Three-Dielectric Electrohydrodynamic Patterning

Abstract

The present invention is titled "Three-Dielectric Electrohydrodynamic Patterning". The present disclosure provides a system for electrohydrodynamically patterning a map of materials, the system comprising: a first electrode having a first voltage; a second electrode having a second voltage different from the first voltage; one or more materials to be patterned located between the first electrode and the second electrode; a gap between at least one surface of at least one of the materials to be patterned and one of the first electrode or the second electrode; at least one patterning material in the gap, wherein the patterning material is a material other than air; and at least one filling material filling any remaining portion of the gap.

Description

Technical Field

[0001] The present disclosure relates to electrohydrodynamic patterning, and more particularly to electrohydrodynamic patterning of materials. Background Art

[0002] Patterning polymeric materials, typically films, can take many forms. A mold or stamper can be pressed into the polymeric film and then the film cured to hold the shape (herein called a feature) in place. Features can include patterns or other shapes pressed into the film, or extensions that extend above the surface of the film. However, the mold can wear, making the features formed by the mold less precise. When making very fine features, removing the mold or stamper can damage the features.

[0003] Electrohydrodynamic patterning of films provides a solution for producing films with fine features. In electrohydrodynamic film patterning (EHD-FP), the controlled application of an electric field causes the film to "move" to form desired features in the film, such as patterns. Once the pattern is formed, the system fixes it in place, such as by cooling the film to harden it, curing the film using heat or ultraviolet light, etc. The advantage of EHD-FP is that there is no contact that occurs when using a mold or stamper. This allows for the formation of features that might otherwise be affected by the removal of the stamper or mold.

[0004] The limitations of EHD-FP patterning are the difficulty in imprinting features onto the surface of the film, forming multi-layer features, and achieving clear features. Summary of the Invention

[0005] According to an aspect illustrated herein, a system for electrohydrodynamically map-patterning a material is provided, including: a first electrode having a first voltage; a second electrode having a second voltage different from the first voltage; one or more materials to be patterned located between the first electrode and the second electrode; a gap between at least one surface of at least one of the materials to be patterned and one of the first electrode or the second electrode; at least one patterning material in the gap, wherein the patterning material is a material other than air; and at least one filling material filling any remaining portion of the gap.

[0006] According to aspects illustrated herein, a system for patterning membrane electrohydrodynamic maps is provided, including: a first electrode having a first voltage; a second electrode; at least one dielectric material to be patterned, the at least one dielectric material to be patterned being located between the first electrode and the second electrode, the first dielectric material responding to an electric field formed between the first electrode and the second electrode; a gap between a surface of the first dielectric material and at least one of the first electrode and the second electrode; at least one patterning material selectively located on the at least one dielectric material to be patterned such that the at least one patterning material fills only a portion of the gap; and a filling material in the gap.

[0007] According to aspects illustrated herein, a method for patterning membrane electrohydrodynamic maps is provided, including: placing at least one material to be patterned on a surface positioned to be inserted into a gap between a first electrode having a first voltage and a second electrode having a second voltage different from the first voltage; depositing at least one patterning material on the at least one material to be patterned such that the at least one patterning material does not fill the gap and the at least one patterning material is a material other than air; and applying an electric field to the gap between the first electrode and the second electrode to cause the at least one material to be patterned to form a predetermined pattern. Description of the Drawings

[0008] Figures 1 to 4 An embodiment of a system for patterning material electrohydrodynamic maps using at least one patterning material is shown.

[0009] Figure 5 An embodiment of a system for patterning material electrohydrodynamic maps using at least two patterning materials is shown.

[0010] Figure 6 An embodiment of a system for patterning material electrohydrodynamic maps using at least two patterning materials is shown.

[0011] Figures 7 to 9 An alternative embodiment of a system for patterning material electrohydrodynamic maps using at least one patterning material is shown.

[0012] Figure 10 An embodiment of a system for patterning material electrohydrodynamic maps using a roll-to-roll process is shown.

[0013] Figure 11 A flowchart of an embodiment of a method for patterning material electrohydrodynamic maps using at least one patterning material is shown. Detailed Description

[0014] Electrohydrodynamic film patterning (EHD-FP) involves applying an electric field to a polymer or other film in order to shape the film surface. Shaping is typically accomplished by applying an electric field that causes the material forming the film to respond. The patterns produced in the film depend on factors such as (to name just a few here): the viscosity and responsiveness of the material to the electric field, the film surface tension, and the electric field strength (which is a function of the applied voltage), as well as the distance between the electrodes.

[0015] An advantage of EHD-FP is that there is no contact between the film to be patterned and the patterning device. In contact patterning applications, such as stamping or die casting, removing the stamp or die can cause damage or alteration of the resulting structure. With EHD-FP, finer features can be formed because the lack of contact does not cause these features to be damaged.

[0016] The embodiments herein employ three or more electro-responsive materials. These materials can have different dielectric constants or different conductivities. The dielectric constant (also known as relative permittivity) is related to the electromagnetic susceptibility of the material, which can include the degree to which the material responds to the applied electric field. In a typical EHD-FP system, two dielectric materials are used. Generally, one material is air or another gas, while the second material is the "material to be patterned" dielectric fluid "material". When an electric field is applied to the two dielectric materials, a net movement of the two dielectric materials occurs naturally or due to differences in field strength caused by field shaping. The material to be patterned can then be solidified to permanently retain the resulting pattern.

[0017] In this embodiment, using a third material as the "patterning" material can alter the response of the other two materials to the field. The patterning material can have a different dielectric constant, or in the case of a conductive material, a different conductivity, or can simply modify the electric field strength by changing the gap between the electrode and the material to be patterned. Multiple materials to be patterned and multiple patterning materials can be used to form more complex patterns. The embodiments herein allow for continuous processing, which produces commercially useful amounts of EHD film that can have more complex patterns with finer features than those formed using a single material and electric field.

[0018] It should be noted that some of the embodiments below use only one material to be patterned, but this is only for ease of discussion and understanding. As described above, more than one material may undergo patterning, and thus, although the discussion focuses on a single material to be patterned, the embodiments can be applied to at least one material to be patterned. Similarly, some of the embodiments below use one patterning material, while some embodiments use two patterning materials. Again, this is neither intended nor implies a limitation. Additionally, the discussion herein does not consider air or other gases as patterning materials, but they may be referred to as "filling" materials as they fill the gaps between the electrodes and / or materials.

[0019] Figure 1 An embodiment of an EHD system using at least three materials is shown: a material to be patterned, a patterning material, and air or other gas in the gap. There may be more than one material to be patterned and more than one patterning material. System 10 has two electrodes 12 and 14 that are separated by a distance D. The electrodes will each have a voltage when activated, where the two voltages are different. The material to be patterned 16 resides in the gap between the two electrodes. Although the material to be patterned is shown as residing on the surface of electrode 12, it may reside on the surface of either electrode or on an intermediate surface between them, as discussed in additional figures. The thickness or height of the first material to be patterned is x, and the thickness of the patterning material is z.

[0020] The patterning material 18 resides on the first material. The patterning material 18 may also be patterned or deposited only on selected regions of the first material. The patterning material 18 may also be deposited on either electrode. If the patterning material 18 itself is patterned, it will generally be patterned based on the desired pattern to be formed in the material to be patterned 16. The thickness of the patterning material 16 is z. In some embodiments, selectively patterning the entire height of the gap D can occur in a three - dielectric system and can produce different effects.

[0021] In one embodiment, the remaining space 20 in the gap between the electrodes is filled with another dielectric material. This material is typically a gas, but it can also be a fluid or semi - solid material, each having its own dielectric constant. To avoid confusion with other systems where air may be considered a patterning material, the embodiments herein have a patterning material that is a substance other than air. The electric field is altered due to differences in the dielectric constants or conductivities of the patterning material, the material to be patterned, and air or other gas. At least one of the materials must have different electrical properties from the other two.

[0022] Additionally, activation of the electrodes causes an electric field to be applied to all dielectric material between the two electrodes. Typically, the electrodes will not apply an electric field until the film stack is in the active region, which is defined as the region between the two electrodes. It is conceivable that a patterning material may be applied to the material to be patterned in the active region, but the electrodes will not become active until the patterning material is applied. As will be discussed below, the material stack will likely be transported into the active region where the electrodes are always "on."

[0023] When the material to be patterned is brought into the presence of an electric field along with the patterning material, the conductivity of the differential of the dielectric constant of the material results in a difference in the electric field experienced by the material to be patterned. In this sense, the patterning material acts very similarly to a patterned electrode that creates a pressure differential across the surface of the membrane in a more traditional EHD-FP setup. This pressure differential in the membrane surface in turn causes the material to be patterned to change shape and reflect the shape of the patterning material. The choice of patterning material and the electrical properties of the patterning material relative to the third material and the material to be patterned will determine the magnitude and direction of the pressure differential and will cause the membrane to have features of different heights based on the difference in the electric field.

[0024] At least one of the electrodes 12 and 14 may also have a pattern for generating a shaped or discontinuous electric field. This may be achieved by a spatially non-uniform voltage distribution on at least one of the electrodes, or by modifying the geometry of the electrodes to form a non-uniform gap D, such as Figure 2 shown.

[0025] exist Figure 2 In the embodiment, the electrode 14 has Figure 1 The geometry of the patterned material 18 is different from that of the patterned material 18, thereby allowing electric field shaping. In this embodiment, the patterned material 18 has its own pattern. Figure 2 The bottom of the diagram shows the resulting shape of material 16 to be patterned. Material 16 has two taller pillars, such as 15, which arise from areas where patterned film 18 remained during the application of the electric field. The dielectric constant or conductivity of 18 causes the material to try to close the gap between the electrodes, which pulls the area of ​​16 upward toward electrode 14. Pillar 17 arises from the same behavior of material 16, but material 16 does not respond as strongly.

[0026] This type of effect can also be achieved without using a pattern in the patterned material 18. Figure 3 As shown, patterning material 18 is deposited directly on top of the film to be patterned 16. In this embodiment, electrode 14 has its own pattern. When a field is applied, material 18 reacts strongly and pulls itself into pillars such as 19, pushing down into material 16. Material 16 also reacts and rises, such as shown at 21, and is displaced by pillars such as 18.

[0027] As described above, the patterned material can fill Figure 1 the entire gap D shown therein. Figure 4 An embodiment is shown in which the patterned material 18 has a column pattern extending from the top surface of the material to be patterned to the upper electrode. Figure 4 The bottom of [the figure] shows the resulting pattern after application of an electric field, in which embodiment the pattern is not shaped. These materials attempt to bridge the gap between the electrodes such that the material columns 18 attempt to touch or do touch the bottom electrode 12. In response to the electric field and the resulting displacement caused by the movement of the material 18, the material 16 to be patterned rises toward the top electrode.

[0028] The addition of patterned electrodes and the ability to pattern or otherwise selectively deposit a second material, as well as the addition of multiple patterned materials and multiple materials to be patterned, allow for better control of patterning and provide multiple levels of design choices to achieve the desired pattern.

[0029] Figure 5 An embodiment of an EHD-FP system with an additional patterned material 22 is shown, which is different from other patterned materials and does not include air or gas. The additional patterned material can reside partially or entirely on another patterned material and can have some pattern or can be continuous across the electric field. The additional patterned material can have a different dielectric constant or conductivity level from any of the other patterned materials such as 18 and the material 16 to be patterned, or it can have the same dielectric constant or conductivity level as one of the other materials. For simplicity, air or gas 20 is not shown herein, but can be included.

[0030] Figure 6 Another level of control is shown, in which a pattern is to be formed in the material 16 to be patterned, but consists of two patterned materials 18 and 22 on the material to be patterned. The two materials can be part of the same pattern across the surface of the first material, or can form two separate patterns on either the surface of the first material or the surface of the electrodes. The material to be patterned can react differently to the different materials 18 and 22, thus providing more complex control of the final pattern.

[0031] Figure 7 An embodiment is shown in which the patterned material 18 is in contact with at least one of the electrodes (electrode 14 in this example). The pattern formed by the patterned material forms the negative part of the field formed in a shape affected by the patterned material. The struts in the patterned material 18 form a characteristic pattern in the film 16 to be patterned, which includes raised regions, namely struts such as 30 and 32, and a lower region 34 therebetween.

[0032] Figure 8 Another embodiment of the pattern formed in the patterned material 18 is shown, where different recesses in the patterned material, such as 36, 38, and 40, have different depths. When a voltage is applied, these different depths of the recesses form different heights, such as 42, 44, and 46, in the material 16 to be patterned.

[0033] The patterned material 18 can take the form of a film that has sections that are cut and then suspended in a gas 20 (such as air in a space), as Figure 9 shown. The cut sections, such as 48, can all have the same size, as shown, or they can also have different sizes. The presence of the film with cut sections causes the field to form raised portions, such as 50, in the material 16 to be patterned.

[0034] As discussed above, a stack of films of at least two materials will likely be formed before being transported into the active region. This can be done using roll-to-roll or other continuous manufacturing processes. Figure 10 An example of such a system is shown, where the process or system is not intended to be limited in any way to any of the elements discussed.

[0035] Figure 10 The system 60 has two belts 62 and 64. These belts themselves can act as electrodes, or they can be located adjacent to electrodes, such as 74 and 76, that form the active region. A stack of materials of at least one material 66 to be patterned and at least one patterned material 68 is in the active region between the two electrodes or belts. A gas, such as air, can reside in the gap 70. After patterning, the stack of materials can be transported to a curing device 78 that fixes the pattern in place in any of the materials in the stack, such as by the application of heat or UV light. Alternatively, only the material with the pattern can be allowed to dry, or cool to solidify. The patterned material can be removed before, after, or during curing. The material can be removed by a physical process, dissolution, evaporation, or any other suitable process.

[0036] Although Figures 1 to 9 the systems shown illustrate different variations and alternatives, any of these can be used with any other embodiments and features discussed. There is no intention or implication of a limitation to any particular combination of embodiments.

[0037] Figure 11 A flowchart of an embodiment of a process for forming a patterned film using EHD-FP is shown. At 80, at least one material to be patterned is placed on a surface, which can be as Figure 4The belt, another processing surface, or electrode shown. The material to be patterned can be selected from many different materials, including materials selected from the following: thermoplastic polymers; polystyrene; polyurethane; polypropylene; polyamide; polyethylene; polyvinyl; acrylate; acrylonitrile butadiene styrene; thermosetting polymers; thermosetting epoxy resins; two-component epoxy resins; UV-curable epoxy resins; polyester; phenol formaldehyde; silicone; and vinyl ester.

[0038] Then, at 82, at least one patterning material other than air is deposited on the first material. For example, inkjet printing or a stencil and a squeegee can be used to deposit the patterning material in a pattern. Alternatively, the patterning material can be "wiped" onto the material to be patterned using only a squeegee or a brush, or it can be selectively poured onto different areas of the material to be patterned. These are just examples. The patterning material can include at least one of many materials, including materials selected from the following: synthetic oils; natural oils; fluorinated oils; barium titanate particles; and PVDF.

[0039] If the additional materials shown as a box with a dashed line are used at 84 to indicate their optional nature, they will also be deposited at 84 on the material to be patterned or at least partially deposited on another patterning material.

[0040] At 86, an electric field is applied to the gap between the electrodes. The stack of materials can be transported to the active area to apply the electric field, or the electric field can be applied while the stack is stationary in the active area. In cases where one of the goals is to form a commercially useful amount of the patterned film, a continuous process in which the film is deposited and then moved into and out of the active area is more likely. This type of continuous process allows the process to produce a film at one end of the process while forming a new film at the other end of the process.

[0041] If the material to be patterned is curable after being patterned, the material with the pattern will be cured to fix the pattern in place. This part of the process can also involve removing the patterning material. If additional patterns or patterning materials are used, these will also be cured and / or removed.

[0042] It should be understood that variations or alternatives of the features and functions disclosed above and others can be combined into many other different systems or applications. Those skilled in the art can then make various substitutions, modifications, variations, or improvements that are currently unforeseen or unanticipated, and these are also intended to be covered by the appended claims.

Claims

1. A system for electrohydrodynamic patterning of materials, comprising: A first electrode having a first voltage; A second electrode having a second voltage different from the first voltage; One or more materials to be patterned, the one or more materials to be patterned being located between the first electrode and the second electrode; A gap between at least one surface of at least one of the materials to be patterned and one of the first electrode or the second electrode; At least one patterning material deposited only on selected regions of the at least one material to be patterned such that the at least one patterning material fills only a portion of the gap, wherein the patterning material is a material other than air and has a different dielectric constant from the material to be patterned, or has a different conductivity from the material to be patterned, or modifies the electric field strength by changing the gap between the electrode and the material to be patterned; And At least one filling material filling any remaining portion of the gap.

2. The system according to claim 1, wherein at least one of the first electrode and the second electrode is patterned such that the gap between the first electrode and the second electrode is spatially non-uniform.

3. The system according to claim 1, wherein at least one of the first electrode and the second electrode has a spatially non-uniform voltage such that the electric field between the first electrode and the second electrode is spatially non-uniform.

4. The system according to claim 1, wherein the first electrode comprises a first strip and the second electrode comprises a second strip, wherein at least one of the materials to be patterned resides at least partially in contact with one of the first strip and the second strip.

5. The system according to claim 1, wherein the at least one patterning material is conductive.

6. The system according to claim 1, wherein the at least one material to be patterned is conductive.

7. The system according to claim 1, wherein the at least one patterning material is physically patterned based on a desired pattern to be formed in the at least one material to be patterned.

8. The system according to claim 1, wherein at least a portion of the electrode has patterned features.

9. The system according to claim 1, wherein the filling material comprises a gas.

10. A system for electrohydrodynamic patterning of a membrane, comprising: A first electrode having a first voltage; A second electrode; At least one dielectric material to be patterned, the at least one dielectric material to be patterned being located between the first electrode and the second electrode, the first dielectric material responsive to an electric field formed between the first electrode and the second electrode; A gap between the surface of the first dielectric material and at least one of the first electrode and the second electrode; At least one patterned material, the at least one patterned material being selectively located on the at least one dielectric material to be patterned such that the at least one patterned material only fills a portion of the gap; and a filling material, the filling material being in the gap.

11. The system according to claim 10, wherein the first electrode includes a first strip and the second electrode includes a second strip, wherein the at least one dielectric material to be patterned directly resides on and contacts one of the first strip and the second strip.

12. The system according to claim 10, wherein at least one of the first electrode and the second electrode is patterned such that the voltage distribution or the gap between the electrodes on at least one of the first electrode and the second electrode is spatially non-uniform.

13. The system according to claim 12, wherein the at least one patterned dielectric material is patterned based on a desired pattern to be formed in the at least one material to be patterned.

14. The system according to claim 12, wherein the filling material includes a gas.

15. A method of patterning a membrane electrohydrodynamic map, comprising: placing at least one material to be patterned on a surface positioned to be inserted into a gap between a first electrode having a first voltage and a second electrode having a second voltage different from the first voltage; depositing at least one patterned material on the at least one material to be patterned such that the at least one patterned material does not fill the gap and the at least one patterned material is a material other than air; and applying an electric field to the gap between the first electrode and the second electrode to cause the at least one material to be patterned to form a predetermined pattern.

16. The method according to claim 15, further comprising depositing a filling material into the gap.

17. The method according to claim 15, wherein depositing the at least one patterned material includes depositing a second patterned material on a first patterned material using one of: inkjet, doctor blading the second patterned material onto the first patterned material, or selectively pouring the second patterned material onto the first patterned material.

18. The method according to claim 17, wherein generating the electric field includes generating a discontinuous electric field.

19. The method according to claim 18, wherein generating the discontinuous electric field includes generating a shaping electric field to form the predetermined pattern, and the method further includes directly providing the second patterned material on and in contact with the at least one material to be patterned before generating the electric field.

20. The method according to claim 15, further comprising curing the material to be patterned in a desired pattern.

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