Nano-particle 3D printing equipment assisted by low-temperature cold field and printing method

Abstract

The invention discloses nano-particle 3D printing equipment assisted by a low-temperature cold field and a printing method. The printing equipment comprises a shell, a bearing table, a refrigeration structure and a printing assembly. A cavity is formed in the shell; the bearing table is arranged in the cavity, the bearing table is provided with a bearing surface, and the bearing table can be controlled to keep the bearing surface within a certain temperature range; the printing assembly is arranged in the cavity and comprises a spray head structure capable of moving relative to the bearing table, the spray head structure comprises a plurality of spraying heads, and the spraying heads are used for spraying nano-particle structure materials and supporting materials to the bearing face. According to the nano-particle 3D printing equipment assisted by the low-temperature cold field and the printing method, nano-particles can be controlled in a three-dimensional space, and a micro-nano cross-scale three-dimensional structure can be constructed.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a low-temperature cold field assisted nanoparticle 3D printing device and a printing method. Background Art

[0002] Direct inkjet printing is a revolutionary manufacturing technology that enables people to freely and controllably design new materials and devices at the micro-nano scale using nanoparticle materials as functional primitives. Its application covers multiple fields such as electronics, optics, and sensors. At present, the development of equipment for this technology is mainly represented by two companies, XJET and Nanodimension. XJET directly sprays metal or ceramic nanoparticle ink and melts the nanoparticles at a high temperature of more than 300°C online to achieve high-precision three-dimensional metal or ceramic structure printing; Nanodimension configures dual nozzles and infrared sintering nanosilver online to achieve the printing of nanosilver-photosensitive resin composite multilayer circuit boards. These technologies often require the assistance of external fields to control the molding structure.

[0003] The external fields that have been studied so far mainly include electric fields, thermal fields, and optical fields. However, electric fields require conductive materials; thermal fields require high-temperature molten materials, and high temperatures also pose a great challenge to the reliability of inkjet print heads that are several millimeters away from the substrate; and optical fields often require photocurable materials. The advantage of inkjet printing technology lies in its multi-material nature, but the introduction of the external fields mentioned above offsets this advantage to a certain extent. Therefore, it is an urgent problem to be solved in direct inkjet 3D printing to achieve inkjet printing of complex three-dimensional structures while reducing the restrictions of external fields on the types of formable nanoparticle materials.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a low-temperature cold field assisted nanoparticle 3D printing device and printing method, which can manipulate nanoparticles in three-dimensional space and construct micro-nano cross-scale three-dimensional structures.

[0006] To achieve the above-mentioned purpose, an embodiment of the present invention provides a low-temperature cold field assisted nanoparticle 3D printing device, including a shell, a carrier, a refrigeration structure and a printing component. A chamber is formed in the shell; the carrier is arranged in the chamber, the carrier has a bearing surface, and the carrier can be controlled to keep its bearing surface within a certain temperature range; the printing component is arranged in the chamber, the printing component includes a nozzle structure that can move relative to the carrier, the nozzle structure includes a plurality of nozzles, and the plurality of nozzles are respectively used to spray nanoparticle structure materials and support materials onto the bearing surface.

[0007] In one or more embodiments of the present invention, the low-temperature cold field assisted nanoparticle 3D printing device also includes a roller structure, which is arranged parallel to the bearing surface of the bearing platform, and the roller structure is arranged to rotate and move relative to the bearing surface to controllably flatten the printing material on the bearing surface.

[0008] In one or more embodiments of the present invention, the low-temperature cold field assisted nanoparticle 3D printing device also includes a cover body, which can be separated from the carrier platform. When the cover body is set on the carrier platform, a sealed space for accommodating printing materials can be formed between the cover body and the carrier surface.

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

[0010] In one or more embodiments of the present invention, a circulating coolant flow channel is designed inside the support platform, and a pipeline connected to the coolant flow channel is connected to the support platform. The pipeline can be connected to an external refrigeration mechanism to keep the support surface stably within a certain temperature range.

[0011] In one or more embodiments of the present invention, the printing assembly further comprises a first movable structure, the nozzle structure is arranged on the first movable structure, and the first movable structure is configured to enable the nozzle structure to move in a horizontal direction relative to the supporting platform.

[0012] In one or more embodiments of the present invention, the low-temperature cold field assisted nanoparticle 3D printing device also includes a monitoring structure, which is arranged on the first movable structure, including a first microscope for observing the supporting platform, and a second microscope for observing the injection head.

[0013] In one or more embodiments of the present invention, the low-temperature cold field assisted nanoparticle 3D printing device also includes a second movable structure, the carrier platform is arranged on the second movable structure, and the second movable structure is configured to enable the carrier platform to move in a vertical direction.

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

[0015] An embodiment of the present invention also provides a method for printing 3D nanoparticles, using the above-mentioned low-temperature cold field assisted nanoparticle 3D printing equipment, including: configuring nanoparticle structural materials and supporting materials; controlling the carrier platform to maintain a temperature below 0°C; filling the chamber with inert gas; controlling the nozzle structure to spray the nanoparticle structural materials and supporting materials on the carrier platform in layers, and after each layer is sprayed, flattening the sample to be completed until the complete sample is completed; and in-situ freeze-drying the complete sample to form the desired sample.

[0016] In one or more embodiments of the present invention, the support platform is controlled to maintain a temperature of minus 40° C. or lower.

[0017] In one or more embodiments of the present invention, the support platform is subjected to liquid nitrogen refrigeration or circulating cooling refrigeration to keep the temperature of the support platform at or below -40°C.

[0018] In one or more embodiments of the present invention, the in-situ freeze-drying of the intact sample includes: controlling the temperature of the support platform to maintain minus 40°C or below minus 40°C; setting a cover on the support platform to cover the intact sample; controlling the atmospheric pressure in the sealed space between the cover and the support platform to be less than 1Pa.

[0019] 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 invention can reduce the cooling temperature of the carrier platform by refrigerating the carrier platform, thereby minimizing the size of ice crystals formed in the sample on the carrier platform and improving the structural quality of the final required sample.

[0020] According to the low-temperature cold field assisted nanoparticle 3D printing device and printing method of the embodiment of the present invention, multiple nozzles are set to spray nanoparticle structural materials and supporting materials. Due to the addition of supporting materials, the flow of nanoparticle structural materials-ink droplets on the surface of the unfinished sample before freezing can be avoided to a certain extent, thereby allowing complex three-dimensional structures to be printed more freely.

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

[0022] According to the low-temperature cold field assisted nanoparticle 3D printing device and printing method of the embodiment of the present invention, in-situ freeze drying is achieved on the support platform, thereby avoiding the risk of damaging the complete sample when transferring the complete sample to the freeze dryer after printing, and avoiding the risk of internal tissue damage of the sample due to temperature field changes during sample transfer. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0026] Figure 4 Schematic diagram of the process steps for printing 3D nanoparticles according to an embodiment of the present invention.

[0027] Figure 5 Schematic diagram of the process steps for printing 3D nanoparticles according to another embodiment of the present invention. DETAILED DESCRIPTION

[0028] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0029] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0030] As mentioned in the background technology, the introduction of external fields such as electric fields, thermal fields and light fields offsets the multi-material advantages of inkjet printing technology to a certain extent. Therefore, it is an urgent problem to be solved in direct inkjet 3D printing to realize inkjet printing manufacturing of complex three-dimensional structures and reduce the restrictions of external fields on the types of formable nanoparticle materials.

[0031] The applicant found that in fact, the cold field, which is opposite to the hot field, can also effectively control the high-quality molding of the jet droplets. Based on this, the applicant systematically studied the freezing crystallization mechanism of the ink under the action of the cold field, the concentration mechanism of the nanoparticle ink between ice crystals, and the precipitation and shrinkage molding mechanism of the nano-wet particles from the ice crystals during the sublimation process by printing a variety of nanoparticle (PS nanospheres, graphene oxide, nano silver wire) inks on a freezing table. In addition, the applicant can provide certain assistance for the printing and molding of nanoparticle three-dimensional microstructures under freezing conditions by scientifically designing the ink formula. The study found that the minimum characteristic size of 2μm can be achieved by applying the orientation arrangement characteristics of two-dimensional material nanoparticles between ice crystals and on the surface of ice structures. The ink solvent formula includes water, tert-butanol and glycerol. Among them, water is mainly used to construct ice structures; tert-butanol is used to reduce the size of ice crystals, make the surface of the ice structure smoother, precipitate nano-wet particles more uniformly, and improve the quality of structural molding; glycerol provides capillary force for the final molding of nanoparticles confined between ice crystals.

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

[0033] First, since the final forming is based on the principle of accumulation of nano-wet particles between ice crystals precipitated by sublimation, and the existing inks are limited by the jetting capacity of the experimental nozzles and have a low solid content (including concentrated liquid between ice crystals), the three-dimensional forming process of the nanoparticles is often destroyed by excessive liquid flow.

[0034] Secondly, in the current cold field, the freezing temperature of the freezing table is -40°C. Although the nanoparticle ink has been specially configured and tert-butyl alcohol has been added to reduce the size of ice crystals, it is far from enough to improve the overall structure and surface quality.

[0035] Next, using only nanoparticle ink is not enough to achieve complex cross-scale three-dimensional microstructures with full freedom.

[0036] Finally, there is a risk of damaging the sample when transferring it to a freeze dryer after printing.

[0037] Finally, this application proposes a low-temperature cold field-assisted ice crystal-induced nanoparticle 3D printing device and printing method, which overcomes the fluid limitations of nanoparticle structural materials and realizes a new, environmentally friendly direct inkjet 3D printing technology that is suitable for a wider variety of nanoparticles, providing a new set of solutions for the controllable preparation, innovative device design and application of nanoparticle three-dimensional microstructure devices.

[0038] like Figure 1 and Figure 2The low temperature cold field assisted nanoparticle 3D printing device according to one embodiment of the present invention comprises a housing 10, a carrier 20, a printing assembly 30 and a roller structure 40. The carrier 20, the printing assembly 30 and the roller structure 40 are all disposed 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 opened 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 carrier 20 is arranged in the chamber, and the carrier 20 has a bearing surface, which serves as a supporting surface for 3D printing of nanoparticles. A circulating coolant flow channel can be formed in the carrier 20, and a pipeline connected to the coolant flow channel is connected to the carrier 20, and the pipeline can be connected to an external refrigeration mechanism. The coolant is controlled to flow in the coolant flow channel by the external refrigeration mechanism so that the carrier 20 can always stably keep the bearing surface within a certain temperature range during printing, wherein the certain temperature range is a range below 0°C, preferably, a range below minus 40°C but above or equal to minus 150°C. Alternatively, a accommodating space can be formed in the carrier 20, and liquid nitrogen is transported into the accommodating space so that the carrier 20 can always keep the bearing surface within a certain temperature range during printing, wherein the certain temperature range is a range below 0°C, preferably, a range below minus 40°C but above or equal to minus 150°C.

[0041] In one embodiment, the carrier 20 can move in a vertical direction relative to the housing 10. Exemplarily, a second moving structure is provided between the carrier 20 and the housing 10, and the carrier 20 is provided on the second moving structure. The second moving structure can be a cylinder, which drives the carrier 20 to move longitudinally.

[0042] The printing assembly 30 is disposed in the chamber, and includes a nozzle structure 31 and a first moving structure for driving the nozzle structure 31 to move relative to the carrier 20. Under the action of the first moving structure, the nozzle structure 31 can perform inkjet printing of the sample on the carrying surface of the carrier 20 according to the design requirements.

[0043] The first movable structure includes a nozzle structure 31 that can move the nozzle structure 31 in a first direction ( Figure 1 The nozzle structure 31 can be moved in the second direction ( Figure 1 The nozzle structure 31 is fixed on the y-axis moving structure.

[0044] The x-axis moving structure includes an x-axis track group 3211, an x-axis motor 3212 and an x-axis slider 3213; the two groups of x-axis track groups 3211 are fixed to the inner bottom wall of the shell 10 through the bracket 320, and are located on opposite sides of the support platform 20; the x-axis motor 3212 is fixed to the x-axis track group 3211 and is connected to the x-axis slider 3213, driving the x-axis slider 3213 to complete the predetermined movement requirements in the x-direction.

[0045] The y-axis moving structure includes 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 on the x-axis slider 3213, the y-axis motor 3222 is fixed on the y-axis track group 3221, and its output shaft is connected to the y-axis slider 3223, the nozzle structure 31 is installed on the y-axis slider 3223 through the mounting plate 3224, and the y-axis motor 3222 rotates to drive the y-axis slider 3223 to move along the y direction, driving the mounting plate 3224 and the nozzle structure 31 to complete the movement requirements in the z direction according to the set distance. It can be understood that the spraying direction of the nozzle structure 31 is always toward the carrier 20.

[0046] In other embodiments, the carrier 20 may remain stationary, and the nozzle structure 31 may move relative to the carrier 20 in the horizontal and vertical directions. Of course, a three-dimensional moving mechanism may also be used for movement assistance. The three-dimensional moving mechanism may use existing technology, which will not be elaborated in this application.

[0047] The nozzle structure 31 includes a plurality of nozzles, and the plurality of nozzles are respectively used to spray nanoparticle structure materials and support materials onto the bearing surface. Among them, the nanoparticle structure material is the main body of the sample, which will be partially retained 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, it is necessary to print both the molding structure (required sample) and the support structure. The technology of printing the molding structure and the support structure separately with dual nozzles or multiple nozzles is the key to forming complex three-dimensional structures. It is understandable that ordinary inkjet nozzles require that the viscosity (usually <16cP) and solid content of the jettable ink need to be reduced to a lower range to achieve stable jetting, but low viscosity and low solid content are not conducive to the molding of three-dimensional structures, which requires the hardware to be configured with an internal circulation nozzle with a higher viscosity and solid content of the jettable ink. At the same time, because the present application adopts a cold field for printing, the carrier 20 with a relatively low temperature will have a greater impact on the nozzle structure 31 and the ink in the nozzle hole that are close to it. Once the reliability of the nozzle is reduced or the ink in the nozzle hole is crystallized due to the low temperature, it will have a fatal impact on the entire device. Therefore, the nozzle needs to have its own temperature control technology. Based on this, the nozzle in this application can be purchased by purchasing the nozzles of Xaar and Toshiba in the world. Both Xaar and Toshiba's nozzles have developed internal circulation piezoelectric nozzles with built-in temperature control technology, which can realize the injection of 100cp high-viscosity ink, and can achieve the purpose of improving the viscosity and solid content of the ejectable ink. Alternatively, the following methods can be used to ensure the reliability of the nozzle structure 31 and prevent the ink from crystallizing in the nozzle hole, for example: the temperature field distribution simulation and measurement can be performed above the carrier 20 and within the plane where the nozzle is located; by increasing the printing scanning speed; by adjusting the printing distance, etc.

[0048] It is understandable that, in order to observe the sample printing on the carrier 20, a first microscope 331 can be installed on the mounting plate 3224. The height of the first microscope 331 relative to the carrier 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 track group 3211 or the bracket 320. The field of view of the second microscope 332 covers the nozzle structure 31.

[0049] The roller structure 40 is arranged parallel to the bearing surface of the carrier 20. The roller structure 40 is arranged to be self-rotating and to be able to move relative to the bearing surface to control the printing material on the flat bearing surface. Exemplarily, the roller structure 40 can be arranged on the y-axis track group 3221 and located at the bottom of the y-axis track group 3221. In this embodiment, before the roller structure 40 flattens and limits the printing material on the bearing surface, the roller structure 40 can also be pre-cooled to below 0°C (the actual design will control the pre-cooling temperature to about -40°C) to prevent it from damaging the printing material when flattening the printing material due to excessive temperature. In addition, in order to cooperate with the roller structure 40, a recovery groove can also be designed around the carrier 20 to recover the ice crystals condensed from all the supporting materials and part of the nanoparticle structure material pushed away by the roller structure.

[0050] In the above technical solution, due to the existence of the support structure, it is possible to use a roller structure to flatten the surface of each layer of graphics and strictly define the thickness of each layer, thereby obtaining a smoother and more accurate printing sample.

[0051] Generally speaking, the printed sample structure on the cryogenic refrigeration platform 20 needs to be transferred to a freeze dryer to remove ice crystals (condensed from all supporting materials and part of the nanoparticle structure material) through sublimation. However, once the printed sample structure is separated from the cryogenic refrigeration platform 20, its temperature will rise sharply and uncontrollably, causing the internal ice structure to melt, thereby destroying the printed sample structure. In order to maximize the protection of the printed sample structure from being destroyed during the transfer process, the present application also proposes an in-situ freeze drying technology.

[0052] In one embodiment of the present application, a cover 50 may be further provided on the carrier 20. The cover 50 may be separated from the carrier 20. When the cover 50 is provided on the carrier 20, a sealed space for accommodating printing materials can be formed between the cover 50 and the carrier surface. A pipeline is connected to the cover 50, and the pipeline can be connected to an external vacuum pump mechanism to form a sealed freezing chamber between the cover 50 and the carrier surface. The sealed freezing chamber is used for the freeze-drying process after printing is completed.

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

[0054] For ease of operation, the low-temperature cold field assisted nanoparticle 3D printing device further includes a frame 60, on which the shell 10 is disposed, and an air-floating vibration isolation structure is disposed between the shell 10 and the frame 60 to further improve printing accuracy.

[0055] refer to Figure 3 As shown, the present application also provides a method for printing 3D nanoparticles using the above-mentioned low-temperature cold field assisted nanoparticle 3D printing equipment, including: s1, configuring nanoparticle structural materials and supporting materials; s2, controlling the carrier platform to maintain a temperature below 0°C; s3, filling the chamber with inert gas; s4, controlling the nozzle structure to spray the nanoparticle structural materials and supporting materials on the carrier platform in layers, and after each layer is sprayed, the sample to be completed is flattened until the complete sample is completed; s5, in-situ freeze-drying the complete sample to form the desired sample.

[0056] Wherein, in step s2, preferably, the platform 20 is refrigerated by liquid nitrogen or circulating cooling to keep the platform 20 at a temperature of minus 40°C or lower. In step s5, the complete sample is freeze-dried in situ, including: controlling the platform to maintain a temperature of minus 40°C or lower; placing a cover on the platform to cover the complete sample; and controlling the atmospheric pressure in the sealed space between the cover and the platform to be less than 1Pa.

[0057] Embodiment 1:

[0058] Graphene oxide ink was used as the nanoparticle structural material ink, and the configuration was as follows: 80 g of water, 20 g of tert-butyl alcohol, 0.01 g of graphene oxide powder, and 0.05 g of propylene glycol were prepared into a uniform ink through an ultrasonic machine and a mixer, and filtered through a 5-micron filter.

[0059] A mixture of water and tert-butanol was used as the supporting material ink, and the configuration was as follows: 80 g of water and 20 g of tert-butanol were prepared into a uniform ink by an ultrasonic machine and a mixer.

[0060] refer to Figure 4 As shown, the configured nanoparticle structure material ink a and support material ink b are printed on a low-temperature carrier through a nozzle structure 31 (the nozzle structure includes a double nozzle), wherein the temperature of the carrier is controlled to be minus 40 degrees Celsius. During the printing process, the nozzle state of the nozzle is dynamically detected by a second microscope device. Afterwards, the surface of each layer of the pattern is flattened by a roller structure 40 and the thickness of each layer is strictly defined. Figure 4 In the figure, 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 made transparent in the figure, rather than indicating that the structure formed by the nanoparticle structure material ink a is formed on the surface of the structure formed by the support material ink b.

[0061] After printing is completed, the printed sample structure (a+b) is freeze-dried in situ, that is, a cover body with connected pipelines is loaded on the carrier and evacuated to make the printing environment pressure inside the cover body less than 1Pa. A transparent window is designed above the cover body to facilitate the observation of the sublimation shrinkage process with the first microscope. During the sublimation process, the support material is completely sublimated, and the solvent in the structural material is partially sublimated, so that the printed sample structure shrinks proportionally, further reducing the feature size, referring to Figure 4 Iiiiiii in.

[0062] Embodiment 2:

[0063] The printing process can be expanded to a multi-material printing process, with nanosilver ink and PEDOT:PSS ink as nanoparticle structure material inks. The configuration is as follows: Nanosilver ink: 80g water, 20g tert-butyl alcohol, 0.01g nanosilver powder, 0.01g glycerol are prepared into a uniform ink through an ultrasonic machine and a mixer, and filtered through a 5-micron filter. PEDOT:PSS ink: 80g water, 20g tert-butyl alcohol, 0.01g PEDOT:PSS powder, 0.01g glycerol are prepared into a uniform ink through an ultrasonic machine and a mixer, and filtered through a 5-micron filter.

[0064] A mixture of water and tert-butanol was used as the supporting material ink, and the configuration was as follows: 80 g of water and 20 g of tert-butanol were prepared into a uniform ink by an ultrasonic machine and a mixer.

[0065] refer to Figure 5 As shown, the configured nanoparticle structure material ink (a / c) and support material ink (b) are printed on a low-temperature carrier through a nozzle structure 31 (the nozzle structure includes three nozzles), wherein the temperature of the carrier is controlled to be minus 50 degrees Celsius. During the printing process, the nozzle state of the nozzle is dynamically detected by a second microscope device. Afterwards, the surface of each layer of the pattern is flattened by a roller structure and the thickness of each layer is strictly defined.

[0066] After printing is completed, the printed sample structure is freeze-dried in situ, that is, a cover body with connected pipelines is loaded on the carrier and evacuated to make the printing environment pressure inside the cover body less than 1Pa. A transparent window is designed above the cover body to facilitate the observation of the sublimation shrinkage process by the first microscope; during the sublimation process, the support material is completely sublimated, and the solvent in the structural material is partially sublimated, so that the printed sample structure shrinks proportionally, further reducing the feature size. After sublimation, nanosilver and PEDOT:PSS will form a tightly 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 invention can reduce the cooling temperature of the carrier platform by refrigerating the carrier platform, thereby minimizing the size of ice crystals formed in the sample on the carrier platform and improving the structural quality of the final required sample.

[0068] According to the low-temperature cold field assisted nanoparticle 3D printing device and printing method of the embodiment of the present invention, multiple nozzles are set to spray nanoparticle structural materials and supporting materials. Due to the addition of supporting materials, the flow of nanoparticle structural materials-ink droplets on the surface of the unfinished sample before freezing can be avoided to a certain extent, thereby allowing complex three-dimensional structures to be printed more freely.

[0069] According to the low-temperature cold field assisted nanoparticle 3D printing device and printing method of the embodiment of the present invention, by setting a roller structure, the height of each layer of graphics in the complete sample is accurately defined, and the surface of each layer is flattened so that the subsequently ejected material can land on a flat substrate.

[0070] According to the low-temperature cold field assisted nanoparticle 3D printing device and printing method of the embodiment of the present invention, in-situ freeze drying is achieved on the support platform, thereby avoiding the risk of damaging the complete sample when transferring the complete sample to the freeze dryer after printing, and avoiding the risk of internal tissue damage of the sample due to temperature field changes during sample transfer.

[0071] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A low temperature cold field assisted nanoparticle 3D printing device, characterized in that: include: a housing having a chamber formed therein; A carrying platform is arranged in the chamber, the carrying platform has a carrying surface, and the carrying platform can be controlled to keep its carrying surface within a certain temperature range; A printing component is arranged in the chamber, and the printing component includes a nozzle structure that can move relative to the supporting platform. The nozzle structure includes a plurality of nozzles, and the plurality of nozzles are respectively used to spray nanoparticle structure materials and support materials onto the supporting surface.

2. The low temperature cold field assisted nanoparticle 3D printing device according to claim 1, characterized in that: It also includes a roller structure, which is arranged parallel to the bearing surface of the bearing platform, and the roller structure is arranged to be able to rotate and move relative to the bearing surface to controllably flatten the printing material on the bearing surface.

3. The low temperature cold field assisted nanoparticle 3D printing device according to claim 1, characterized in that: It also includes a cover body, which can be separated from the bearing platform. When the cover body is set on the bearing platform, a sealed space for accommodating printing materials can be formed between the cover body and the bearing surface.

4. The low temperature cold field assisted nanoparticle 3D printing device according to claim 3, characterized in that: The cover body is connected with a pipeline, and the pipeline can be communicated with an external vacuum pump mechanism to form the enclosed space between the cover body and the bearing surface. The enclosed space is used for the freeze-drying process after printing is completed.

5. The low temperature cold field assisted nanoparticle 3D printing device according to claim 1, characterized in that: A coolant flow channel is designed inside the carrying platform, and a pipeline connected to the coolant flow channel is connected to the carrying platform, and the pipeline can be connected to an external refrigeration mechanism to keep the carrying surface within a certain temperature range; and / or; The low-temperature cold field assisted nanoparticle 3D printing device also includes a second moving structure, the carrying platform is arranged on the second moving structure, and the second moving structure is configured to enable the carrying platform to move in a vertical direction.

6. The low temperature cold field assisted nanoparticle 3D printing device according to claim 1, characterized in that: The printing assembly further comprises a first movable structure, the nozzle structure is arranged on the first movable structure, and the first movable structure is arranged to enable the nozzle structure to move relative to the supporting platform in a horizontal direction.

7. The low temperature cold field assisted nanoparticle 3D printing device according to claim 6, characterized in that: It also includes a monitoring structure, which is arranged on the first movable structure and includes a first microscope for observing the supporting platform and a second microscope for observing the injection head.

8. A method for printing 3D nanoparticles, using the low-temperature cold field assisted nanoparticle 3D printing device as described in any one of claims 2 to 7, characterized in that: include: configuring nanoparticle structural materials and supporting materials; Control the platform to maintain a temperature below 0°C; The chamber is filled with an inert gas; Control the nozzle structure to spray the nanoparticle structure material and the support material layer by layer on the carrier. After each layer is sprayed, the sample to be completed is flattened until the complete sample is completed. The intact sample is freeze-dried in situ to form the desired sample structure.

9. The method for printing 3D nanoparticles according to claim 8, characterized in that: The support platform is controlled to maintain a temperature of minus 40° C. or lower than minus 40° C.

10. The method for printing 3D nanoparticles according to claim 8, characterized in that: The in-situ freeze drying of the complete sample comprises: Controlling the bearing platform to maintain a temperature of minus 40°C or lower than minus 40°C; placing a cover on the carrier to cover the complete sample; The atmospheric pressure in the sealed space between the cover body and the supporting platform is controlled to be less than 1Pa.

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