KR102646731B1 - Method for preparing chiral nanostructures using block copolymers - Google Patents

Abstract

The present application relates to a method for producing chiral nanostructures by self-assembly of block copolymers and racemic compounds, and to chiral nanostructures produced thereby.

Description

Method for producing chiral nanostructures using block copolymers {METHOD FOR PREPARING CHIRAL NANOSTRUCTURES USING BLOCK COPOLYMERS}

The present application relates to a method for producing chiral nanostructures by self-assembly of block copolymers and racemic compounds, and to chiral nanostructures produced thereby.

The self-assembly method of block copolymers creates dense, periodically aligned nanoregions, the size of which is as small as tens of nm or less. The block copolymer serves as a soft template, and nanoparticles with a regular and periodic arrangement can be manufactured by utilizing its self-assembly. In addition, the block copolymer suppresses agglomeration of nanoparticles due to the introduction of a polymer layer and improves the solubility of nanoparticles in various organic solvents. The block copolymer controls self-assembly to control the size and size of nanoparticles. The shape can also be adjusted.

Chirality refers to a material that has a molecular structure without mirror surface or inversion symmetry, and the chirality can be confirmed through physical properties that react differently to left- and right-polarized light. All substances existing in nature have chirality. For example, in the case of amino acids, most are composed of L-amino acids, and in the case of saccharides, D-saccharides are the mainstay. Since biological organic substances always have one-chirality, if they react biologically with substances that filter them, fatal damage occurs to the organism. The nanostructure having the above chirality can be prepared by synthesizing a chiral nanoparticle core, wrapping the surface with a chiral organic ligand, or arranging achiral nanoparticles into a chiral tissue ensemble. Nanostructures with chirality have different refractive indices for left- and right-polarized light, and accordingly, when linearly polarized light is incident on a chiral material, a photoactive property in which the polarization state rotates appears. Organic-inorganic nanoparticles with chirality have recently received much attention as promising materials for chiral catalysts, enantiomer separation, sensing, and medical diagnosis. Conventionally, chiral nanostructures are manufactured by introducing chiral ligands or arranging achiral nanoparticles into a chiral tissue ensemble, but they have the disadvantages that the synthesis process is complicated, chirality is lost during purification, or solution processing is impossible. In addition, conventional chiral nanostructures synthesized without the help of chiral molecules and templates have chirality due to an asymmetric structure and asymmetric chiral surface defects, and have a hollow porous internal structure, resulting in weak and unstable chirality.

Republic of Korea Patent Publication No. 10-2173227

The present application relates to a method for producing chiral nanostructures by self-assembly of block copolymers and racemic compounds, and to chiral nanostructures produced thereby.

However, the problem to be solved by the present application is not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

The first aspect of the present application is to (a) mix a block copolymer and a racemic compound in a first non-polar solvent to obtain a mixture, and (b) add a precursor of a nanostructure to the mixture to form a nanostructure with a chiral center. A method for producing a chiral nanostructure is provided, including obtaining the structure.

A second aspect of the present application provides a chiral nanostructure prepared according to the method for producing a chiral nanostructure according to the first aspect.

According to embodiments of the present application, a chiral nanostructure can be formed due to self-assembly of a block copolymer and a racemic mixture. Specifically, a core of a reverse micelle structure is formed using a block copolymer and a racemic mixture, which are achiral molecules. A nanostructure having chirality can be formed.

The method for producing chiral nanostructures according to the embodiments of the present application can be prepared by simple administration of a precursor and a simple stirring process, and can be prepared using a conventional method having a complex synthetic process for arranging chiral ligands or achiral nanoparticles into a chiral tissue ensemble. A simpler manufacturing method is used compared to other manufacturing methods. Specifically, although the chiral nanostructure according to the embodiments of the present application does not use chiral molecules and chiral templates, the prepared chiral nanostructure is similar to the conventional chiral nanostructure using chiral molecules and chiral templates. It may have chirality.

The chiral nanostructure according to the embodiments of the present application maintains its chirality stably even after the purification process due to the characteristic of being synthesized in-situ within the block copolymer template.

Figure 1a shows a method for producing inorganic nanoparticles having reverse micelles and chirality by self-assembling a structure of a block copolymer and an inorganic nanoparticle according to an example of the present application.
Figure 1b shows a method for producing organic-inorganic perovskite nanocrystals with reverse micelles and chirality by self-assembling a structure of a block copolymer and an organic-inorganic perovskite nanocrystal according to an example of the present application. It is shown.
Figure 2 shows the absorption spectra of chiral plasmonic gold nanoparticles, chiral plasmonic silver nanoparticles, chiral plasmonic palladium nanoparticles, and chiral TiO ₂ nanoparticles prepared according to Example 1 of the present application, respectively.
Figure 3 shows the absorption spectrum of organic-inorganic perovskite nanocrystals prepared according to Example 2 of the present application.
Figure 4 shows an XRD pattern of an organic-inorganic perovskite nanocrystal with chirality prepared according to Example 2 of the present application.
Figure 5 shows the fluorescence spectrum of an organic-inorganic perovskite nanocrystal with chirality prepared according to Example 2 of the present application.
Figure 6 shows Fourier transform infrared spectra of DL-alanine (blue), PS-b-PVP (black), and PS-b-PVP/DL-alanine (red) according to an example of the present application.
Figure 7 shows the hydrogen-bonded molecular structure of PS-b-PVP and DL-alanine, according to an example of the present application.
Figure 8 shows the Fourier transform infrared spectrum of inorganic nanoparticles (Au NP, Ag NP, TiO ₂ NP, Pd NP) and PS-b-PVP/DL-alanine using various inorganic precursors according to Example 1 of the present application. It is shown.
Figure 9 is a Fourier transform infrared spectrum of DL-alanine (blue), PS-b-PVP/DL-alanine (red), and PS-b-PVP/DL-alanine/MAPbBr ₃ (green) according to an example of the present application. It represents.
Figure 10 shows the circular dichroism spectrum of a material mixed with DL-alanine and PVP using a mixed solvent of ethanol/water or toluene according to an example of the present application.
Figure 11 shows the circular dichroism spectrum when PS-b-PVP or DL-alanine/PS-b-PVP is dissolved in toluene according to an example of the present application.
Figure 12 shows the circular dichroism spectra of chiral plasmonic gold nanoparticles, chiral plasmonic silver nanoparticles, chiral plasmonic palladium nanoparticles, and chiral TiO ₂ nanoparticles prepared according to Example 1 of the present application, respectively. .
Figure 13 shows a circular dichroism spectrum of an organic-inorganic perovskite nanocrystal with chirality prepared according to Example 2 of the present application.
Figure 14 shows circular polarization after centrifugation of chiral inorganic nanostructures (chiral plasmonic gold nanoparticles, chiral plasmonic silver nanoparticles, and chiral organic-inorganic perovskite nanocrystals) prepared according to the examples of the present application. Each dichroism spectrum is shown.
Figure 15 shows an atomic force microscope image of a mixed material of DL-alanine and PS-b-PVP, according to an example of the present application.
Figure 16 shows transmission electron microscope images of chiral plasmonic gold nanoparticles, chiral plasmonic silver nanoparticles, chiral plasmonic palladium nanoparticles, and chiral TiO ₂ nanoparticles prepared according to Example 1 of the present application, respectively.
Figure 17 shows a transmission electron microscope image of an organic-inorganic perovskite nanocrystal with chirality prepared according to Example 2 of the present application.

Hereinafter, with reference to the attached drawings, implementation examples and embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present application may be implemented in various different forms and is not limited to the implementation examples and examples described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout this specification, when a part is said to be “connected” to another part, this includes not only the case where it is “directly connected,” but also the case where it is “electrically connected” with another element in between. do.

Throughout this specification, when a member is said to be located “on” another member, this includes not only the case where the member is in contact with the other member, but also the case where another member exists between the two members.

Throughout the specification of the present application, when a part “includes” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

As used herein, the terms “about,” “substantially,” and the like are used to mean at or close to a numerical value when manufacturing and material tolerances inherent in the stated meaning are presented, and to aid understanding of the present application. It is used to prevent unscrupulous infringers from unfairly exploiting disclosures in which precise or absolute figures are mentioned.

The terms “step of” or “step of” as used throughout the specification herein do not mean “step for.”

Throughout this specification, the term "combination(s) thereof" included in the Markushi format expression means a mixture or combination of one or more selected from the group consisting of the components described in the Markushi format expression, It means containing one or more selected from the group consisting of the above components.

Throughout this specification, description of “A and/or B” means “A or B, or A and B.”

Throughout the specification herein, the description of “reverse micelle” refers to a closed microstructure in which the hydrophobic portion of the amphiphilic material is directed to the outside (shell) and the hydrophilic portion is directed to the interior (core).

Throughout this specification, the description of “racemic compound” refers to a compound in which right-handed and left-handed optical isomers of chiral molecules are mixed in equal amounts.

Throughout the specification herein, the description of “nanostructure” encompasses both inorganic nanoparticles and organic-inorganic perovskite nanocrystals.

Hereinafter, embodiments of the present application have been described in detail, but the present application may not be limited thereto.

The first aspect of the present application is to (a) mix a block copolymer and a racemic compound in a first non-polar solvent to obtain a mixture, and (b) add a precursor of a nanostructure to the mixture to form a nanostructure with a chiral center. A method for producing a chiral nanostructure is provided, including obtaining the structure.

In one embodiment of the present application, in step (a), the racemic compound may include an amino acid.

In one embodiment of the present application, the amino acid of the racemic compound may be one or more selected from DL-alanine, DL-valine, DL-isoleucine, DL-cysteine, DL-glycine, and DL-leucine, but is limited thereto. That is not the case.

In one embodiment of the present application, in step (a), the block copolymer is polystyrene-block-polyvinylpyridine, poly(2-vinylpyridine)-block-polystyrene, poly(4-vinylpyridine)-block- It may be one or more selected from polystyrene, polystyrene-block-polyethylene oxide, and polystyrene-block-polyacrylic acid, but is not limited thereto.

In one embodiment of the present application, all of the block copolymers are achiral molecules, where the achiral molecule refers to a molecule that does not have chirality, is structurally symmetrical, has no enantiomers, and is similar to the actual molecule. Mirror image molecules have the property of being stacked on top of each other.

In one embodiment of the present application, by self-assembly of the block copolymer and the racemic compound, the block copolymer undergoes micro phase separation to form a nanostructure with a regular and periodic arrangement (nanopattern or nanoscale). You can.

In one embodiment of the present application, the block copolymer and the racemic compound may be mixed at a molar ratio of about 1:1 to about 1:4, but are not limited thereto. Specifically, the block copolymer and the racemic compound are about 1:1 to about 1:4, about 1:1 to about 1:3, about 1:1 to about 1:2, and about 1:2 to about 1. :4, about 1:2 to about 1:3, or about 1:3 to about 1:4, but is not limited thereto. For example, because one DL-alanine (racemic compound) hydrogen bonds per pyridine molecule of the block copolymer, they can be mixed at a molar ratio of about 1:1, and because the solubility of DL-alanine in toluene is low, about The DL-alanine may be mixed in a molar ratio of up to 1:4 with excess.

In one embodiment of the present application, in step (a), the first non-polar solvent is toluene, benzene, xylene, chlorobenzene, dichlorobenzene, tetrahydrofuran, dichloromethane, dimethylformamide, diethyl ether, iso It may include one or more selected from propyl alcohol and dimethyl sulfoxide, but is not limited thereto.

In one embodiment of the present application, in step (b), the precursor of the nanostructure may include an inorganic nanoparticle precursor or a perovskite nanocrystal precursor, but is not limited thereto.

In one embodiment of the present application, the inorganic nanoparticle precursor may include one or more selected from HAuCl ₄ , AgNO ₃ , TiCl ₄ , PtCl ₄ , CuCl ₂ and PdCl ₂ , but is not limited thereto. Specifically, the inorganic nanoparticle precursor may be any precursor capable of producing inorganic substances such as metals and semiconductors without limitation.

In one embodiment of the present application, the perovskite nanocrystals may be organic or inorganic perovskite nanocrystals, and may be one or more selected from MAPbBr ₃ , CsPbBr ₃ , CsPbI ₃ , CsPbCl ₃ , and MAPbCl ₃ However, it is not limited to this. Specifically, when producing perovskite nanocrystals of MAPbBr ₃ , precursors of MABr and PbBr ₂ may be used, and when producing perovskite nanocrystals of MAPbCl ₃ , MACl and PbCl ₂ may be used.

In one embodiment of the present application, in the method for producing a nanostructure containing the inorganic nanoparticle precursor, heating may be performed after step (a) to form a spherical, tubular, gyroidal, or lamellar structure; , the spherical, tubular, gyroidal, or lamellar structures may have microporosity. Specifically, in the method for producing a nanostructure containing the inorganic nanoparticle precursor, any shape in which the block copolymer is phase-separated after step (a) is possible. Additionally, the spherical structure may be in a core-shell form, and may specifically have a reverse micelle structure. In addition, the shape such as spherical, tubular, gyroid, etc. may vary depending on the relative composition ratio of the polymer blocks in the block copolymer, their molecular weight, and the solvent used.

In one embodiment of the present application, in the method for producing a nanostructure containing the inorganic nanoparticle precursor, after administering the precursor in step (b), a reducing agent may be additionally administered to obtain a nanostructure having a chirality in the center. there is.

In one embodiment of the present application, in the method for producing a nanostructure containing the perovskite precursor, after administering the precursor in step (b), a second non-polar solvent is administered to form a perovskite nanocrystal in the center. It may be something to obtain.

In one embodiment of the present application, the second non-polar solvent may be one or more selected from toluene, benzene, xylene, chlorobenzene, dichlorobenzene, tetrahydrofuran, dichloromethane, diethyl ether, and isopropyl alcohol, It is not limited to this.

In one embodiment of the present application, the first non-polar solvent and the second non-polar solvent may be the same or different. When toluene, the non-polar solvent, is used, the perovskite nanoprecursor can form crystals in the reverse micelle hydrophilic core to avoid contact with toluene.

In one embodiment of the present application, the reducing agent used in the chiral nanostructure may be one or more selected from ascorbic acid, hydroquinone, oxalic acid, and sodium citrate, but is not limited thereto. The reducing agent may be a weak reducing agent, and if a strong reducing agent such as hydrazine or sodium borohydride is used, the chiral nanostructure may not be formed.

In one embodiment of the present application, in the method of manufacturing the nanostructure containing the inorganic nanoparticle precursor, the heating may be performed at a temperature of about 70°C to about 100°C. Specifically, the heating is from about 70°C to about 100°C, about 70°C to about 95°C, about 70°C to about 90°C, about 70°C to about 85°C, about 70°C to about 80°C, or about 70°C. It may be performed at a temperature of from about 75°C, but is not limited thereto. At this time, inorganic nanoparticles are formed, but chirality is not observed. When the heating is performed at a temperature above about 100° C., the inorganic nanostructures do not form.

In one embodiment of the present application, in the method for producing the nanostructure containing the inorganic nanoparticle precursor, step (b) may be performed at room temperature, and after step (b), the nanostructure having a central center having chirality It may be to obtain a structure. At this time, if the process is carried out at a high temperature as in step (a), inorganic nanoparticles may be formed, but chiral nanostructures may not be obtained.

In one embodiment of the present application, in the method for producing a nanostructure containing the perovskite precursor, step (a) may be performed by stirring at room temperature. Specifically, since the nanostructure containing the perovskite precursor itself has temperature instability, when stirring is performed at high temperature in the above manufacturing method, structural changes occur and phase separation occurs.

In one embodiment of the present application, in the method for producing a nanostructure containing the perovskite precursor, a precipitant may be additionally added in step (b) and dissolved in a second non-polar solvent.

In one embodiment of the present application, the precipitant may be one or more selected from n-hexane, pentane, cyclohexane, heptane, and octane, but is not limited thereto.

In one embodiment of the present application, the functional group of a pyridine group, carbonyl group, ether or carboxyl group capable of hydrogen bonding or polar bonding of the block copolymer and the hydroxy group of the racemic compound may be hydrogen bonded to each other.

In one embodiment of the present application, the method for producing the chiral nanostructure may further include the step of purifying the nanostructure by centrifugation after obtaining the nanostructure in step (b).

In one embodiment of the present application, in the method for producing the chiral nanostructure, a nanostructure having a central core may be obtained after the purification process, and the nanostructure having the chirality may be formed in the block copolymer template in- Because it is synthesized in situ, it has the advantage of maintaining chirality even after purification.

In one embodiment of the present application, the method for manufacturing the chiral nanostructure is manufactured through a simple stirring process, which has the advantage of being simpler than the conventional manufacturing method of arranging chiral ligands or achiral nanoparticles into a chiral tissue ensemble. There is.

A second aspect of the present application provides a chiral nanostructure prepared according to the method for producing a chiral nanostructure according to the first aspect.

Detailed description of parts overlapping with the first aspect of the present application has been omitted, but the description of the first aspect of the present application can be applied equally even if the description is omitted in the second aspect of the present application.

In one embodiment of the present application, the chiral nanostructure may include one selected from chiral organic-inorganic perovskite nanocrystals, inorganic nanoparticles, and semiconductor nanoparticles. The inorganic nanoparticles may include those selected from plasmonic metal nanoparticles and plasmonic metal oxide nanoparticles, and the metal may be selected from gold, silver, palladium, and titanium.

The chiral nanostructure can be used as a material for chiral catalysts, enantiomer separation, sensing, and medical diagnosis, but is not limited thereto.

Hereinafter, the present application will be described in more detail using examples. However, the following examples are merely illustrative to aid understanding of the present application, and the content of the present application is not limited to the following examples.

[Example]

Example 1: Preparation of chiral inorganic nanoparticles based on block copolymers

A method for producing inorganic nanoparticles with chirality in a reverse micelle structure by self-assembling a precursor of a block copolymer and an inorganic nanoparticle is shown in Figure 1(a). The production method according to a in Figure 1 is, first, a block copolymer, polystyrene-block-polyvinylpyridine (PS-b-PVP; polystyrene-block-polyvinylpyridine; polymer solution concentration 0.5 mg/mL; no chirality) and DL- Alanine (not chiral; racemicized mixture) was added to toluene solvent (nonpolar solvent) at a molar ratio of 1:4 and stirred at a temperature of 80°C for one day to obtain a first mixture having a reverse micelle structure. Afterwards, the inorganic nanoparticle precursor (HAuCl ₄ , AgNO ₃ , TiCl ₄ , PdCl ₂ ; 0.5 times the number of moles of vinylpyridine) was dissolved in isopropyl alcohol or dimethylformamide (DMF), and then the second mixture was added. Obtained, it was dissolved in the first mixture by stirring for one day. Ascorbic acid (4 times the number of moles of the inorganic precursor) was used as a reducing agent, and the reducing agent was added to the first mixture and stirred for 5 days, and then the undissolved residue was removed through a PTFE filter, and the reverse Inorganic nanoparticles (plasmonic gold nanoparticles, plasmonic silver nanoparticles, plasmonic palladium nanoparticles, and TiO ₂ nanoparticles) having chirality of micelle structure were obtained.

Here, when the PS-b-PVP is dissolved in toluene, a nonpolar solvent that selectively interacts with hydrophobic PS, reverse micelles composed of a PS shell and a PVP core are formed, and the carboxyl group of DL-alanine hydrogen bonds with pyridine. Since the amine group interacts strongly with the inorganic precursor, inorganic nanoparticles are eventually created in the PVP core to which DL-alanine is bound.

Example 2: Preparation of chiral organic-inorganic perovskite nanocrystals based on block copolymers

A method for producing organic-inorganic perovskite nanocrystals with chirality in a reverse micelle structure through self-assembly of a block copolymer and a perovskite precursor is shown in Figure 1b. In the manufacturing method according to b in Figure 1, first, polystyrene-block-polyvinylpyridine (PS-b-PVP; polystyrene-block-polyvinylpyridine; polymer solution concentration 0.5 mg/mL), a block copolymer, and DL-alanine are mixed at a ratio of 1:4. It was mixed at a molar ratio of , added to dimethylformamide solvent, and stirred at room temperature for about a day to obtain the first mixture (not reverse micelle structure). Afterwards, perovskite precursors (MABr, PbBr ₂ ; same mole number as VP) were added to the first mixture and stirred for one day (no reverse micelle structure). Thereafter, the first mixture solution (50 μL) was added to toluene (2 mL) under vigorous stirring, and n-hexane, a precipitant, was added in an amount twice the volume of the entire mixture. After centrifugation (10,000 rpm, 10 minutes), the precipitate was dissolved in toluene and reduced to obtain organic-inorganic perovskite nanocrystals with chirality of a reverse micelle structure.

Experiment example

1. Absorbance spectrum analysis

In order to confirm the presence of inorganic nanoparticles in the reverse micelle nanostructure obtained in Example 1, various nanoparticles with chirality, namely, plasmonic gold nanoparticles, plasmonic silver nanoparticles, plasmonic palladium nanoparticles, and TiO The absorption spectra of _{the two} nanoparticles were measured respectively (Figure 2). As can be seen in Figure 2, the chiral plasmonic gold nanoparticles showed a surface plasmon resonance peak at 513 nm, and the chiral plasmonic silver nanoparticles showed surface plasmon resonance peaks at 390 nm and 515 nm. The plasmonic palladium nanoparticles showed a surface plasmon resonance peak at 290 nm, and the chiral TiO ₂ nanoparticles showed a wide absorption peak at 370 nm. Therefore, when peaks corresponding to each inorganic nanoparticle appeared in the absorption spectrum, it was confirmed that inorganic nanoparticles existed in the obtained reverse micelle nanostructure.

Likewise, in order to confirm the presence of the reverse micelle organic-inorganic perovskite nanocrystals obtained in Example 2, the absorption spectrum was measured and shown in FIG. 3. In Figure 3, since the organic-inorganic perovskite nanocrystals showed a wide peak at 514 nm corresponding to the perovskite nanocrystals, the perovskite nanocrystals were found in the reverse micelle nanostructure obtained through the absorption spectrum. Its existence has been confirmed.

2. XRD pattern (X-ray diffraction pattern)

In order to confirm whether organic-inorganic perovskite nanocrystals were obtained, the XRD pattern of the nanocrystals was measured (FIG. 4). Looking at Figure 4, peaks appeared at (100), (110), (200), and (210), and it can be seen that the positions of the peaks are consistent with the bulk MAPbBr ₃ perovskite. As a result, It was confirmed that perovskite nanocrystals were obtained.

3. Fluorescence spectrum

In order to confirm whether the obtained organic-inorganic perovskite nanocrystals were formed uniformly, the fluorescence spectrum of the organic-inorganic perovskite nanocrystals with chirality was measured under 365 nm ultraviolet irradiation (FIG. 5). In Figure 5, the organic-inorganic perovskite nanocrystals showed a fluorescence peak at 530 nm, a full width at half maximum as small as 22 nm, and luminous efficiency was measured at 12%. Since the full width at half maximum was small, it was confirmed that uniform perovskite nanocrystals were formed. Here, the full width at half maximum represents the width of the function and means the spectrum width at a position that is 1/2 the peak.

4. Fourier transform infrared spectrum

To confirm the bond between PS-b-PVP and DL-alanine, the Fourier transform infrared spectrum was measured, specifically, DL-alanine (blue), PS-b-PVP (black), and PS-b-PVP. The spectra of /DL-alanine (red) were compared (Figure 6). In Figure 6, a vibration peak appears at 1439 cm ^-1 , which is the peak of pyridine in PS-b-PVP, and in PS-b-PVP/DL-alanine, pyridine is formed by binding with PS-b-PVP and DL-alanine. You can see that the peak is separated into two bands. Therefore, referring to Figure 6, it can be confirmed that hydrogen bonding occurred between the hydroxyl group of DL-alanine and the pyridine group of PS-b-PVP in PS-b-PVP/DL-alanine, and thus PS-b The hydrogen bonded molecular structure of -PVP and DL-alanine is shown in Figure 7.

With reference to the above, the Fourier transform infrared spectra of various inorganic nanoparticles (Au NP, Ag NP, TiO ₂ NP, Pd NP) and PS-b-PVP/DL-alanine were compared (Figure 8). In Figure 8, in the spectrum of PS-b-PVP/DL-alanine using various inorganic nanoparticle precursors, the vibration peak (1594 cm ^-1 ) corresponding to the amine group of DL-alanine decreases, and ranges from 1600 cm ^-1 to 1660. A broad peak occurred at cm ^-1 . This means that a strong interaction (coordination bond) has occurred between the amine group and the nanoparticle precursor ion, and this strong interaction causes the chirality of the pyridine bound to DL-alanine to be generated in situ in the polyvinylpyridine core. It can be understood that it is effectively delivered to organic-inorganic nanoparticles.

In addition, the Fourier transform infrared spectra of DL-alanine, PS-b-PVP/DL-alanine, and PS-b-PVP/DL-alanine/MAPbBr ₃ were also compared (FIG. 9). In Figure 9, in the Fourier transform infrared spectrum of PS-b-PVP/DL-alanine/MAPbBr ₃ (green), the vibration peak (1594 cm ^-1 ) corresponding to the amine group of DL-alanine decreases, and from 1600 cm ^-1 It was found that a wide peak occurred at 1660 cm ^-1 . This shows that a strong interaction (coordination bond) between the amine group and the precursor ion has occurred, and this strong interaction causes the chirality of the pyridine bound to DL-alanine to be generated in situ in the polyvinylpyridine core. It can be understood that it was effectively transferred to inorganic perovskite nanocrystals.

5. Circular dichroism spectrum

PVP combined with DL-alanine has a chemical structure similar to polyphenylisocyanides or polyphenylacetylenes containing L or D-alanine. DL-alanine is insoluble in non-polar solvents, but PVP When mixed with in a non-polar solvent, it dissolves while forming a hydrogen bond with the pyridine group. In order to confirm the selective interaction and chirality of the compound with specific isomers, the circular dichroism spectrum was measured (Figure 10). Circular dichroism spectrum utilizes the polarization phenomenon that occurs when light is transmitted through enantiomers.

Referring to Figure 10, the circular dichroism spectrum of a material combining DL-alanine and PVP using a mixed solvent of ethanol/water or a solvent of toluene is shown. When toluene is used, negative circular dichroism is observed at 280 nm. It was confirmed that a peak appeared. Here, the part where the negative peak appears corresponds to the aromatic part (235 nm to 280 nm) of the mixture, that is, it is due to the pyridine group of PVP to which DL-alanine is hydrogen-bonded. Therefore, given that the peak appears in the range of 235 nm to 280 nm, when DL-alanine and PVP are dissolved in toluene, the pyridine group prefers hydrogen bonding with D-alanine rather than hydrogen bonding with L-alanine. Therefore, it can be inferred that it has chirality.

In addition, the circular dichroism spectrum was confirmed when PS-b-PVP was dissolved in toluene or DL-alanine/PS-b-PVP was dissolved in toluene (Figure 11), DL-alanine/PS-b -When PVP was dissolved in toluene, it was confirmed that a negative circular dichroism peak appeared at 280 nm. Here, the part where the negative peak appears corresponds to the aromatic part (235 nm to 280 nm) of the mixture, that is, it is due to the pyridine group of PVP to which DL-alanine is hydrogen-bonded. Additionally, the broad negative circular dichroism signal appearing above 300 nm is due to the polymer chains. Therefore, when looking at the negative circular dichroism signal, when the DL-alanine/PS-b-PVP is dissolved in toluene, the pyridine group hydrogen bonds with D-alanine more than it hydrogen bonds with L-aladdin. Because it is preferred, it can be inferred that it has chirality.

With reference to the above, the circular dichroism spectra of chiral plasmonic gold nanoparticles, chiral plasmonic silver nanoparticles, chiral plasmonic palladium nanoparticles, and chiral TiO ₂ nanoparticles were measured, and the respective results are shown in Figure 12. It was. ^The chiral plasmonic gold nanoparticles showed a g ^- factor of - 8.0 ^-4 (at 513 nm). In addition, chiral plasmonic _palladium nanoparticles showed a g ^- factor of - ^1.3 indicated. Therefore, it was confirmed that the inorganic nanoparticles formed in the reverse micelle core had chirality because the inorganic nanoparticles using the inorganic nanoparticle precursor had a negative g-factor near the absorption peak.

In addition, the circular dichroism spectrum of organic-inorganic perovskite nanocrystals with chirality was measured (Figure 13). Looking at Figure 13, the organic-inorganic perovskite nanocrystals showed a g-factor (anisotropy factor) of ^-2.0 It was confirmed that the organic-inorganic perovskite nanocrystals formed also had chirality.

With reference to the above, circular dichroism spectra were measured to confirm whether the chiral nanostructures (chiral inorganic nanoparticles and chiral organic-inorganic perovskite nanocrystals) could maintain chirality even after the purification process. In the case of the chiral inorganic nanoparticles, the nanoparticles were centrifuged, precipitated, and dissolved in toluene again to measure the circular dichroism spectrum. In the case of the chiral organic-inorganic perovskite nanocrystals, the nanocrystals were An n-hexane precipitant was added to precipitate the solution through centrifugation, and the solution was dissolved in tetrahydrofuran (a nonpolar solvent, but more polar than toluene), and then the circular dichroism spectrum was measured (FIG. 14). In Figure 14, it can be seen that the nanostructures using Au NPs, Ag NPs, and MAPbBr ₃ all produced negative g-factors. Therefore, it can be seen that the nanostructures maintained their chirality even after the purification process, and from this, it can be inferred that the chiral nanostructures can be applied to various chiral devices and systems that require a purification process.

6. Atomic force microscope image

After mixing DL-alanine and PS-b-PVP with toluene, the solution was spin-coated on a substrate (2000 rpm, 60 seconds) and an atomic force microscope image was measured (FIG. 15). It was confirmed that the reverse micelle structure was formed by referring to the formation of a dot pattern in the atomic force microscope image (FIG. 15), and as is well known in the prior art, PS-b- Since PVP forms a reverse micelle structure when dissolved in toluene by applying heat, the reverse micelle structure is maintained even when DL-alanine is added together, so DL-alanine does not affect the self-assembly structure of the block copolymer. was confirmed.

7. Transmission electron microscopy images

To confirm whether various inorganic nanoparticles with chirality have a reverse micelle structure, transmission electron microscope images of chiral plasmonic gold nanoparticles, chiral plasmonic silver nanoparticles, chiral plasmonic palladium nanoparticles, and chiral TiO ₂ nanoparticles were measured. (Figure 16). Referring to Figure 16, the chiral plasmonic gold nanoparticles formed a single spherical nanoparticle with an average diameter of 12 nm in the reverse micelle core, and the chiral plasmonic silver nanoparticles formed several spherical nanoparticles with an average diameter of 7 nm in the reverse micelle core. Several spherical silver nanoparticles were formed, the chiral plasmonic palladium nanoparticles formed several spherical palladium nanoparticles with an average diameter of 3 nm in the reverse micelle core, and the chiral TiO ₂ nanoparticles had an average diameter in the reverse micelle core. One TiO ₂ nanoparticle of 37 nm was formed. Therefore, through transmission electron microscope images, it can be confirmed that chiral inorganic nanoparticles with a reverse micelle structure are produced.

Just as transmission microscopy images of various inorganic nanoparticles with chirality were measured, transmission microscopy images of organic-inorganic perovskite nanocrystals with chirality were measured (FIG. 17). As can be seen in Figure 17, the organic-inorganic perovskite nanocrystals have one perovskite nanocrystal with an average diameter of 40 nm formed in one reverse micelle core. Therefore, it can be confirmed through transmission electron microscope images that organic-inorganic perovskite nanocrystals with a reverse micelle structure are produced.

In summary, the present invention shows that when PS-b-PVP and DL-alanine are mixed, the pyridine group of PS-b-PVP and the hydroxyl group of DL-alanine are hydrogen bonded to form a reverse micelle nanostructure, and the core of the nanostructure is formed. It has the characteristic of having chirality. In addition, the present invention can obtain chiral nanostructures through a simpler precursor administration and stirring process than the prior art, and due to the feature of in-situ synthesis within the block copolymer template, their chirality will be stably maintained even after the purification process. It has been confirmed that there are possible benefits. On the other hand, the conventional technology has a disadvantage in terms of cost because it uses chiral ligands or chiral templates to obtain chiral nanostructures, whereas the present invention uses only achiral materials without using chiral ligands or chiral templates, resulting in low-cost nanostructures. There is an advantage in that chiral organic-inorganic nanostructures can be obtained using a simple process method called soft template of block copolymer. In addition, although the chiral nanostructure of the present application does not use chiral molecules and chiral templates, the prepared chiral nanostructure has a similar level of chirality as the conventional chiral nanostructure using chiral molecules and chiral templates.

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

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

Claims (14)

(a) mixing the block copolymer and DL-alanine in a first non-polar solvent to obtain a mixture,
(b) Adding a nanostructure precursor to the mixture to obtain a nanostructure with chirality in the center.
Method for producing a chiral nanostructure, including.
delete delete According to claim 1,
In step (a), the block copolymer is at least one selected from polystyrene-block-polyvinylpyridine, poly(2-vinylpyridine)-block-polystyrene, and poly(4-vinylpyridine)-block-polystyrene. Phosphorus, method for producing chiral nanostructures.
According to claim 1,
In step (a), the first non-polar solvent is selected from toluene, benzene, xylene, chlorobenzene, dichlorobenzene, tetrahydrofuran, dichloromethane, dimethylformamide, diethyl ether, isopropyl alcohol, and dimethyl sulfoxide. A method for producing a chiral nanostructure, comprising one or more of the following.
According to claim 1,
In step (b), the precursor of the nanostructure includes an inorganic nanoparticle precursor,
The inorganic nanoparticle precursor includes one or more selected from HAuCl ₄ , AgNO ₃ , TiCl ₄ , PtCl ₄ , CuCl ₂ and PdCl ₂ , a method for producing a chiral nanostructure.
According to claim 1,
In step (b), the precursor of the nanostructure includes a perovskite nanocrystal precursor,
The perovskite nanocrystals are MAPbBr ₃ , CsPbBr ₃ , CsPbI ₃ , CsPbCl ₃ , and MAPbCl _3. A method of producing a chiral nanostructure.
According to claim 6,
A method of producing a chiral nanostructure, in which heating is performed after step (a) to form a spherical, tubular, gyroidal, or lamellar structure.
According to claim 6,
A method for producing a chiral nanostructure, in which a nanostructure having a central chirality is obtained by additionally administering a reducing agent after the precursor is administered in step (b).
According to claim 7,
A method for producing a chiral nanostructure, wherein after administering the precursor in step (b), a second non-polar solvent is administered to obtain a perovskite nanocrystal at the center.
According to claim 8,
A method of producing a chiral nanostructure, wherein the heating is performed at a temperature of 70°C to 100°C.
According to clause 9,
Step (a) is a method of producing a chiral nanostructure, in which stirring is performed at room temperature.
According to claim 4,
A method for producing a chiral nanostructure, wherein the functional group of the pyridine group capable of hydrogen bonding or polar bonding of the block copolymer and the hydroxy group of the DL-alanine are hydrogen bonded to each other.
A chiral nanostructure prepared according to the method for producing a chiral nanostructure according to any one of claims 1, 4 to 13.