Selective ink transfer printing method based on liquid-like surface

Abstract

The invention discloses a selective ink transfer printing method based on a liquid-like surface. The selective ink transfer printing method comprises the following steps that 1, the surface of a base body is treated through oxygen plasma; step 2, dissolving a reaction monomer in methylbenzene containing saturated water; step 3, placing the substrate subjected to oxygen plasma treatment in the reaction solution in the step 2 to form a PDMS molecular brush; step 4, performing pattern design on the surface of the PDMS molecular brush by adopting a mask process, treating by using an alkali solution, selectively removing the molecular brush in an unprotected area, and restoring the molecular brush to a hydrophilic glass surface; step 5, coating oil-based ink on the surface treated in the step 4 to form a clear pattern; and step 6, enabling the surface of the printing ink with the pattern to be in direct contact with a target substrate, and applying pressure to transfer the printing ink. According to the method, the problems of resolution, ink diffusion control and pattern uniformity of the existing printing technology are solved, and the printing precision and applicability are improved.

Description

Technical Field

[0001] The present invention relates to a transfer printing method, specifically to a method for realizing selective transfer printing of ink by using a liquid-like surface. Background Art

[0002] At present, in the fields of micro-nano manufacturing, flexible electronics, patterned printing, etc., the transfer printing technology of fine patterns is crucial. The existing technologies mainly include photolithography, flexible printing (such as offset printing, gravure printing), and inkjet printing, etc., but all have certain limitations. For example, the photolithography process requires multiple steps of exposure, development, and etching, with complex processes and high costs. At the same time, it is difficult to control the fine patterning of organic inks; although flexible printing is suitable for large-area manufacturing, affected by the plate-making accuracy, the ink is prone to diffusion, resulting in blurred boundaries and difficult to meet the high-resolution requirements; inkjet printing is limited by the nozzle size and ink viscosity, and it is difficult to control high-viscosity inks, affecting the pattern uniformity. In addition, it is difficult to accurately control the wettability and diffusibility of the ink during the printing process in the existing technologies, resulting in problems such as blurred boundaries and uneven ink aggregation during the transfer process. Therefore, it is of great significance to develop a simple, controllable, high-resolution transfer printing method suitable for printing complex patterns.

[0003] Modifying a flat solid surface with highly flexible molecular chains such as polydimethylsiloxane (PDMS) can endow the surface with super-slippery characteristics similar to liquids. Therefore, such surfaces are also called liquid-like surfaces. When the PDMS molecular brush surface comes into contact with an organic liquid, due to the swelling effect of the organic liquid on the liquid-like molecules, it can further increase the fluidity of the surface molecular chains and reduce the relaxation time of the chain ends, showing a static oleophilic and dynamic oleophobic effect macroscopically. For the oily ink on the liquid-like surface, under static conditions, a weak interaction occurs between the PDMS molecular chain ends and the oily ink. While during dynamic contact, due to the entropy elastic response of the PDMS molecular chains and the solvent-induced swelling effect, the interface shows significant oleophobic characteristics. This "static wetting - dynamic repulsion" intelligent response mechanism, combined with controllable molecular chain relaxation kinetics, provides an ideal physical and chemical platform for realizing the controllable adhesion - release conversion of the ink, and further opens up an innovative path for the development of new high-resolution transfer printing technologies. Summary of the Invention

[0004] The object of the present invention is to provide a selective ink transfer printing method based on a liquid-like surface. By covalently grafting liquid-like molecular brushes (such as PDMS) on a solid surface such as glass, combined with selective etching with an alkali solution, precise patterning deposition and efficient transfer of the ink are realized. This method solves the problems of the existing printing technologies in terms of resolution, ink diffusion control, and pattern uniformity, and improves the printing accuracy and applicability, and is applicable to the fields of micro-nano pattern preparation, electronic device manufacturing, and other high-precision patterning processes.

[0005] The object of the present invention is achieved by the following technical solutions:

[0006] A selective ink transfer printing method based on the surface of a liquid-like substance, comprising the following steps:

[0007] Step 1: Treat the surface of the substrate with oxygen plasma for 0.5 - 20 min to form a rich hydroxyl group (Si-OH), and the substrate is glass, silicon wafer, metal or polymer film, etc.;

[0008] Step 2: Dissolve 0.01 - 1 mL of the reaction monomer in 40 mL of toluene containing saturated water. After stirring the solution for 30 - 60 s, let it stand at room temperature for 1 - 10 min before use. The concentration of the toluene containing saturated water is 0.024 mM, and the reaction monomer is dimethyldichlorosilane (DMDCS), 1,3-dichlorotetramethyldisiloxane (DCTDS) or 1,7-dichlorooctamethyltetrasiloxane (DCTTS);

[0009] Step 3: Place the oxygen plasma-treated substrate in the reaction solution of Step 2 for 0.5 - 60 min to form a PDMS molecular brush;

[0010] Step 4: Use a masking process to design a pattern on the surface of the PDMS molecular brush, and treat it with an alkali solution for 0.1 - 30 min to selectively remove the molecular brush in the unprotected area, restoring it to a hydrophilic glass surface. The alkali solution is one of NaOH, KOH, and tetramethylammonium hydroxide (TMAH), and the mass concentration is 1 - 20%;

[0011] Step 5: Coat an oil-based ink on the surface treated in Step 4. Due to the surface energy difference, the ink selectively aggregates in the oleophilic area and does not adhere to the hydrophilic etching area, thus forming a clear pattern;

[0012] Step 6: Directly contact the ink surface with the pattern with the target substrate, apply a pressure of 1 - 20 N to transfer the ink, and at the same time control the contact time and separation speed to improve the pattern clarity and reduce the boundary diffusion. The target substrate is plastic, metal, paper, etc.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. High-precision printing: Utilizing the selective wetting characteristics of the liquid-like molecular brush, sub-micron precision patterned ink deposition can be achieved (the precision can reach within 500 nm), which is more than 5 times higher than that of traditional flexographic printing.

[0015] 2. Ink diffusion control: The ultra-low contact angle hysteresis characteristics of the PDMS molecular brush prevent the ink from diffusing at the pattern edge, and the boundary clarity is increased by 40%.

[0016] 3. Simple process: The traditional lithography process requires 5 to 7 steps, while the present invention reduces it to 3 to 4 steps, significantly reducing the manufacturing cost and time.

[0017] 4. Strong reusability: The surface of covalently grafted liquid-like molecular brushes can withstand more than 1000 times of mechanical friction and chemical cleaning.

[0018] 5. Material saving and environmental protection: By reducing the use of chemical reagents such as photoresist and developer, environmental pollution can be reduced. Compared with the traditional lithography method, more than 30% of the ink usage can be saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a process flow chart of a selective ink transfer printing method based on a liquid-like surface;

[0020] Figure 2 FIG. is a schematic diagram of the selective aggregation effect of ink in hydrophilic and lipophilic regions;

[0021] Figure 3 FIG. is a transferred printed product drawing. DETAILED DESCRIPTION OF THE INVENTION

[0022] The technical solutions of the present invention will be further described below in conjunction with embodiments, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the protection scope of the present invention.

[0023] Example 1

[0024] Step 1: Treat the glass surface with oxygen plasma for 3 min.

[0025] Step 2: Dissolve 0.5 mL of dimethyldichlorosilane (DMDCS) in 40 mL of toluene containing saturated water (0.024 mM). After stirring the solution for about 30 s, let it stand at room temperature for 5 min.

[0026] Step 3: Place the oxygen plasma-treated glass in the reaction solution for 30 min to finally form a PDMS molecular brush.

[0027] Step 4: Use a masking process to perform pattern design on the surface of the molecular brush, and use 1% NaOH to treat it for 20 min to selectively remove the molecular brush in the unprotected area, restoring it to a hydrophilic glass surface. For the ink, the contact angle of the PDMS molecular brush area is small (as shown on the left), and the contact angle becomes larger after NaOH treatment (as shown on the right). Figure 2 As shown on the left, Figure 2 As shown on the right.

[0028] Step 5: Coat the treated surface with oil-based ink, directly contact the ink surface with the pattern with the target substrate, and apply a pressure of 10 N to transfer the ink. The specific microscope images after transfer are as Figure 3 shown.

[0029] Example 2

[0030] Step 1: Treat the surface of the silicon wafer with oxygen plasma for 5 min to form abundant hydroxyl (Si-OH) groups.

[0031] Step 2: Dissolve 0.3 mL of DCTDS in 40 mL of toluene containing saturated water (0.024 mM). After stirring the solution for about 30 s, let it stand at room temperature for 3 min.

[0032] Step 3: Place the oxygen plasma-treated silicon wafer in the reaction solution for 50 min to finally form a PDMS molecular brush.

[0033] Step 4: Use a mask process to design a pattern on the surface of the molecular brush, and treat it with 20% TMAH for 3 min to selectively remove the molecular brush in the unprotected area, restoring it to a hydrophilic glass surface.

[0034] Step 5: Coat the treated surface with oil-based ink, directly contact the ink surface with the pattern with the target substrate, and apply a pressure of 20 N to transfer the ink.

[0035] Example 3

[0036] Step 1: Treat the surface of the aluminum sheet with oxygen plasma for 3 min.

[0037] Step 2: Dissolve 0.5 mL of 1,7-dichlorooctamethyltetrasiloxane (DCTTS) in 40 mL of toluene containing saturated water (0.024 mM). After stirring the solution for about 30 s, let it stand at room temperature for 5 min.

[0038] Step 3: Place the oxygen plasma-treated glass in the reaction solution for 30 min to finally form a PDMS molecular brush.

[0039] Step 4: Use a mask process to design a pattern on the surface of the molecular brush, and treat it with 1% NaOH for 20 min to selectively remove the molecular brush in the unprotected area, restoring it to a hydrophilic glass surface.

[0040] Step 5: Coat the treated surface with oil-based ink, directly contact the ink surface with the pattern with the target substrate, and apply a pressure of 1 N to transfer the ink.

[0041] Example 4

[0042] Step 1: Treat the surface of the PET film with oxygen plasma for 5 minutes to form abundant hydroxyl (Si-OH) groups.

[0043] Step 2: Dissolve 0.5 mL of DCTDS in 40 mL of toluene containing saturated water (0.024 mM). After stirring the solution for about 30 s, let it stand at room temperature for 3 minutes.

[0044] Step 3: Place the oxygen plasma-treated silicon wafer in the reaction solution for 50 minutes to finally form a PDMS molecular brush.

[0045] Step 4: Use a masking process to perform pattern design on the surface of the molecular brush, and treat it with 20% KOH for 5 minutes to selectively remove the molecular brush in the unprotected area, restoring it to a hydrophilic glass surface.

[0046] Step 5: Coat the treated surface with oil-based ink, directly contact the ink surface with the pattern with the target substrate, and apply a pressure of 5 N to transfer the ink.

Claims

1. A selective ink transfer printing method based on the surface of a liquid-like substance, characterized in that The method includes the following steps: Step 1: Treat the substrate surface with oxygen plasma for 0.5 - 20 min; Step 2: Dissolve 0.01 - 1 mL of the reaction monomer in 40 mL of toluene containing saturated water. After stirring the solution for 30 - 60 s, let it stand at room temperature for 1 - 10 min; Step 3: Place the substrate treated with oxygen plasma in the reaction solution of Step 2 for 0.5 - 60 min to form a PDMS molecular brush; Step 4: Use a mask process to perform pattern design on the surface of the PDMS molecular brush, and treat it with an alkali solution for 0.1 - 30 min to selectively remove the molecular brush in the unprotected area and restore it to a hydrophilic glass surface; Step 5: Coat an oil-based ink on the surface treated in Step 4 to form a clear pattern; Step 6: Directly contact the ink surface with the pattern with the target substrate, and apply pressure to transfer the ink.

2. The selective ink transfer printing method based on the liquid-like surface according to claim 1, wherein The substrate is glass, silicon wafer, metal or polymer film.

3. The selective ink transfer printing method based on the surface of a liquid-like substance according to claim 1, wherein The concentration of the toluene containing saturated water is 0.024 mM.

4. The selective ink transfer printing method based on the liquid-like surface according to claim 1, wherein The reaction monomer is dimethyldichlorosilane, 1,3 - dichlorotetramethyldisiloxane or 1,7 - dichlorooctamethyltetrasiloxane.

5. The selective ink transfer printing method based on a liquid-like surface according to claim 1, characterized in that The alkali solution is one of NaOH, KOH, and tetramethylammonium hydroxide.

6. The selective ink transfer printing method based on a liquid-like surface according to claim 1 or 5, characterized in that The mass concentration of the alkali solution is 1 - 20%.

7. The selective ink transfer printing method based on a liquid-like surface according to claim 1, characterized in that The target substrate is plastic, metal or paper.

8. The selective ink transfer printing method based on the surface of a liquid-like substance according to claim 1, characterized in that The pressure is 1 - 20 N.

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