KR20230138220A - An electronic device based on micropattern formed by addictive printing using smart materials, and a manufacturing method thereof - Google Patents

Abstract

One embodiment of the present invention provides a technique for laminating and patterning a transparent stimulus-variable material (programmable material) based on 3D printing technology on a flexible/stretchable conductive device (film) to enable it to deform itself in three dimensions in response to an external stimulus in a desired shape. An electronic device based on smart material micropatterned additive manufacturing, according to an embodiment of the present invention, includes: a conductive part formed of a conductive material and having electrical conductivity and flexibility; and a stimulus variable part formed by laminating and patterning a stimulus variable material whose molecular arrangement changes by an external physical stimulus onto a surface of the conductive part.

Description

Electronic devices based on smart material micropattern laminated printing and their manufacturing method {AN ELECTRONIC DEVICE BASED ON MICROPATTERN FORMED BY ADDICTIVE PRINTING USING SMART MATERIALS, AND A MANUFACTURING METHOD THEREOF}

The present invention relates to an electronic device based on smart material micro-pattern lamination printing and a method of manufacturing the same. More specifically, the present invention relates to a transparent stimulus-tunable material (programmable material) based on 3D printing technology on a flexible/stretchable conductive element (film). It is about a technology that enables three-dimensional transformation in response to external stimuli into a desired shape by patterning.

4D deformation technology refers to a technology for structures that undergo three-dimensional deformation by external stimulation sources such as temperature changes and magnetic field changes over time. Such 4D deformation technology includes soft robots, micro biological robots, micro grippers, It can be used in a variety of fields such as wearable devices and artificial muscles, so research on it is increasing.

In existing 4D printing research for the formation of 4D deformable structures, devices are mainly manufactured using non-conductive smart materials, the deformation of the smart materials is studied, and the smart materials themselves are used as deformable devices. Therefore, there are limitations in its application mainly to the movements of grippers or soft robots that require only mechanical properties.

In U.S. Patent Publication No. 2020-0316847 (title of the invention: Object of additive manufacture with encoded predicted shape change and method of manufacturing same), dispensing multiple layers of a first polymeric material from a three-dimensional printer, three-dimensional Manufacturing a device having two layers by performing steps such as distributing multiple layers of the second polymerizable material from a printer, and the second polymerization rather than the swelling property of the first polymerizable material in response to an external stimulus of temperature change. It is disclosed that the swellability of the material is low and that the element changes into a predetermined shape by external stimulation.

In Republic of Korea Patent No. 10-1749212 (title of the invention: 4D printing assembly structure), a frame of a straight structure is formed as an integrated extension and designed to be deformed in a specific part by a 4D printer, and a frame is provided between the frames to prevent the passage of time. An assembly structure is disclosed that includes a plurality of joints that undergo deformation according to , wherein the joints are set to have different thermal conductivities.

As described above, in the prior art 4D printing technology, there is a limitation in that it mainly prints non-conductive smart materials and uses modifications of the smart materials.

US Patent Publication No. 2020-0316847 Republic of Korea Patent No. 10-1749212

The purpose of the present invention to solve the above problems is to laminate and pattern a transparent stimulus-variable material (programmable material) on a flexible/stretchable conductive element (film) based on 3D printing technology to form a desired shape that responds to external stimuli on its own. This makes dimensional transformation possible.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

The configuration of the present invention for achieving the above object includes a conductive portion formed of a conductive material and having electrical conductivity and flexibility; And a magnetic pole variable portion formed by layering and patterning a magnetic pole variable material whose molecular arrangement changes due to an external physical stimulus on the surface of the conductive portion, and a magnetic pole variable portion whose shape is variable due to deformation of the magnetic pole variable portion due to an external physical stimulus. It is characterized by

In an embodiment of the present invention, the conductive part may have the shape of a film, fiber, or tube.

In an embodiment of the present invention, the stimulus variable material may include a liquid crystal elastomer.

In an embodiment of the present invention, the stimulus-tunable material includes a reactive liquid crystal monomer (reactive mesogen) having a liquid crystalline phase, a chain extender that provides easy viscosity for 3D printing, and a slag reagent used in a photopolymerization reaction ( It can be formed by a synthetic reaction using a photoinitiator and a catalyst used in the crosslinking reaction.

In an embodiment of the present invention, the reactive liquid crystal monomer is 1,4-Bis-[4-(3-acryloyloxyhexyloxy) benzoyloxy]-2-methylbenzene (RM 257), and the chain extender is 2,2-(ethylenedioxy) These may be diethanethiol (EDDET) and pentaerythritol terakis (3-mercaptopropionate) (PETMP).

In an embodiment of the present invention, in the first step, the slag reagent may be 2-Hydroxy-2-methylpropiophenone (HHMP), and the catalyst may be Dipropyl amine (DPA).

In an embodiment of the present invention, the conductive material may be formed by mixing an organic polymer and a conductive metal nanowire.

In an embodiment of the present invention, in the composition ratio of the conductive material, the proportion of conductive metal nanowires may be 80 to 90 wt%, and the proportion of organic polymer may be 10 to 20 wt%.

In an embodiment of the present invention, the conductive portion and the magnetic pole variable portion may be formed by 3D printing.

The configuration of the present invention for achieving the above object includes a first step of synthesizing the stimulus-tunable material using the reactive liquid monomer, the chain extender, the slag reagent, and the catalyst; A second step of generating the conductive material; A third step of forming the conductive portion by performing 3D printing using the conductive material; And a fourth step of forming the magnetic pole variable portion by performing 3D printing on the surface of the conductive portion using the magnetic pole variable material.

In an embodiment of the present invention, between the third step and the fourth step, an inspection step of forming a confirmation structure by 3D printing the stimulus-tunable material and inspecting the alignment of the liquid crystal molecules using the confirmation structure. More may be included.

The effect of the present invention according to the above configuration is that a 4D printing technology that allows the magnetic pole variable portion to move by acting as a supporting layer and driving layer for the conductive portion can be implemented.

Additionally, the effect of the present invention is that it can be applied to various conductive materials/devices whose shapes are known because it is a technology that induces deformation by layer-printing programmable materials.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a schematic diagram of an electronic device according to each embodiment of the present invention.
Figure 2 is an image of a method of manufacturing an electronic device according to an embodiment of the present invention.
Figures 3 and 4 are images for confirming the alignment of liquid crystal molecules according to an embodiment of the present invention.
5 and 6 are images of deformation of electronic devices according to an embodiment of the present invention.
Figure 7 is an image showing the deformation of an electronic device over time according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this means not only "directly connected" but also "indirectly connected" with another member in between. "Includes cases where it is. Additionally, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

The terms used in this specification are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, the present invention will be described in detail with reference to the attached drawings.

1 is a schematic diagram of an electronic device according to each embodiment of the present invention. Specifically, Figure 1 (a) represents the first electronic device 11 according to the first embodiment, Figure 1 (b) represents the second electronic device 12 according to the second embodiment, and (c) in 1 represents the third electronic device 13 according to the third embodiment. As shown in Figure 1, the electronic device of the present invention can be formed by adjusting the shape, position, and number of the magnetic pole variable parts 100.

As shown in Figure 1, the electronic device of the present invention includes a conductive portion 200 formed of a conductive material and having electrical conductivity and flexibility; And a magnetic pole variable portion 100 formed by layering and patterning a stimulus variable material whose molecular arrangement changes due to an external physical stimulus on the surface of the conductive portion 200.

The electronic device of the present invention may have a variable shape due to deformation of the magnetic pole variable portion 100 caused by an external physical stimulus. Here, shape change means three-dimensional shape change.

External physical stimuli can refer to various stimuli such as temperature changes, magnetic or electric fields, and physical contact. In addition, stimulus-variable materials may be smart materials or programmable materials, whose physical properties can change depending on the external environment/stimulus.

The conductive portion 200 and the magnetic pole variable portion 100 may be formed by 3D printing. That is, the conductive portion 200 may be formed by lamination molding, and the magnetic pole variable portion 100 may be formed by lamination molding. Accordingly, 4D deformation technology can be implemented in structures made of conductive materials that are not easily 4D printed.

Here, 4D printing technology refers to a technology that 3D prints an object that changes its shape or manufactures itself into a new form when a pre-designed time or arbitrary environmental condition is met.

The conductive portion 200 may have the shape of a film, fiber, or tube. Here, at least one magnetic pole variable portion 100 may be formed, and the magnetic pole variable portion 100 may be laminated and molded into various shapes such as a linear shape, a predetermined geometric shape, or a three-dimensional structure.

In the embodiment of the present invention, the shape of the conductive portion 200 is described as being formed as above, but it is not limited thereto, and the conductive portion 200 may be formed in various shapes.

As shown in FIG. 1, when the conductive portion 200 is formed in a film shape, a magnetic pole variable material may be patterned on the upper or lower surface of the conductive portion 200 to form the magnetic pole variable portion 100.

In addition, when the conductive portion 200 is formed in the shape of a fiber, a magnetic pole variable material may be patterned on the outer surface of the conductive portion 200 to form the magnetic pole variable portion 100, and the conductive portion 200 When formed in the shape of a tube, the magnetic pole variable portion 100 may be formed on the outer or inner surface of the conductive portion 200.

The stimulus-tunable material may include a liquid crystal elastomer. To synthesize a liquid crystal elastomer, it can be basically based on thiol-acrylate Michael addition and photo polymerization. Michael addition is one of the most suitable methods to form C-C bonds, and through this, it can be printed to have printable viscosity properties and then completely hardened through photopolymerization by irradiating an ultraviolet (UV) light source.

Stimulus-tunable materials include a reactive liquid crystal monomer (reactive mesogen) with a liquid crystalline phase, a chain extender that provides easy viscosity for 3D printing, a photoinitiator used in photopolymerization reactions, and a cross-linking reaction. It can be formed through a synthetic reaction using a catalyst.

Specifically, the reactive liquid crystal monomer is 1,4-Bis-[4-(3-acryloyloxyhexyloxy) benzoyloxy]-2-methylbenzene (RM 257), and the chain extender is 2,2-(ethylenedioxy) diethanethiol (EDDET) and pentaerythritol terakis. It may be (3-mercaptopropionate)(PETMP).

Here, as a chain extender, a thiol spacer is used instead of the amine spacer commonly used, allowing room temperature printing and forming a longer and more flexible chain. The above-mentioned EDDET is a di-functional flexible spacer, and PETMP is a tetra-functional crosslinking monomer.

Additionally, the slag reagent may be 2-Hydroxy-2-methylpropiophenone (HHMP), and the catalyst may be Dipropyl amine (DPA).

In the process of forming stimulus-tunable materials, the synthesis ratio is very important, and if the ratio of thiol spacer, a chain extender, is too low compared to the reactive liquid crystal monomer, gelation will not occur and the viscosity may be too low like water, making it unsuitable for printing. On the other hand, if you mix more than a certain amount of catalyst, the material may harden in less than a few minutes during the mixing process.

Conductive materials can be formed by mixing organic polymers and conductive metal nanowires. Here, in the composition ratio of the conductive material, the ratio of the conductive metal nanowires may be 80 to 90 wt%, and the ratio of the organic polymer may be 10 to 20 wt%.

The ratio and combination of elastomeric solution, an organic polymer that can give flexible mechanical properties to a conductive material, which is a conductive elastomer, and conductive micro/nanoparticles may be important.

Polydimethylsiloxane (PDMS), a silicon-based organic polymer, can be used as the organic polymer, and the conductive metal nanowire can be formed of silver or gold.

In addition, by forming the ratio of conductive metal nanowires as described above, it can be easy for the conductive metal nanowire particles to be electrically connected within the organic polymer. The mixture of organic polymer and conductive metal nanowire as described above can be uniformly mixed using a high-viscosity mixer that is convenient for dispersing and defoaming the high-viscosity paste.

3D printable materials can have shear-thinning properties where viscosity decreases as shear rate increases. In order to measure these rheological characteristics, the viscosity of the magnetically variable material according to the shear rate was measured using a rheometer, and it was confirmed that it had shear-thinning characteristics.

A micro gripper containing the electronic device of the present invention can be formed. When forming a micro gripper with the electronic device of the present invention as described above, a micro object having a length of micro units is brought into contact with the electronic device of the present invention, and then a temperature change stimulus is provided to the electronic device of the present invention to A part of the electronic device of the invention can be used as a micro gripper by surrounding a micro object and allowing gripping.

And, in this way, electricity can be applied through the conductive portion 200 to the held micro-object or to a structure formed around the micro-object. In this way, 4D printing technology can be implemented that causes the magnetic pole variable portion 100 to move by acting as a supporting layer and driving layer for the conductive portion 200.

Hereinafter, the manufacturing method of the electronic device of the present invention will be described.

Figure 2 is an image of a method of manufacturing an electronic device according to an embodiment of the present invention. Specifically, Figure 2 (a) is an image of a tool path design drawing for the 3D printing structure of an electronic device, Figure 2 (b) is about the printing of the conductive portion 200, and Figure 2 (c) is an image of the magnetic pole variable portion 100 being printed on the surface of the conductive portion 200.

As shown in Figure 2, in the first step, a stimulus-tunable material can be synthesized using a reactive liquid monomer, a chain extender, a slag reagent, and a catalyst. And, in the second step, a conductive material can be created. The synthesis process of the magnetic pole-tunable material and the synthesis process of the conductive material are described above.

Next, in the third step, the conductive portion 200 can be formed by performing 3D printing using a conductive material. Then, in the fourth step, the magnetic pole variable portion 100 can be formed by performing 3D printing on the surface of the conductive portion 200 using a magnetic pole variable material.

Here, in order to form the electrode element of the present invention in various shapes, the third and fourth steps may be performed repeatedly. In this case, lamination molding can be performed while the nozzle discharging the conductive material and the nozzle discharging the magnetic pole variable material are alternately used.

In the third step, a 27G nozzle with an inner diameter of 210㎛ was basically used, and the discharge pressure could be fixed at the level of 700 kPa.

As shown in Figure 2 (b), due to the high viscosity and shear-thinning characteristics of the conductive material solution, the material is discharged uniformly and the shape is well maintained, making it suitable for 3D printing.

In the fourth step, the printing nozzle uses a 30G nozzle with an inner diameter of 140 ㎛, and the printing line width is adjusted by varying the printing speed. The discharge pressure is fixed at approximately 500 kPa, and the printing speed can be changed to 100, 200, 300 and 500 mm/min.

As the printing speed increases, the line width decreases, and when the printing speed is 500 mm/min, the line width is at least 50 ㎛. At this time, the line width can be adjusted within a desired range by varying the printing speed, discharge pressure, and inner diameter of the nozzle.

In the fourth step, as shown in FIG. 2, after determining the printing thickness information of the conductive portion 200, the magnetic pole variable portion 100 can be printed in various patterns on the surface of the conductive portion 200.

The remaining details of the manufacturing method of the electronic device of the present invention are the same as the description of the electronic device of the present invention described above.

Figures 3 and 4 are images for confirming the alignment of liquid crystal molecules according to an embodiment of the present invention. Specifically, Figure 3(a) relates to the generated confirmation structure 300. In addition, in the case where one confirmation structure 300 is placed between crossed polarizers placed on the backlight to check the alignment of the liquid crystal molecules, each of (b) to (d) in Figure 3 is a line plane This is an image for the case where the alignment directions of the tube plate and the molecules of the magnetic pole-tunable material (liquid crystal molecules) are 0 degrees, 45 degrees, and 90 degrees.

For the case where another confirmation structure 300 is placed between the cross polarizers placed on the backlight to check the alignment of the liquid crystal molecules, (a) to (c) in Figure 4 each have a linear polarizer and a magnetic pole. This is an image for the case where the alignment directions of the molecules of the variable material (liquid crystal molecules) are 0 degrees, 45 degrees, and 90 degrees.

Here, one confirmation structure 300 may represent a confirmation structure 300 with excellent liquid crystal molecule alignment, and the other confirmation structure 300 may represent a confirmation structure 300 with low liquid crystal molecule alignment. .

In order to confirm the alignment of liquid crystal molecules as described above, the manufacturing method of the electronic device of the present invention involves 3D printing a stimulus-tunable material on a substrate between the third and fourth steps to form a confirmation structure 300 and confirm it. An inspection step of inspecting the alignment of liquid crystal molecules using the dragon structure 300 may be further included.

Here, the degree of liquid crystal molecule alignment may mean the alignment ratio of the liquid crystal molecules, which are molecules of the magnetic pole-tunable material, when the magnetic pole-tunable material is printed.

As shown in Figures 3 (b) to (d), the confirmation structure 300, which is a liquid crystal elastomer, can be placed between crossed polarizers placed on the backlight to check the alignment of the liquid crystal molecules. . And, while dark light comes out when the linear polarizer is at 0° and 90°, when it is placed at 45°, light is visible due to the optical anisotropy characteristics of the liquid crystal molecules.

On the other hand, as shown in FIG. 4, if the liquid crystal elastomer solution, which is a stimulus-tunable material solution, is diluted or the alignment of the liquid crystal molecules is broken due to a delay in the photocuring process, light may not be visible even when placed at 45°. In addition, since the molecules are formed randomly, a lot of light scattering occurs, so the printed shape may appear blurry.

5 and 6 are images of deformation of electronic devices according to an embodiment of the present invention. Specifically, Figures 5 (a) and (b) each represent the first electronic element 11, the second electronic element 12, the third electronic element 13, and the magnetic pole variable unit 100 in Figure 1. This is an image taken from the top and side of the comparative electronic device 14, which is the conductive portion 200 itself without formation.

6 (a) and (b) are images of the modified first electronic device 11 and the comparative electronic device 14, and FIGS. 6 (c) and (d) are images of the second electronic device ( 12) and the comparative electronic device 14, and (e) and (f) in Figures 6 are images of the third electronic device 13 and the comparative electronic device 14.

The conductive portion 200 and the magnetic pole variable portion 100 can be formed using the manufacturing method of the electronic device of the present invention as described above. At this time, the total upper surface area of the conductive portion 200 is on the order of sub-cm. To secure the deformation technology of fine devices, it can be set to 10 mm Х6 mm.

As shown in Figures 5 and 6, it can be confirmed that the shape of the electronic device of the present invention changes as the shape of the conductive part 200 changes due to the shape deformation of the magnetic pole variable part 100 above a predetermined temperature.

Figure 7 is an image showing the deformation of an electronic device over time according to an embodiment of the present invention. Specifically, as shown in (a) to (d) of FIG. 7, the shape of the first electronic device 11 changes over time (0, 2, 6, 12 seconds (s)) at the transition temperature for shape deformation. You can see that the transformation is implemented.

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the patent claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

11: first electronic element
12: Second electronic element
13: Third electronic element
14: Comparative electronic device
100: Magnetic pole variable part
200: conductive part
300: Confirmation structure

Claims (12)

A conductive portion formed of a conductive material and having electrical conductivity and flexibility; and
It includes a magnetic pole variable portion formed by layering and patterning a stimulus variable material whose molecular arrangement changes in response to an external physical stimulus on the surface of the conductive portion,
An electronic device based on smart material fine pattern lamination printing, characterized in that the shape is variable due to deformation of the magnetic pole variable portion due to external physical stimulation.
In claim 1,
An electronic device based on smart material micropattern lamination printing, characterized in that the conductive part has the shape of a film, fiber, or tube.
In claim 1,
The stimulus-tunable material is a smart material micropattern laminated printing-based electronic device, characterized in that it includes a liquid crystal elastomer.
In claim 3,
The stimulus-tunable material is a reactive liquid crystal monomer (reactive mesogen) with a liquid crystalline phase, a chain extender that provides easy viscosity for 3D printing, a photoinitiator used in photopolymerization reaction, and a cross-linking reaction. An electronic device based on smart material micropattern lamination printing, characterized in that it is formed by a synthesis reaction using a catalyst.
In claim 4,
The reactive liquid crystal monomer is 1,4-Bis-[4-(3-acryloyloxyhexyloxy) benzoyloxy]-2-methylbenzene (RM 257), and the chain extender is 2,2-(ethylenedioxy) diethanethiol (EDDET) and pentaerythritol terakis ( An electronic device based on smart material micropattern layered printing, characterized by 3-mercaptopropionate (PETMP).
In claim 5,
An electronic device based on smart material micropattern lamination printing, characterized in that the slag reagent is 2-Hydroxy-2-methylpropiophenone (HHMP), and the catalyst is Dipropyl amine (DPA).
In claim 1,
The conductive material is a smart material micropattern layered printing-based electronic device, characterized in that it is formed by mixing an organic polymer and a conductive metal nanowire.
In claim 7,
In the composition ratio of the conductive material, the proportion of conductive metal nanowires is 80 to 90 wt%, and the proportion of organic polymer is 10 to 20 wt%. An electronic device based on smart material fine pattern lamination printing.
In claim 1,
An electronic device based on smart material fine pattern layered printing, characterized in that the conductive part and the magnetic pole variable part are formed by 3D printing.
A micro gripper comprising an electronic device based on smart material fine pattern layered printing according to any one of claims 1 to 9.
In the method of manufacturing an electronic device based on smart material fine pattern lamination printing of claim 4,
A first step of synthesizing the stimulus-tunable material using the reactive liquid monomer, the chain extender, the slag reagent, and the catalyst;
A second step of generating the conductive material;
A third step of forming the conductive portion by performing 3D printing using the conductive material; and
A method of manufacturing an electronic device based on smart material fine pattern lamination printing, comprising a fourth step of forming the magnetic pole variable portion by performing 3D printing on the surface of the conductive portion using the magnetic pole variable material.
In claim 11,
Between the third step and the fourth step, the smart device further includes an inspection step of forming a confirmation structure by 3D printing the stimulus-tunable material and inspecting the alignment of the liquid crystal molecules using the confirmation structure. Manufacturing method of electronic devices based on material fine pattern additive printing.