KR20230157834A - Surface treated inorganic nano-particle and complex film comprising the same - Google Patents

Abstract

The present disclosure relates to inorganic nanoparticles; A first dispersant linked to the inorganic nanoparticles; and a second dispersant connected to the inorganic nanoparticles; It relates to surface-treated inorganic nanoparticles having different molecular weights (Mn) of the first and second dispersants, and a composite film in which the surface-treated inorganic nanoparticles are dispersed in a polymer.

Description

Surface-treated inorganic nanoparticles and composite film containing the same {SURFACE TREATED INORGANIC NANO-PARTICLE AND COMPLEX FILM COMPRISING THE SAME}

The present disclosure relates to surface-treated inorganic nanoparticles and a composite film containing the same, and can be used, for example, in an optical lens of a camera module.

The main optical properties that camera lens materials must have can be broadly divided into refractive index, birefringence, Abbe number, and transmittance, and it is important to design them to be advantageous for each characteristic. Among them, the refractive index is the most important item. As the refractive index increases, the thinner lens can be manufactured and the resolution can be increased, so it is a central characteristic in the development of lens materials.

To manufacture camera lenses with such a high refractive index, inorganic materials such as glass or high refractive index polymers are used. Polymer materials are light, do not break easily, and are inexpensive, so they have many advantages over inorganic materials. In addition, the range of refractive index can be adjusted depending on the chemical structure of the polymer, so it is used as an optical material to suit the intended purpose.

However, because there are limits to increasing the refractive index by changing the chemical structure of the polymer, research has recently been conducted to increase the refractive index by incorporating high-refractive nanoparticles into the polymer matrix.

One of the several objects of the present disclosure is to provide surface-treated inorganic nanoparticles that can be uniformly distributed in an optical polymer, and a composite film in which the surface-treated inorganic nanoparticles are dispersed in an optical polymer, for example, for an optical lens of a camera module. It provides composite films.

One of several solutions proposed through the present disclosure is to modify the inorganic nanoparticles to have a multiple surface treatment structure, for example, a double surface treatment structure, using a plurality of dispersants having different molecular weights (Mn).

For example, surface-treated inorganic nanoparticles according to one example include inorganic nanoparticles; A first dispersant linked to the inorganic nanoparticles; and a second dispersant connected to the inorganic nanoparticles; It includes, and the first and second dispersants may have different molecular weights (Mn).

For example, a composite film according to one example may include polymers; and surface-treated inorganic nanoparticles dispersed in the polymer; It includes, wherein the surface-treated inorganic nanoparticles include inorganic nanoparticles, a first dispersant linked to the inorganic nanoparticles, and a second dispersant linked to the inorganic nanoparticles, wherein the first and second dispersants have a molecular weight (Mn) may be different.

One effect of the present disclosure is surface-treated inorganic nanoparticles that can be uniformly distributed in an optical polymer, and a composite film in which the surface-treated inorganic nanoparticles are dispersed in an optical polymer, for example, an optical lens of a camera module. A composite film can be provided.

Figure 1 schematically shows an example of surface-treated inorganic nanoparticles.
Figure 2 schematically shows an example of a surface treatment process for inorganic nanoparticles.
Figures 3 and 4 schematically show the connection form of the second dispersant after secondary surface treatment of the surface-treated inorganic nanoparticles, respectively.
Figure 5 schematically shows an example of measuring the synthesis of end groups of surface-treated inorganic nanoparticles by NMR.
Figure 6 schematically shows an example of measuring the particle size of each surface-treated inorganic nanoparticle using TEM.
Figure 7 schematically shows various examples of composite films.
Figure 8 schematically shows the transparency of the composite film according to the surface treatment structure of the inorganic nanoparticles.
Figure 9 schematically shows the refractive index according to the wavelength of the composite film manufactured by dispersing inorganic nanoparticles with a double surface treatment structure compared with the reference.
Figure 10 schematically shows the transmittance depending on the wavelength of the composite film manufactured by dispersing inorganic nanoparticles with a double surface treatment structure compared with the reference.
Figure 11 schematically shows the transparency of the composite film according to the type of second dispersant for secondary surface treatment of inorganic nanoparticles.
Figure 12 schematically shows the transparency of the composite film according to the molecular weight of the second dispersant for secondary surface treatment of inorganic nanoparticles.

Hereinafter, the present disclosure will be described with reference to the attached drawings. The shapes and sizes of elements in the drawings may be exaggerated or reduced for clearer explanation.

Surface treated inorganic nanoparticles

In order to manufacture camera lenses with a high refractive index, high-refractive optical polymers with various advantages are used. However, there is a limit to increasing the refractive index by changing the chemical structure of the polymer, so high-refractive nanoparticles are mixed into the polymer matrix to increase the refractive index. It is required to increase.

Here, nanoparticles such as zirconium oxide and titanium oxide must be smaller than the minimum wavelength of light to reduce light scattering, so they must be prepared with a uniform diameter of 15 nm or less. Additionally, in order to prevent the intensity of transmitted light from being reduced due to Rayleigh scattering and to efficiently increase the refractive index of the composite film, it must be evenly dispersed within the polymer matrix.

Meanwhile, composite films used for optical purposes can be manufactured by incorporating nanoparticles into thermosetting polymers or thermoplastic polymers. Nanoparticle and thermosetting polymer composite films can be manufactured by mixing acrylic liquid monomer and nanoparticles and then polymerizing them. In this case, the surface of the nanoparticle can react with acrylic and is modified into a molecule with a structure similar to acrylic, thereby increasing the miscibility of the two heterogeneous materials.

In addition, in order to incorporate nanoparticles using thermoplastic polymers, a method of mixing molten polymers and nanoparticles by applying heat or a method of dissolving both polymers and nanoparticles in a solvent and then removing the solvent can be used. In this case as well, Additionally, surface modification of nanoparticles with a dispersant may be necessary to increase the affinity of the interface between two dissimilar materials and to evenly disperse the nanoparticles in the solvent.

In particular, cyclic olefin, polyester, polycarbonate, etc. can be used as optical thermoplastic polymers. Among these, polyester and polycarbonate, which contain a large number of aromatic rings in a high volume ratio, are preferably used as high refractive thermoplastic polymers. It can be. Among aromatic rings, fluorene does not cause birefringence due to its structural characteristics, making it advantageous for use as optical lenses. Therefore, in order to increase the affinity of the interface between a thermoplastic polymer having a fluorene group and a nanoparticle, for example, a zirconia nanoparticle having a hydrophilic surface, design of the chemical structure of the dispersant suitable for this structure may be required.

On the other hand, if the surface of the nanoparticles is treated only with a low molecular weight dispersant, agglomeration with the nanoparticles can be controlled, but since they do not mix with the matrix polymer, phase separation occurs and an opaque composite film can be produced. In addition, if the surface of the nanoparticles is treated only with a high molecular weight dispersant, the mixing characteristics with the polymer improves, but the fixation density is lowered, so it may not be possible to suppress aggregation between nanoparticles.

From this point of view, the surface-treated inorganic nanoparticles 100 according to one example, as exemplarily shown in FIG. 1, include inorganic nanoparticles 110 and a first dispersant 121 connected to the inorganic nanoparticles 110. , and may include a second dispersant 131 connected to the inorganic nanoparticles 110. Each of the first and second dispersants (121, 131) may be covalently connected to the inorganic nanoparticles (110), and a portion of each of the first and second dispersants (121, 131) may be attached to the inorganic nanoparticles (110) by hydrogen. It can also be connected by combination. The first and second dispersants 121 and 131 may have different molecular weights (Mn). In the present disclosure, the molecular weight (Mn) may be the number average molecular weight, and may be measured using, for example, GPC of the Agilent 1200 series model.

More specifically, a first surface treatment layer 120 may be disposed on the inorganic nanoparticles 110, a second surface treatment layer 130 may be disposed on the first surface treatment layer 120, and a second surface treatment layer 130 may be disposed on the inorganic nanoparticles 110. Each of the first and second surface treatment layers 120 and 130 may include first and second dispersants 121 and 131. A portion of the second dispersant 131 may penetrate the first surface treatment layer 120.

In this way, the inorganic nanoparticles 110 are surface-treated by modifying the inorganic nanoparticles 110 into a structure having multiple surface treatment layers 120 and 130 using a plurality of dispersants 121 and 131 having different molecular weights (Mn). After obtaining (100), when it is dispersed in a polymer, the mutually exclusive problems described above can be solved, such as suppressing the agglomeration of nanoparticles and improving the mixing characteristics with the polymer at the same time.

These surface-treated inorganic nanoparticles 100, as exemplarily shown in FIG. 2, are inorganic nanoparticles subjected to primary surface treatment by first surface-treating the inorganic nanoparticles 110 with a first dispersant 121. (105) can be obtained, and then the inorganic nanoparticles (105) that have undergone primary surface treatment can be obtained by secondary surface treatment with a second dispersant (131), but are not limited to this.

Meanwhile, the first dispersant 121 may have a molecular weight (Mn) smaller than that of the second dispersant 131. For example, the first dispersant 121 may have a molecular weight (Mn) of 2000 or less, for example, about 800 to 1800, and the second dispersant 131 may have a molecular weight (Mn) greater than this. The molecular weight (Mn) of the second dispersant 131 may have a relative range with respect to the molecular weight (Mn) of the matrix polymer of the composite film, which will be described later. In this case, it may be more desirable to solve the mutually exclusive problem described above.

Meanwhile, the molecular weight (Mn) of the first and second dispersants (121, 131) may vary depending on the repeating units of the chain included in each compound. As the number of repeating units increases, the length of the chain increases and the molecular weight (Mn) increases. You can. For example, the repeating unit of the chain of the compound included in the first dispersant 121 may be smaller than the repeating unit of the chain of the compound included in the second dispersant 131, and therefore the chain may be shorter in length, Therefore, the thickness of the first surface treatment layer 120 may be thinner than the thickness of the second surface treatment layer 130.

Hereinafter, each component included in the surface-treated inorganic nanoparticles 110 according to an example will be described in more detail.

The inorganic nanoparticles 100 are not particularly limited as long as they have high refractive properties, and for example, nanoparticles such as zirconia (ZrO ₂ ), titania (TiO ₂ ), barium titanate (BTO), or zinc sulfide (ZnS). It can be included.

The first and second dispersants 121 and 131 may each include a compound including a chain having a repeating unit and a terminal group connected to the end of the chain. The repeating unit of the chain may include an aliphatic chain, and may also include an ether group (-O-) or an amide group (-N(-C(=O)-R)-) connected to the aliphatic chain. The terminal group may include a functional group capable of forming a chemical bond, such as a covalent bond, with the inorganic nanoparticle 110.

Meanwhile, in the present disclosure, for convenience of explanation, the dispersant can be described without distinguishing before and after covalent bonding with the inorganic nanoparticles. This is because some of the dispersants may not be covalently bonded to the inorganic nanoparticles but may remain hydrogen bonded. In this case, the structure of the end group of the dispersant before and after covalent bonding with the inorganic nanoparticle can be understood as a structure that is obvious to those skilled in the art through the main structure of the end group described below. For example, the phosphate structure may be a structure derived from phosphoric acid prior to chemical bonding, such as covalent bonding, with the inorganic nanoparticle.

The aliphatic chain may be a saturated hydrocarbon chain. Saturated hydrocarbon chains may be straight or fractured. Preferably, the aliphatic chain is a saturated hydrocarbon chain of C ₂ to C ₆ , for example -(CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ )- etc., and more preferably a saturated hydrocarbon chain of C ₂ to C ₄ , for example, -(CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ )-, -(CH ₂ - It may be CH ₂ -CH ₂ -CH ₂ )-, etc., but is not limited thereto.

R of the amide group (-N(-C(=O)-R)-) is a substituent, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, sec-butyl group, 1-methyl-butyl group, 1-ethyl-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, 1-methylpentyl group, 2-methylpentyl group, C ₁ to C ₁₀ alkyl groups such as 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, heptyl group, 1-methylhexyl group, octyl group, nonyl group, decyl group, etc. It may be an alkyl group of C ₁ to C ₄ , preferably a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, sec-butyl group, etc., but is limited thereto. no.

For example, the chain of the compound included in each of the first and second dispersants 121 and 131 may include polyethylene or polyoxazoline, and the terminal group may include a silane structure, a phosphate structure, or a carboxyl structure. However, it is not limited to this. The FT-IR (Ge Crystal ATR accessory) of the Thermo Fisher iN 10 model can be used to analyze the structure and functional group of the compounds included in the first and second dispersants (121, 131), and the synthesis of end groups can be determined using JEOL JNM. -This can be confirmed by NMR of the ECX500 II model.

As a non-limiting example, the compound included in the first dispersant 121 may include poly(ethylene glycol)methyl ether as a chain having a repeating unit, and may include a phosphate structure as an end group. For example, the first dispersant 121 may include a structure derived from a compound represented by the following [Chemical Formula 1], but is not limited thereto.

[Formula 1]

Here, n1 may be an integer of 15 to 50, and in this case, it may have the preferred range of molecular weight (Mn) described above, but is not limited thereto.

As another non-limiting example, the compound included in the first dispersant 121 may include poly(2-ethyl-2-oxazoline) as a chain having a repeating unit, and may include a phosphate structure as an end group. there is. For example, the first dispersant 121 may include a structure derived from a compound represented by the following [Chemical Formula 2], but is not limited thereto.

[Formula 2]

Here, m1 may be an integer of 5 to 35, and in this case, it may have the above-described preferred range of molecular weight (Mn), but is not limited thereto.

As a non-limiting example, the compound included in the second dispersant 131 may include poly(ethylene glycol)methyl ether as a chain having a repeating unit, and may include a phosphate structure as an end group. For example, the second dispersant 131 may include a structure derived from a compound represented by the following [Formula 3], and in this case, the surface-treated inorganic nanoparticles 100A are illustratively shown in FIG. 3. As described above, after secondary surface treatment, poly(ethylene glycol)methyl ether may be linked to inorganic nanoparticles through a phosphate structure, but is not limited to this. Whether the phosphate structure has been synthesized can be confirmed by P31 NMR, for example, as shown in FIG. 5.

[Formula 3]

Here, n2 may be an integer of 110 to 260, and in this case, it may have a desirable molecular weight (Mn) range in relation to the matrix polymer of the composite film, which will be described later, but is not limited thereto.

As another non-limiting example, the compound included in the second dispersant 131 may include poly(2-ethyl-2-oxazoline) as a chain having a repeating unit, and may include a phosphate structure as an end group. there is. For example, the second dispersant 131 may include a structure derived from a compound represented by the following [Formula 4], in which case the surface-treated inorganic nanoparticles 100B are illustratively shown in FIG. 4 As described above, after secondary surface treatment, poly(2-ethyl-2-oxazoline) may be linked to inorganic nanoparticles through a phosphate structure, but is not limited to this. Whether the phosphate structure has been synthesized can be confirmed by P31 NMR, for example, as shown in FIG. 5.

[Formula 4]

Here, m2 may be an integer of 110 to 230, and in this case, it may have a desirable molecular weight (Mn) range in relation to the matrix polymer of the composite film, which will be described later, but is not limited thereto.

A compound containing poly(ethylene glycol) methyl ether as a chain having a repeating unit and a phosphate structure as an end group can be prepared through [Reaction Scheme 1].

[Scheme 1]

Here, n may be n1 or n2, and in this case, it may have the desired molecular weight (Mn) range described above, but is not limited thereto.

A compound containing poly(2-ethyl-2-oxazoline) as a chain having a repeating unit and a phosphate structure as an end group can be prepared through [Reaction Scheme 2].

[Scheme 2]

Here, m may be m1 or m2, and in this case, it may have a preferred range of the molecular weight (Mn) described above, but is not limited thereto.

The surface-treated inorganic nanoparticles 100 may have a particle size of 1 nm to 30 nm, preferably 3 nm to 15 nm, as shown in FIG. 6 . If the particle size is larger than this, the transmittance due to particle scattering decreases, making it difficult to make a transparent material, and if the particle size is smaller than this, there may be difficulties in controlling agglomeration. Particle size can be measured with a TEM of the JEOL JEM-ARM200F model.

composite film

The composite film according to one example may include a polymer and the above-described surface-treated inorganic nanoparticles dispersed in the polymer. A composite film according to one example can be manufactured by combining a polymer and the surface-treated inorganic nanoparticles described above. For example, it can be manufactured by applying a composition containing the above-described surface-treated inorganic nanoparticles to a polymer, drying the solvent, and then heat-compressing it. Alternatively, it can be prepared by adding a polymer to a composition containing the above-mentioned surface-treated inorganic nanoparticles, drying the solvent, and then heat-compressing it. After heat compression, the composite film may be in a thick film state. The polymer and the above-mentioned surface-treated inorganic nanoparticles may be bonded to each other through hydrogen bonding or the like.

Meanwhile, polymers can be used as materials for optical lenses for camera modules, and therefore can be polymers with high refractive index. For example, it may be a thermoplastic polymer having a fluorene group, specifically, polyester having a fluorene group, polycarbonate having a fluorene group, etc., but is not limited thereto. Inorganic nanoparticles, such as zirconia nanoparticles, are relatively hydrophilic and can be more easily combined with thermoplastic polymers, such as polyester and polycarbonate, through hydrogen bonds.

On the other hand, when the molecular weight (Mn) of the polymer is P and the molecular weight (Mn) of the above-mentioned second dispersant is N, the composite film according to one example has a P/N of 0.5 to 8, preferably about 1 to 4. You can. In this case, the optimal dispersion state can be secured. If the value of P/N is smaller than this, the secondary surface treatment molecular weight is too large to secure the dispersion density to suppress nanoparticle aggregation, and if it is larger than this, the secondary surface treatment length is too short and does not mix well with the matrix polymer, resulting in phase separation. It can happen. As a non-limiting example, the molecular weight (Mn) of the injectable optical polymer may be about 10,000 to 30,000, and the molecular weight (Mn) of the second dispersant may have a range that satisfies the range of P/N described above, but is limited thereto. It doesn't work.

Meanwhile, the refractive index may vary depending on the content of surface-treated inorganic nanoparticles dispersed in the polymer. For example, when zirconia nanoparticles with a refractive index of about 2.1 are dispersed in an optical polymer with a refractive index of about 1.68 after double surface treatment, a highly transparent composite film with a refractive index of about 1.7 or more can be produced. Surface-treated nanoparticles can be dispersed in an amount ranging from 1 wt% to 90 wt%, but in order to increase the refractive index and facilitate thermoformability, the amount may be more preferable from 5 wt% to 70 wt%. The refractive index can be measured at a wavelength of 550 nm, and can be measured using Metricon's 2010M model Prism Coupler.

Meanwhile, the composite film may be manufactured as a thick film type with a thickness of approximately 1 mm as shown in (a) of Figure 7, or as an aspherical lens type as shown in (b), but is not limited thereto.

Meanwhile, the content of the present disclosure is not limited to optical lenses for camera modules, and of course can also be applied to other optical functional materials, such as AR glass lenses and meta-lenses.

Experiment example

(Production Example 1)

Zirconia nanoparticles are surface-treated using a dispersant with a molecular weight (Mn) of 1000 containing polyethylene glycol as a chain and a carboxyl structure (e.g., carboxylic acid) as an end group, thereby producing zirconia nanoparticles with a single surface-treated structure. prepared. Next, a nanosol containing surface-treated zirconia nanoparticles was mixed with a solution containing a thermoplastic polyester containing fluorene with a molecular weight (Mn) of 12000, so that the surface-treated zirconia nanoparticles were dispersed in the thermoplastic polyester. A composite sol was formed, and then the solvent was dried to form a thin film. The thin film was then thermocompressed to prepare a composite film in the form of a 1 mm thick thick film.

(Production Example 2)

In Preparation Example 1, after surface treatment of zirconia nanoparticles, a second dispersant with a molecular weight (Mn) of 5000 containing poly(ethylene glycol) methyl ether as a chain and a phosphate structure (e.g., phosphoric acid) as a terminal group was used. A composite film with a thickness of approximately 1 mm was manufactured in the same manner, except that zirconia nanoparticles with a double surface treatment structure were prepared by secondary surface treatment.

(Production Example 3)

Zirconia nanoparticles are first surface treated using a first dispersant with a molecular weight (Mn) of 1000 that contains polyethylene glycol as a chain and a carboxyl structure (e.g., carboxylic acid) as an end group, and then polydies as a chain. Zirconia nanoparticles were subjected to secondary surface treatment with a second dispersant having a molecular weight (Mn) of 1000 containing methylsiloxane and a phosphate structure (e.g., phosphoric acid) as an end group, thereby producing zirconia nanoparticles with a double surface treatment structure. Ready. Next, a composite film was prepared by dispersing surface-treated zirconia nanoparticles in thermoplastic polyester containing fluorene with a molecular weight (Mn) of 12000.

(Production Example 4)

In Preparation Example 3, the same method was used as the second dispersant, except that a compound having a molecular weight (Mn) of 10000 containing polydimethylsiloxane as a chain and a phosphate structure (e.g., phosphoric acid) as an end group was used. A composite film was manufactured.

(Production Example 5)

In Preparation Example 3, except that a compound having a molecular weight (Mn) of 10000 containing poly(ethylene glycol) methyl ether as a chain and a phosphate structure (e.g., phosphoric acid) as a terminal group was used as the second dispersant. produced a composite film using the same method.

(Production Example 6)

In Preparation Example 3, a compound having a molecular weight (Mn) of 10000 containing poly(2-ethyl-2-oxazoline) as a chain and a phosphate structure (e.g., phosphoric acid) as a terminal group was used as the second dispersant. The composite film was manufactured in the same manner except that.

(Production Example 7)

Zirconia nanoparticles are subjected to primary surface treatment using a first dispersant with a molecular weight (Mn) of 1000 containing poly(ethylene glycol) methyl ether as a chain and a phosphate structure (e.g., phosphoric acid) as an end group, Afterwards, the zirconia nanoparticles were subjected to secondary surface treatment with a second dispersant having a molecular weight (Mn) of 1000 containing poly(ethylene glycol) methyl ether as a chain and a phosphate structure (e.g., phosphoric acid) as an end group. Zirconia nanoparticles with a surface-treated structure were prepared. Next, a composite film was prepared by dispersing surface-treated zirconia nanoparticles in thermoplastic polyester containing fluorene with a molecular weight (Mn) of 12000.

(Production Example 8)

In Preparation Example 7, zirconia nanoparticles containing poly(ethylene glycol)methyl ether as a chain and a phosphate structure (e.g., phosphoric acid) as a terminal group and having a molecular weight (Mn) of 5000 were used as a second dispersant. The composite film was manufactured in the same manner except for surface treatment.

(Production Example 9)

In Preparation Example 7, zirconia nanoparticles containing poly(ethylene glycol)methyl ether as a chain and a phosphate structure (e.g., phosphoric acid) as a terminal group and having a molecular weight (Mn) of 10000 were used as a second dispersant. The composite film was manufactured in the same manner except for surface treatment.

(Production Example 10)

In Preparation Example 7, zirconia nanoparticles were used as a second dispersant with a molecular weight (Mn) of 20000, which contains poly(ethylene glycol)methyl ether as a chain and a phosphate structure (e.g., phosphoric acid) as an end group. The composite film was manufactured in the same manner except for surface treatment.

(Example 1)

The transparency of the composite films of Preparation Examples 1 and 2 was observed with the naked eye, and the results are shown in (a) and (b) of [FIG. 8], respectively. Referring to the drawing, when single surface-treated zirconia nanoparticles were used as in Preparation Example 1, the nanoparticles were aggregated to obtain an opaque composite film. On the other hand, when using double surface-treated zirconia nanoparticles as in Preparation Example 2, a transparent composite film was obtained.

In particular, as shown in [FIG. 9], the refractive index of the composite film of Preparation Example 2 measured at a wavelength of 550 nm was about 1.70, which was higher than the refractive index of 1.68 of the reference composite film. Here, the reference composite film refers to a composite film with a thickness of approximately 1 mm produced by solvent drying and heat-pressing only a solution containing thermoplastic polyester containing fluorene with a molecular weight (Mn) of 12000 without dispersion of zirconia nanoparticles. . The refractive index can be measured using Metricon's 2010M model Prism Coupler.

In addition, as shown in [FIG. 10], the composite film of Preparation Example 2 has a transmittance of approximately 83% measured at a wavelength of 550 nm, and, like the reference composite film, which has a transmittance of approximately 87%, it has a high transmittance of 70% or more. was able to secure. Here, the reference composite film refers to a composite film with a thickness of approximately 1 mm produced by solvent drying and heat-pressing only a solution containing thermoplastic polyester containing fluorene with a molecular weight (Mn) of 12000 without dispersion of zirconia nanoparticles. . Transmittance and haze can be measured with PerkinElmer's Lambda 1050 model UV-Vis Spectrometer.

(Example 2)

The transparency of the composite films of Preparation Examples 3 to 6 was observed with the naked eye, and the results are shown in (a) to (d) of [FIG. 11]. Referring to the drawings, as in Preparation Examples 3 and 4, when the second dispersant was a compound that did not contain an aliphatic chain, the affinity for the polymer was low and the particles tended to aggregate. In particular, this tendency was greater when the molecular weight (Mn) of the second dispersant was small. On the other hand, as in Preparation Examples 5 and 6, when the second dispersant was a compound containing an aliphatic chain, a transparent composite film was obtained.

(Example 3)

The transparency of the composite films of Preparation Examples 7 to 10 was observed with the naked eye, and the results are shown in (a) to (d) of [FIG. 12]. Referring to the drawing, when P/N is too large at 12, as in Preparation Example 7, and when P/N is too small at 0.6, as in Preparation Example 10, an opaque composite film is obtained due to agglomeration of zirconia nanoparticles. lost. In particular, this tendency was greater when the molecular weight (Mn) of the second dispersant was small. On the other hand, as in Preparation Examples 8 and 9, when P/N satisfies the above-mentioned desirable range, a transparent composite film was obtained.

According to the present disclosure, surface-treated inorganic nanoparticles, such as surface-treated zirconia nanoparticles, can be uniformly distributed in optical polymers, such as polyester and/or polycarbonate containing fluorene. In particular, a multi-surface treatment structure, such as a double surface treatment structure, was introduced to suppress aggregation of zirconia nanoparticles and improve miscibility with polymers, which can have better effects. Therefore, for example, by functionalizing the surface of zirconia nanosol prepared using a zirconium precursor and complexing it with a high refractive index polymer, it is possible to apply it to electrical, electronic, and optical functional materials.

The expression 'example' used in the present disclosure does not mean identical embodiments, but is provided to emphasize and explain different unique features. However, the examples presented above do not exclude being implemented in combination with features of other examples. For example, even if a matter explained in a specific example is not explained in another example, it can be understood as an explanation related to the other example, as long as there is no explanation contrary to or contradictory to the matter in the other example.

The terminology used in this disclosure is used to describe examples only and is not intended to limit the disclosure. At this time, singular expressions include plural expressions, unless the context clearly indicates otherwise.

Claims (16)

inorganic nanoparticles;
A first dispersant linked to the inorganic nanoparticles; and
A second dispersant connected to the inorganic nanoparticles; Includes,
The first and second dispersants have different molecular weights (Mn),
Surface-treated inorganic nanoparticles.
According to claim 1,
A first surface treatment layer is disposed on the inorganic nanoparticles,
A second surface treatment layer is disposed on the first surface treatment layer,
Surface-treated inorganic nanoparticles.
According to claim 2,
The first and second surface treatment layers include the first and second dispersants, respectively,
A portion of the second dispersant penetrates the first surface treatment layer,
Surface-treated inorganic nanoparticles.
According to claim 3,
The first dispersant has a smaller molecular weight (Mn) than the second dispersant,
Surface-treated inorganic nanoparticles.
According to claim 4,
The first dispersant has a molecular weight (Mn) of 800 to 1800,
Surface-treated inorganic nanoparticles.
According to claim 1,
The first and second dispersants each include a compound including a chain having a repeating unit and a terminal group connected to the end of the chain,
The compounds included in each of the first and second dispersants have different chain lengths,
Surface-treated inorganic nanoparticles.
According to claim 6,
The repeating unit of the chain includes an aliphatic chain,
Surface-treated inorganic nanoparticles.
According to claim 7,
The chain comprises polyethylene or polyoxazoline,
The terminal group comprises a silane structure, a phosphate structure, or a carboxyl structure,
Surface-treated inorganic nanoparticles.
According to claim 1,
The first dispersant includes a structure derived from a compound represented by the following [Formula 1] or a compound represented by [Formula 2],
[Formula 1]

[Formula 2]

where n1 is an integer of 15 to 50,
where m1 is an integer from 5 to 35,
Surface-treated inorganic nanoparticles.
According to claim 1,
The second dispersant includes a structure derived from a compound represented by the following [Formula 3] or a compound represented by [Formula 4],
[Formula 3]

[Formula 4]

where n2 is an integer from 110 to 260,
where m2 is an integer of 110 to 230,
Surface-treated inorganic nanoparticles.
According to claim 1,
The inorganic nanoparticles include zirconia (ZrO ₂ ), titania (TiO ₂ ), barium titanate (BTO), or zinc sulfide (ZnS).
Surface-treated inorganic nanoparticles.
According to claim 1,
The surface-treated inorganic nanoparticles have a particle size of 3 nm to 15 nm,
Surface-treated inorganic nanoparticles.
polymer; and
Surface-treated inorganic nanoparticles dispersed in the polymer; Includes,
The surface-treated inorganic nanoparticles include inorganic nanoparticles, a first dispersant linked to the inorganic nanoparticles, and a second dispersant linked to the inorganic nanoparticles,
The first and second dispersants have different molecular weights (Mn),
Composite film.
According to claim 13,
When the molecular weight (Mn) of the polymer is P and the molecular weight (Mn) of the second dispersant is N, P/N is 1 to 4,
Composite film.
According to claim 14,
The molecular weight (Mn) of the polymer is 10000 to 30000,
Composite film.
According to claim 13,
The polymer includes polyester containing fluorene or polycarbonate containing fluorene,
Composite film.

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