Method of printing 3D nanoparticles

Abstract

The application discloses a kind of low-temperature cold field assisted nanoparticle 3D printing equipment and printing method, and printing equipment includes shell, bearing table, refrigeration structure and printing component.The cavity is formed in the shell;The bearing table is set in the cavity, the bearing table has a bearing surface, the bearing table can be controlled to keep its bearing surface in certain temperature range;The printing component is set in the cavity, the printing component includes the nozzle structure movable relative to the bearing table, the nozzle structure includes multiple spray heads, multiple the spray head is respectively used to spray nanoparticle structure material and support material to the bearing surface.The low-temperature cold field assisted nanoparticle 3D printing equipment and printing method of the application can control nanoparticle in three-dimensional space and construct micro-nano cross-scale three-dimensional structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of 3D printing technology, in particular to a low-temperature cold field assisted nanoparticle 3D printing device and printing method. BACKGROUND

[0002] Direct inkjet printing is a revolutionary manufacturing technology, which enables people to freely and controllably design new materials and new devices at micro-nano scale with nanoparticle materials as functional units, and its application range covers multiple fields such as electronics, optics and sensors. At present, the development of equipment for this technology is mainly represented by XJET and Nanodimension companies. XJET realizes the printing of high-precision three-dimensional metal or ceramic structures by directly spraying metal or ceramic nanoparticle ink and online melting nanoparticles at a high temperature of 300℃ or above; Nanodimension company realizes the printing of multi-layer circuit board of nanoparticle-silver-photosensitive resin composite material by configuring double nozzles and online infrared sintering of nanoparticle silver.

[0003] At present, the fields studied mainly include electric field, thermal field and light field, but electric field needs conductive materials; thermal field needs high-temperature melting materials, and high temperature also poses a great challenge to the reliability of inkjet print head at a distance of several millimeters from the substrate; light field often needs light-curing materials. The advantage of inkjet printing technology lies in multi-material, but the introduction of the above-mentioned fields has to some extent offset such advantage. Therefore, it is an urgent problem to be solved for direct inkjet 3D printing to realize inkjet printing manufacturing of complex three-dimensional structures and reduce the limitation of formable nanoparticle materials by external field.

[0004] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be taken as admitting that such information in the prior art. SUMMARY

[0005] The present application relates to the field of 3D printing technology, in particular to a low-temperature cold field assisted nanoparticle 3D printing device and printing method.

[0006] To achieve the above object, embodiments of the present application provide a low-temperature cold field assisted nanoparticle 3D printing device, comprising a shell, a bearing table, a refrigeration structure and a printing assembly. The shell has a cavity formed therein; the bearing table is arranged in the cavity, and has a bearing surface, and the bearing table can be controlled to keep the bearing surface within a certain temperature range; and the printing assembly is arranged in the cavity, and comprises a nozzle structure movable relative to the bearing table, wherein the nozzle structure comprises a plurality of jet heads, and the jet heads are respectively used to jet nanoparticle structure material and support material to the bearing surface.

[0007] In one or more embodiments of the present application, the low-temperature cold field assisted nanoparticle 3D printing device further comprises a roller structure arranged parallel to the bearing surface of the bearing table, and the roller structure is arranged to rotate and move relative to the bearing surface to control the printing material on the bearing surface to be flat.

[0008] In one or more embodiments of the present application, the low-temperature cold field assisted nanoparticle 3D printing device further comprises a cover arranged separately from the bearing table, and when the cover is arranged on the bearing table, a sealed space for containing printing material can be formed between the cover and the bearing surface.

[0009] In one or more embodiments of the present application, a pipeline is connected to the cover, and the pipeline can be in communication with an external vacuum pump mechanism to form the sealed space between the cover and the bearing surface, and the sealed space is used for a freeze-drying process after printing is completed.

[0010] In one or more embodiments of the present application, a circulating coolant flow channel is designed inside the bearing table, a pipeline connected to the coolant flow channel is arranged on the bearing table, and the pipeline can be in communication with an external refrigeration mechanism to keep the bearing surface stably within a certain temperature range.

[0011] In one or more embodiments of the present application, the printing assembly further comprises a first moving structure, and the nozzle structure is arranged on the first moving structure, and the first moving structure is arranged to move the nozzle structure relative to the bearing table in a horizontal direction.

[0012] In one or more embodiments of the present application, the low-temperature cold field assisted nanoparticle 3D printing device further comprises a monitoring structure arranged on the first moving structure, and the monitoring structure comprises a first microscope used to observe the bearing table and a second microscope used to observe the jet heads.

[0013] In one or more embodiments of the present application, the low-temperature cold field assisted nanoparticle 3D printing device further comprises a second moving structure, the carrier table is arranged on the second moving structure, and the second moving structure is arranged to move the carrier table in the vertical direction.

[0014] In one or more embodiments of the present application, the low-temperature cold field assisted nanoparticle 3D printing device further comprises a frame, and the shell is arranged on the frame, and an air floating vibration isolation structure is arranged between the shell and the frame.

[0015] The embodiments of the present application also provide a method for printing 3D nanoparticles, which adopts the low-temperature cold field assisted nanoparticle 3D printing device described above, and comprises the following steps: configuring nanoparticle structure material and support material; controlling the carrier table to keep a temperature below 0℃; filling the chamber with inert gas; controlling the nozzle structure to spray the nanoparticle structure material and the support material on the carrier table layer by layer, performing leveling treatment on the sample to be completed after each layer of spraying is completed, and until the complete sample is completed; and performing in-situ freeze drying on the complete sample to form a required sample.

[0016] In one or more embodiments of the present application, the temperature of the carrier table is controlled to be below -40℃ or below -40℃.

[0017] In one or more embodiments of the present application, the carrier table is cooled by liquid nitrogen or circulating cooling to keep the temperature of the carrier table below -40℃ or below -40℃.

[0018] In one or more embodiments of the present application, the in-situ freeze drying of the complete sample comprises the following steps: controlling the carrier table to keep a temperature below -40℃ or below -40℃; arranging a cover on the carrier table to cover the complete sample; and controlling the atmospheric pressure in the sealed space between the cover and the carrier table to be less than 1 Pa.

[0019] Compared with the prior art, the low-temperature cold field assisted nanoparticle 3D printing device and the printing method according to the embodiments of the present application can reduce the cooling temperature of the carrier table by cooling the carrier table, minimize the size of ice crystals formed in the sample on the carrier table, and improve the structural quality of the final required sample.

[0020] The low-temperature cold field assisted nanoparticle 3D printing device and the printing method according to the embodiments of the present application can spray nanoparticle structure material and support material by arranging multiple nozzles, and can to some extent avoid the flow of nanoparticle structure material-ink droplets on the surface of the sample to be completed before freezing, and thus can more freely print complex three-dimensional structures.

[0021] According to the low-temperature cold field assisted nanoparticle 3D printing device and printing method of the embodiment of the present application, by setting the roller structure, the height of each layer pattern in the complete sample is accurately defined, and the surface of each layer is flattened, so that the subsequently sprayed material can land on the flat base.

[0022] According to the low-temperature cold field assisted nanoparticle 3D printing device and printing method of the embodiment of the present application, by realizing in-situ freeze-drying on the bearing table, the risk of damaging the complete sample after printing is avoided, and the risk of internal tissue damage of the sample caused by temperature field change during sample transfer is also avoided. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of a low-temperature cold field assisted nanoparticle 3D printing device according to an embodiment of the present application;

[0024] Figure 2 is a structural schematic diagram of a low-temperature cold field assisted nanoparticle 3D printing device according to an embodiment of the present application;

[0025] Figure 3 is a flowchart of a method for printing 3D nanoparticles according to an embodiment of the present application.

[0026] Figure 4 is a schematic diagram of the process steps for printing 3D nanoparticles according to an embodiment of the present application.

[0027] Figure 5 is a schematic diagram of the process steps for printing 3D nanoparticles according to another embodiment of the present application. DETAILED DESCRIPTION

[0028] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present application is not limited by the specific embodiments.

[0029] Unless otherwise explicitly stated, throughout the specification and claims, the term "comprise" or its variants such as "comprises" or "comprising" will be understood to encompass the stated element or elements, but not to exclude the presence of other elements or additional elements.

[0030] As described in the background, the introduction of external fields such as electric field, thermal field and optical field to some extent offsets the multi-material advantage of inkjet printing technology, so that both inkjet printing manufacturing of complex three-dimensional structures and reduction of the limitation of external field on the type of formable nanoparticle material are the problems to be solved in direct inkjet 3D printing.

[0031] Applicant found that the cold field, which is opposite to the hot field, can also effectively control the high-quality forming of the ejected micro-droplets. Based on this, the applicant systematically studied the freezing and crystallization mechanism of the ink under the action of the cold field, the concentration mechanism of the nanoparticle ink between the ice crystals, the precipitation and shrinkage forming mechanism of the nano-wet particles from the ice crystals during the sublimation process, and the like by printing various nanoparticle (PS nanosphere, graphene oxide, nano-silver wire) inks on the freezing stage. Moreover, the applicant can provide certain assistance for the printing and forming of the three-dimensional microstructure of the nanoparticle under the freezing condition by scientifically designing the ink formula. The research found that the orientation arrangement characteristics of the two-dimensional material nanoparticles between the ice crystals and the ice structure surface can realize a feature size of at least 2 μm. The ink solvent formula includes water, tert-butyl alcohol and glycerol. Among them, water is mainly used to build ice structure; tert-butyl alcohol is used to reduce the ice crystal size, make the ice structure surface smoother, and make the precipitation of nano-wet particles more uniform, thereby improving the structure forming quality; and glycerol provides the capillary force for the final forming of the nanoparticle limited between the ice crystals.

[0032] However, the above printing concept of the three-dimensional microstructure of the nanoparticle still has the following problems:

[0033] Firstly, since the final forming is based on the accumulation principle of the ice crystal nanoparticle wet particles precipitated by sublimation, and the existing ink is limited by the ejection ability of the experimental nozzle, the solid content is low (including the concentrated liquid between the ice crystals), which leads to the destruction of the nanoparticle three-dimensional forming process by excessive liquid flow.

[0034] Secondly, at present, the freezing temperature of the freezing stage in the cold field is-40℃, although the nanoparticle ink is specially configured and tert-butyl alcohol is added to reduce the ice crystal size, but it is far from enough to improve the overall and surface quality of the structure.

[0035] Then, only using the nanoparticle ink is not enough to realize the completely free and complex cross-scale three-dimensional microstructure.

[0036] Finally, there is a risk of damaging the sample when the sample is transferred to the freeze-drying machine after printing.

[0037] Finally, the present application proposes an ice crystal induced nanoparticle 3D printing equipment and printing method assisted by a low-temperature cold field, which overcomes the fluid limitation of the nanoparticle structure material, realizes a new, more suitable for more types of nanoparticle, environmentally friendly direct inkjet 3D printing technology, and provides a new solution for the controllable preparation, innovative device design and application of the three-dimensional microstructure device of the nanoparticle.

[0038] As Figure 1 and Figure 2The low-temperature cold field assisted nanoparticle 3D printing device according to an embodiment of the present application comprises a housing 10, a bearing table 20, a printing assembly 30, and a roller structure 40. The bearing table 20, the printing assembly 30, and the roller structure 40 are all arranged in the housing 10.

[0039] A chamber is formed in the housing 10, and the chamber can be filled with an inert gas such as nitrogen to isolate water vapor and form a printing environment. A glove window can be formed on the housing 10, and a sealing glove is arranged at the glove window to facilitate operation in the chamber through the glove window.

[0040] The bearing table 20 is arranged in the chamber, and the bearing table 20 has a bearing surface as a support surface for nanoparticle 3D printing. A circulating coolant flow channel can be formed in the bearing table 20, and a pipeline connected to the coolant flow channel is arranged on the bearing table 20 and can be communicated with an external refrigeration mechanism. The external refrigeration mechanism controls the flow of the coolant in the coolant flow channel to keep the bearing surface of the bearing table 20 within a certain temperature range during printing, and the certain temperature range is below 0°C, and preferably below -40°C but above or equal to -150°C. Alternatively, a containing space can be formed in the bearing table 20, and liquid nitrogen is supplied to the containing space to keep the bearing surface of the bearing table 20 within a certain temperature range during printing, and the certain temperature range is below 0°C, and preferably below -40°C but above or equal to -150°C.

[0041] In an embodiment, the bearing table 20 can move in the vertical direction relative to the housing 10. For example, a second moving structure is arranged between the bearing table 20 and the housing 10, and the bearing table 20 is arranged on the second moving structure. The second moving structure can be a pneumatic cylinder to drive the bearing table 20 to move longitudinally.

[0042] The printing assembly 30 is arranged in the chamber, and the printing assembly 30 comprises a nozzle structure 31 and a first moving structure to drive the nozzle structure 31 to move relative to the bearing table 20. The nozzle structure 31 can perform inkjet printing of a sample on the bearing surface of the bearing table 20 according to design requirements under the action of the first moving structure.

[0043] The first moving structure comprises an x-axis moving structure to enable the nozzle structure 31 to approach or move away from the bearing table 20 in an x-axis direction (x-axis direction) of a first direction (x-axis direction) and a y-axis moving structure arranged on the x-axis moving structure to enable the nozzle structure 31 to approach or move away from the bearing table 20 in a y-axis direction (y-axis direction) of a second direction (y-axis direction). Figure 1 Figure 1 The nozzle structure 31 is fixed to the y-axis moving structure.

[0044] ​The x-axis moving structure comprises an x-axis track group 3211, an x-axis motor 3212 and an x-axis slider 3213. The two x-axis track groups 3211 are fixed to the inner bottom wall of the shell 10 through a support 320 and are located on opposite sides of the bearing table 20. The x-axis motor 3212 is fixed to the x-axis track group 3211 and is connected with the x-axis slider 3213 to drive the x-axis slider 3213 to complete the movement requirement in the x direction.

[0045] The y-axis moving structure comprises a y-axis track group 3221, a y-axis motor 3222 and a y-axis slider 3223. The y-axis track group 3221 is fixed to the x-axis slider 3213. The y-axis motor 3222 is fixed to the y-axis track group 3221 and its output shaft is connected with the y-axis slider 3223. The nozzle structure 31 is installed on the y-axis slider 3223 through a mounting plate 3224. The y-axis motor 3222 rotates to drive the y-axis slider 3223 to move in the y direction, drives the mounting plate 3224 and the nozzle structure 31 to complete the movement requirement in the z direction by a set distance. It can be understood that the spraying direction of the nozzle structure 31 is always towards the bearing table 20.

[0046] In other embodiments, the bearing table 20 can be kept stationary and the nozzle structure 31 moves relative to the bearing table 20 in the horizontal and vertical directions. Of course, a three-dimensional moving mechanism can also be used for movement assistance. Based on the three-dimensional moving mechanism, the prior art can be used and this application will not be expanded here.

[0047] The nozzle structure 31 comprises a plurality of ejection heads, which are respectively used to spray the nanoparticle structure material and the support material to the bearing surface. The nanoparticle structure material is the sample main body, which is partially reserved in the subsequent sublimation process; the support material is completely sublimated in the subsequent sublimation process. In order to realize the printing of complex three-dimensional structures, both the forming structure (the required sample) and the support structure need to be printed. The double-nozzle or multi-nozzle printing of the forming structure and the support structure is the key to forming complex three-dimensional structures. It can be understood that the ordinary inkjet ejection head requires that the viscosity (usually < 16 cP) and solid content of the sprayable ink need to be reduced to a lower range to realize stable spraying, but low viscosity and low solid content are not conducive to the formation of three-dimensional structures, which requires the configuration of an internal circulation nozzle with higher sprayable ink viscosity and solid content in hardware. At the same time, since the cold field is used for printing in the present application, the bearing table 20 with lower temperature will have a greater impact on the nozzle structure 31 and the ink in the ejection head hole close to it, and once the ejection head reliability is reduced or the ink in the ejection head hole is crystallized due to too low temperature, it will cause fatal damage to the entire device. Therefore, the ejection head needs to have temperature control technology. Based on this, the ejection head in the present application can be purchased from the current international Xaar and Toshiba ejection heads. Xaar and Toshiba ejection heads have developed internal circulation piezoelectric ejection heads with temperature control technology, which can realize the spraying of 100 cp high viscosity ink, and can achieve the purpose of improving the viscosity and solid content of the sprayable ink. Alternatively, the following methods can be used to ensure the reliability of the nozzle structure 31 and prevent the ink in the ejection head hole from crystallizing, such as: temperature field distribution simulation and measurement can be performed in the plane range of the ejection head above the bearing table 20; by improving the printing scanning speed; by adjusting the printing distance, etc.

[0048] It can be understood that in order to observe the sample printing on the bearing table 20, a first microscope 331 can be installed on the mounting plate 3224. The height of the first microscope 331 relative to the bearing table 20 is adjustable. At the same time, in order to observe the printing ink droplet ejection of the nozzle structure 31, a second microscope 332 can be installed on the x-axis rail group 3211 or the bracket 320. The field of view range of the second microscope 332 covers the nozzle structure 31.

[0049] The roller structure 40 is arranged parallel to the bearing surface of the bearing table 20. The roller structure 40 is arranged to rotate and move relative to the bearing surface to flatten the printing material on the bearing surface. For example, the roller structure 40 can be arranged on the y-axis rail group 3221 and located at the bottom of the y-axis rail group 3221. In this embodiment, the roller structure 40 can be pre-cooled to below 0°C (the actual design will control the pre-cooling temperature to about -40°C) before flattening and limiting the printing material on the bearing surface, to prevent damage to the printing material when flattening the printing material due to high temperature. In addition, to cooperate with the roller structure 40, a recovery groove can be designed around the bearing table 20 to recover the ice crystals formed by the condensation of the entire support material and part of the nano-particle structure material pushed away by the roller structure.

[0050] In the above technical solution, the presence of the support structure makes it possible to apply the roller structure to flatten the surface of each layer of pattern and strictly define the thickness of each layer, thereby obtaining a smoother and more accurate printed sample.

[0051] For the printed sample structure on the low-temperature refrigeration bearing table 20, it is generally necessary to be transferred to a freeze dryer to remove ice crystals (formed by the condensation of the entire support material and part of the nano-particle structure material) by sublimation, but once the printed sample structure is separated from the low-temperature refrigeration bearing table 20, its temperature will uncontrollably rise sharply, causing the internal ice structure to melt, thereby damaging the printed sample structure. In order to maximize the protection of the printed sample structure from damage during the transfer process, the application also proposes an in-situ freeze-drying technology.

[0052] In an embodiment of the application, the bearing table 20 can further be provided with a cover 50. The cover 50 and the bearing table 20 can be arranged separately, and when the cover 50 is arranged on the bearing table 20, the cover 50 and the bearing surface can form a sealed space containing the printing material. The cover 50 is connected with a pipeline, which can communicate with an external vacuum pump mechanism to form a sealed freezing cavity between the cover 50 and the bearing surface, which is used for the freeze-drying process after printing is completed.

[0053] After printing is completed, the cover 50 is loaded above the bearing table 20, and the external vacuum pump mechanism is turned on to perform in-situ freeze-drying on the printed sample structure on the bearing table 20. The cover 50 can also be designed with a transparent window to facilitate observation of the sublimation shrinkage process. To achieve online observation, the height of the cover 50 is not higher than the 20mm working distance of the lens of the first microscope 331.

[0054] To facilitate operation, the low-temperature cold field assisted nano-particle 3D printing equipment further comprises a frame 60, and the housing 10 is arranged on the frame 60. An air floating vibration isolation structure is arranged between the housing 10 and the frame 60, further improving the printing precision.

[0055] Reference Figure 3 As shown in the above, the present application also provides a method for printing 3D nanoparticles by using the above low-temperature cold field assisted nanoparticle 3D printing device, comprising: s1, configuring nanoparticle structure material and support material; s2, controlling the temperature of the bearing table to be below 0℃; s3, filling the chamber with inert gas; s4, controlling the nozzle structure to spray nanoparticle structure material and support material on the bearing table by layers, and after each layer is completed, the sample to be completed is flattened until the complete sample is completed; s5, in-situ freeze-drying the complete sample to form the required sample.

[0056] In step s2, preferably, the bearing table 20 is cooled by liquid nitrogen or circulating cooling to keep the temperature of the bearing table 20 at or below -40℃. In step s5, in-situ freeze-drying the complete sample, comprising: controlling the temperature of the bearing table to be at or below -40℃; setting the cover on the bearing table to cover the complete sample; controlling the atmospheric pressure in the sealed space between the cover and the bearing table to be less than 1 Pa.

[0057] Example 1:

[0058] The graphene oxide ink is used as the nanoparticle structure material ink, which is configured as follows: 80g of water, 20g of t-butyl alcohol, 0.01g of graphene oxide powder, and 0.05g of glycerol are prepared into a uniform ink by an ultrasonic machine and a mixing machine, and filtered through a 5-micron filter.

[0059] The water and t-butyl alcohol mixture is used as the support material ink, which is configured as follows: 80g of water and 20g of t-butyl alcohol are prepared into a uniform ink by an ultrasonic machine and a mixing machine.

[0060] Reference Figure 4 As shown in the above, the present application also provides a method for printing 3D nanoparticles by using the above low-temperature cold field assisted nanoparticle 3D printing device, comprising: s1, configuring nanoparticle structure material and support material; s2, controlling the temperature of the bearing table to be below 0℃; s3, filling the chamber with inert gas; s4, controlling the nozzle structure to spray nanoparticle structure material and support material on the bearing table by layers, and after each layer is completed, the sample to be completed is flattened until the complete sample is completed; s5, in-situ freeze-drying the complete sample to form the required sample. Figure 4 In the above, the structure formed by the nanoparticle structure material ink a is located inside the structure formed by the support material ink b, in order to facilitate the observation of the structure formed by the nanoparticle structure material ink a, the structure formed by the support material ink b is transparentized in the figure, and the structure formed by the nanoparticle structure material ink a is not shown to be formed on the surface of the structure formed by the support material ink b.

[0061] After printing, the printed sample structure (a+b) is freeze-dried in situ, i.e. a cover connected with pipelines is loaded above the bearing table and vacuumized, so that the gas pressure in the printing environment in the cover is less than 1 Pa. A transparent window is designed above the cover, facilitating the first microscope to observe the sublimation shrinkage process. During the sublimation process, the support material is completely sublimated, and part of the solvent in the structure material is sublimated, so that the printed sample structure is proportionally shrunk, further reducing the feature size, referring to Figure 4 iiiiii in the foregoing.

[0062] Example 2:

[0063] The printing process can be expanded to a multi-material printing process, taking nano-silver ink and PEDOT: PSS ink as the nano-particle structure material ink. The configuration is as follows: nano-silver ink: 80 g of water, 20 g of t-butyl alcohol, 0.01 g of nano-silver powder, and 0.01 g of glycerol are prepared into a uniform ink by an ultrasonic machine and a mixer, and filtered through a 5-micron filter. PEDOT: PSS ink: 80 g of water, 20 g of t-butyl alcohol, 0.01 g of PEDOT: PSS powder, and 0.01 g of glycerol are prepared into a uniform ink by an ultrasonic machine and a mixer, and filtered through a 5-micron filter.

[0064] The mixture of water and t-butyl alcohol is used as the support material ink, and the configuration is as follows: 80 g of water and 20 g of t-butyl alcohol are prepared into a uniform ink by an ultrasonic machine and a mixer.

[0065] Referring to Figure 5 The prepared nano-particle structure material ink (a / c) and support material ink (b) are printed on the low-temperature bearing table through the nozzle structure 31 (the nozzle structure includes three jet heads), wherein the temperature of the bearing table is controlled to be minus 50 degrees Celsius. During the printing process, the jet hole state of the jet head is dynamically detected by the second microscope device. Then the surface of each layer of pattern is flattened by the roller structure and the thickness of each layer is strictly defined.

[0066] After printing, the printed sample structure is freeze-dried in situ, i.e. a cover connected with pipelines is loaded above the bearing table and vacuumized, so that the gas pressure in the printing environment in the cover is less than 1 Pa. A transparent window is designed above the cover, facilitating the first microscope to observe the sublimation shrinkage process; during the sublimation process, the support material is completely sublimated, and part of the solvent in the structure material is sublimated, so that the printed sample structure is proportionally shrunk, further reducing the feature size. After the sublimation is completed, the nano-silver and PEDOT: PSS form a closely connected heterojunction.

[0067] Compared with the prior art, the low-temperature cold field assisted nanoparticle 3D printing device and printing method according to the embodiments of the present application can reduce the cooling temperature of the bearing table by refrigerating the bearing table, minimize the size of ice crystals formed in the sample on the bearing table, and improve the structural quality of the final sample.

[0068] The low-temperature cold field assisted nanoparticle 3D printing device and printing method according to the embodiments of the present application can print complex three-dimensional structures more freely by setting multiple spray heads to spray nanoparticle structural materials and support materials, which can to some extent avoid the flow of nanoparticle structural material-droplets on the surface of the sample to be completed before freezing, and further can print complex three-dimensional structures more freely.

[0069] The low-temperature cold field assisted nanoparticle 3D printing device and printing method according to the embodiments of the present application can precisely define the height of each layer pattern in the complete sample and flatten the surface of each layer by setting the roller structure, so that the subsequently sprayed materials can land on the flat base.

[0070] The low-temperature cold field assisted nanoparticle 3D printing device and printing method according to the embodiments of the present application can avoid the risk of damaging the complete sample during the transfer of the complete sample to the freeze dryer after printing, and avoid the risk of internal tissue damage of the sample caused by the change of the temperature field during the transfer of the sample.

[0071] The foregoing description of specific exemplary embodiments of the present application is intended to be illustrative only and is not intended to limit the present application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the present application. The particular exemplary embodiments were chosen and described in order to explain the principles of the present application and its practical application to thereby enable others skilled in the art to best utilize the present application and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the present application be defined by the claims and their equivalents.

Claims

1. A method for printing 3D nanoparticles by using a low-temperature cold field assisted nanoparticle 3D printing device, characterized in that, the low-temperature cold field assisted nanoparticle 3D printing device comprises: a housing in which a chamber is formed; a bearing table arranged in the chamber, the bearing table having a bearing surface, and the bearing table being capable of being controlled to keep the bearing surface within a certain temperature range; a printing assembly arranged in the chamber, the printing assembly comprising a nozzle structure movable relative to the bearing table, the nozzle structure comprising a plurality of jetting heads, and each of the plurality of jetting heads being used for jetting a nanoparticle structure material and a support material to the bearing surface; the method comprises: configuring the nanoparticle structure material and the support material, the nanoparticle structure material comprising nanoparticles and an ink solvent, the ink solvent comprising water, tert-butyl alcohol and glycerol, and the support material comprising a mixture of water and tert-butyl alcohol; controlling the bearing table to keep a temperature below 0℃; filling the chamber with inert gas; controlling the nozzle structure to jet the nanoparticle structure material and the support material layer by layer on the bearing table, and after each layer is completed, performing a leveling process on the sample to be completed until the complete sample is completed; performing in-situ freeze-drying on the complete sample to form a required sample structure.

2. The method of printing 3D nanoparticles of claim 1, wherein, controlling the bearing table to keep a temperature of 40℃ below zero or below 40℃ below zero.

3. The method of printing 3D nanoparticles of claim 1, wherein, the in-situ freeze-drying on the complete sample comprises: controlling the bearing table to keep a temperature of 40℃ below zero or below 40℃ below zero; arranging a cover on the bearing table to cover the complete sample; controlling the atmospheric pressure in the sealed space between the cover and the bearing table to be less than 1 Pa.

4. The method of printing 3D nanoparticles of claim 1, wherein, The low-temperature cold field assisted nanoparticle 3D printing device further comprises a roller structure arranged parallel to the bearing surface of the bearing table, and the roller structure is arranged to rotate and move relative to the bearing surface to control the leveling of the printing material on the bearing surface.

5. The method of printing 3D nanoparticles of claim 1, wherein, The low-temperature cold field assisted nanoparticle 3D printing device further comprises a cover which is arranged separately from the bearing table, and when the cover is arranged on the bearing table, a sealed space for containing the printing material can be formed between the cover and the bearing surface.

6. The method of printing 3D nanoparticles of claim 5, wherein, A pipeline is connected to the cover, and the pipeline can communicate with an external vacuum pump mechanism to form the sealed space between the cover and the bearing surface, and the sealed space is used for the freeze-drying process after printing is completed.

7. The method of printing 3D nanoparticles of claim 1, wherein, The bearing table of the low-temperature cold field assisted nanoparticle 3D printing device is internally designed with a coolant flow channel, and a pipeline connected to the coolant flow channel is connected to the bearing table, and the pipeline can communicate with an external refrigeration mechanism to keep the bearing surface within a certain temperature range; and / or The low-temperature cold field assisted nanoparticle 3D printing device further comprises a second moving structure, and the bearing table is arranged on the second moving structure, and the second moving structure is arranged to move the bearing table in the vertical direction.

8. The method of printing 3D nanoparticles of claim 1, wherein, The printing assembly of the low-temperature cold field assisted nanoparticle 3D printing device further comprises a first moving structure, and the nozzle structure is arranged on the first moving structure.

9. The method of printing 3D nanoparticles of claim 8, wherein, The low-temperature cold field assisted nanoparticle 3D printing device further comprises a monitoring structure arranged on the first moving structure, and the monitoring structure comprises a first microscope for observing the carrier table and a second microscope for observing the nozzle.

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