KR102247349B1 - Colorimetric photonic crystal structure and use thereof - Google Patents

Abstract

The present invention relates to a color conversion photonic crystal structure and a use thereof. According to the present invention, it is possible to provide a color conversion photonic crystal structure in which a color is converted so as to be visually determined according to a change in humidity, which is an external stimulus, and by using the same, it is possible to provide a photonic crystal color conversion humidity sensor with high sensitivity and a color conversion film for preventing counterfeiting.

Description

Color conversion photonic crystal structure and its use {COLORIMETRIC PHOTONIC CRYSTAL STRUCTURE AND USE THEREOF}

The present invention relates to a color conversion photonic crystal structure and a use thereof, and in detail, to a color conversion photonic crystal structure sensitive to a change in humidity, a color conversion photonic crystal sensor using the same, and a use as a color conversion film for preventing counterfeiting.

The photonic crystal structure is a periodic arrangement of dielectric materials having different refractive indices, and overlapping interference occurs between the light scattered at each regular grid point and selectively reflects the light without transmitting it in a specific wavelength range. It refers to a material that forms an optical band gap. This photonic crystal structure uses photons instead of electrons as a means of information processing, and is emerging as a core material for improving the efficiency of the information industry due to its excellent information processing speed.

The photonic crystal structure can be implemented as a one-dimensional structure in which photons move in the main axis direction, a two-dimensional structure that moves along a plane, or a three-dimensional structure that freely moves in all directions through the entire material. It can be applied to various fields because it is easy to control characteristics. For example, it may be applied to optical devices such as solar cells, photonic crystal fibers, light emitting devices, photovoltaic devices, photonic crystal sensors, and semiconductor lasers. In particular, the Bragg stack is a photonic crystal structure having a one-dimensional structure, and can be easily manufactured only by stacking two layers having different refractive indices, and it is easy to control optical properties by adjusting the refractive index and thickness of the two layers. Has an advantage. Due to this characteristic, the Bragg stack is widely used not only as an energy device such as a solar cell, but also as a photonic crystal sensor that senses electrical, chemical, and thermal stimuli. Accordingly, research on various materials and structures for easily manufacturing a photonic crystal sensor having excellent sensitivity and reproducibility has been actively conducted.

Accordingly, the inventors of the present invention were intensifying research on the photonic crystal structure, as described later, as a polymer containing a specific substituent was included in the repeating layer of the Bragg stack, the color sensitively sensitive to changes in humidity through color conversion. It was confirmed that a converted photonic crystal structure can be provided, and the present invention was completed.

An object of the present invention is to provide a color conversion photonic crystal structure capable of color conversion so as to be sensitive to changes in humidity with high sensitivity as well as to enable immediate visual evaluation, and a use thereof.

In order to achieve the above object, in the present invention, a first refractive index layer comprising a first polymer having a first refractive index, which are alternately stacked; And a second refractive index layer including a second polymer having a second refractive index, wherein the first refractive index and the second refractive index are different, and one of the first polymer and the second polymer is represented by Formula 1 and There is provided a photonic crystal structure, which is a polymer containing the structural unit represented by Chemical Formula 2.

[Formula 1]

[Formula 2]

[In Chemical Formulas 1 and 2,

R ₁ and R ₂ are each independently hydrogen or C1-C5 alkyl;

Each R ₁₁ is independently hydroxy, halogen, nitro, C1-C5 alkyl or C1-C5 alkoxy;

L ₁ is -O- or -NH-;

Y ₁ is substituted or unsubstituted benzoylphenyl, the substitution being substituted with one or more substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy;

a is an integer selected from 0 to 7, and when a is an integer of 2 or more, R ₆ may be the same as or different from each other.]

In the photonic crystal structure according to an embodiment of the present invention, R ₁ and R ₂ in Formulas 1 and 2 are each independently hydrogen or methyl; Each of R ₁₁ is independently methyl, ethyl, propyl or butyl; L ₁ is -O- or -NH-; Y ₁ is unsubstituted benzoylphenyl; The a may be an integer selected from 0 to 3.

In the photonic crystal structure according to an embodiment of the present invention, the other of the first polymer and the second polymer may be a polymer including structural units represented by the following Chemical Formulas 3 to 5.

[Formula 3]

[Formula 4]

[Formula 5]

[In Chemical Formulas 3 to 5,

R ₃ to R ₅ are each independently hydrogen or C1-C5 alkyl;

L ₂ is -O- or -NH-;

Y ₂ is substituted or unsubstituted benzoylphenyl, the substitution being substituted with one or more substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy;

X ₁ to X ₅ are each independently -N= or -CR=, _{but at least one of X 1} to X ₅ is -N=, and R is hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6 -C20 aryl or a combination thereof;

X ₁₁ to X ₁₅ are each independently N ⁺ R'X ^- or -CR"=, but at least one of _{X 11} to X ₁₅ ^{is N +} R'X ^- , and R'and R" are each independently Hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, or a combination thereof, and X ^- is a monovalent anion.]

In the photonic crystal structure according to an embodiment of the present invention, X ₁₁ of Formula 5 is N ⁺ R'X ^- , and X ₁₂ to X ₁₅ are each independently -CR"=; X ₁₂ is N ⁺ R'X ^- and X ₁ , X ₃ to X ₅ are each independently -CR"=; Or the X ₁₃ is N ⁺ R'X ^- , and X ₁ , X ₂ , X ₄ and X ₅ are each independently -CR"=, wherein R'is methyl, ethyl, propyl, butyl, pentyl, phenyl, benzyl or phenylethyl, wherein R "is hydrogen, methyl, ethyl or phenyl, wherein X ^- is ^{F -, Cl -, Br -} , I -, ClO 4 -, SCN -, NO 3 -, or CH ₃ CO ₂ ^- can be.

In the photonic crystal structure according to an embodiment of the present invention, the polymer including the structural units represented by Chemical Formulas 3 to 5 contains 10% of the structural units represented by Chemical Formula 5 with respect to the total ratio of the structural units. It may be included in the above.

In the photonic crystal structure according to an embodiment of the present invention, the total number of stacked unit layers including the first refractive index layer and the second refractive index layer may be 5 to 30 layers.

In the photonic crystal structure according to an embodiment of the present invention, the first refractive index layer may be a high refractive index layer having a thickness of 10 to 100 nm, and the second refractive index layer may be a low refractive index layer having a thickness of 50 to 130 nm. have.

In the photonic crystal structure according to an embodiment of the present invention, a reflected wavelength may be shifted by an external stimulus.

In the photonic crystal structure according to an embodiment of the present invention, the external stimulus may be caused by a change in humidity.

In addition, in the present invention, a color conversion humidity sensor including the above-described photonic crystal structure is provided.

In the color conversion humidity sensor according to an embodiment of the present invention, the color conversion may be observed with the naked eye.

In addition, in the present invention, a color conversion film for preventing counterfeiting including the photonic crystal structure described above is provided.

The color conversion film for anti-counterfeiting according to an embodiment of the present invention may be color converted by an external stimulus having a relative humidity of 70% or more.

According to the present invention, a color may be converted to be visually determined according to a change in humidity, which is an external stimulus, and by using this, a photonic crystal color conversion humidity sensor having high sensitivity may be provided. In addition, according to the present invention, an anti-counterfeiting film is provided that can easily determine the authenticity of an article by a simple external stimulus such as breathing, and since the film can be easily handled, bills, security documents, etc. that require flexibility It has the advantage that it can be usefully applied as a security element to anti-counterfeiting products.

1 shows a color conversion photograph of the photonic crystal structure according to the present invention by breathing (0 to 6 seconds) (Examples 1 to 3),
2 shows a color conversion photograph according to the relative humidity (10 to 90%) of the photonic crystal structure according to the present invention (Examples 1 to 3 and Comparative Example 1),
3 shows a color conversion photograph according to the relative humidity (10 to 90%) of the photonic crystal structure according to the present invention (Examples 5 to 8),
Figure 4 shows a photograph of applying a humidity sensor film comprising a photonic crystal structure according to the present invention to a vial,
5 is a view for explaining a method of determining the authenticity of a bill including a forgery prevention film including a photonic crystal structure according to the present invention,
6 is a view for explaining a method of checking a QR image in a security element including a forgery prevention film including a photonic crystal structure according to the present invention,
7 shows photographs applied to a black background and a white background using a humidity sensor film formed on a TIO substrate including a photonic crystal structure according to the present invention.

The color conversion photonic crystal structure according to the present invention and its use will be described later, but unless otherwise defined in the technical and scientific terms used at this time, those of ordinary skill in the art to which this invention belongs are commonly understood. Descriptions of known functions and configurations that have meanings and may unnecessarily obscure the subject matter of the present invention in the following description will be omitted.

As used herein, the singular form may be intended to include the plural form unless otherwise indicated in the context.

Units used in the present specification without particular mention are based on weight, and as an example, the unit of% or ratio means% by weight or a weight ratio.

Numerical ranges used herein include lower and upper limits and all values within the range, increments that are logically derived from the shape and width of the defined range, all of which are limited, and the upper and lower limits of the numerical range defined in different forms. Includes all possible combinations of. As an example, when the numerical value is 100 to 10,000, and specifically limited to 500 to 5,000, the numerical range of 500 to 10,000 or 100 to 5,000 should also be interpreted as described in the specification of the present invention. Unless otherwise defined in the specification of the present invention, values outside the numerical range that may occur due to experimental errors or rounding of values are also included in the defined numerical range.

In the present specification, the term "includes" is an open-type substrate having a meaning equivalent to expressions such as "have", "includes", "have" or "features". Further, it does not exclude elements, materials or processes that are not further listed. In addition, the expression "substantially composed of?" means that other elements, materials or processes not listed together with the specified element, material, or process are unacceptable to at least one basic and novel technical idea of the invention. It means that it can be present in an amount that does not have a significant effect on.

As used herein, the term "alkyl" is an organic radical derived from an aliphatic hydrocarbon by the removal of one hydrogen, and includes both straight-chain or branched-chain forms.

As used herein, the term "alkoxy" refers to alkyl-O-*, and the alkyl follows the above definition.

As used herein, the term "cycloalkyl" is an organic radical derived from a fully saturated or partially unsaturated alicyclic hydrocarbon ring, and includes fused cyclic, bridged cyclic and spirocyclic groups, and the like. For example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, decalin, bike[3.1.1]heptane, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, bike[3.2. 2] nonane, spiro [2.5] octane, spiro [3.5] nonane, adamantyl, and the like, but is not limited thereto.

As used herein, the term "aryl" refers to an organic radical derived from an aromatic hydrocarbon by the removal of one hydrogen, suitably containing 4 to 7, preferably 5 or 6 ring atoms in each ring or fused It includes a ring system, and includes a form in which a plurality of aryls are connected by a single bond. For example, phenyl, naphthyl, biphenyl, terphenyl, anthryl, indenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, peryleneyl, chrysenyl, naphthyl, fluoranthenyl, etc. , Is not limited thereto.

As used herein, the term "halogen" refers to a fluorine (F), chlorine (Cl), bromine (Br) or iodine (I) atom.

In the present specification, the terms "high refractive index layer" and "low refractive index layer" are classified according to a difference in relative refractive index among two layers included in the color conversion photonic crystal structure according to the present invention.

As used herein, the term "unit layer" refers to a layer in which one first refractive index layer and one second refractive index layer are stacked as a part of the color conversion photonic crystal structure according to the present invention.

While intensifying research on the photonic crystal structure, the present inventors used a copolymer containing a repeating unit including a quaternary ammonium cation and a repeating unit derived from an acrylate-based monomer having a photoactive functional group. Including a refractive index layer and a high refractive index layer using a copolymer including a repeating unit including naphthalene and a repeating unit derived from an acrylate-based monomer having a photoactive functional group at the same time, the color is converted so that it can be visually judged according to changes in humidity The color conversion photonic crystal structure was devised.

The present invention can freely control the hydrophilicity by controlling the degree of quaternization and the thickness of each layer. A film that changes color only at high humidity can be applied as an anti-counterfeiting film, and a film that exhibits various color changes from low humidity to high humidity can be used as a humidity sensor. In addition, in the case of the color conversion photonic crystal structure according to the present invention, compared to any photonic crystal structure by the present inventors, the sensitivity is excellent and the difference in refractive index can be more remarkably adjusted.

The color conversion photonic crystal structure according to the present invention can be immediately visually checked by a change in the reflected wavelength of the shifted visible light region within a few seconds, and since the color is changed differently according to its concentration when in contact with moisture, the converted color is observed. Humidity can be checked. In addition, since the color conversion photonic crystal structure is sensitive to changes in humidity, it can be usefully used as a security element applied to anti-counterfeiting articles. In addition, these can be quickly restored to their original state when contact with moisture, which is an external stimulus, is stopped, so that they can be reused repeatedly.

Against this background, the present inventors devise a color conversion photonic crystal structure including a copolymer having the above-described structural characteristics, and confirm the above-described effects through this, and propose the present invention.

Hereinafter, the present invention will be described in detail.

The present invention provides a first refractive index layer comprising a first polymer having a first refractive index, which is alternately stacked; And a second refractive index layer including a second polymer having a second refractive index, wherein the first refractive index and the second refractive index are different, and one of the first polymer and the second polymer is represented by Formula 1 and It provides a photonic crystal structure, which is a polymer containing a structural unit represented by Chemical Formula 2.

[Formula 1]

[Formula 2]

[In Chemical Formulas 1 and 2,

R ₁ and R ₂ are each independently hydrogen or C1-C5 alkyl;

Each R ₁₁ is independently hydroxy, halogen, nitro, C1-C5 alkyl or C1-C5 alkoxy;

L ₁ is -O- or -NH-;

Y ₁ is substituted or unsubstituted benzoylphenyl, the substitution being substituted with one or more substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy;

a is an integer selected from 0 to 7, and when a is an integer of 2 or more, R ₆ may be the same as or different from each other.]

In the photonic crystal structure according to an embodiment of the present invention, the polymer provided in the first refractive index layer and the second refractive index layer may have an arrangement such as a block copolymer, an alternating copolymer, or a graft copolymer, It is not limited to the above-described arrangement.

In addition, in the photonic crystal structure according to an embodiment of the present invention, the refractive index layer including the polymer including the structural units represented by Chemical Formulas 1 and 2 may be a high refractive index layer having a relatively high refractive index.

In the photonic crystal structure according to an embodiment of the present invention, the polymer including the structural units represented by Formulas 1 and 2 implements a remarkably improved refractive index by introducing a repeating unit including naphthalene. In addition, humidity changes as it is alternately stacked with a low refractive index layer using a copolymer containing a repeating unit containing a quaternary ammonium ion and a repeating unit derived from an acrylate monomer having a photoactive functional group, which will be described later. The sensitivity to the is remarkably improved. This effect is not confirmed in the photonic crystal structure having a substituent similar to this, the present invention is a point of attention.

In the photonic crystal structure according to an embodiment of the present invention, in this case, the polymer including the structural units represented by Chemical Formulas 1 and 2 has a molar ratio (Chemical Formula 1: Chemical Formula 2) of 100:1 to 100:20. Can be.

For example, it may satisfy 95:5 to 80:20.

For example, it may satisfy 95:5 to 80:20 and 95:5 to 90:10.

In addition, the polymer including the structural units represented by Formulas 1 and 2 may have a number average molecular weight (Mn) of 10,000 to 100,000 g/mol, and specifically, may be 30,000 to 50,000 g/mol.

In addition, the polymer including the structural units represented by Chemical Formulas 1 and 2 may exhibit a refractive index of 1.6 to 1.7.

_{For example, each of R 1} in the structural unit represented by Formula 1 is independently hydrogen or C1-C3 alkyl; L ₁ is -O- or -NH-; Y ₁ is substituted or unsubstituted benzoylphenyl, and the substitution may be substituted with 1 to 4 substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy.

_{For example, Y 1} of the structural unit represented by Chemical Formula 1 may be an unsubstituted benzoylphenyl advantageously in terms of ease of photocuring.

_{For example, each of R 2} in the structural unit represented by Formula 2 is independently hydrogen or C1-C3 alkyl; Each of R ₁₁ is independently hydroxy, halogen, nitro, C1-C5 alkyl or C1-C5 alkoxy; Wherein a is an integer selected from 0 to 3, and when a is an integer of 2 or more, R ₆ may be the same as or different from each other.

_{For example, R 1} and R ₂ of the structural units represented by Chemical Formulas 1 and 2 are each independently hydrogen or methyl; Each R ₁₁ is independently methyl, ethyl, propyl or butyl; L ₁ is -O- or -NH-; Y ₁ is unsubstituted benzoylphenyl; The a may be an integer selected from 0 to 3.

In the photonic crystal structure according to an embodiment of the present invention, the other of the first polymer and the second polymer may be a polymer including structural units represented by the following Chemical Formulas 3 to 5.

[Formula 3]

[Formula 4]

[Formula 5]

[In Chemical Formulas 3 to 5,

R ₃ to R ₅ are each independently hydrogen or C1-C5 alkyl;

L ₂ is -O- or -NH-;

Y ₂ is substituted or unsubstituted benzoylphenyl, the substitution being substituted with one or more substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy;

X ₁ to X ₅ are each independently -N= or -CR=, _{but at least one of X 1} to X ₅ is -N=, and R is hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6 -C20 aryl or a combination thereof;

X ₁₁ to X ₁₅ are each independently N ⁺ R'X ^- or -CR"=, but at least one of _{X 11} to X ₁₅ ^{is N +} R'X ^- , and R'and R" are each independently Hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, or a combination thereof, and X ^- is a monovalent anion.]

In the photonic crystal structure according to an embodiment of the present invention, the refractive index layer including the polymer including the structural units represented by Chemical Formulas 3 to 5 may be a low refractive index layer having a relatively low refractive index.

In addition, in the photonic crystal structure according to an embodiment of the present invention, the polymer including the structural units represented by Chemical Formulas 3 to 5 has increased hydrophilicity through the structural units represented by Chemical Formulas 4 and 5, such as moisture. They are better able to respond to external stimuli. In addition, since the refractive index can be changed depending on the number of quaternary ammonium ions and the type of counter ions, a color conversion photonic crystal structure having a desired reflection wavelength can be implemented by adjusting this.

The structural unit represented by Formula 5 is the compound R'-X in the quaternization reaction of the method for producing a photonic crystal structure described later (here, the definition of R'is the same as defined in Formula 5, and X is the formula It exists without reacting as a leaving group (leaving group) capable of generating a monovalent anion by a nucleophilic substitution reaction of the structural unit represented by 5). In other words, the structural unit represented by Chemical Formula 5 is prepared by reaction of the structural unit represented by Chemical Formula 4 with an R'-X compound.

For example, the structural unit represented by Chemical Formula 5 is generated by a quaternization reaction of a photonic crystal structure in which a refractive index layer including the structural unit represented by Chemical Formula 4 is stacked with an R'-X compound. The structural unit represented by Chemical Formula 4 that did not participate may remain in the finally prepared photonic crystal structure. Accordingly, the molar ratio of the structural unit represented by Formula 5 and the structural unit represented by Formula 4 in the refractive index layer may be adjusted according to the quaternization reaction conditions.

In the photonic crystal structure according to an embodiment of the present invention, X ₁₁ of Formula 5 is N ⁺ R'X ^- , and X ₁₂ to X ₁₅ are each independently -CR"=; X ₁₂ is N ⁺ R'X ^- and X ₁ , X ₃ to X ₅ are each independently -CR"=; Or the X ₁₃ is N ⁺ R'X ^- , and X ₁ , X ₂ , X ₄ and X ₅ are each independently -CR"=, wherein R'is methyl, ethyl, propyl, butyl, pentyl, phenyl, benzyl or phenylethyl, wherein R "is hydrogen, methyl, ethyl or phenyl, wherein X ^- is ^{F -, Cl -, Br -} , I -, ClO 4 -, SCN -, NO 3 -, or CH ₃ CO ₂ ^- can be.

In the photonic crystal structure according to an embodiment of the present invention, the polymer including the structural units represented by Chemical Formulas 3 to 5 includes 10 structural units represented by Chemical Formula 5 with respect to the total ratio of the total polymer structural units. It may contain more than %. Specifically, the structural unit represented by Chemical Formula 5 is at least 14%, more specifically the structural unit represented by Chemical Formula 5 is at least 25%, and most specifically, the structural unit represented by Chemical Formula 5 is 30% to 60%. It may be to include. In this case, the sum of the proportions of structural units constituting the internal structure of the polymer is taken as a standard (100%).

_{For example, each of R 3} in the structural unit represented by Formula 3 is independently hydrogen or C1-C3 alkyl; L ₂ is -O- or -NH-; The Y ₂ is substituted or unsubstituted benzoylphenyl, and the substitution may be substituted with 1 to 4 substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy.

_{For example, the Y 2} of the structural unit represented by Chemical Formula 3 may be an unsubstituted benzoylphenyl advantageously in terms of ease of photocuring.

For example, in the structural units represented by Chemical Formulas 4 and 5, R ₄ and R ₅ are each independently hydrogen or C1-C3 alkyl; X ₁ to X ₅ are each independently -N= or -CR=, _{but at least one of X 1} to X ₅ is -N=, and R is hydrogen, methyl, ethyl or phenyl; The X ₁₁ to X ₁₅ are each independently N ⁺ R'X ^- or -CR"=, but at least one of _{the X 11} to X ₁₃ ^{is N +} R'X ^- , and the rest are each independently -CR"= provided that, wherein R 'is methyl, ethyl, propyl, butyl, pentyl, phenyl, benzyl or phenylethyl, wherein R "is hydrogen, methyl, ethyl or phenyl, wherein X ^- is F ^-, Cl ^-, Br ^{-, _{I -, ClO 4 -, SCN}} -, NO 3 -, or CH ₃ CO ₂ ^- may be one of.

In the photonic crystal structure according to an embodiment of the present invention, in this case, the polymer including the structural units represented by Chemical Formulas 3 to 5 has a molar ratio (Chemical Formula 3: Chemical Formula 4: Chemical Formula 5) of 100:100 to 10:30 It may be one that satisfies ~1.

For example, it may satisfy 85:10:5 to 45:45:10.

For example, it may be 80:15:5 to 45:45:10.

In addition, the polymer including the structural unit represented by Chemical Formulas 3 to 5 may have a number average molecular weight (Mn) of 10,000 to 500,000 g/mol, and specifically, may be 30,000 to 400,000 g/mol.

In addition, the polymer containing the structural unit represented by Chemical Formulas 3 to 5 may exhibit a refractive index of 1.5 to 1.6, and the polymer has a relative refractive index than the polymer including the structural units represented by Chemical Formulas 1 and 2 This is low. A photonic crystal structure that reflects light of a desired wavelength may be implemented by the difference in refractive index 　 as described above, and according to the present invention, a difference in refractive index of at least 0.03 may be satisfied.

Specifically, the photonic crystal structure according to an embodiment of the present invention includes a first refractive index layer disposed at the bottom, a second refractive index layer disposed on the first refractive index layer, and a first refractive index layer and a first refractive index layer disposed on the second refractive index layer. It has a structure in which the 2　 refractive index layers are alternately repeated and stacked. In addition, the photonic crystal structure may further include a substrate on the other side of the first 　 refractive index layer disposed at the lowermost part, on which the second 　 refractive index layer is not disposed, depending on the use. Accordingly, in this case, a substrate may be located at the lowermost portion of the photonic crystal structure.

For example, the first 　 refractive index layer may be located on the top of the photonic crystal structure. Accordingly, a first refractive index layer is additionally stacked on a laminate in which the first and second refractive index layers are alternately stacked, so that the photonic crystal structure may have an odd number of refractive index layers. In this case, as will be described later, constructive interference between lights reflected from the interface of each layer increases, so that the intensity of the reflected wavelength of the photonic crystal structure may increase. In addition, unit layers including the first and second refractive index layers are alternately stacked, so that the photonic crystal structure may have an even number of refractive index layers. In this case, it is possible to show a response to a change in humidity more quickly.

For example, when the quaternized low refractive index layer according to the present invention is formed on the uppermost layer, the response speed may be faster.

For example, the photonic crystal structure may exhibit various colors by moving a reflection wavelength of 100 nm or more within a few seconds, specifically within 10 seconds, in response to a change in humidity.

For example, in the photonic crystal structure, the total number of stacked units of the unit layer may be one or more, and specifically, may be 5 to 30 layers.

For example, the substrate may include a carbon-based material having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness; A metal material including at least one metal selected from zinc, aluminum, indium, and tin; Thin glass; Silicon (Si)-based materials; Polymer films such as plastic, polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and the like; paper; And clothing or wearable material; but is not limited thereto, and of course, various materials having flexibility or not flexibility may be used depending on the application to which it is applied.

For example, when the substrate is indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (ITZO), or the like, a more improved visibility effect may be implemented. In addition, in the case of the above-described metal oxide substrate, since different color conversion can be implemented according to the color of the background, it may be advantageous in terms of inducing color conversion in more various modes.

The first 　 refractive index layers alternately stacked on the substrate include a first polymer having a first 　 refractive index, and the second 　 refractive index layer includes a second polymer having a second 　 refractive index. In this case, a difference between the first 　 refractive index and the second 　 refractive index may be 0.03 to 1.0.

For example, the difference between the first and second refractive indexes may be from 0.03 to 0.08, specifically from 0.03 to 0.08, more specifically from 0.03 to 0.05, and most specifically from 0.03 to 0.04. As the difference between the refractive indices increases, the optical band gap of the photonic crystal structure increases, and thus the difference between the refractive indices within the above-described range can be adjusted so that light of a desired wavelength is reflected. In this case, since the high refractive index layer according to the present invention includes a polymer including the structural units represented by Chemical Formulas 1 and 2, a higher refractive index is realized, and the difference between the refractive indices is greater.

In the photonic crystal structure according to an embodiment of the present invention, the first refractive index layer may be a high refractive index layer having a thickness of 10 to 100 nm, and the second refractive index layer may be a low refractive index layer having a thickness of 50 to 130 nm. have.

For example, a ratio of the thickness of the low refractive index layer to the thickness of the high refractive index layer may be 1:7 to 1:1. Specifically, the above-described ratio of thickness is satisfied, but the thickness of the low refractive index layer may be 50 to 130 nm, and the thickness of the high refractive index layer may be 10 to 100 nm. By adjusting the thickness within the above-described range, the reflected wavelength of the photonic crystal structure can be adjusted. The thickness of each 　 refractive index layer can be adjusted by varying the concentration of the polymer in the polymer dispersion composition or the coating speed of the dispersion composition.

The photonic crystal structure according to an embodiment of the present invention is a high refractive index layer in which the first refractive index layer is formed to a thickness of 10 to 100 nm, and the second refractive index layer is formed to a thickness of 50 to 130 nm, particularly in terms of color conversion. It is a formed low refractive index layer, and the structure in which the low refractive index layer is located at the top is preferable. In this case, the interference of the light reflected from each layer boundary surface may be sufficiently caused to have a reflection intensity such that a change in color due to an external stimulus can be detected.

For example, the high refractive index layer is preferably 10 to 95 nm, 15 to 90 nm.

For example, the low refractive index layer is preferably 55 to 120 nm and 60 to 115 nm.

On the other hand, when multicolor white light of all colors in equal proportion is incident on the photonic crystal structure, partial reflection of the incident light occurs at each layer interface, and the reflection wavelength concentrated at one wavelength due to the interference of the partially reflected lights ( It can represent a color according to λ).

Specifically, the reflection wavelength (λ) of the color conversion photonic crystal structure 10 may be determined by the following Equation 1:

[Equation 1]

λ = 2(n1*d1 + n2*d2)

[In Equation 1 above,

n1 is the refractive index of the first refractive index layer;

n2 means the 　 refractive index of the second 　 refractive index layer,

d1 and d2 mean the thickness of the first and second refractive index layers, respectively.]

Accordingly, the desired reflection wavelength λ can be realized by controlling the types of the first and second polymers and the thickness of the first and second refractive index layers 13 and 15.

The photonic crystal structure according to an embodiment of the present invention exhibits a reflection wavelength (λ) corresponding to a visible light region of 380 to 760 nm according to Equation 1 when there is no external stimulus, and thus reflects the color of the photonic crystal structure. I can confirm.

In addition, when the photonic crystal structure is located in an environment subjected to external stimulation, the crystal lattice structures of the first polymer and the second polymer constituting the first and second refractive index layers are changed. As the shape scattered in is changed, the photonic crystal structure reflects the shifted wavelength λ'. Therefore, compared to the case in which there is no external stimulus, the color implemented by the photonic crystal structure can be converted. If the intensity of the external stimulus is high, the degree of change in the crystal lattice structure of the first polymer and the second polymer increases, so that the reflected wavelength is further shifted, so that the intensity of the external stimulus can be detected according to the color implemented. In addition, when a structure in which the low refractive index layer is positioned at the top is implemented, the interference of light reflected from each layer boundary surface is sufficiently caused to have a reflection intensity sufficient to detect a color change due to an external stimulus.

In the color conversion of the photonic crystal structure according to an embodiment of the present invention, a reflected wavelength is shifted according to a change in humidity. That is, the shift in the reflected wavelength of the photonic crystal structure is due to a change in the refractive index of the photonic crystal structure and an increase in the thickness of each layer thereof when moisture is absorbed. In this case, the thickness of the photonic crystal structure in which moisture is absorbed may be up to twice the initial thickness.

For example, when the photonic crystal structure is in contact with moisture, that is, when the photonic crystal structure is exposed to air containing moisture or is impregnated with liquid water, a portion of the photonic crystal structure absorbs moisture and swells. The thickness changes accordingly. In addition, it has excellent reactivity with water having a large polarity, including quaternary ammonium cations and counter anions thereof, and thus synergizes its effect. Accordingly, the reflected wavelength of the photonic crystal structure according to Equation 1 may be shifted. At this time, the shifted reflected wavelength (λ') is in the range of 380 nm to 760 nm, so that the color change can be observed with the naked eye. The reflected wavelength λ and the shifted reflected wavelength λ'can be measured with a device such as a reflectometer.

In addition, in the photonic crystal structure, the higher the humidity, that is, the higher the moisture content, the longer the reflected wavelength may be. Accordingly, the shifted reflected wavelength λ'of the photonic crystal structure may have a larger value than the reflected wavelength λ when there is no external stimulus.

The photonic crystal structure as described above can be manufactured by a manufacturing method including the following steps. Specifically, a first step of preparing a first 　 refractive index layer using a first dispersion composition containing a first polymer; A second step of preparing a second 　 refractive index layer using a second dispersion composition containing a second polymer on the first 　 refractive index layer; A third step of repeating the steps 1 and 2 to prepare a structure in which the first and second refractive index layers are alternately stacked; And a 4 step of manufacturing a photonic crystal structure by contacting the photonic crystal structure with a compound represented by R'-X. It can be manufactured by a manufacturing method comprising a.

In the method of manufacturing a photonic crystal structure according to an embodiment of the present invention, a description of the first 　 refractive index, the first polymer, the second 　 refractive index, the second polymer, the first 　 refractive index layer, and the second 　 refractive index layer, and in the formula R'-X Description of R'and X is as described above.

First, a first dispersion composition and a second dispersion composition are prepared. Each dispersion composition may be prepared by dispersing a polymer in a solvent, wherein the dispersion composition is used as a term indicating various states such as solution, slurry or paste. At this time, any solvent that can dissolve the first and second polymers may be used, and the first and second polymers may be included in an amount of 0.5 to 5% by weight, respectively, based on the total weight of the dispersion composition. In the above-described range, a dispersion composition having a viscosity suitable to be applied on a substrate can be prepared.

For example, the first dispersion composition may be composed of a solvent and a first polymer, and the second dispersion composition may be composed of a solvent and a second polymer. That is, a separate photoinitiator and crosslinking agent for photocuring, or inorganic particles may not be included.

Accordingly, according to the present invention, a photonic crystal structure can be manufactured more easily and economically, and variations in optical characteristics depending on the position of the manufactured photonic crystal structure can be reduced because no additional additives are included. However, depending on the purpose, since it may further include a separate additive selected from a photoinitiator, a crosslinking agent, and inorganic particles, the use of them should not be limited.

Next, after applying the prepared first dispersion composition on a substrate or substrate, light irradiation is performed to prepare a first 　 refractive index layer, and then, after applying the prepared second dispersion composition on the first 　 refractive index layer. By performing light irradiation, a second 　 refractive index layer may be prepared.

For example, spin coating, dip coating, roll coating, screen coating, spray coating by applying the dispersion composition onto a substrate or a refractive index layer. ), spin casting, flow coating, screen printing, ink jet, or drop casting, but are not limited thereto.

For example, the light irradiation step may be performed by irradiating a wavelength of 652 mJ/cm 2 without nitrogen conditions. By the light irradiation, the benzophenone moiety contained in the polymer acts as a photoinitiator to prepare a photo-cured 　 refractive index layer.

In the method of manufacturing a photonic crystal structure according to an embodiment of the present invention, after a structure in which the first refractive index layer and the second refractive index layer are alternately stacked is manufactured, it is contacted with a compound represented by R'-X. To proceed with the quaternization reaction. At this time, the quaternization reaction is a nucleophilic substitution reaction between the nitrogen atom of the structural unit represented by Chemical Formula 4 and R'-X, and the quaternary ammonium cation and X ^- anion are bonded to the nitrogen atom having a lone pair Is created. Through this quaternization reaction, the structural unit represented by Chemical Formula 4 is converted to the structural unit represented by Chemical Formula 5. Accordingly, it is possible to manufacture a photonic crystal structure having a desired composition of a high refractive index layer by controlling the quaternization reaction conditions.

Hereinafter, the use of the present invention will be described.

The use of the above-described photonic crystal structure may be a color conversion humidity sensor for detecting a change in humidity.

In addition, it may be a color conversion film for anti-counterfeiting.

The color conversion humidity sensor for detecting a change in humidity according to an embodiment of the present invention changes colors differently according to the degree (e.g., relative humidity) when in contact with moisture, so the degree of humidity is observed by observing the converted color. You can check. In addition, the color conversion humidity sensor not only has a clear shift in color conversion or reflected wavelength depending on humidity, but also can quickly recover to its original state when contact with an external stimulus is stopped, so that it can be reused repeatedly. Has.

In addition, the anti-counterfeiting 　 color conversion 　 film according to an embodiment of the present invention may include one or a plurality of the aforementioned 　 photonic crystals 　 structures.

For example, the anti-counterfeiting 　 color conversion 　 film may include two or more or two to 100 　 photonic crystals 　 structures described above, but the number is not limited thereto. In view of the ease of manufacture and the function as an identification mark, 3 to 20 are preferred.

For example, in the case of including a plurality of 　 photonic crystal 　 structures, the types of the first polymer and the second polymer described above; Thicknesses of the first refractive index layer and the second refractive index layer; And the total number of stacks of the first refractive index layer and the second refractive index layer; the conditions selected from may be the same or different from each other.

For example, a plurality of 　 photonic crystal 　 structures may have different total stacked numbers of the first refractive index layer and the second refractive index layer, respectively. Accordingly, the plurality of 　 photonic crystals 　 structures may be converted into different colors respectively by the external 　 stimulation. Therefore, in the case of a color conversion film for anti-counterfeiting including a plurality of 　 photonic crystal 　 structures, it is converted into various colors by external stimulus so that forgery and modulation are impossible, and it is possible to give pleasure to consumers.

In addition, the anti-counterfeiting 　 color conversion 　 film according to an embodiment of the present invention may include a substrate for fixing the photonic crystal structure. In addition, the type of the substrate is as described above.

Since the 　 photonic crystal 　 structure according to an embodiment of the present invention has the form of a thin 　 film and can be manufactured in various sizes and shapes, the color conversion humidity sensor or the color conversion film for preventing counterfeiting having the same can be used in various sizes and shapes depending on the usage. Can be manufactured.

The 　 photonic crystal 　 structure according to the present invention enables immediate confirmation of the authenticity of an article when an external stimulus such as breath is applied. In addition, when the contact with the external stimulus is stopped, the original state can be quickly restored.

For example, the color conversion film for anti-counterfeiting according to an embodiment of the present invention may be color converted by an external stimulus having a relative humidity of 70% or more. At this time, an external stimulus with a relative humidity of 70% or more may be breathing.

For example, the color conversion 　 film 　 in the forgery prevention 　 photonic crystal 　 structure recovers to its original color after a certain period of time even after one use, so it may be reused repeatedly. Therefore, regardless of the time or stage of the distribution channel, a plurality of consumers can use it to determine the authenticity of the product, which is eco-friendly and economical.

As described above, the color conversion film for anti-counterfeiting of the present invention may be manufactured by a manufacturing method including the following steps, but is not limited thereto. Specifically, after applying a first dispersion composition containing a first polymer having a first refractive index on a substrate, light irradiation is performed while placing a plurality of mask patterns having a predetermined shape to form a single or a plurality of first dispersions. A first step of preparing a refractive index layer and removing the mask pattern; And after applying a second dispersion composition comprising a second polymer having a second refractive index on the first refractive index layer, light irradiation is performed while the mask pattern is positioned to prepare a second refractive index layer, A second step of removing the mask pattern; It can be manufactured by a manufacturing method comprising a. In addition, it goes without saying that steps 1 and 2 can be repeated as necessary.

For example, it may be manufactured in a form in which a plurality of 　photonic crystals 　 structures in which 3 to 30 layers are stacked are stacked.

For example, in order to allow a plurality of 　 photonic crystals 　 structures to display separate colors, light irradiation may be performed by placing a mask pattern excluding some shapes of the mask patterns when repeating steps 1 and 2.

In addition, the present invention provides an article comprising the above-described anti-counterfeiting color conversion film. Specifically, the article may be a target article to be prevented from forgery and tampering in order to protect the brand. For example, it may be bills, contracts, pharmaceuticals, toys, cosmetics, cigarettes, alcohol, clothing, food, sports goods, shoes, automobile parts, credit cards, gift cards, etc., but is not limited thereto.

Hereinafter, the present invention will be described in more detail by the following examples. However, these examples are only intended to aid understanding of the present invention, and the scope of the present invention is not limited thereto in any sense.

Unless otherwise stated in the specification, all temperatures are in degrees Celsius, and each component is used in grams. In addition, the temperature is performed at 25° C. and atmospheric pressure (1 atm) unless otherwise stated in the specification.

(Assessment Methods)

1. Observation of color conversion according to changes in relative humidity

In order to check the degree of color conversion according to the change in humidity, the photonic crystal structures prepared in the following Examples and Comparative Examples were respectively subjected to relative humidity of 10%, 20%, 30%, 40%, 50%, 60%, 70%, and 80%. And after exposure to the environment of 90%, the changed color was observed, and the results are shown in FIG. 2 below.

In addition, after exposure to the environment from 10% to 90% relative humidity, the specular reflectance according to the relative humidity was measured using a reflectometer (USB 4000, Ocean Optics), and the results are shown in Table 2 below.

2. Observation of color conversion by breathing

In order to check the degree of color conversion according to the breath, after blowing breath on the photonic crystal structures prepared in the following Examples and Comparative Examples, the changed color was observed, and the results are shown in FIGS. 1, 3, and 4 below. .

3. Measurement of polymer properties

The measurement of the physical properties of the polymer obtained from Preparation Example was performed as follows, and the results are shown in Table 1 below.

1) Mn (number average molecular weight): Polymethyl methacrylate was used as a standard sample for calibration and measured using gel permeation chromatography (GPC).

2) Content of BPAA structural unit: measured by NMR.

3) Refractive index: It was measured by ellipsometer.

(Table 1)

(Production Example 1)

Step 1) Preparation of N-(4-benzoylphenyl)acrylate (BPA)

After adding 25 g of 4-hydroxybenzophenone, 26 mL of triethylamine, and 180 mL of dichloromethane to a 250 mL round flask, the flask was placed in ice water. After 15 mL of acryloyl chloride was added, the mixture was stirred for 12 hours. After the completion of the reaction, the solvent was removed and dried in a vacuum oven to obtain the title compound as a yellow solid (BPA, yield = 96%).

Step 2) Manufacturing of Poly(4VP-BPA)

5.1 ml of 4-vinyl pyridine, 1.3 g of BPA prepared in step 1, and 0.01 g of azobisisobutyronitrile were added to a 25 ml Schrank round flask, and then the flask was placed in a 70 degree oil bath for 14 hours. The reaction proceeded. After completion of the reaction, the polymer was extracted and dried in a vacuum oven at room temperature (25° C.) to obtain the title compound (Poly(4VP-BPA), n:m=93:7, yield=60%).

(Production Example 2)

Step 1) Manufacturing of Poly(VNP-BPA)

5 g of 2-vinyl naphthalene, 0.9 g of BPA prepared in step 1, and 0.01 g of azobisisobutyronitrile were added to a 25 ml round flask, followed by 24 at 80°C. Time reaction proceeded. After the reaction was completed, the polymer was extracted and dried in a vacuum oven at room temperature (25° C.) to obtain the title compound (Poly(VNP-BPA), n:m=90:10, yield=66%).

(Example 1)

Step 1) The photonic crystal structure was put in a 100 ml vial containing 5 ml of dimethylformamide (DMF) and 4 ml of chloropropane, and subjected to quaternization reaction at 50° C. for 48 hours, followed by precipitation with ether and drying. , A photonic crystal structure (QVP-51%, n:z:m=46:47:7) was prepared.

Step 2)

A 2.5% by weight low refractive index dispersion composition (10ml) was prepared by dissolving quaternized Poly(4VP-BPA)-51% prepared in step 1 in ethanol, and Poly(VNP-BPA) prepared in Preparation Example 2 was chloro Dissolved in benzene to prepare a 1.5% by weight high refractive index dispersion composition (10ml).

The low refractive index dispersion composition was applied on the PET substrate at 2,300 rpm for 12 seconds using a spin coater, and then cured at 652 mJ/cm 2 for 2 minutes to form a low refractive index layer. Next, the high refractive index dispersion composition was applied on the low refractive index layer at 2,300 rpm for 12 seconds using a spin coater, and then cured at 652 mJ/cm 2 for 2 minutes to form a high refractive index layer.

Next, a high refractive index layer (thickness 59 nm) and a low refractive index layer (thickness 64 nm) were repeatedly stacked on the low refractive index layer (thickness 64 nm) to prepare a structure stacked with a total of 10 layers.

(Example 2)

A photonic crystal structure was manufactured in a similar manner to Example 1 above. Specifically, by changing the amount of chloropropane to 3 ml in Example 1, a photonic crystal structure (QVP-37%, n:z:m=58:35:7) was prepared.

The photonic crystal structure was stacked in a total of 10 layers by repeatedly stacking a high refractive index layer (thickness 64 nm) and a low refractive index layer (thickness 60 nm) on a low refractive index layer (thickness 60 nm).

(Example 3)

A photonic crystal structure was manufactured in a similar manner to Example 1 above. Specifically, by changing the amount of chloropropane to 2 ml in Example 1, a photonic crystal structure (QVP-25%, n:z:m=71:22:7) was prepared.

The photonic crystal structure was stacked in a total of 10 layers by repeatedly stacking a high refractive index layer (thickness 56 nm) and a low refractive index layer (thickness 62 nm) on a low refractive index layer (thickness 62 nm).

(Example 4)

A photonic crystal structure was manufactured in a similar manner to Example 1 above. Specifically, by changing the amount of chloropropane to 1 ml in Example 1, a photonic crystal structure (QVP-14%, n:z:m=80:13:7) was prepared.

The photonic crystal structure was stacked in a total of 10 layers by repeatedly stacking a high refractive index layer (thickness 56 nm) and a low refractive index layer (thickness 64 nm) on a low refractive index layer (thickness 64 nm).

(Example 5)

In step 2 of Example 1, a 1.2 wt% low refractive index dispersion composition (10 ml) was prepared by dissolving in quaternized Poly(4VP-BPA)-51% ethanol, and Poly(VNP-BPA) prepared in Preparation Example 2 was prepared. It was dissolved in chlorobenzene to prepare a 2.3% by weight high refractive index dispersion composition (10ml).

The low refractive index dispersion composition was applied on the PET substrate at 2,300 rpm for 12 seconds using a spin coater, and then cured at 652 mJ/cm 2 for 2 minutes to form a low refractive index layer. Next, the high refractive index dispersion composition was applied on the low refractive index layer at 2,300 rpm for 12 seconds using a spin coater, and then cured at 652 mJ/cm 2 for 2 minutes to form a high refractive index layer.

Next, a high refractive index layer (thickness 83 nm) and a low refractive index layer (thickness 59 nm) were repeatedly stacked on the low refractive index layer (thickness 59 nm) to prepare a structure T1 stacked with a total of 10 layers.

(Example 6)

A photonic crystal structure was manufactured in a similar manner to Example 5 above. Specifically, in Example 5, the concentration of quaternized Poly(4VP-BPA)-51% was changed to 1.5% by weight, and the concentration of Poly(VNP-BPA) was changed to 2.0% by weight, and used.

Next, a high refractive index layer (59 nm thick) and a low refractive index layer (64 nm) were repeatedly stacked on the low refractive index layer (64 nm) to prepare a photonic crystal structure (T2) with a total of 10 layers.

(Example 7)

A photonic crystal structure was manufactured in a similar manner to Example 5 above. Specifically, in Example 5, the concentration of quaternized Poly(4VP-BPA)-51% was changed to 2.0% by weight, and the concentration of Poly(VNP-BPA) was changed to 1.5% by weight, and used.

Next, a high refractive index layer (thickness 40 nm) and a low refractive index layer (74 nm) were repeatedly stacked on the low refractive index layer (74 nm) to prepare a photonic crystal structure (T3) with a total of 10 layers.

(Example 8)

A photonic crystal structure was manufactured in a similar manner to Example 5 above. Specifically, in Example 5, the concentration of quaternized Poly(4VP-BPA)-51% was changed to 2.5% by weight, and the concentration of Poly(VNP-BPA) was changed to 1.2% by weight, and used.

Next, a high refractive index layer (thickness 16 nm) and a low refractive index layer (115 nm) were repeatedly stacked on the low refractive index layer (115 nm) to prepare a photonic crystal structure (T4) with a total of 10 layers.

(Comparative Example 1)

A photonic crystal structure was manufactured in a similar manner to Example 1 above. Poly(4VP-BPA) prepared in Preparation Example 1 was dissolved in ethanol to prepare a 2.5% by weight low refractive index dispersion composition (10ml), and Poly(VNP-BPA) prepared in Preparation Example 2 was dissolved in chlorobenzene and 1.5 A weight% high refractive index dispersion composition (10 ml) was prepared.

The low refractive index dispersion composition was applied on the PET substrate at 2,300 rpm for 12 seconds using a spin coater, and then cured at 652 mJ/cm 2 for 2 minutes to form a low refractive index layer. Next, the high refractive index dispersion composition was applied on the low refractive index layer at 2,300 rpm for 12 seconds using a spin coater, and then cured at 652 mJ/cm 2 for 2 minutes to form a high refractive index layer.

Next, a high refractive index layer (thickness 65 nm) and a low refractive index layer (thickness 74 nm) were repeatedly stacked on the low refractive index layer (thickness 74 nm) to prepare a structure stacked with a total of 10 layers.

As shown in Table 2 below and FIGS. 2 and 3, the photonic crystal structure according to the present invention shows a shift in a reflected wavelength according to a change in relative humidity, and thus it can be confirmed that the sensitivity to a change in moisture is excellent. In addition, it can be seen that the reflected wavelength of the photonic crystal structure shifts in a direction in which the wavelength increases as the relative humidity increases. At this time, since the shifted reflected wavelength corresponds to the visible light region, a change in the reflected wavelength of the photonic crystal structure can be visually observed, and thus it can be confirmed that the photonic crystal structure according to the embodiment can be used to check the relative humidity. In addition, the photonic crystal structure according to the present invention can freely control the hydrophilicity by controlling the degree of quaternization and the thickness of each layer, and exhibits various color changes from low humidity to high humidity to detect changes in humidity. It will be useful to apply. On the other hand, in the case of Comparative Example 1 and Comparative Example 2, the change in the shift of the reflected wavelength was insignificant according to the change in the relative humidity, and the change could not be observed with the naked eye.

As shown in FIG. 1 below, when an external stimulus such as breathing is applied to the photonic crystal structure according to the present invention, it is possible to immediately confirm the authenticity of the article by showing a shift in the reflected wavelength.

As shown in FIG. 4 below, the color conversion humidity sensor including the photonic crystal structure according to the present invention is sensitive to changes in humidity, and changes in the reflected wavelength according to the change in humidity can be observed with the naked eye. It was confirmed that it can be usefully applied to a sensor.

As shown in Figs. 5 and 6 below, the identification mark does not appear until the article with the identification mark including the photonic crystal structure according to the present invention is blown, whereas the identification mark is clearly visible by blowing the breath. Appearance can be confirmed. In addition, as shown in FIG. 7 below, even when the same photonic crystal structure is used, it can be seen that color conversion appears differently depending on the color of the background. Specifically, it can be seen that when a black background is applied, a color conversion occurs by a reflected wavelength, and when a white background is applied, a color conversion into a synthesized color by a wavelength other than the reflected wavelength occurs.

Therefore, the photonic crystal structure according to the present invention can be usefully applied as a security element to anti-counterfeiting articles such as banknotes and security documents, as well as article consumers who purchase articles with an identification mark including them, It can be seen that the 　authenticity 　 of the goods can be easily determined.

As described above, a specific part of the present invention has been described in detail, and it is obvious that these specific techniques are merely embodiments, and the scope of the present invention is not limited thereto for those of ordinary skill in the art. Therefore, it will be said that the practical scope of the present invention is determined by the appended claims and their equivalents.

Claims (13)

A first refractive index layer comprising a first polymer having a first refractive index, which is alternately stacked; And a second refractive index layer including a second polymer exhibiting a second refractive index,
The first refractive index and the second refractive index are different,
One of the first polymer and the second polymer is a polymer including structural units represented by the following Chemical Formulas 1 and 2;
The other is a polymer containing structural units represented by the following Chemical Formulas 3 to 5, wherein the polymer contains 30 to 60% of the structural units represented by Chemical Formula 5 with respect to the total ratio of the total structural units. , Photonic crystal structure:
[Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,
R ₁ and R ₂ are each independently hydrogen or C1-C5 alkyl;
Each R ₁₁ is independently hydroxy, halogen, nitro, C1-C5 alkyl or C1-C5 alkoxy;
L ₁ is -O- or -NH-;
Y ₁ is substituted or unsubstituted benzoylphenyl, the substitution being substituted with one or more substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy;
a is an integer selected from 0 to 7, and when a is an integer of 2 or more, R ₁₁ may be the same as or different from each other;
[Formula 3]

[Formula 4]

[Formula 5]

In Chemical Formulas 3 to 5,
R ₃ to R ₅ are each independently hydrogen or C1-C5 alkyl;
L ₂ is -O- or -NH-;
Y ₂ is substituted or unsubstituted benzoylphenyl, the substitution being substituted with one or more substituents selected from hydroxy, halogen, nitro, C1-C5 alkyl and C1-C5 alkoxy;
X ₁ to X ₅ are each independently -N= or -CR=, _{but at least one of X 1} to X ₅ is -N=, and R is hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6 -C20 aryl or a combination thereof;
X ₁₁ to X ₁₅ are each independently N ⁺ R'X ^- or -CR"=, but at least one of _{X 11} to X ₁₅ ^{is N +} R'X ^- , and R'is hydrogen or C1-C20 alkyl And R" is hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, or a combination thereof, and X ^- is a monovalent anion. The method of claim 1,
In Chemical Formulas 1 and 2,
R ₁ and R ₂ are each independently hydrogen or methyl;
Each of R ₁₁ is independently methyl, ethyl, propyl or butyl;
L ₁ is -O- or -NH-;
Y ₁ is unsubstituted benzoylphenyl;
a is an integer selected from 0 to 3, photonic crystal structure. delete The method of claim 1,
In Chemical Formula 5,
Wherein X ₁₁ is N ^{+ R'X -} , and X ₁₂ to X ₁₅ are each independently -CR"=;
Wherein X ₁₂ is N ^{+ R'X -} , and X ₁ , X ₃ to X ₅ are each independently -CR"=; or
Wherein X ₁₃ is N ^{+ R'X -} , and X ₁ , X ₂ , X ₄ and X ₅ are each independently -CR"=, wherein R'is methyl, ethyl, propyl, butyl, or pentyl, the R "is hydrogen, methyl, ethyl or phenyl, wherein X ^- is ^{F -, Cl -, Br -} , I -, ClO 4 -, SCN -, NO 3 -, or CH ₃ CO ₂ ^- is, the photonic crystal structure. delete The method of claim 1,
The total number of stacked unit layers including the first refractive index layer and the second refractive index layer is 5 to 30 layers, a photonic crystal structure. The method of claim 1,
The first refractive index layer is a high refractive index layer having a thickness of 10 to 100 nm,
The second refractive index layer is a low refractive index layer having a thickness of 50 to 130 nm, a photonic crystal structure. The method of claim 1,
A photonic crystal structure in which a reflected wavelength is shifted by an external magnetic pole. The method of claim 8,
The external stimulus is,
The photonic crystal structure due to a change in humidity. A color conversion humidity sensor comprising the photonic crystal structure of any one of claims 1, 2, 4, and 6 to 9. The method of claim 10,
The color conversion,
Color conversion humidity sensor that can be observed with the naked eye. Claims 1, 2, 4, and claim 6 to claim 9, comprising the photonic crystal structure of any one of, anti-counterfeiting color conversion film. The method of claim 12,
Color conversion film for preventing counterfeiting, which is color-converted by external stimuli with a relative humidity of 70% or more.

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