KR20190063918A - Manufacturing method of multi-scale porous three-dimensional suspended structures using super or sub critical fluid and three-dimensional suspended structures thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a multi-scale porous 3D structure using a supercritical or subcritical fluid and the multi-scale porous 3D structure. The present invention, specifically, relates to a manufacturing method of a multi-scale porous 3D structure having a structure in which micro-scale and nano-scale pores are mixed in a polymer material, through a post-treatment process for controlling a nucleation rate and size distribution while making a carbon dioxide fluid into a supercritical or subcritical state and penetrating the product into a polymer material, after using a 3D printing technique to manufacture the polymer material into a 3D structure having a milli-scale or micro-scale void structure. The present invention also relates to the multi-scale porous 3D structure manufactured thereby.

Description

Technical Field The present invention relates to a method for manufacturing a multi-scale porous three-dimensional structure using a supercritical or subcritical fluid and a multiscale porous three-dimensional structure using the same. }

The present invention relates to a method for manufacturing a multiscale porous three-dimensional structure using a supercritical or subcritical fluid and a multiscale porous three-dimensional structure, and more particularly, to a method for manufacturing a multiscale porous three- And a supercritical or subcritical carbon dioxide fluid is permeated into the polymer material and then grown to form a multi-scale porous structure in which micro-scale and nanoscale pores are mixed. ≪ / RTI > relates to a technique for manufacturing a three-dimensional porous structure.

Generally, a three-dimensional printing technique includes a nozzle body member detachably mounted on a nozzle body member and a needle member discharged on the other surface of the nozzle body member, and a molten filament manufacturing method based on extrusion-spinning a molten polymer solution through a needle member (fused filament fabrication).

In another three-dimensional printing technique, a filament feeding pipe is disposed at the upper center of the nozzle body to serve as a piston, so that the extruded micro fibers are squeezed and adhered to each other by relative movement with a bed controlled in temperature There is a way.

3D printing technology was a rapid prototyping method that was simply made to check the design product shape or to check the prototype, but now it is spreading rapidly to various industrial fields due to the development of technology. In particular, it is a lamination processing technology that can easily cope with design changes in a manner suitable for modern small-lot order production. In addition, it is a manufacturing method that is expected to achieve one industry by being applied to various fields because the system configuration is simple, easy to use, and relatively easy to access.

However, despite the advantages described above, when the conventional three-dimensional printing technology is used, a suspended three-dimensional structure in which a discontinuity exists due to abrupt and high viscosity of a polymer melt discharged through a nozzle ). ≪ / RTI >

In addition, as a general manufacturing method using a conventional three-dimensional printing technique, there is a problem that it is difficult to manufacture a structure having a microscale or nanoscale shape due to the limitation of the accuracy of the transfer device.

Due to these limitations, most 3D printing techniques recommend a possible continuous ejection method by changing the direction of lamination manufacturing, or outputting ancillary supports together to remove them during post-processing. Thus, most processes are limited to continuous two-dimensional shapes such as sheets.

In the past, research and commercialization of techniques for forming microscale pores in polymer sheets have been conducted, and research and development on pores of nanoscale have recently been progressed. Until now, research on single-scale polymer sheets has been the mainstream.

However, in the material made of a single scale, the control of the physical properties is narrow and the control is limited. The material with the lowest known coefficient of thermal conductivity to date is known as aerogels, but its application is very limited because it is too weak to break easily.

For this reason, conventional microscale or nanoscale structures have been applied to simple and continuous shapes such as thin films, films, and sheets.

Particularly, a polymer thin film or sheet having a pore diameter of 10 nm to 100 μm can be manufactured. However, when the pore diameter is increased, the membrane wall is broken and shrunk to obtain desired excellent physical properties, and only a few hundred micron pores are present The strength is greatly reduced.

As a general process, both microscale and nanoscale pores are present at the same time and the desired size distribution can not be obtained.

Korean Registered Patent Publication No. 10-1506704 (March 23, 2015) Japanese Laid-Open Patent Publication No. P2015-226935A (Dec. 17, 2015)

In order to solve the above problems, an object of the present invention is to make a polymer material into a three-dimensional structure having a mill scale or a micro-scale air gap structure by using a three-dimensional printing technique and then to make a carbon dioxide fluid into a supercritical or subcritical state A method of manufacturing a multi-scale porous three-dimensional structure having a structure in which microscale and nanoscale pores are mixed in a polymer material through a post-treatment process of controlling nucleation rate and size distribution while infiltrating into a polymer material And a multi-scale porous three-dimensional structure manufactured therefrom.

According to another aspect of the present invention, there is provided a method of forming a three-dimensional structure, the method including: forming a three-dimensional structure having a mill scale or a micro-scale void structure by three-dimensionally printing with a polymer material;

A step (S200) of stabilizing the three-dimensional printed three-dimensional structure through a curing and drying process;

(S300) of introducing the working fluid into the supercritical or subcritical fluid region through the multi-stage compression and multi-stage cooling process in the reactor;

(S400) penetrating and diffusing supercritical or subcritical working fluid into the three-dimensional structure in the reactor;

(S500) of adjusting the process flow from the supercritical fluid region to the liquid region through the depressurization and cooling / heating process to form the size and distribution of the multi-scale forer cell inside the three-dimensional structure;

And then drying the three-dimensional structure having the multi-scale porous structure formed therein (S600). The method for manufacturing a multi-scale porous three-dimensional structure using the supercritical or subcritical fluid is also provided.

In a preferred embodiment, the step (S100) may be a step of printing a three-dimensional structure of a suspended freeform having a mill scale or micro-scale void structure.

In a preferred embodiment, the step (S100) may be configured to incorporate hollow particles or nano-fillers or graphene nanoplets into the polymer material during three-dimensional printing to promote bubble generation in which uneven forer cell formation is initiated.

In a preferred embodiment, step (S100) is a step of changing the printing speed in three-dimensional printing to change the internal residual stress of the output of the three-dimensional structure, thereby controlling the formation and distribution of pores in a subsequent process .

In a preferred embodiment, the step (S100) may be performed by changing the printing height in three-dimensional printing to change the aspect ratio (aspect ratio) of one layer of the output path, stacking it at an arbitrary height, So that the shape and size distribution of the bubbles can be controlled in the process.

In a preferred embodiment, the step (S500) comprises the steps of: maintaining the state of the working fluid for a certain time for forer cell growth or forocell coalescence or forer cell stabilization; And expanding or heating the working fluid in multiple stages.

In a preferred embodiment, the step (S500) comprises the steps of: maintaining a working fluid at a constant pressure and a constant temperature for a predetermined time; The step of decompressing and cooling / heating the working fluid may be carried out at least twice or more times.

In a preferred embodiment, the step (S500) comprises the steps of providing a fixture for fixation or a resilient support using a porous metal plate or mesh to a multi-scale porous three-dimensional structure, Thereby relieving the stress and maintaining the original shape.

In a preferred embodiment, step (S500) may comprise setting the temperature within the +/- 10% range based on the absolute temperature of the glass transition temperature of the polymeric material used for for cell growth.

In a preferred embodiment, the step (S500) comprises the steps of pressurizing at a liquid storage temperature of room temperature, maintaining a low temperature of 0 DEG C or less maintained at a supercritical state for a predetermined time, And adjusting the pressure to adjust the inner nucleation parallax to perform at least one step of the pressure drop.

The present invention also provides, in another embodiment,

Dimensional structure by using the supercritical or subcritical fluid, the outside of the three-dimensional structure is formed to have a mill scale or micro-scale void structure, and the inside of the polymer material constituting the three- Dimensional porous structure having a multi-scale porous structure in which a micro-scale pore and a nanoscale pore are mixed.

In a preferred embodiment, the three-dimensional structure may be a suspended free-form structure.

In a preferred embodiment, the interior of the polymer material constituting the three-dimensional structure may be formed by surrounding a plurality of nanoscale pores around one microscale pore.

The present invention having such characteristics as described above can freely adjust the physical properties of the structure and the product of the three-dimensional structure by selectively controlling the formation of the multi-scale pores consisting of microscale and nanoscale within the functional three-dimensional structure, It is possible to manufacture a product in the form of a three-dimensional structure having various types of tissues and flexibility by using two or more process conditions in combination.

Further, the present invention can manufacture a three-dimensional structure having a pore scale of millimeter or micrometer or more by adjusting the nozzle output interval in the three-dimensional printing process, thereby enabling the size and shape of the outer pore to be adjusted. This has the effect of significantly increasing the rate at which the supercritical or subcritical fluid penetrates and diffuses into the polymer by significantly increasing the unit surface area and significantly shortening the process time.

In addition, arbitrarily controlling the size and shape of the inner pores of the foaming polymer can remarkably improve thermal, dielectric, and permeability properties.

In addition, in solid state foaming, since the shape and size distribution of various pores are different according to the process conditions in the inside, the flexibility and the heat insulating property are excellent and the cell is not generated on the outer surface. Therefore, It is possible to obtain a high-performance functional material having high compressive strength and high bending strength per unit mass.

In addition, the multi-scale porous three-dimensional structure to which the technology according to the present invention is applied has not only a low thermal conductivity coefficient but also a strength of a super insulative material having excellent strength and cost competitiveness and has a large number of nanoscale pores Is formed to have a considerable thickness. Thus, the Knudsen effect remarkably lowers the thermal conductivity coefficient, thereby achieving an excellent performance as a high-performance functional material.

As described above, the present invention is a useful invention having various effects, and the invention is highly expected to be used in industry.

FIG. 1 is a process flow chart for manufacturing a multi-scale porous three-dimensional structure according to an embodiment of the present invention,
FIG. 2 is a conceptual view of a multi-scale pore formed in a polymer material according to an embodiment of the present invention,
3 is an example of a cross-sectional view of a suspended three-dimensional structure provided in three-dimensional printing according to an embodiment of the present invention,
FIG. 4 is a view showing a multi-scale porous three-dimensional structure manufactured by post-processing using a supercritical fluid after printing a three-dimensional structure according to an embodiment of the present invention,
5 is a scanning electron microscope (SEM) photograph of a specimen section manufactured according to an embodiment of the present invention,
FIG. 6 is a diagram of a super critical point, a state diagram showing a triple point, and a process path (decompression and cooling or heating process) of a working fluid (CO2) used in the present invention,
7 and 8 are graphs showing an example of the number of pores, the probability distribution function, and the expansion ratio when the technique of the present invention is applied,
9 is a graph showing an example of cell density and nucleation density when the technique of the present invention is applied,
FIGS. 10 and 11 are graphs showing photographs and distribution functions of pores in a multiscale three-dimensional structure to which the present invention technology is applied.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention relates to a method for producing a polymer having a free form of a polymer having a very large surface area per unit area by using a three-dimensional printing technique, a polymer (co-polymer), a mixture of two or more kinds of polymers, Rapidly saturated with suspended solids in a supercritical or subcritical fluid having high permeability to polymers, high solubility, and high diffusing properties, in suspending structures, By applying the critical fluid process technology to obtain foam with desired properties by controlling the size and distribution of the pores formed inside the polymer by controlling the pressure and temperature by using the pore growth mechanism, A pore having a size of a microscale or a nanoscale, and a pore having a size of a mill scale or a micro scale Dimensionally porous three-dimensional structure by forming a suspended freeform three-dimensional structure formed to have a gap equal to or larger than a kale size. The millimeter scale, the microscale scale, and the nanoscale scale are referred to as a millimeter scale, a micrometer scale, and a nanometer scale. Hereinafter, the scale is referred to as a mill scale, a microscale, and a nanoscale .

Although the three-dimensional printing technique has been described mainly for the material extrusion method (ME, FFF, FDM) for the sake of convenience, a three-dimensional printing technique may also be applied to other methods such as photopolymerization (PP) BJ (binder jetting) for spraying only the binder onto the material powder, powder bed fabrication (PBF) for bonding the particles on the fixed bed, together with the particles (MJ, material jetting) It is also possible to use a method of increasing the surface area per unit mass by manufacturing a free-form free shape by using a direct energy deposition (DED) method in which a high-power energy source is irradiated and fused.

In addition, the present invention can control the nucleation rate and size distribution in a desired direction by controlling the process path and process speed of the supercritical / subcritical fluid in the prepared three-dimensional free porous structure, It is possible to manufacture a three-dimensional structure having a structure of a structure in which porous pores of several hundreds of nm and about 1 to 1000 μm are scattered and surrounds a large number of nanoscale pores around large pores of a microscale. In this step, the prepared three-dimensional structure is placed in a batch reactor, and supercritical or subcritical fluid, typically liquid carbon dioxide, is pumped into the supercritical, The step of forming a nucleus in the three-dimensional structure by controlling the pressure reduction rate, the temperature holding time and the post-treatment forming temperature at a pressure level of at least one step or more, This gives a pore of the desired size and distribution. Through this, a multi-scale porous structure can be manufactured by controlling various structures and sizes and distributions of internal pores, and a three-dimensional structure having desired physical properties can be manufactured according to process conditions and process paths.

The supercritical fluid process applied to the present invention, particularly supercritical carbon dioxide-based foaming technology, has attracted much attention as a clean production technology that does not use solvents harmful to the global environment. This is because supercritical fluids exhibit excellent solvent properties with a very high diffusion rate and solubility in the medium. Nanoscale foams have received much attention due to the Kudsen effect, where the pore size is substantially equal to the average free path of air (about 70 nm) at standard atmospheric pressure and temperature, which significantly reduces the thermal conductivity coefficient of the gas. The heat transfer in the material consists of the heat transfer through the solid, the heat transfer through the gas, the convection heat transfer through the gas, the radiation heat transfer through the pore, and the coupling effect between the medium.

In transparent amorphous polymers such as PMMA and PC, when the pore size is significantly smaller than the wavelength of the visible light, the light transmittance is very high. In addition, it can be utilized for filtration, gas separation, energy storage, catalyst support, and the like.

Thus, by realizing a multi-scale three-dimensional structure in which a large number of nanoscales exist around the microscale pores inside the polymer, it is possible to remarkably expand the physical properties and the control range.

In addition, the multi-scale three-dimensional structure technique is highly useful in the development of a high-performance high-performance material having a remarkably excellent strength as an atypical discontinuous suspension form. In the suspended three-dimensional structure according to the present invention, It is possible to manufacture a material having micro-scale and nanoscale pores and to control the physical properties such as porosity, strength, permeability and density of the produced matrix, thereby making it possible to produce a high- do.

2 is a conceptual view of a multi-scale pore formed in a polymer material according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a multi- Figure 4 is a cross-sectional view of a suspended three-dimensional structure provided in three-dimensional printing in accordance with an embodiment of the present invention. Figure 4 is a cross- FIG. 5 is a scanning electron microscope (SEM) photograph of a specimen section manufactured according to an embodiment of the present invention. FIG.

As shown in the drawing, the present invention has a step (S100) of forming a three-dimensional structure 1 having a mill scale or micro scale gap 10 structure by three-dimensionally printing with a polymer material.

At this time, the three-dimensional structure having a millisecale pore structure is preferably three-dimensionally printed in the form of a structure having a suspended freeform. Structures with suspended freeform have a very large surface area per unit mass, so that the diffusion of the supercritical fluid is very fast, which is a good environment for loading micro-scale pores, nanoscale pores or micro-nanoscale pores in the interior .

In addition, the flexibility and strength of the structure are controlled by adjusting the aspect ratio of the laminate section once for three-dimensional printing according to the purpose. In this case, since there is a characteristic that pores are difficult to be generated in the outer periphery once laminated in the 3D printing, the shape of the pendant structure is printed by laminating several times.

In addition, when the polymer material is three-dimensionally printed, the cross section of the formed shape resembles a flattened tube, so that most of the expansion occurs in the thickness direction and inside.

In addition, since the contact area of the outer surface of each layer is large, the tear strength is increased, so that slip between the layers at the time of loading hardly occurs and flexibility is increased.

In addition, since the interval and direction between neighboring layers can be freely adjusted, it is possible to manufacture a freeform that can adjust the interval of the outer contact surfaces from the mill scale to the microscale, and thus the penetration diffusion in the supercritical or subcritical fluid process The speed can be greatly improved and the process time can be significantly reduced.

3 is a sectional view of the three-dimensional structure, but the angle of the atypical grid line can be arbitrarily changed or adjusted when viewed from above.

In addition, the heat transfer path becomes longer (tortuosity (folding property, increased meandering)), and it becomes possible to have high performance insulation, sound absorption and insulation characteristics.

As the material of the filament which is used for the three-dimensional printing, a single polymer (including a copolymer) including thermoplastic such as PLA, PET, PC, PMMA, PEI, and PBT and a combination thereof may be used .

In addition, a polymer material that acts as a nucleation promoter that promotes the formation of bubbles in which heterogeneous nuclei are formed by incorporating hollow microparticles, nanoparticles, and graphene nano-platelets into a polymer material used for three-dimensional printing Filaments can be used.

In the reactor, when a pore grows inside the polymer material, nano-fillers such as hollow microparticles, nanoparticles and graphene nano-platelets are present in the walls or inside of the polymer, It becomes possible to manufacture a high-performance heat insulating material serving as a scattering mechanism. That is, the saturation concentration of the subcritical fluid can be increased under the low temperature process condition, and the efficiency of pore generation can be increased by using less energy.

In addition, nanofibers can increase toughness and improve mechanical strength.

In addition, the printing speed can be changed during the three-dimensional printing to change the internal residual stress of the printout, so that printing can be performed so as to affect formation and distribution of pores in the subsequent process.

In addition, when the printing height is changed in three-dimensional printing, the shape and size distribution of the pores can be controlled in the subsequent process by changing the aspect ratio (aspect ratio) of one cross section of the output path.

And then stabilizing the three-dimensional printed three-dimensional structure through the curing (cooling) and drying processes (S200).

And then introducing the working fluid into the supercritical or subcritical fluid region through the multi-stage compression and multi-stage cooling process in the reactor (S300). A carbon dioxide fluid is preferably used as a working fluid to be used at this time. This step also introduces the working fluid into the supercritical fluid or subcritical fluid region through the multi-stage compression / multi-stage cooling process to improve the adsorption performance. At this time, the carbon dioxide used as the working fluid can be configured so that the recovery system is supplied and recovered through the integrated recirculation system.

Thereafter, the step of penetrating and diffusing the supercritical or subcritical working fluid into the three-dimensional structure (S400) is performed in the reactor.

This step may include adjusting the concentration gradient within the three-dimensional structure.

Thereafter, adjusting the process path from the supercritical fluid region to the liquid region through the depressurization and cooling / heating process (S500) for forming the size and distribution of the multi-scale pores inside the three-dimensional structure. Here, the liquid region is a gas at atmospheric pressure, but in most cases, it is a liquid region because the inside of the reactor is at a high pressure. Depending on the route, it may be gas, but the possibility is extremely low.

This step may include a step of waiting for a predetermined period of time at a certain pressure / constant temperature for the working fluid for the forerel growth or the forecell coalescence or forer cell stabilization in the polymer material constituting the three-dimensional structure. That is, it may include a step of maintaining the reaction tank in the thermostat bath for about 10 minutes or less (usually, 3 minutes or less).

The operation fluid may be maintained at a constant pressure for a predetermined time without changing the state of the working fluid, and the pressure reducing and cooling / heating operations may be performed at least two times. Here, the time of each process is arbitrarily distributed based on the equilibrium or the equal ratio.

This step may also include setting the temperature within the +/- 10% range based on the absolute temperature of the glass transition temperature of the polymeric material used for for cell growth.

In addition, this step is performed at a liquid storage temperature of room temperature, and after passing through a supercritical state, it is maintained at a low temperature of 0 ° C or lower. After equilibrium is reached, pressure And controlling the inner nucleation parallax by adjusting the inner nucleation time difference.

This step adjusts the size and size distribution of the pores distributed within the polymer material by setting and controlling the process conditions (dP, T_foam, t_foam).

In this step, the porous multi-scale porous three-dimensional structure is provided with a porous metal plate or an elastic support such as a shape fixture or spring using a plurality of mesh having different mesh sizes (mesh number) And a step of maintaining the original plane by alleviating the residual stress in the three-dimensional structure generated in the course of performing the path maintenance step. In other words, it is a step to suppress non-uniform expansion during expansion due to non-uniform residual stress distribution inside the polymer in the post-foaming process set for for-cell growth.

Thereafter, drying the three-dimensional structure having the multi-scale porous structure (S600) is performed. This step is to block the change of additional forer cell; An immobilization step in a low-temperature thermostat bath, and an oven-drying step.

When the above step is performed, the outside of the three-dimensional structure 1 printed with a three-dimensional pattern using the polymer material is formed to have a mill scale or a microscale gap 10 structure, and the inside of the polymer material constituting the three- A multi-scale porous three-dimensional structure having a multi-scale porous structure in which the scale pores 11 and the nanoscale pores 12 are mixed is manufactured.

The multi-scale porous three-dimensional structure, which is a three-dimensional structure of the present invention in which a multi-scale pore is formed according to the present invention, can reduce the manufacturing cost and increase the pore formation efficiency by designing and manufacturing various shapes of the molten filament. Productivity can be increased by adjusting the size and spatial distribution of the intrinsic pores.

This multi-scale porous three-dimensional structure manufacturing technology is a high performance functional material industry such as insulation, absorption, filtration, fuel cell filtration, separation of gas, energy storage, catalyst support and tissue engineering scaffold, dielectric property, Special materials industry for military, and other decorative arts.

Specific applications include high performance insulation, window frames that can withstand high airtightness and load, insulation materials for skyscrapers, filter materials for fine dust removal, core of vacuum insulation panels (VIP), energy storage Functional films for devices, functionally graded materials, plant culture support materials in plant factories, and the like. In other words, the high performance functional materials industry such as insulation, sound absorption, vibration damper (dustproof material), filtration filter, fuel cell, separation of gas, separation of energy, energy storage and catalyst support, biomaterial industry such as scaffold and artificial bone for artificial cell culture tissue engineering, dielectric materials, electromagnetic shielding, in-situ resource utilization, cultural industries such as the construction industry, space industry, clean production, environment-friendly energy industry, and other decorative arts.

FIG. 5 is a scanning electron micrograph (SEM) (magnification: 100x, 10,000x, 30,000x, and 50,000x) of a cross section of the right photograph of FIG.

FIG. 6 is a schematic diagram of a CO2 phase diagram of a supercritical point, a triple point state diagram and a process path (decompression and cooling process) of a working fluid (CO2) used in the present invention, And on the right is the pressure-enthalpy diagram of CO2, optionally with three process paths in red, blue and green color. The process path (decompression, cooling or heating process) generally cools down at the same time during the decompression process (eg up to the pressure specified at 10 MPa = 100 atmospheres) and then reaches a balance state In the multi-step process of the present invention, the next cooling process is performed before the equilibrium state is established.

FIGS. 7 and 8 are graphs showing an example of the number of pores, the probability distribution function, and the expansion ratio when the technique of the present invention is applied.

7 shows the relationship between the size of the forer cell and the number of foreshells obtained by image processing the SEM photographs for each experimental condition (eg saturation temperature: -20 ° C., postfoaming temperature: 20 ° C. to 80 ° C.) (Solid vertical line, bar graph), and the solid line shows the distribution of the density as a function of the log-normal probability distribution function (PDF) and the cumulative distribution function (CDF) One example of a result (right vertical axis, red and blue curves).

FIG. 8 is a graph showing the expansion ratios of the three-dimensional structure and the filament according to saturation temperature: -20 ° C., saturation pressure: 5 MPa, postfoaming temperature: 20 ° C., 40 ° C., 60 ° C. and 80 ° C.

FIG. 9 is a graph showing an example of cell density and nucleation density when the technique of the present invention is applied. FIG. 9 is a graph showing the number density and nucleation density of forells per unit volume (cc) under the condition of FIG.

10 and 11 are graphs showing a photograph and a distribution function of a pore in a multiscale three-dimensional structure to which the technique of the present invention is applied, and Fig. 10 is a graph showing a photograph of a pore in a multiscale three- FIG. 11 shows an example of a multi-scale probability distribution function and a cumulative distribution function by image processing a cross-sectional photograph of a multi-scale three-dimensional structure in which a microscale forer cell and a nanoscale pore are present together And controlling the size and distribution of the pores by controlling the process.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims and their equivalents. Of course, such modifications are within the scope of the claims.

(1): Porous three-dimensional structure
(10): Millimeter or micro-scale air gap
(11): Microscale Pore
(12): Nanoscale pores

Claims (13)

Dimensional printing with a polymer material to form a three-dimensional structure having a milky-scale pore structure (S100);
A step (S200) of stabilizing the three-dimensional printed three-dimensional structure through a curing and drying process;
(S300) of introducing the working fluid into the supercritical or subcritical fluid region through the multi-stage compression and multi-stage cooling process in the reactor;
(S400) penetrating and diffusing supercritical or subcritical working fluid into the three-dimensional structure in the reactor;
(S500) of adjusting the process flow from the supercritical fluid region to the liquid region through the depressurization and cooling / heating process to form the size and distribution of the multi-scale forer cell inside the three-dimensional structure;
(S600) drying the three-dimensional structure having the multi-scale porous structure formed thereon. The method for manufacturing a multi-scale porous three-dimensional structure using supercritical or subcritical fluid according to claim 1,
The method according to claim 1,
Wherein the step (S100) is a step of printing with a three-dimensional structure of a suspended freeform having a mill scale pore structure. The method of manufacturing a multi-scale porous three-dimensional structure using supercritical or subcritical fluid according to claim 1,
The method according to claim 1,
In the step (S100), the hollow particles, the nanofiller, or the graphene nanoflash are mixed with the polymer material during the three-dimensional printing, thereby promoting the formation of bubbles in which the formation of the heterogeneous forer cell is started. A method for manufacturing a multi -
The method according to claim 1,
The step (S100) is a step of changing the printing speed during 3D printing to change the internal residual stress of the output of the three-dimensional structure, thereby controlling the formation and distribution of pores in the following process. Method of manufacturing a multi - scale porous three - dimensional structure using critical or subcritical fluid.
The method according to claim 1,
In the step (S100), in the three-dimensional printing, the printing height is changed to change the aspect ratio (aspect ratio) of one cross section of the output path or to laminate at an arbitrary height, or to adjust the shape And controlling the size distribution of the porous multi-functional three-dimensional structure by using the supercritical or subcritical fluid.
The method according to claim 1,
The step (S500) may include maintaining a predetermined pressure and a constant temperature for a predetermined period of time without changing the state of the working fluid for forer cell growth or forer cell coalescence or forer cell stabilization; And expanding or heating the working fluid in a multi-stage manner. The method for manufacturing a multi-scale porous three-dimensional structure using supercritical or subcritical fluid according to claim 1,
The method of claim 6,
In operation S500, the operation fluid is maintained at a predetermined pressure and a predetermined temperature for a certain period of time; Wherein the step of depressurizing and cooling / heating the working fluid is performed at least twice or more. ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
In the step (S500), a shape fixing fixture or an elastic support using a porous metal plate or mesh is installed on the multi-scale porous three-dimensional structure to relax the residual stress in the three-dimensional structure generated during the process path maintenance step, And maintaining the shape of the porous multi-functional three-dimensional structure using the supercritical or subcritical fluid.
The method according to claim 1,
The step (S500) includes setting the temperature within a range of +/- 10% based on the absolute temperature of the glass transition temperature of the polymer material used for forer cell growth. The supercritical or subcritical (Method for manufacturing multi - scale porous three -
The method according to claim 1,
The step (S500) may be performed at a liquid storage temperature of room temperature to maintain a low temperature of 0 ° C or less maintained in a supercritical state for at least a certain period of time, so as to bring about a sudden pressure drop And controlling the pressure to adjust the inner nucleation parallax so as to perform at least the step of forming the porous multi-functional three-dimensional structure using the supercritical or subcritical fluid.
A method for manufacturing a multi-scale porous three-dimensional structure using supercritical or subcritical fluid according to any one of claims 1 to 10, wherein the outer part of the three-dimensional structure is formed to have a millis- Wherein the inside of the polymer material constituting the multi-scale porous three-dimensional structure is composed of a multi-scale porous structure in which a micro-scale pore and a nanoscale pore are mixed.
The method of claim 11,
Wherein the three-dimensional structure is a pendent free-form structure.
The method of claim 11,
Wherein the inside of the polymer material constituting the three-dimensional structure is formed by surrounding a plurality of nanoscale pores around one microscale pore.

Images