KR102296429B1 - Method of fabricating 3d printable ink and method of semi transparent electromagnetic field shielding structures using 3d printable ink - Google Patents

Abstract

The present invention relates to a composition of an ink capable of 3D printing containing 2D MXene (transition metal carbide, nitride, carbonitride) and implementation of a translucent electromagnetic wave shielding structure using the same. Multi-variety and small-volume production industry (ex. medical equipment, etc.) and 3D printing industry currently limited to prototype production are expected to rapidly expand through the technology. In addition, the present invention is expected to show an eco-friendly effect by using water as a solvent instead of an existing volatile organic solvent.

Description

Method of manufacturing ink for 3D printing and manufacturing method of translucent electromagnetic wave shielding structure using ink for 3D printing

The present invention relates to a composition of an ink capable of 3D printing containing 2D MXene (transition metal carbide, nitride, carbonitride) and the implementation of a semi-transparent electromagnetic wave shielding structure using the same.

Electrical pollution generated by humans, such as radiation and electromagnetic noise, including electromagnetic (EM) wavelengths, has been continuously increasing due to the rapid increase of radio and the like since the 1820s. This electromagnetic pollution causes electromagnetic interference (EMI).

One of the most effective ways to protect electronic devices from undesirable electrical contamination is to add an EMI shielding structure between the EM source and target to mitigate the forces of EM radiation by reflection, absorption, and multiple internal reflections.

In recent years, EMI shielding has become an essential element for electromagnetic compatibility (EMC) with advances in precision wireless communication devices, autonomous vehicles, and the Internet of Things (IoT) using multi-channel variable frequencies.

3D printing technology, which can construct desired 3D objects and complex structures with flexible design criteria, offers the possibility to fabricate cost-effective, time-efficient and environmentally friendly EMI shielding. Among 3D printing technologies, the liquid deposition modeling (LDM) method is the most versatile 3D printing technology for creating 3D type objects using any material. The advantage of LDM 3D printing is that the printing system including syringes, nozzles and printing substrates can be easily modified. Another advantage of LDM 3D printing is that 3D structures can be printed on non-planar surfaces, whereas other 3D printing systems require a planar printed substrate. Shielding, electrically functional 3D printable composites are needed to unlock the full potential of LDM 3D printing in the field of EMI.

MXene is a class of 2D nanoscale materials composed of transition metal carbide, nitride and carbonitride layers several atoms thick. MXene exhibits metal-like conductivity and high dielectric constant, is hydrophilic with hydroxyl or oxygen terminating groups, and offers uncomplicated surface modification potential. For this reason, much effort has been devoted to the development of EMI shielding based on MXene composites and structures (e.g. MXene films, MXene airgels and MXene coated fabrics), but the use of 3D printing to create EMI shielding structures has not been reported to date. didn't

In particular, the conventional method of implementing an electromagnetic wave shielding structure made by processing a metal thin film is not economically and time-efficient because a new mold must be manufactured in order to respond to a rapidly changing integrated circuit design.

An object of the present invention is to synthesize a water-based ink for 3D printing by utilizing the thixotropy expressed by mixing 2D MXene (transition metal carbide, nitride, carbonitride) and a polymer binder, and using this to implement an electromagnetic wave shielding structure having a customized shape. will be.

A method of manufacturing an ink for 3D printing according to an embodiment of the present invention comprises the steps of preparing a MAX phase represented by the following Chemical Formula 1; synthesizing MXene by etching the layer A of the MAX phase compound represented by Formula 1; and mixing MXene with polyethylene oxide (PEO) and deionized water (DI water) to prepare a composite ink.

[Formula 1]

M _n+1 AX _n

In Formula 1, M is an early transition metal, A is at least one selected from the group consisting of Al, Si, P, S, Ga, As, In, Sn, Tl and Pb, and X is carbon or It contains any one of nitrogen, and n is an integer of 1-4.

The preceding transition metal is Ti.

The composite ink is maxine (MXene)-polyethylene oxide (PEO), and the maxine is represented by formula (2).

[Formula 2]

M _n+1 X _n T _x

In Formula 2, M is an early transition metal, X includes any one of carbon or nitrogen, n is an integer of 1 to 4, and T _x is a surface functional group =O, -OH, - either F.

The content of the maxine (MXene)-polyethylene oxide (PEO) in the ink is 30 wt% or less, and preferably, the content of the maxine (MXene)-polyethylene oxide (PEO) is 10 to 30 wt%.

A method for manufacturing a semi-transparent electromagnetic wave shielding structure using an ink for 3D printing according to an additional embodiment of the present invention includes: preparing a MAX phase represented by the following Chemical Formula 1; synthesizing MXene by etching the layer A of the MAX phase compound represented by Formula 1; preparing a composite ink by mixing the maxine (MXene) with polyethylene oxide (PEO) and deionized water (DI water); and printing the electromagnetic wave shielding structure using the dispenser.

[Formula 1]

M _n+1 AX _n

In Formula 1, M is an early transition metal, A is at least one selected from the group consisting of Al, Si, P, S, Ga, As, In, Sn, Tl and Pb, and X is carbon or It contains any one of nitrogen, and n is an integer of 1 to 3.

The preceding transition metal is Ti.

The composite ink is maxine (MXene)-polyethylene oxide (PEO), and the maxine is represented by formula (2).

[Formula 2]

M _n+1 X _n T _x

In Formula 2, M is an early transition metal, X includes any one of carbon or nitrogen, n is an integer of 1 to 4, and T _x is a surface functional group =O, -OH, - either F.

The content of the maxine (MXene)-polyethylene oxide (PEO) in the ink is 30 wt% or less, and preferably, the content of the maxine (MXene)-polyethylene oxide (PEO) is 10 to 30 wt%.

It is also expected that this technology will serve as an opportunity for the rapid expansion of the 3D printing industry, which is currently limited to the production of prototypes, through this technology.

In addition, it is expected to show an eco-friendly effect by using water as a solvent instead of the existing volatile organic solvent.

1 shows a flowchart of a manufacturing method of ink for 3D printing according to an embodiment of the present invention.
2 is a graph showing G' is a storage modulus, and G" is a loss modulus (loss modulus).
3 is a graph showing the shear rate according to the content of maxine (MXene)-polyethylene oxide (PEO) in the 3D printing ink of the present invention.
Figure 4 shows a flowchart of a method of manufacturing a translucent electromagnetic wave shielding structure using an ink for 3D printing according to an embodiment of the present invention.
5a to 5c show the _{synthesis of Ti 3} C ₂ T _x by the MILD method, the molecular structure of PEO, and the _{formation of hydrogen bonds in Ti 3} C ₂ T _x /PEO ink, respectively.
6a to 6c show _{the rheological properties of the Ti 3} C ₂ T _x /PEO ink prepared in Examples, respectively, the viscosity versus the shear rate, the shear stress versus the shear rate, and the Ti ₃ C ₂ T _x /PEO ink. A schematic diagram of the solid-liquid transformation is shown.
Figure 7 shows the manufacturing state of the translucent electromagnetic wave shielding structure using the ink for 3D printing according to an embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS Various embodiments are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In this specification for purposes of explanation, various descriptions are presented to provide an understanding of the present invention. However, it is apparent that these embodiments may be practiced without these specific descriptions. In other instances, well-known structures and devices are presented in block diagram form in order to facilitate describing the embodiments.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements.

The terms used in the present application are used only to describe specific embodiments and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, step, operation, component, part, or combination thereof described in the specification is present, but one or more other features or steps , it should be understood that it does not preclude the possibility of the existence or addition of , operation, components, parts, or combinations thereof.

The present invention relates to a composition of an ink capable of 3D printing containing 2D MXene (transition metal carbide, nitride, carbonitride) and the implementation of a semi-transparent electromagnetic wave shielding structure using the same.

1 shows a flowchart of a manufacturing method of ink for 3D printing according to an embodiment of the present invention.

The manufacturing method of the ink for 3D printing according to an embodiment of the present invention comprises the steps of producing a MAX phase (S 110); synthesizing MXene by etching the layer A of the MAX phase compound (S 120); and mixing MXene with polyethylene oxide (PEO) and deionized water (DI water) to prepare a composite ink (S 130).

In step S 110, a MAX phase represented by the following Chemical Formula 1 is prepared.

[Formula 1]

M _n+1 AX _n

In Formula 1, M is an early transition metal, A is at least one selected from the group consisting of Al, Si, P, S, Ga, As, In, Sn, Tl and Pb, and X is carbon or It contains any one of nitrogen, and n is an integer of 1 to 3.

The preceding transition metal may be at least one selected from the group consisting of Ti, Cr, Hf, V, Mo, Ta or Nb, and most preferably Ti.

In step S 120, MXene is synthesized by etching the A layer of the MAX phase compound represented by Chemical Formula 1. The etchant used in the step of etching the A layer of the max phase compound may be any suitable etchant containing fluoride ions, and is preferably one from the group consisting _{of HF, LiF, HCl and NH 4} HF _{2 .} It is the one selected above, and LiF is most preferable.

In step S 130, a composite ink is prepared by mixing MXene, polyethylene oxide (PEO) and deionized water (DI water). In the present invention, an eco-friendly effect is achieved by using water as a solvent instead of a conventional volatile organic solvent as a solvent.

The composite ink is maxine (MXene)-polyethylene oxide (PEO), and in this case, maxine (MXene) is represented by the following formula (2),

[Formula 2]

M _n+1 X _n T _x

In Formula 2, M is an early transition metal, X includes any one of carbon or nitrogen, n is an integer of 1 to 4, and T _x is a surface functional group =O, -OH, - either F.

Preferably, the composite ink in the present invention may be Ti ₃ C ₂ T _x -polyethylene oxide (PEO).

In an embodiment of the present invention, an ink for 3D printing was prepared for a liquid deposition modeling (LDM) method, and in this case, the content of maxine (MXene)-polyethylene oxide (PEO) in the ink is preferably controlled to 30wt% or less, More preferably, it is preferably controlled to 10 to 30 wt%.

2 is a graph showing G' is a storage modulus, and G" is a loss modulus (loss modulus). In the graph of FIG. 2, 3D printing is possible when G'>G", and G'< The point at which G" becomes a crossover point is called a crossover point. At a shear rate above this point, it flows in the form of a liquid, so 3D printing itself is impossible.

3 is a graph showing the shear rate at which a crossover point occurs according to the content of maxine-polyethylene oxide (PEO) in the 3D printing ink of the present invention. As shown in FIG. 3 , it can be seen that the shear rate at which the crossover point is generated increases as the content of maxine (MXene)-polyethylene oxide (PEO) increases. If it is less than 10 wt%, since the shear rate is too low, 3D printing itself by extrusion may not be properly performed during 3D printing. In addition, the content of maxine (MXene)-polyethylene oxide (PEO) is preferably controlled to 20 to 30 wt% having a certain shear rate without exceeding the crossover point.

Figure 4 shows a flowchart of a method of manufacturing a translucent electromagnetic wave shielding structure using an ink for 3D printing according to an embodiment of the present invention.

A method of manufacturing a translucent electromagnetic wave shielding structure using an ink for 3D printing according to an embodiment of the present invention comprises the steps of: preparing a MAX phase (S410); synthesizing MXene by etching the layer A of the MAX phase compound (S420); Preparing a composite ink by mixing maxine (MXene), polyethylene oxide (PEO) and deionized water (DI water) (S 430); and printing the electromagnetic wave shielding structure using the dispenser (S440). Since each step has been sufficiently described above, repeated description will be omitted. The dispenser may use a dispenser for 3D printing.

Hereinafter, the content of the present invention will be further described along with specific examples.

* Materials used

The MAX312 phase (Ti3AlC2) was manufactured by LG Chem. Hydrochloric acid (HCl, 35% - 37%) and lithium fluoride (LiF, 95.5%) were purchased from Daeong Chemical and Alfa Aesar, respectively. Poly(ethylene oxide) (PEO) with a MW of 200,000 was purchased from Sigma Aldrich.

* Synthesis of _{Ti 3} C ₂ T _{x MXene}

Ti ₃ C ₂ T _x MXene was synthesized according to the MILD (Minimum Intensive Layer delamination) method. The etchant solution was prepared by stirring 3 g of LiF in 60 mL of 6M HCl via magnetic stirring. After complete dissolution, 3 g of Ti3AlC2 MAX phase was carefully added to prevent explosive reaction and stirred at 50°C for 24 h. The overall reaction when using the MILD method is shown in the reaction equation below.

Ti ₃ AlC ₂ + 3LiF + 3HCl → Ti ₃ C ₂ + AlF ₃ +3LiCl +3/2H ₂

After a reaction time of 24 hours, a solid precipitate of acidic product was collected in the form of a cake by vacuum filtration. The cake was washed with 3M HCl to remove residual LiF and Al using a rotation/revolution mixer and separated by vacuum filtration. This procedure was repeated several times. HCl and then washed and washed with deionized water Ti ₃ C ₂ T _x T _x a Ti ₃ C ₂ in the same process until the pH exceeds 6, the solution (DI water).

* _{Preparation of Ti 3} C ₂ T _x / PEO ink

Ti ₃ C ₂ T _x / PEO inks were prepared using a rotary/revolutionary mixer. The ratio of Ti ₃ C ₂ T _x to PEO was determined to be 8:2 based on electrical conductivity. Ti ₃ C ₂ T _x and PEO were co-dissolved in deionized water (DI) to vary the total solids content of the ink (eg 10/20/30 wt.%). _{Ti 3} C ₂ T _x was dispersed in the PEO matrix after the rotation/revolution speed was gradually increased to achieve a high distribution. After the mixing process, deionized water was added to compensate for solvent loss due to evaporation due to heat generated in the high shear mixing process.

* 3D printing

To investigate the _{3D printability of the inks, the viscosity and shear stress behavior of Ti 3} C ₂ T _x /PEO 3D printable inks were evaluated using the AREG2 instrument at 500 μm spacing under cone and plate mode varying shear rates between 0.01 and 1000. was measured as a function of shear rate.

The LDM method was applied to the 3D printed EMI shielding structure. The LDM 3D printing process was performed using a pneumatic dispenser. The ink was placed in a 3cc Luer-lock syringe and injected through a 20 gauge. (ID, 0.61mm) The syringe head was moved horizontally along the designed trajectory in the XY plane and Ti ₃ C ₂ T _x / PEO ink is now layer complete. It was extruded by applying pneumatic pressure until

In this example, a 3D printed MXene architecture for EMI shielding applications was fabricated. First, a 3D printing aqueous Ti ₃ C ₂ T _x / polyethylene oxide (PEO) composite ink for LDM 3D printing was prepared. _{By enabling numerous reversible hydrogen bonds between Ti 3} C ₂ T _x and PEO in water, they provided thixotropic properties for rapid solid-liquid transition, providing inks capable of 3D printing. In addition, the EMI shielding performance was studied by applying the ink to a 3D printed EMI shielding architecture with translucency.

To prepare an aqueous 3D printable composite ink for LDM 3D printing, Ti ₃ C ₂ T _x and PEO were uniformly dispersed by high shear mixing in deionized water. PEO was selected as a binder in the ink formulation to take advantage of its hydrophilic properties and _{high compatibility with Ti 3} C ₂ T _{x .}

Using deionized water (DI water) as the solvent minimizes the environmental impact compared to the volatile organic solvents used in previous studies, making the ink system much more environmentally friendly. The Ti ₃ C ₂ T _x / PEO ink dispersion showed high stability without phase separation, which _{may indicate high compatibility between Ti 3} C ₂ T _x , PEO and DI water.

The prepared ink exhibited a typical behavior of a thixotropic fluid, which showed that η gradually decreased when subjected to external agitation, thereby recovering the viscosity and/or modulus when not shaken. Through these properties, the extruded Ti ₃ C ₂ T _x / PEO ink can rapidly solidify into continuous filaments and form 3D objects. The _{thixotropy of Ti 3} C ₂ T _x /PEO ink was obtained by the formation of numerous hydrogen bonds, and as shown in Figs. 5a and 5b, Ti ₃ C ₂ T _x is a potential hydrogen bonding site (-F and -O). There are many and PEO has potential hydrogen bonding sites (-O) that are repeated over and over again, so multiple hydrogen bonding occurs when the two materials are mixed together (Fig. 5c). These hydrogen bonds break when the external shear stress exceeds the yield stress, but reform when the shear stress is reduced to zero.

For the _{study of the thixotropy of Ti 3} C ₂ T _x /PEO inks, rheological investigations were performed at three different concentrations of 10/20/30 wt.%. The viscosity (η) and shear stress (τ) responses of Ti ₃ C ₂ T _x ^{/PEO inks were measured by varying the shear rate from 10 −1} to 10 ³ , and the results are shown in FIGS. 6A and 6B . η and τ over the entire shear rate range demonstrated that the developed ink exhibited typical thixotropic behavior.

The overall η of the Ti ₃ C ₂ T _x /PEO ink increases with the solid loading content and exhibits the typical shear dilution behavior of non-Newtonian fluids over the entire shear rate range, indicating that the ink system is a rheological fluid inconsistent with respect to η. . (Fig. 6a). For example, η for 30 wt.% Ti ₃ C ₂ T _x /PEO ink was continuously varied and decreased from ~18,000 Pa·s to 4 Pa·s with increasing shear rate. In addition, _{the viscosity η of Ti 3} C ₂ T _x / PEO ink 30 wt.% was ~18,000 Pa·s at a shear rate of 0.01, 180 times thicker than that of toothpaste (~100 Pa·s), a representative thixotropic fluid. The viscosities of the 20 wt.% and 10 wt.% inks at a shear rate of 0.01 were ~92,500 Pa·s and ~28,500 Pa·s, respectively. Due to this very high viscosity, it was confirmed that the extruded ink formed continuous filaments (Fig. 6c) and the printed layers were well agglomerated with each other. Through this, the electromagnetic wave shielding structure could be made, and the manufacturing state of the translucent electromagnetic wave shielding structure using ink for 3D printing according to an embodiment of the present invention can be seen in FIG. 7 .

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can.

Claims (11)

preparing a MAX phase represented by the following Chemical Formula 1;
[Formula 1]
M _n+1 AX _n
In Formula 1, M is an early transition metal, A is at least one selected from the group consisting of Al, Si, P, S, Ga, As, In, Sn, Tl and Pb, and X is carbon or containing any one of nitrogen, n is an integer of 1 to 4,
synthesizing MXene by etching the layer A of the MAX phase compound represented by Formula 1; and
Including the step of preparing a composite ink by mixing maxine (MXene) and polyethylene oxide (PEO) and deionized water (DI water),
A method of manufacturing ink for 3D printing.
The method of claim 1,
The preceding transition metal is Ti,
A method of manufacturing ink for 3D printing.
The method of claim 1,
The composite ink is maxine (MXene)-polyethylene oxide (PEO),
The maxine is represented by Formula 2,
[Formula 2]
M _n+1 X _n T _x
In Formula 2, M is an early transition metal, X includes any one of carbon or nitrogen, n is an integer of 1 to 4, and T _x is a surface functional group =O, -OH, - any of F,
A method of manufacturing ink for 3D printing.
4. The method of claim 3,
The content of the maxine (MXene)-polyethylene oxide (PEO) in the ink is 30wt% or less,
A method of manufacturing ink for 3D printing.
5. The method of claim 4,
The maxine (MXene) - the content of polyethylene oxide (PEO) is 10 to 30 wt%,
A method of manufacturing ink for 3D printing.
Claims 1 to 5, prepared according to any one of the method, 3D printing ink.
preparing a MAX phase represented by the following Chemical Formula 1;
[Formula 1]
M _n+1 AX _n
In Formula 1, M is an early transition metal, A is at least one selected from the group consisting of Al, Si, P, S, Ga, As, In, Sn, Tl and Pb, and X is carbon or containing any one of nitrogen, n is an integer of 1 to 3,
synthesizing MXene by etching the layer A of the MAX phase compound represented by Formula 1;
preparing a composite ink by mixing the maxine (MXene), polyethylene oxide (PEO) and deionized water (DI water); and
Including the step of printing the electromagnetic wave shielding structure using a dispenser,
A method of manufacturing a translucent electromagnetic wave shielding structure using ink for 3D printing.
8. The method of claim 7,
The preceding transition metal is Ti,
A method of manufacturing a translucent electromagnetic wave shielding structure using ink for 3D printing.
8. The method of claim 7,
The composite ink is maxine (MXene)-polyethylene oxide (PEO),
The maxine is represented by Formula 2,
[Formula 2]
M _n+1 X _n T _x
In Formula 2, M is an early transition metal, X includes any one of carbon or nitrogen, n is an integer of 1 to 4, and T _x is a surface functional group =O, -OH, - any of F,
A method of manufacturing a translucent electromagnetic wave shielding structure using ink for 3D printing.
10. The method of claim 9,
The content of the maxine (MXene)-polyethylene oxide (PEO) in the ink is 30wt% or less,
A method of manufacturing a translucent electromagnetic wave shielding structure using ink for 3D printing.
11. The method of claim 10,
The maxine (MXene) - the content of polyethylene oxide (PEO) is 10 to 30 wt%,
A method of manufacturing a translucent electromagnetic wave shielding structure using ink for 3D printing.

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