Local induction electrofluid jet printing manufacturing device and method

Abstract

The invention discloses a local induction electrofluid jet printing manufacturing device and method, and the method comprises the steps: carrying out the local surface pretreatment of a substrate, enabling sheath gas to change the local surface energy through the specific binding of a local induction nozzle and a pretreatment region, forming a hydrophobic region, and enabling an untreated region to be a hydrophilic region; meanwhile, electric field force is applied to functional material ink in a spray head, micro-nano-scale jet flow is formed based on the electrohydrodynamic effect and electrojet, printing forming is conducted on a hydrophilic area on a substrate by means of the hydrophilicity of the material, bending and deviation areas in the printing process can be self-assembled to the hydrophilic area from a hydrophobic area under the surface energy regulation and control effect, and printing forming is achieved. The process is real-time, real-time high-precision high-efficiency positioning printing of electrofluid jet printing is realized, the problems of poor printing repeatability, incapability of positioning deposition, difficulty in patterning and the like caused by factors such as jet flow whipping and residual charges in traditional printing are solved, and the characteristic size of a functional unit can be reduced by virtue of the advantage of electrojet high-resolution printing.

Description

Technical Field

[0001] The invention belongs to the field of advanced manufacturing technology, and in particular relates to a local induced electrofluid printing manufacturing device and method. Background Art

[0002] Electrofluidic printing is a new type of inkjet printing technology. Traditional inkjet printing technology uses extrusion to squeeze the solution out of the nozzle, while electrofluidic printing uses the strong electric field between the nozzle and the substrate to deposit the solution onto the substrate in a "pulling" manner through the electric field drive. During the electrofluidic printing process, the strong electric field applied between the nozzle and the substrate causes an induced charge to form on the curved liquid surface at the front end of the nozzle, which is then affected by the electric field force. Under the action of the electric field force, surface tension and gravity, a Taylor cone is formed on the liquid surface, and a jet is generated from the cone tip. This technology can effectively overcome the resolution limitation of nozzle size in inkjet printing and extrusion printing, and is compatible with a variety of ink materials, such as polymer semiconductors, piezoelectric materials, conductive silver pastes and biomaterials, and can be widely used in aerospace, biomedicine, electronic information and other fields.

[0003] Functional materials rely on electric field forces to form cone jets. Therefore, during the electrofluid printing process, the materials that have been printed on the substrate will carry residual charges of corresponding density. As the material accumulates on the substrate, the density of the residual charges increases. The polarity of the residual charges is the same as the polarity of the charges on the electrojet interface. Coulomb repulsion is generated between charges of the same polarity. This Coulomb repulsion will cause the jet to whip. As the residual charge density increases, the whipping phenomenon becomes more serious, which leads to a decrease in the jet stability and print structure consistency during the printing process. At present, the main method to improve printing stability and consistency is to add an annular electrode to the nozzle. By adding an annular electrode with a voltage lower than the nozzle between the nozzle and the substrate, this method can significantly reduce the voltage between the electrode ring and the substrate, and reduce the influence of substrate polarization on printing. However, the electric field formed between the nozzle and the annular ground electrode has a radial component pointing to the annular electrode. The ejected charged jet is very easy to print on the annular electrode, resulting in an inability to accurately print on the substrate. Summary of the invention

[0004] In order to solve the problems of the prior art, the present invention provides a local induced electrofluid printing manufacturing device and method.

[0005] The device of the present invention is used for local induced electrofluid printing manufacturing. First, the substrate is pretreated locally on the surface. The local induced material (i.e., sheath gas) is specifically combined with the pretreated area through the nozzle (physical and chemical effects), and its local surface energy is changed to form a hydrophobic area. The untreated area is a hydrophilic area. At the same time, the electric field force is applied to the functional material ink in the nozzle. Based on the electrofluidic effect, the electrojet forms a micro-nanoscale jet. The hydrophilicity of the material is used to print and form the hydrophilic area on the substrate. The bending and offset areas of the printing process will self-assemble from the hydrophobic area to the hydrophilic area under the surface energy regulation, so as to achieve high-precision deposition of the printed structure. The present invention realizes the local surface energy follow-up regulation of the printed substrate, solves the problems of poor printing repeatability, inability to locate deposition, and difficulty in patterning caused by the whipping of the traditional printing jet, and with the advantage of high-resolution printing of electrojet, the characteristic size of the functional unit can be reduced.

[0006] Specifically, firstly, the surface of the non-printing area of ​​the substrate is pretreated so that it can specifically bind to the sheath gas; the sheath gas is introduced into the pressure-regulating gas pump through the high-pressure gas cylinder, and the pressure-regulating pump drives the sheath gas into the outer nozzle of the local induction nozzle, and the functional material ink is pushed into the inner nozzle of the local induction nozzle by the micro-injection pump. Under the push of air pressure and mechanical pressure, the functional material ink and the sheath gas flow out from the inner nozzle and the outer nozzle of the local induction nozzle respectively at the same time, and flow out from the nozzle port under the action of the electric field to form a stable fine jet, and the sheath gas specifically binds to the pre-treated area of ​​the substrate to change the pre-treated area. The local surface energy changes the pre-treated area from hydrophilic to hydrophobic, while the untreated area remains hydrophilic, eventually forming hydrophilic and hydrophobic regions with different surface energy on the substrate; the motion module drives the substrate to move, and the jet infiltrates the hydrophilic area on the substrate and repels the hydrophobic area; during the printing process, the jet bending and position shift caused by residual charge and electric field crosstalk will self-assemble from the hydrophobic area to the hydrophilic area under the control of surface energy, so that all printing layers are accurately deposited in the untreated area, and the process is real-time, which can realize real-time, high-precision and efficient positioning printing of electrofluidic printing.

[0007] In order to achieve the above object, the specific technical solution adopted by the present invention is as follows:

[0008] A local induced electrofluid printing manufacturing device, comprising an electrofluid printing module, a control module and a local induced surface energy regulation module;

[0009] The electrofluid printing module includes a high-pressure gas cylinder and a local induction nozzle, wherein the high-pressure gas cylinder contains sheath gas, and the local induction nozzle contains an inner nozzle needle and an outer nozzle needle. The pressure gas cylinder is connected to one end of a pressure regulating gas pump through a corrosion-resistant conduit a, and the other end of the pressure regulating gas pump is connected to the outer nozzle needle through a corrosion-resistant conduit b, and the inner nozzle needle is located inside the outer nozzle needle. The module also includes a micro-injection pump and a high-voltage power supply, and an injector is fixedly mounted on the micro-injection pump, and the functional material ink is contained inside the injector, and the injector is connected to the inner nozzle needle through a quartz conduit.

[0010] The local induced surface energy regulation module includes a printing substrate, which is fixed on an XY motion module. The positive output end of the high-voltage power supply is connected to the local induced nozzle, and the negative electrode is connected to the printing substrate, so that a stable electric field is formed between the local induced nozzle and the printing substrate; the outer wall of the inner nozzle is hydrophobicized to effectively prevent the material from climbing along the outer wall.

[0011] Furthermore, the control module includes a host computer, which is connected to the positioning camera, observation camera and XY motion module through wires respectively. The positioning camera is connected to the local induction nozzle through a connecting rod to ensure that the distance between the positioning camera and the local induction nozzle is equal. One end of the XY motion module is grounded.

[0012] Furthermore, the printing substrate is made of silicon wafer or metal.

[0013] Furthermore, the tip of the outer spray needle is ground flat using a needle grinder, and the inner side is finely ground into a cone, the length of the cone area is 0.5 mm, and the cone angle is 60°, so as to facilitate the focusing of the sheath gas on the fine jet.

[0014] Furthermore, the material of the functional material ink is one of piezoelectric material, semiconductor polymer material and silver sol.

[0015] Furthermore, the inner diameter of the inner spray needle is 60-200 μm, the inner diameter of the outer spray needle is 400-800 μm, and the inner spray needle and the outer spray needle are coaxially arranged; the inner diameter of the quartz tube is 150-200 μm, and the outer diameter is 350-400 μm.

[0016] Furthermore, the injector range is 10-500 μL; the injector flow rate is 0.01-1 μL / min.

[0017] Furthermore, the movement speed range of the XY motion module is 0.001-400mms -1 The high voltage power supply provides a voltage of 400-5000V to the local induction nozzle.

[0018] Furthermore, the air pressure range of the pressure regulating air pump is 1-50 Pa.

[0019] A local induced electrofluid printing manufacturing method, the steps are as follows:

[0020] S1: Modified substrate surface;

[0021] S2: forming a fine jet of electrospray printing;

[0022] S3: Precise deposition of printed layers;

[0023] S4: forming a self-assembled deposition structure.

[0024] Furthermore, step S1 is specifically as follows:

[0025] The mask is placed above the printing substrate for pretreatment. The light-transmitting part of the mask is the pretreatment area, and the light-shielding part is the untreated area. The pretreatment area is roughened by a laser to increase the surface roughness of the area, forming a rough / smooth interval. Subsequently, the pressure-regulating air pump is turned on, and the sheath gas with surface modification function enters the pressure-regulating air pump from the high-pressure gas cylinder through the corrosion-resistant conduit a, and the pressure in the pressure-regulating air pump reaches stability. The pressure and time of the pressure-regulating air pump are set, and then the sheath gas enters the outer spray needle from the corrosion-resistant conduit b and is sprayed out at the bottom nozzle of the outer spray needle. The sheath gas combines with the pretreatment area on the printing substrate to modify the surface energy of this area, so that the surface energy of this area changes from hydrophilic to hydrophobic, while the untreated area remains hydrophilic. The host computer controls the movement of the XY motion module, thereby driving the printing substrate to move, and the next pretreatment area is then treated to be hydrophobic, forming an interval between the hydrophilic and hydrophobic areas.

[0026] Furthermore, step S2 is specifically as follows:

[0027] A high-voltage power supply applies voltage to the local induction nozzle. The functional material ink flows from the injector through the quartz conduit to the inner nozzle of the local induction nozzle under the push of the micro-injection pump. The distance between the local induction nozzle and the printing substrate is adjusted according to the inner diameter of the inner nozzle, the viscosity of the functional material ink and the material of the printing substrate, so that the distance between the end of the local induction nozzle and the printing substrate is in the range of 0.2 to 1 mm. Under the action of the electric field and the gravity field, a stable Taylor cone is formed at the outlet of the inner nozzle, and a stable fine jet is generated.

[0028] Furthermore, step S3 is specifically as follows:

[0029] The host computer controls the movement of the XY motion module, calculates the starting position of the fine jet based on the distance between the positioning camera and the local induction nozzle, and then accurately prints on the untreated area of ​​the printing substrate to form a printing layer. The observation camera transmits the printing conditions of the printing layer and the fine jet in the field of view to the host computer in real time, and the forming process is detected by the host computer.

[0030] Furthermore, step S4 is specifically as follows:

[0031] During the forming process, the printed layer cannot be accurately printed in the untreated area due to factors such as charge accumulation, electric field crosstalk, and motion errors; the untreated area is still hydrophilic after combining with the sheath gas, and the surface energy of the pretreated area changes after combining with the sheath gas, becoming a hydrophobic modified area. There is a surface energy difference between the hydrophilic and hydrophobic interfaces. When the printed layer is printed in the hydrophobic modified area, it will self-assemble under the action of surface energy and move from the hydrophobic area to the hydrophilic untreated area, eventually forming a self-assembled deposition structure.

[0032] Beneficial effects of the present invention:

[0033] (1) The present invention proposes a local induced electrofluid printing manufacturing device and method, which realizes high-precision self-assembly and positioned deposition manufacturing of printed structures, realizes real-time linkage between surface modification and electrofluid printing, prints microstructures on modified substrates in real time, and realizes positioned deposition of structures through self-assembly.

[0034] (2) The present invention utilizes a surface modification method to achieve fast, accurate and efficient printing throughout the entire electrospray printing process. The surface energy difference of the printing substrate avoids the wetting and spreading of the printing droplets, thereby achieving large-area, high-positioning precision printing manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of a local induced electrofluid printing device;

[0036] Figure 2 Schematic diagram of local induced surface modification treatment;

[0037] Figure 3 Schematic diagram of surface energy driven self-assembly and positioned deposition of printed layers. DETAILED DESCRIPTION

[0038] The present invention is further described in conjunction with the technical scheme and the accompanying drawings.

[0039] Example 1

[0040] like Figure 1 As shown, a local induced electrofluid printing manufacturing device includes an electrofluid printing module, a control module and a local induced surface energy regulation module;

[0041] The electrofluid printing module includes a high-pressure gas cylinder 1 and a local induction nozzle 11, wherein the high-pressure gas cylinder 1 contains sheath gas 24, and the local induction nozzle 11 includes an inner spray needle 9 and an outer spray needle 8. The pressure gas cylinder 1 is connected to one end of the pressure regulating gas pump 3 through a corrosion-resistant conduit a2, and the other end of the pressure regulating gas pump 3 is connected to the outer spray needle 8 through a corrosion-resistant conduit b4. The inner spray needle 9 is located inside the outer spray needle 8. It also includes a micro-injection pump 5 and a high-voltage power supply 12. The micro-injection pump 5 is fixedly mounted with an injector 6, and the functional material ink 23 is contained in the injector 6. The injector 6 is connected to the inner spray needle 9 through a quartz conduit 7. The tip of the outer spray needle 8 is ground flat using a needle grinder, and the inner side is finely ground to a cone. The length of the cone area is 0.5 mm, and the cone angle is 60°, so as to facilitate the focusing of the sheath gas on the fine jet 22. The inner diameter of the corrosion-resistant conduit a2 is 500 μm.

[0042] The local induced surface energy regulation module includes a printing substrate 16, which is fixed on an XY motion module 17. The positive output end of the high-voltage power supply 12 is connected to the local induced nozzle 11, and the negative electrode is connected to the printing substrate 16, so that a stable electric field is formed between the local induced nozzle 11 and the printing substrate 16; the outer wall of the inner nozzle 9 is hydrophobicized to effectively prevent the material from climbing along the outer wall.

[0043] The control module includes a host computer 15, which is connected to the positioning camera 13, the observation camera 14 and the XY motion module 17 through wires. The positioning camera 13 is connected to the local induction nozzle 11 through a connecting rod to ensure that the distance between the positioning camera 13 and the local induction nozzle 11 is equal. One end of the XY motion module 17 is grounded.

[0044] The sheath gas 24 in the high-pressure gas cylinder 1 enters the pressure-regulating air pump 3 through the corrosion-resistant conduit a2, and after the pressure is stabilized, it enters the outer nozzle needle 8 of the local induction nozzle 11 through the corrosion-resistant conduit b4; the functional material ink 23 is filled in the injector 6, and the push handle of the micro-injection pump 5 pushes the injector 6 to feed accurately at a certain flow rate, and the functional material ink 23 enters the inner nozzle needle 9 of the local induction nozzle 11 through the quartz conduit 7; the positive output end of the high-voltage power supply 12 is connected to the local induction nozzle 11, and the negative electrode is connected to the printing substrate 16, forming a stable electric field between the local induction nozzle 11 and the printing substrate 16; the functional material ink 23 and the sheath gas 24 flow out from the nozzle outlet under the push of the micro-injection pump 5 and the pressure-regulating air pump 3, and at the same time, under the action of the electric field, the functional material ink 23 forms a stable Taylor cone 10 at the outlet of the inner nozzle needle 9, and further forms a jet 22.

[0045] The host computer 15 can control the positioning camera 13, the observation camera 14 and the XY motion module 17. The positioning camera 13 is used to realize the starting position positioning of the jet 22 on the printing substrate 16, and the observation camera 14 is used to detect the stability of the jet 22 in the printing area and the printing path of the printing layer 20; the XY motion module 17 can realize XY direction movement under the control of the host computer 15 to form various motion paths to meet various printing requirements.

[0046] Example 2

[0047] like Figure 2-3 As shown, a local induced electrofluid printing manufacturing method, the steps are as follows:

[0048] S1: Modified substrate surface

[0049] The mask is placed on the printing substrate 16 for pretreatment. The light-transmitting part of the mask is the pretreatment area 19, and the light-shielding part is the untreated area 18. The pretreatment area 19 is roughened by laser to improve the surface roughness of the area, forming a rough / smooth interval. Subsequently, the pressure-regulating air pump 3 is turned on, and the sheath gas 24 (fluorosilane) with surface modification function enters the pressure-regulating air pump 3 from the high-pressure gas cylinder 1 through the corrosion-resistant conduit a2, and the pressure in the pressure-regulating air pump 3 reaches a stable state. The pressure of the pressure-regulating air pump 3 is set to 5 Pa, and the fluorine Silane enters the outer spray needle 8 from the corrosion-resistant conduit b4, and then the sheath gas 24 enters the outer spray needle 8 from the corrosion-resistant conduit b4 and is sprayed out at the bottom nozzle of the outer spray needle 8. The sheath gas 24 combines with the pre-treated area 19 on the printing substrate 16 to modify the surface energy of this area, so that the surface energy of this area changes from hydrophilic to hydrophobic, while the untreated area 18 remains hydrophilic; the upper computer 15 controls the movement of the XY motion module 17, thereby driving the printing substrate 16 to move, and then treating the next pre-treated area 19 to be hydrophobic, forming an interval between the hydrophilic and hydrophobic areas.

[0050] The printing area is protected by a mask, and the non-printing area is pre-treated. The pre-treated area 19 can specifically bind to the sheath gas 24 , and the untreated area 18 does not react with the sheath gas 24 .

[0051] S2: Forming fine jets for electrospray printing

[0052] The high voltage power supply 12 applies a voltage of 3000V to the local induction nozzle 11, and the silver sol is loaded into the 100μL sample injector 6, and the flow rate is set to 1μL / min. The silver sol flows from the sample injector 6 through the quartz conduit 7 to the inner spray needle 9 of the local induction nozzle 11 under the push of the micro-injection pump 5, so that the distance between the end of the local induction nozzle 11 and the printing substrate 16 is 1mm. Under the action of the electric field and the gravity field, a stable Taylor cone 10 is formed at the outlet of the inner spray needle 9, and a stable fine jet 22 is generated;

[0053] S3: Precision deposition of printed layers

[0054] The host computer 15 controls the movement of the XY motion module 17, and calculates the starting position of the fine jet 22 according to the distance between the positioning camera 13 and the local induction nozzle 11, and then accurately prints on the untreated area 18 of the printing substrate 16 to form a printing layer 20. The observation camera 14 transmits the printing conditions of the printing layer 20 and the fine jet 22 in the field of view to the host computer 15 in real time, and the forming process is detected by the host computer 15.

[0055] S4: Formation of self-assembled deposition structure 25

[0056] During the forming process, due to factors such as charge accumulation, electric field crosstalk, and motion errors, the printed layer 20 cannot be accurately printed on the untreated area 18; the untreated area 18 is still hydrophilic after combining with the sheath gas, and the surface energy of the pre-treated area 19 changes after combining with the sheath gas 24, becoming a hydrophobic modified area 21. There is a surface energy difference between the hydrophilic and hydrophobic interfaces. When the printed layer 20 is printed on the hydrophobic modified area 21, it will self-assemble under the action of surface energy and move from the hydrophobic area to the hydrophilic untreated area 18, eventually forming a self-assembled deposition structure 25.

[0057] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A local induced electrofluid printing manufacturing device, characterized in that: It includes an electrofluid printing module, a control module and a local induced surface energy regulation module.

2. A local induction electrofluid printing manufacturing device as claimed in claim 1, characterized in that: The electrofluid printing module comprises a high-pressure gas cylinder (1) and a local induction nozzle (11), wherein the high-pressure gas cylinder (1) contains sheath gas (24), and the local induction nozzle (11) comprises an inner nozzle needle (9) and an outer nozzle needle (8), wherein the high-pressure gas cylinder (1) is connected to one end of a pressure regulating gas pump (3) through a corrosion-resistant conduit a (2), and the other end of the pressure regulating gas pump (3) is connected to the outer nozzle needle (8) through a corrosion-resistant conduit b (4), and the inner nozzle needle (9) is located inside the outer nozzle needle (8), and further comprises a micro-injection pump (5) and a high-voltage power supply (12), wherein an injector (6) is fixedly mounted on the micro-injection pump (5), wherein the functional material ink (23) is contained inside the injector (6), and the injector (6) is connected to the inner nozzle needle (9) through a quartz conduit (7).

3. A local induction electrofluid printing manufacturing device as claimed in claim 1, characterized in that The local induced surface energy control module comprises a printing substrate (16), the printing substrate (16) is fixed on an XY motion module (17), the positive output end of a high voltage power supply (12) is connected to a local induced nozzle (11), and the negative electrode is connected to the printing substrate (16), so that a stable electric field is formed between the local induced nozzle (11) and the printing substrate (16); and the outer wall of the inner nozzle needle (9) is subjected to a hydrophobic treatment.

4. A local induction electrofluid printing manufacturing device as claimed in claim 1, characterized in that The control module comprises a host computer (15), the host computer (15) is connected to a positioning camera (13), an observation camera (14) and an XY motion module (17) through wires, respectively; the positioning camera (13) is connected to a local induction nozzle (11) through a connecting rod to ensure that the distance between the positioning camera (13) and the local induction nozzle (11) is equal; and one end of the XY motion module (17) is grounded.

5. A local induced electrofluid printing manufacturing method, the method is based on the manufacturing device according to any one of claims 1 to 4, characterized in that: Here are the steps: S1: Modified substrate surface; S2: forming a fine jet of electrospray printing; S3: Precise deposition of printed layers; S4: forming a self-assembled deposition structure.

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