glass ink. The ink components are uniform and transparent, and the viscosity range of the ink is: <5000 cP@5 s -1 ; the transmittance of the ink in the visible light range is ≥90%.

[0010] On the other hand, the present invention also protects a preparation method of the transparent nanoporous glass ink, including the following steps:

[0011] S1. Select metal salts, deionized water, photocurable monomers, photoinitiators, and precursor compounds according to a mass ratio of (1 - 20):(2 - 50):(5 - 20):(0.1 - 1):100;

[0012] S2. Dissolve the metal salt in the deionized water, add a pH regulator, and fully dissolve and chelate to obtain a transparent solvent.

[0013] S3. Dropwise add the precursor compound into the transparent solvent and stir until the reaction is complete to obtain a transparent sol.

[0014] S4. After mixing the photocurable monomer and the photoinitiator, drop them into the transparent sol, stir evenly until the sol is transparent, photocurable, and no bubbles float on the surface to obtain an ink with low viscosity.

[0015] S5. After establishing a 3D model using 3D modeling software and performing slicing processing, place the ink into the 3D printer cartridge to print out the gel.

[0016] S6. After drying, sintering, and annealing the gel, a transparent nanoporous glass is obtained. The specific surface area of this transparent nanoporous glass material > 490 m 2 / g, the pore size ranges from 2 to 50 nm, and the visible light transmittance > 95%.

[0017] In a preferred embodiment, the present invention also protects a preparation method of a transparent nanoporous ink. In step S2, the metal salt is one or more of aluminum lactate, aluminum acetate, zinc acetate, calcium lactate, and gallium nitrate. The pH regulator is selected from one or several of ammonia water, sodium dodecyl sulfate, magnesium acetate, sodium hydrogen phosphate and sodium dihydrogen phosphate, hydrochloric acid, nitric acid, sodium hydroxide, potassium hydroxide, carbonic acid, and sodium bicarbonate.

[0018] In a preferred embodiment, the present invention also protects a preparation method of a transparent nanoporous glass ink. In step S3, the precursor compound is one or several of tetraethyl orthosilicate, aluminum isopropoxide, tetrabutyl titanate, and isopropyl titanate.

[0019] In a preferred embodiment, the present invention also protects a preparation method of a transparent nanoporous glass ink. In step S4, the photocurable monomer is one or several of acrylic acid, methyl acrylate, acrylic anhydride, 3-acryloxypropyltrimethoxysilane, and crotonic acid. The photoinitiator is one or several of TPO, TPO-L, diacylphosphine oxide 819, omnirad184, and BASF 651.

[0020] In a preferred embodiment, the present invention also protects a preparation method of a transparent nanoporous glass ink. The stirring in steps S3 and S4 means maintaining for 5 to 300 min at a stirring speed of 700 - 1500 r / min in an ultrasonic environment of 0 - 120 kHz.

[0021] In yet another aspect, the present invention also protects a transparent nanoporous glass prepared by using the above-mentioned transparent nanoporous glass ink and an additive manufacturing (3D printing) method.

[0022] In a preferred embodiment, the present invention also protects a transparent nanoporous glass prepared by using the above-mentioned transparent nanoporous glass ink and an additive manufacturing (3D printing) method, wherein the inorganic content of the transparent nanoporous glass ink is > 68 wt% after sintering at a temperature above 600 °C for more than 2 hours. The specific surface area of the transparent nanoporous glass is > 490 m 2 / g, the pore diameter is between 2 and 50 nm, and the transmittance in the visible light band is ≥ 95%.

[0023] In yet another aspect, the present invention also protects a method for preparing the above-mentioned transparent nanoporous glass, the method comprising: establishing a 3D model, printing a green body after slicing, and obtaining the transparent nanoporous glass after drying, sintering, and annealing the green body.

[0024] In a preferred embodiment, the present invention also protects a method for preparing the above-mentioned transparent nanoporous glass, wherein the drying process is to raise the temperature from room temperature of 30 °C to 100 - 150 °C at a heating rate of 1 - 5 °C / min, hold at 30 °C for 6 hours, and then hold for 6 h for every 10 °C increase in temperature. The sintering process is to raise the temperature from room temperature to 100 - 150 °C at a heating rate of 1 - 5 °C / min and hold for 6 - 10 h; then raise the temperature to 300 - 400 °C at a heating rate of 0.5 - 1.5 °C / min and hold for 10 - 20 h; continue to raise the temperature to 700 - 900 °C at a rate of 0.1 - 3 °C / min and hold for 1 - 3 h, and then cool naturally. The annealing is to raise the temperature of the transparent nanoporous glass from room temperature to 600 - 800 °C at a rate of 2 - 10 °C / min under air pressureless conditions and hold for 10 - 30 h. A transparent nanoporous glass device is obtained.

[0025] Compared with the prior art, the advantages of this method are: (1) the viscosity of the transparent nanoporous glass ink is < 5000 cP @ 5 s -1 , the transmittance in the visible light range is ≥ 90%, and the inorganic content is > 68 wt% after sintering at a temperature above 600 °C for more than 2 hours; (2) preparing glass devices at a low temperature of 600 - 800 °C; (3) the specific surface area of the transparent nanoporous glass is > 490 m 2 / g, the pore diameter is between 2 and 50 nm, the transmittance in the visible light band is ≥ 95%, and the nanopore distribution is uniform; (4) the design range of the printing ink components is wider; (5) there is no need to customize a mold according to the formed device; (6) it is possible to design a 3D model by computer and quickly print transparent nanoporous glass devices applied to different scenarios, with free geometric design and molding, which greatly expands the application scenarios of transparent nanoporous glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Transmittance of the transparent nanoporous glass in Example 2

[0027] Figure 2 BET adsorption diagrams of transparent nanoporous glasses with different components in Examples 2, 4, 6, and 8 Detailed implementation manners

[0028] For the sake of providing a more concise description, some quantitative expressions given herein are not modified with the term "about". It should be understood that whether or not the term "about" is explicitly used, each quantity given herein is intended to refer to the actual given value, and is also intended to refer to the approximate value of these given values reasonably inferred by those of ordinary skill in the art, including the approximate values of these given values caused by experimental and / or measurement conditions

[0029] The following further elaborates the present invention in conjunction with specific embodiments. It is necessary to point out here that the embodiments are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the content of the present invention above. The test methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, all percentages and parts are by weight

[0030] The sources, names, and specifications of the experimental materials or experimental instruments used in the embodiments of the present invention are shown in the following table

[0031]

[0032]

[0033] The following further illustrates the present invention in conjunction with the embodiments, but should not limit the protection scope of the present invention

[0034] Example 1: Ink

[0035] Weigh 0.63 g of aluminum lactate and dissolve it in 1.60 g of deionized water. Dropwise add hydrochloric acid to adjust the pH of the dispersion to approximately 3.5. Use a magnetic stirrer to maintain it at a stirring speed of 1000 r / min for 30 min. Dropwise add a mixed solution composed of 4.46 g of tetraethyl orthosilicate and 2.80 g of ethanol at a speed of 500 μl / min. Use a magnetic stirrer to maintain it at a stirring speed of 800 r / min for 360 min; add a photosensitive unit composed of 0.494 g of 3-acryloxypropyltrimethoxysilane and 0.025 g of TPO. Use a magnetic stirrer to maintain it at a stirring speed of 500 r / min for 30 min; obtain a clear and transparent sol ink, with a transmittance > 90% in the visible light range; the ink has good fluidity

[0036] Test Example 1: Ink Transparency

[0037] Test Sample: Ink Prepared in Example 1

[0038] Test Equipment: UV-Visible Spectrophotometer (AMBDA 750, PerkinElmer, USA); Test Range: 300 - 800 nm;

[0039] The transmittance of the ink prepared in Example 1 is 91.7%.

[0040] Test Example 2: Viscosity Test

[0041] Test Sample: Ink Prepared in Example 1

[0042] The rheological properties of the ink were tested using a rotational rheometer (Anton Paar) with a parallel plate diameter of 20 mm. The viscosity was measured at 25°C, and the shear rate increased steadily from 0.1 to 1000 s -1 while using a solvent trap to reduce evaporation.

[0043] The viscosity of the ink prepared in Example 1 is 50 cP@10 s -1 .

[0044] Test Example 3: Thermogravimetric Test

[0045] Test Sample: Ink Prepared in Example 1

[0046] The weight loss of the ink at different temperatures was tested using EXSTAR TG / DTA7300 (SII, Japan). In the temperature range of 50 - 1000°C, TG-DTA analysis was performed on the powdered, ground, and dried sample at a heating rate of 10°C min-1.

[0047] The TG analysis of the ink prepared in Example 1 showed that the inorganic content was 72.5 wt%.

[0048] Example 2: Glass Gel Printing and Sintering

[0049] According to the scenario, a 3D model was established using 3D modeling software. After the computer sliced the 3D model, the resulting dataset was transferred to a Max printer produced by Asiga. The ink prepared in Example 1 was loaded into the 3D printer to print the glass gel for later use.

[0050] The sintering of the printed glass gel was carried out in three steps: drying, sintering, and annealing.

[0051] Drying means heating the printed glass gel from room temperature of 30°C to 100°C at a heating rate of 1°C / min, holding at 30°C for 6 hours, and then holding for 6 hours at each 10°C increase in temperature.

[0052] Sintering refers to discharging the organic matter inside the printed glass gel and generating a nanoporous structure to ensure obtaining pure inorganic transparent nanoporous glass. It is heated from room temperature to 120°C at a heating rate of 3°C / min and held for 6 h; then it is heated to 400°C at a heating rate of 0.5°C / min and held for 20 h; it is continuously heated to 700°C at a rate of 0.5°C / min and held for 2 h, and then the sintered body is taken out after natural cooling.

[0053] Annealing is carried out in a muffle furnace under air pressureless conditions, heating from room temperature to 650°C at 6°C / min and holding for 30 h to eliminate residual stress and oxygen vacancy defects, obtaining transparent nanoporous glass for standby.

[0054] Test Example 4: Nanopore performance test

[0055] Test sample: Transparent nanoporous glass prepared in Example 2;

[0056] Test equipment: Nitrogen adsorption-desorption instrument (Autosorb iQ, Anton Paar, Austria);

[0057] The specific surface area of the transparent nanoporous glass prepared in Example 2 is 496.3 m 2 g -1 ; The average pore diameter is 6.2 nm;

[0058] Test Example 5: Component test

[0059] Test sample: Transparent nanoporous glass prepared in Example 2;

[0060] Test equipment: Transmission electron microscope (HEOL-2010, USA); Energy dispersive X-ray spectroscopy (EDS) detector (Oxford Instruments, UK)

[0061] The oxide component of the transparent nanoporous glass prepared in Example 2 is Al 2 O 3 -SiO 2 ;

[0062] As Figure 2 shown, the energy dispersive X-ray spectroscopy (EDS) elemental map proves this. Al 2 O 3 -SiO 2 In the transparent nanoporous glass, Al, O, and Si are evenly distributed on the micro-characters. It shows that the prepared ink components are uniform, which is beneficial to component design and optical applications.

[0063] Example 3: Ink

[0064] Weigh 0.86 g of aluminum lactate and 0.2 g of calcium lactate, dissolve them in 3.19 g of deionized water, add hydrochloric acid dropwise to adjust the pH of the dispersion to approximately 6.5, use a magnetic stirrer to maintain for 40 min at a stirring speed of 1200 r / min, and add dropwise a mixed solution composed of 8.92 g of tetraethyl orthosilicate and 5.59 g of ethanol at a speed of 500 μl / min. Then use a magnetic stirrer to maintain for 400 min at a stirring speed of 1000 r / min; add a photosensitive unit composed of 0.99 g of acrylic acid and 0.05 g of TPO-L, and use a magnetic stirrer to maintain for 20 min at a stirring speed of 1000 r / min; obtain a clear and transparent sol ink with a transmittance in the visible light range > 90%; the ink has good fluidity.

[0065] Test Example 6: Ink Transparency

[0066] Test Sample: Ink Prepared in Example 3

[0067] Test Equipment: UV-Visible Spectrophotometer (AMBDA 750, PerkinElmer, USA); Test Range: 300 - 800 nm;

[0068] The transmittance of the ink prepared in Example 3 is 93.4%.

[0069] Test Example 7: Viscosity Test

[0070] Test Sample: Ink Prepared in Example 3

[0071] Use a rotational rheometer (Anton Paar) with a parallel plate diameter of 20 mm to test the rheological properties of the ink. The viscosity is measured at 25°C, and the shear rate increases steadily from 0.1 to 1000 s -1 while using a solvent trap to reduce evaporation.

[0072] The viscosity of the ink prepared in Example 3 is 500 cP @ 10 s -1 .

[0073] Test Example 8: Thermogravimetric Test

[0074] Test Sample: Ink Prepared in Example 3

[0075] Use EXSTAR TG / DTA7300 (SII, Japan) to test the weight loss of the ink at different temperatures. In the temperature range of 50 - 1000°C, perform TG-DTA analysis on the powdered and ground dry sample at a heating rate of 10°C min-1.

[0076] The TG analysis of the ink prepared in Example 3 shows that the inorganic content is 69.8 wt%.

[0077] Example 4: Glass Gel Printing and Sintering

[0078] According to the scenario, a 3D model is established using 3D modeling software. After the computer slices the 3D model, the resulting dataset is transferred to the Max printer produced by Asiga. The ink prepared in Example 3 is loaded into the 3D printer to print out the glass gel for standby.

[0079] The sintering of the printed glass gel is carried out in three steps: drying, sintering, and annealing.

[0080] Drying means heating the printed glass gel from room temperature of 30°C to 150°C at a heating rate of 3°C / min, holding at 30°C for 6 h, and then holding for 6 h every time the temperature is increased by 10°C.

[0081] Sintering means discharging the organic matter inside the printed glass gel and generating a nanoporous structure to ensure obtaining pure inorganic transparent nanoporous glass. It is heated from room temperature to 150°C at a heating rate of 5°C / min and held for 10 h; then it is heated to 350°C at a heating rate of 1°C / min and held for 20 h; it continues to be heated to 750°C at a rate of 0.5°C / min and held for 3 h, and then the sintered body is taken out after natural cooling.

[0082] Annealing is carried out in a muffle furnace under air-free pressure conditions, heating from room temperature to 600°C at a rate of 10°C / min and holding for 30 h to eliminate residual stress and oxygen vacancy defects, obtaining transparent nanoporous glass for standby.

[0083] Test Example 9: Nanopore performance test

[0084] Test sample: Transparent nanoporous glass prepared in Example 4;

[0085] Test equipment: Nitrogen adsorption-desorption instrument (Autosorb iQ, Anton Paar, Austria);

[0086] The specific surface area of the transparent nanoporous glass prepared in Example 4 is 594.3 m 2 g -1 ; The average pore diameter is 6.1 nm;

[0087] Test Example 10: Component test

[0088] Test sample: Transparent nanoporous glass prepared in Example 4;

[0089] Test equipment: Transmission electron microscope (HEOL-2010, USA); Energy dispersive X-ray spectroscopy (EDS) detector (Oxford Instruments, UK)

[0090] The oxide component of the transparent nanoporous glass prepared in Example 4 is CaO-P 2 O 5-Al 2 O 3 -SiO 2 ;

[0091] Example 5: Ink

[0092] Weigh 0.48 g of aluminum lactate and 0.15 g of zinc acetate and dissolve them in 1.60 g of deionized water. Dropwise add ammonia water to adjust the pH of the dispersion to approximately 7.5. Use a magnetic stirrer to maintain for 30 min at a stirring speed of 900 r / min. Dropwise add a mixed solution composed of 4.46 g of tetraethyl orthosilicate and 2.80 g of ethanol at a speed of 500 μl / min. Use a magnetic stirrer to maintain for 360 min at a stirring speed of 800 r / min; add a photosensitive unit composed of 0.494 g of crotonic acid and 0.025 g of BASF 651, and use a magnetic stirrer to maintain for 30 min at a stirring speed of 600 r / min; obtain a clear and transparent sol ink, with a transmittance in the visible light range > 90%; the ink has good fluidity.

[0093] Test Example 11: Ink Transparency

[0094] Test sample: Ink prepared in Example 5

[0095] Test equipment: UV-visible spectrophotometer (AMBDA 750, PerkinElmer, USA); test range: 300 - 800 nm;

[0096] The transmittance of the ink prepared in Example 5 is 95.1%.

[0097] Test Example 12: Viscosity Test

[0098] Test sample: Ink prepared in Example 5

[0099] Use a rotational rheometer (Anton Paar) with a parallel plate diameter of 20 mm to test the rheological properties of the ink. The viscosity is measured at 25 °C, and the shear rate increases steadily from 0.1 to 1000 s -1 and a solvent trap is used to reduce evaporation.

[0100] The viscosity of the ink prepared in Example 5 is 100 cP@5 s -1 .

[0101] Test Example 13: Thermogravimetric Test

[0102] Test sample: Ink prepared in Example 5

[0103] The weight loss of the ink at different temperatures was tested using EXSTAR TG / DTA7300 (SII, Japan). In the temperature range of 50 - 1000 °C, TG-DTA analysis was performed on the powdered and ground dry sample at a heating rate of 10 °C min-1.

[0104] TG analysis of the ink prepared in Example 5 showed that the inorganic content was 73.4 wt%.

[0105] Example 6: Glass gel printing and sintering

[0106] According to the scenario, a 3D model was established using 3D modeling software. After the computer sliced the 3D model, the data set was transferred to the Max printer produced by Asiga. The ink prepared in Example 5 was loaded into the 3D printer to print the glass gel for standby.

[0107] The sintering of the printed glass gel was carried out in three steps: drying, sintering, and annealing.

[0108] Drying means heating the printed glass gel from room temperature of 30 °C to 110 °C at a heating rate of 1 °C / min, holding at 30 °C for 6 hours, and then holding for 6 hours every time the temperature is increased by 10 °C to obtain a dried body.

[0109] Sintering means discharging the internal organic matter of the printed glass gel and generating a nanoporous structure to ensure obtaining pure inorganic transparent nanoporous glass. It was heated from room temperature to 150 °C at a heating rate of 2 °C / min and held for 8 hours; then it was heated to 370 °C at a heating rate of 1.3 °C / min and held for 15 hours; it was continued to be heated to 800 °C at a rate of 0.8 °C / min and held for 1.5 hours, and then naturally cooled to take out the sintered body.

[0110] Annealing was carried out in a muffle furnace under air pressureless conditions, heating from room temperature to 700 °C at 8 °C / min and holding for 25 hours to eliminate residual stress and oxygen vacancy defects, obtaining transparent nanoporous glass for standby.

[0111] Test Example 14: Nanopore performance test

[0112] Test sample: Transparent nanoporous glass prepared in Example 6;

[0113] Test equipment: Nitrogen adsorption - desorption instrument (Autosorb iQ, Anton Paar, Austria);

[0114] The specific surface area of the transparent nanoporous glass prepared in Example 6 was 450.9 m 2 g -1 ; The average pore diameter was 6.03 nm;

[0115] Test Example 15: Component test

[0116] Test sample: Transparent nanoporous glass prepared in Example 6;

[0117] Test equipment: Transmission electron microscope (HEOL-2010, USA); Energy-dispersive X-ray spectroscopy (EDS) detector (Oxford Instruments, UK)

[0118] The oxide components of the transparent nanoporous glass prepared in Example 6 are ZnO-Al 2 O 3 -SiO 2 ;

[0119] Example 7: Ink

[0120] Weigh 0.81 g of aluminum lactate and dissolve it in 2.40 g of deionized water. Add nitric acid dropwise to adjust the pH of the dispersion to approximately 1.5. Use a magnetic stirrer to maintain the stirring speed at 800 r / min for 20 min. Then, add dropwise a mixed solution composed of 6.69 g of tetraethyl orthosilicate, 0.135 g of tetrabutyl titanate, and 4.19 g of ethanol at a rate of 500 μl / min. Use a magnetic stirrer to maintain the stirring speed at 1200 r / min for 240 min. Add a photosensitive unit composed of 0.99 g of acrylic anhydride and 0.038 g of diacylphosphine oxide 819, and use a magnetic stirrer to maintain the stirring speed at 950 r / min for 40 min. A clear and transparent sol ink is obtained, with a transmittance > 90% in the visible light range; the ink has good fluidity.

[0121] Test Example 16: Ink transparency

[0122] Test sample: Ink prepared in Example 7

[0123] Test equipment: UV-visible spectrophotometer (AMBDA 750, PerkinElmer, USA); Test range: 300 - 800 nm;

[0124] The transmittance of the ink prepared in Example 7 is 90.05%.

[0125] Test Example 17: Viscosity test

[0126] Test sample: Ink prepared in Example 7

[0127] Use a rotational rheometer (Viscotester iQ Air, HAAKE) with a parallel plate diameter of 20 mm to test the rheological properties of the ink. The viscosity is measured at 25 °C, and the shear rate increases steadily from 0.1 to 1000 s -1 to reduce evaporation using a solvent trap.

[0128] The viscosity of the ink prepared in Example 7 is 243 cP @ 5 s -1 .

[0129] Test Example 18: Thermogravimetric Test

[0130] Test sample: The ink prepared in Example 7

[0131] Use EXSTAR TG / DTA7300 (SII, Japan) to test the weight loss of the ink at different temperatures. In the temperature range of 50 - 1000 °C, TG-DTA analysis was performed on the powder ground and dried sample at a heating rate of 10 °C min-1.

[0132] TG analysis of the ink prepared in Example 7 shows that the inorganic content is 69.9 wt%.

[0133] Example 8: Green body printing and sintering

[0134] According to the scenario, a 3D model was established using 3D modeling software. After the computer sliced the 3D model, the dataset was transferred to the Max printer produced by Asiga. The ink prepared in Example 7 was loaded into the 3D printer to print out the glass gel for standby.

[0135] The sintering of the printed glass gel is divided into three steps: drying, sintering, and annealing.

[0136] Drying means heating the printed glass gel from room temperature of 30 °C to 130 °C at a heating rate of 3.4 °C / min, holding at 30 °C for 6 hours, and then holding for 6 hours every time the temperature is increased by 10 °C.

[0137] Sintering means discharging the organic matter inside the printed glass gel and generating a nanoporous structure to ensure obtaining pure inorganic transparent nanoporous glass. It is heated from room temperature to 140 °C at a heating rate of 2.5 °C / min and held for 9 hours; then it is heated to 390 °C at a heating rate of 1.5 °C / min and held for 18 hours; it continues to be heated to 900 °C at a rate of 0.5 °C / min and held for 1 hour, and then the sintered body is taken out after natural cooling.

[0138] Annealing is carried out in a muffle furnace under air-free pressure conditions, heating from room temperature to 800 °C at 5 °C / min and holding for 20 hours to eliminate residual stress, obtaining transparent nanoporous glass for standby.

[0139] Test Example 19: Nanopore performance test

[0140] Test sample: The transparent nanoporous glass prepared in Example 8;

[0141] Test equipment: Nitrogen adsorption - desorption instrument (Autosorb iQ, Anton Paar, Austria);

[0142] The specific surface area of the transparent nanoporous glass prepared in Example 8 is 504.9 m 2 g -1 ; the average pore diameter is 6.5 nm; it shows that the nano has been successfully introduced into the glass system, providing a basis for the transparent nanopores to load functional molecules.

[0143] Test Example 20: Component Test

[0144] Test sample: The transparent nanoporous glass prepared in Example 8;

[0145] Test equipment: Transmission electron microscope (HEOL-2010, USA); Energy dispersive X-ray spectroscopy (EDS) detector (Oxford Instruments, UK)

[0146] The oxide components of the transparent nanoporous glass prepared in Example 8 are TiO 2 -Al 2 O 3 -SiO 2 ;

[0147] Test Example 21: Transmittance Test

[0148] Test sample: The transparent nanoporous glass prepared in Example 2;

[0149] Test equipment: UV-visible spectrophotometer (AMBDA 750, PerkinElmer, USA);

[0150] Test method: Measure the online transmittance of the sample within the wavelength range;

[0151] As Figure 1 shown, in the 200 - 900 nm band, the transmittance of the transparent nanoporous glass prepared in Example 2 is about 96%. It meets the practical application of optical devices. This verifies the feasibility of using 3D printing to manufacture transparent nanopores.

Claims

1. A method for preparing a transparent nanoporous glass ink, characterized in that, the method comprises the following steps: S1. Select metal salts, deionized water, a photocurable monomer, a photoinitiator, and a precursor compound according to a mass ratio of (1-20):(2-50):(5-20):(0.1-1):100; S2. Dissolve the metal salts in the deionized water, add a pH regulator, and fully dissolve and chelate to obtain a transparent solvent; S3. Dropwise add the precursor compound into the transparent solvent and stir until the reaction is complete to obtain a transparent sol; S4. After mixing the photocurable monomer and the photoinitiator, drop them into the transparent sol, stir evenly until it becomes transparent, photocurable, and no bubbles float on the surface, to obtain an ink with a viscosity range of <5000 cP@5 s -1 and a visible light transmittance of ≥90%; In step S1, the metal salts are one or more of aluminum lactate, aluminum acetate, zinc acetate, calcium lactate, and gallium nitrate.

2. A method for additive manufacturing of a transparent nanoporous glass ink as described in claim 1, characterized in that: In step S2, the dissolution and chelation are carried out at a stirring speed of 700-1500 r / min for 10-60 min; the pH regulator is one or several of ammonia water, sodium dodecyl sulfate, magnesium acetate, sodium hydrogen phosphate and sodium dihydrogen phosphate, hydrochloric acid, nitric acid, sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate; the pH adjustment range is between 2.5 and 9.

5.

3. A method for additive manufacturing of a transparent nanoporous glass ink as described in claim 1, characterized in that: In step S3, the precursor compound is one or more of tetraethyl orthosilicate, aluminum isopropoxide, tetrabutyl titanate, and isopropyl titanate; the stirring in step S3 means maintaining at a stirring speed of 700-1500 r / min for 5-300 min in an ultrasonic environment of 0-120 kHz.

4. A method for additive manufacturing of a transparent nanoporous glass ink as described in claim 1, characterized in that: In step S4, the photocurable monomer is one or more of acrylic acid, methyl acrylate, acrylic anhydride, 3-acryloxypropyltrimethoxysilane, and crotonic acid; the photoinitiator is one or more of TPO, TPO-L, diacylphosphine oxide 819, omnirad 184, and BASF 651.

5. A method for additive manufacturing of a transparent nanoporous glass material using the transparent nanoporous glass ink as described in any one of claims 1-4, characterized in that: the method comprises: - After establishing a 3D model using 3D modeling software and performing slicing processing, place the ink into the 3D printer cartridge and print out a gel; - After drying, sintering, and annealing the gel, transparent nanoporous glass is obtained. The specific surface area of this transparent nanoporous glass material is > 490 m 2 / g, the pore size ranges from 2 to 50 nm, and the visible light transmittance is > 95%.

6. The method for additive manufacturing of a transparent nanoporous glass material as described in claim 5, characterized in that, after sintering the ink at a temperature above 600 °C for more than 2 hours, the inorganic content > 68 wt%.

7. The method for additive manufacturing of a transparent nanoporous glass material as described in claim 5, characterized in that, the drying process is to increase the temperature from room temperature of 30 °C to 100-150 °C at a heating rate of 1-5 °C / min, hold at 30 °C for 6 hours, and then hold for 6 h for every 10 °C increase in temperature.

8. The method for additive manufacturing of a transparent nanoporous glass material as described in claim 5, characterized in that, The sintering process is carried out by heating from room temperature to 100 - 150 °C at a heating rate of 1 - 5 °C / min and holding for 6 - 10 h; then heating to 300 - 400 °C at a heating rate of 0.5 - 1.5 °C / min and holding for 10 - 20 h; continuing to heat to 700 - 900 °C at a rate of 0.1 - 3 °C / min and holding for 1 - 3 h, and then naturally cooling to take out the sintered body.

9. The method for manufacturing an additive - manufactured transparent nanoporous glass material according to claim 5, characterized in that, the annealing is carried out by heating the transparent nanoporous glass from room temperature to 600 - 800 °C at a rate of 2 - 10 °C / min under air - pressureless conditions and holding for 10 - 30 h.

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