A liquid film evaporation graphic printing method and device driven by gas jet

Abstract

The present invention proposes a gas jet driven liquid film evaporation graphic printing method and device, which belongs to the field of printed electronics. It is a technology based on gas jet to drive, cut and punch solution / ink liquid film, based on the "coffee ring" formation principle, assisted by evaporation-induced self-assembly at the three-phase contact line, and guided by a three-axis motion mechanism, so as to realize the manufacturing of functional lines and patterns. The present invention can realize high-precision, low-cost printing and printing based on volatile solution / ink system, without the problem of needle blocking in inkjet technology, and is expected to be widely used in the manufacture of patterned optoelectronic thin film structures.

Description

Technical Field

[0001] The invention belongs to the field of printed electronics, and in particular relates to a liquid film evaporation graphic printing method and device driven by a gas jet. Background Art

[0002] Printed electronics technology is to deposit functional solutions / inks on the surface of substrates by additive methods to form circuits and graphics with functions such as conductivity. It has the advantages of large area, high throughput, green environmental protection, low cost, flexibility, etc., and has shown unprecedented application potential in flexible electronics and sensor manufacturing. Among them, inkjet printing is a non-contact digital printing technology that does not require a mask. It is regarded as a highly promising printed electronics technology and shows great prospects in the fields of flexible printed electronics such as conductive circuits, OLEDs, and photovoltaic cells. However, inkjet printing technology is very easy to cause needle blockage, and its printing line width resolution is about 100 microns. In addition, my country's inkjet print heads are currently mainly imported. In addition, for electrofluidic printing technology, although its line width can be less than 10 microns, it is difficult to promote it in industrial applications because it requires a high voltage electric field to work and has low printing efficiency. Obviously, the booming field of flexible printed electronics urgently needs to develop new low-cost and high-precision printing technologies to achieve more sophisticated cross-scale manipulation and assembly of functional solutions / ink systems to achieve higher precision and higher quality printed circuits and graphic structures. This has also become an important challenge facing the current printed electronics manufacturing field. Summary of the invention

[0003] In response to the problems of needle clogging and difficult process control in traditional digital inkjet printing technology, the present invention proposes a gas jet-driven liquid film evaporation graphic printing method and device, which is a technology based on gas jet to drive, cut and punch solution / ink liquid film, based on the "coffee ring" formation principle, assisted by evaporation-induced self-assembly at the three-phase contact line, and guided by a three-axis motion mechanism, thereby realizing the manufacture of functional lines and patterns.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A gas jet driven liquid film evaporation graphic printing method comprises the following steps:

[0006] Step 1: Place the printed substrate horizontally in a liquid pool, pour a volatile functional solution into the liquid pool until the printed substrate is completely immersed, and the functional solution forms a two-dimensional thin liquid film on the surface of the printed substrate;

[0007] Step 2: Introduce compressed air into the pipeline, set a pressure regulating and flow monitoring module in the pipeline, and connect a micro-air needle at the end of the pipeline to focus the airflow through the micro-air needle, and finally form a stable gas jet with continuously adjustable and controllable flow rate and flow at the outlet of the micro-air needle;

[0008] Step 3, the focused gas flow at the outlet of the micro-gas needle is incident on the two-dimensional thin liquid film, and the two-dimensional thin liquid film is opened under the forced action of the gas jet to form a circular pore;

[0009] Step 4: the gas jet and the two-dimensional thin liquid film are made to move relative to each other along a planned graphical path, and the circular pores caused by the gas jet move, that is, the two-dimensional thin liquid film is cut by the gas flow, and the solute particles in the two-dimensional thin liquid film are self-assembled and solidified under the evaporation-induced effect of the cut edge to form a specific patterned structure;

[0010] Step 5: Take out the printed substrate from the liquid pool, clean the residual liquid film on the surface of the printed substrate that has not evaporated, and observe the fine lines and patterned structures formed on the surface of the printed substrate.

[0011] Furthermore, the method further includes repeating steps 1 to 5 multiple times according to requirements to form a multi-layer structure.

[0012] Furthermore, the method also includes sintering the processed samples according to needs.

[0013] The present invention also provides a gas jet driven liquid film evaporation graphic printing device, comprising a liquid film fine-tuning module, a gas jet driving and monitoring module and a three-dimensional displacement stage module; the liquid film fine-tuning module is fixed on the XY plane of the three-dimensional displacement stage module; the airflow outlet component of the gas jet driving and monitoring module is installed on the Z axis of the three-dimensional displacement stage module; the liquid film fine-tuning module connects the liquid pool and the liquid storage tank through a precision pressure pump, and digitally controls the precision pressure pump to achieve precise regulation of the thickness of the two-dimensional thin liquid film in the liquid pool; or through a precision lifting platform, the thickness of the two-dimensional thin liquid film is adjusted by controlling the height of the printing substrate; the gas jet driving and monitoring module achieves stable gas jet output through a precision air pump and a flowmeter, and the airflow pressure is adjustable and the flow rate is monitorable; the three-dimensional displacement stage module includes an X-axis slide, a Y-axis slide, and a Z-axis slide, and realizes the three-dimensional relative motion path of the two-dimensional thin liquid film and the gas jet through digital programming.

[0014] Furthermore, the solution includes a functional solution system suitable for a solvent that is a volatile liquid and a colloid system containing a dispersant that is a volatile liquid. The functional solution system suitable for a solvent that is a volatile liquid includes a functional nanomaterial solution, and the functional nanomaterial solution includes a conductive nanosilver particle aqueous solution and a nanogold particle aqueous solution; the colloid system containing a dispersant that is a volatile liquid includes a colloid system with polymers, inorganic materials, and metal materials as dispersed substances, and the colloid system includes water-based polystyrene colloids and water-based silica colloids.

[0015] Furthermore, the airflow is a gas jet driven by a precision air pump and focused by micro-air needles with different inner diameters; the airflow is heated and temperature-controlled by installing a heating module on the micro-air needle; the airflow and the two-dimensional thin liquid film move according to a relative motion path planned by the software, and the two-dimensional thin liquid film cutting is achieved through the control of the three-dimensional displacement stage module.

[0016] Furthermore, the substrate of the two-dimensional thin liquid film is loaded with a heating module to heat the two-dimensional thin liquid film, thereby modulating the evaporation self-assembly process of the pore edge to achieve the regulation of the graphic structure.

[0017] Furthermore, a micro-gas needle is arranged at the gas outlet of the gas jet driving and monitoring module, the micro-gas needle is connected to one end of the gas pipeline, and a precision air pump is arranged at the other end of the gas pipeline; a flow meter is arranged on the gas pipeline.

[0018] Beneficial effects:

[0019] The present invention can achieve high-precision, low-cost printing and printing based on a volatile solution / ink system, without the problem of needle clogging in inkjet technology, and is expected to be widely used in the manufacture of patterned optoelectronic thin film structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an overall structural diagram of a gas jet-driven liquid film evaporation graphic printing device of the present invention;

[0021] Figure 2 This is the module diagram for fine-tuning the liquid film;

[0022] Figure 3 This is a schematic diagram of the gas jet driving and monitoring module;

[0023] Figure 4 It is a schematic diagram of a three-dimensional translation stage module;

[0024] Figure 5 This is the photonic crystal strip diagram printed out in Example 1. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] The present invention provides a liquid film evaporation graphic printing method driven by a gas jet, comprising the following steps:

[0027] Step 1: Place the printed substrate horizontally in a liquid pool, then pour a volatile functional solution into the liquid pool until the printed substrate is completely immersed, and the functional solution forms a two-dimensional thin liquid film on the surface of the printed substrate.

[0028] Step 2: Introduce compressed air into the pipeline, set up a pressure regulation and flow monitoring module in the pipeline, and connect a micro-air needle to the end of the pipeline to focus the airflow through the micro-air needle, and finally form a stable gas jet with continuously adjustable and controllable flow rate and flow at the outlet of the micro-air needle.

[0029] Step 3: The focused gas flow at the outlet of the micro-gas needle is incident on the two-dimensional thin liquid film. Under the forced action of the gas jet, the two-dimensional thin liquid film is opened and a circular pore is formed.

[0030] Step 4: Make the gas jet and the two-dimensional thin liquid film move relative to each other along the planned graphical path. The circular pores caused by the gas jet move, that is, the two-dimensional thin liquid film is cut by the airflow. The solute particles in the two-dimensional thin liquid film will self-assemble and solidify under the evaporation-induced effect of the cutting edge to form a specific patterned structure.

[0031] Step 5: Take out the printed substrate from the liquid pool and clean off the residual liquid film on the surface that has not evaporated. Fine lines and patterned structures formed on the surface of the printed substrate can be observed.

[0032] Preferably, the method further comprises: repeating steps 1 to 5 multiple times according to requirements to form a multi-layer structure.

[0033] Preferably, the method further includes: as required, the processed samples can be subjected to post-processing such as sintering to further optimize the structural performance.

[0034] like Figure 1 As shown, based on the above method, the present invention also proposes a gas jet driven liquid film evaporation graphic printing device, which at least comprises a liquid film fine-tuning module, a gas jet driving and monitoring module and a three-dimensional displacement stage module. The liquid film fine-tuning module is fixed on the XY plane of the three-dimensional displacement stage module; the airflow outlet component of the gas jet driving and monitoring module is installed on the Z axis of the three-dimensional displacement stage module.

[0035] like Figure 2 As shown, the liquid film micro-adjustment module mainly connects the liquid pool to the liquid storage tank through a precision pressure pump, and digitally controls the amount of flow pumped out by the precision pressure pump to achieve precise control of the thickness of the thin liquid film in the liquid pool; the thickness of the thin liquid film can also be adjusted by controlling the height of the base through a precision lifting platform.

[0036] like Figure 3 As shown, the gas jet driving and monitoring module mainly realizes the output of stable gas jet through a precision air pump and a flow meter, and the air flow pressure is adjustable and the flow rate is monitorable. A micro-air needle is arranged at the air outlet of the gas jet driving and monitoring module, and the micro-air needle is connected to one end of the gas pipeline, and a precision air pump is arranged at the other end of the gas pipeline. A flow meter is arranged on the gas pipeline.

[0037] like Figure 4 As shown, the three-dimensional displacement stage module includes an X-axis slide, a Y-axis slide, and a Z-axis slide, and its main function is to realize the required three-dimensional relative motion path of the thin liquid film and the gas jet through digital programming. The three slide positions can be arbitrarily combined to realize the three-dimensional motion of the micro-gas needle.

[0038] Preferably, the types of the solution include but are not limited to: a functional solution system suitable for a solvent that is a volatile liquid, including various functional nanomaterial solutions, such as a conductive nanosilver particle aqueous solution, a nanogold particle aqueous solution, etc.; a colloid system including a dispersant that is a volatile liquid, including a colloid system with polymers, inorganic materials, metal materials, etc. as dispersed substances, such as water-based polystyrene colloids, water-based silica colloids, etc.

[0039] Preferably, the airflow is a gas jet driven by a precision air pump and focused by micro-air needles with different inner diameters; the airflow can be heated and temperature-controlled by installing a heating module on the micro-air needle; the airflow and the two-dimensional thin liquid film move according to the relative motion path planned by the software, and the thin liquid film cutting is achieved by controlling the three-dimensional displacement stage module;

[0040] Preferably, the substrate of the two-dimensional thin liquid film can be loaded with a heating module to heat the thin liquid film, thereby modulating the evaporation self-assembly process at the pore edge to achieve regulation of the graphic structure.

[0041] The physical principle used in the present invention is the "coffee ring" effect, that is, the solution at the edge of the circular pore of the two-dimensional thin liquid film, i.e., near the three-phase contact line, evaporates fastest, and a capillary flow toward the edge is formed inside the liquid film. The solute particles are carried to the edge by this capillary flow and deposited, resulting in a solidification effect.

[0042] Embodiment 1

[0043] Aqueous solutions of 100-nanometer polystyrene microspheres are often used as model systems to study issues related to evaporative self-assembly. First, the size of the solute particles is comparable to that of the printed solution below, and second, the orderly arranged microsphere particles can present a photon band gap in the visible light band due to Bragg diffraction, and the quality of the assembled structure can be intuitively judged by observing the color with the naked eye. Therefore, Example 1 uses an aqueous solution of polystyrene microspheres for demonstration.

[0044] A polystyrene microsphere aqueous solution with a diameter of 265 nm was selected and diluted with pure water to 0.1 wt %, and the diluted solution was poured into a liquid storage tank in the droplet fine-tuning module.

[0045] Place a clean glass substrate horizontally in the liquid pool, turn on the precision pressure pump, and allow the solution in the liquid reservoir to slowly enter the liquid pool and cover the glass substrate. Adjust the precision pressure pump so that the thickness of the thin liquid film above the glass substrate is controlled to about 1 mm.

[0046] Start the three-dimensional translation stage module and slowly move the micro-gas needle on the Z-axis slide until the outlet is about 5 mm away from the liquid surface. The inner diameter of the micro-gas needle is 0.16 mm.

[0047] The program sets the running speed to 1m / s, the printing spacing to 1mm, and the line length to 5cm.

[0048] Adjust the pressure regulating valve on the precision air pump to control the pressure in the gas pipeline at 0.2 bar. Turn on the precision air pump.

[0049] Run the program stored in the controller of the three-dimensional translation stage module to start working.

[0050] The airflow first blows toward the glass substrate, forming a circular hole on the two-dimensional thin liquid film on the glass substrate. As the micro-air needle gradually moves, the circular hole gradually changes into a long strip. Due to the "coffee ring" effect, the evaporation rate at the edge of the hole is much higher than that in other liquid film areas, so a capillary flow is formed inside the liquid film to flow toward the edge of the hole. The solute particles are transported to the edge of the hole with the capillary flow, and assembled-deposited. After the airflow runs over, it will return again under the control of the program to blow away the liquid near the original hole edge deposit. At this time, a microstrip structure of a photonic crystal is formed. The airflow moves back and forth many times to form multiple microstrips.

[0051] After the program is completed, adjust the precision pressure pump to allow the liquid pool to return the solution to the storage tank.

[0052] Slowly remove the glass substrate from the liquid bath and clean off any residual liquid.

[0053] When the glass substrate is placed under a microscope, the following structure can be observed: line width 20μm, line spacing 200μm. The light color indicates that the particle structure is neatly arranged, because the individual microspheres are white, this color is the structural color, such as Figure 5 shown.

Claims

1. A gas jet driven liquid film evaporation graphic printing method, characterized in that: The steps include: Step 1: Place the printed substrate horizontally in a liquid pool, pour a volatile functional solution into the liquid pool until the printed substrate is completely immersed, and the functional solution forms a two-dimensional thin liquid film on the surface of the printed substrate; Step 2: Introduce compressed air into the pipeline, set a pressure regulating and flow monitoring module in the pipeline, and connect a micro-air needle at the end of the pipeline to focus the airflow through the micro-air needle, and finally form a stable gas jet with continuously adjustable and controllable flow rate and flow at the outlet of the micro-air needle; Step 3, the focused gas flow at the outlet of the micro-gas needle is incident on the two-dimensional thin liquid film, and the two-dimensional thin liquid film is opened under the forced action of the gas jet to form a circular pore; Step 4: the gas jet and the two-dimensional thin liquid film are made to move relative to each other along a planned graphical path, and the circular pores caused by the gas jet move, that is, the two-dimensional thin liquid film is cut by the gas flow, and the solute particles in the two-dimensional thin liquid film are self-assembled and solidified under the evaporation-induced effect of the cut edge to form a specific patterned structure; Step 5: Take out the printed substrate from the liquid pool, clean the residual liquid film on the surface of the printed substrate that has not evaporated, and observe the fine lines and patterned structures formed on the surface of the printed substrate.

2. The method for liquid film evaporation graphic printing driven by gas jet according to claim 1, characterized in that: The method further comprises repeating steps 1 to 5 for multiple times to form a multi-layer structure.

3. The method for liquid film evaporation graphic printing driven by gas jet according to claim 2, characterized in that: It also includes sintering the processed samples.

4. A gas jet driven liquid film evaporation graphic printing device, characterized in that: The invention comprises a liquid film fine-tuning module, a gas jet driving and monitoring module and a three-dimensional displacement stage module; the liquid film fine-tuning module is fixed on the XY plane of the three-dimensional displacement stage module; the airflow outlet assembly of the gas jet driving and monitoring module is installed on the Z axis of the three-dimensional displacement stage module; a micro-gas needle is arranged at the air outlet of the gas jet driving and monitoring module, the micro-gas needle is connected to one end of the gas pipeline, and a precision air pump is arranged at the other end of the gas pipeline; a flow meter is arranged on the gas pipeline; the airflow is a gas jet driven by a precision air pump and focused by micro-gas needles with different inner diameters; the airflow is heated by installing a heating module on the micro-gas needle. Heat and temperature control; the liquid film micro-adjustment module connects the liquid pool and the liquid storage tank through a precision pressure pump, and digitally controls the precision pressure pump to achieve precise regulation of the thickness of the two-dimensional thin liquid film in the liquid pool; or the liquid film micro-adjustment module adjusts the thickness of the two-dimensional thin liquid film by controlling the height of the printing substrate through a precision lifting platform; the gas jet driving and monitoring module achieves stable gas jet output through a precision air pump and a flowmeter, and the airflow pressure is adjustable and the flow rate is monitorable; the three-dimensional displacement stage module includes an X-axis slide, a Y-axis slide, and a Z-axis slide, and realizes the three-dimensional relative motion path of the two-dimensional thin liquid film and the gas jet through digital programming.

5. The gas jet driven liquid film evaporation graphic printing device according to claim 4, characterized in that: The functional solution for forming the two-dimensional thin liquid film is a volatile solvent in which functional particles are dispersed, and the functional particles include metal nanoparticles, carbon-based nanomaterials, insulating nanoparticles, inorganic semiconductor nanoparticles, organic semiconductor nanoparticles, organic-inorganic hybrid semiconductor nanoparticles, and biomacromolecules; the volatile solvent includes water, hydrocarbon solvents, alcohol solvents, ether solvents, halogenated hydrocarbon solvents, ketone solvents, ester solvents, acid and alkali solvents, ammonia and ammonia solvents, and sulfur compound solvents.

6. The gas jet driven liquid film evaporation graphic printing device according to claim 4, characterized in that: The substrate of the two-dimensional thin liquid film is loaded with a heating module to heat the two-dimensional thin liquid film, thereby modulating the evaporation self-assembly process of the pore edge to achieve the regulation of the graphic structure.

7. The gas jet driven liquid film evaporation graphic printing device according to claim 5, characterized in that: Metal nanoparticles include gold, silver, and copper; carbon-based nanomaterials include graphene, carbon nanotubes, and conductive carbon black; insulating nanoparticles include silicon dioxide and titanium dioxide; inorganic semiconductor nanoparticles include copper selenide, zinc sulfide, molybdenum disulfide, and MXene; organic semiconductor nanoparticles include polystyrene and polythiophene; organic-inorganic hybrid semiconductor nanoparticles include perovskite quantum dots; and biological macromolecules include cells, DNA, and proteins.

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