JP4370239B2 - Gel-immobilized colloidal crystals - Google Patents

Description

The present invention relates to a gel-immobilized colloidal crystal, and more specifically, a monomer used for gelling and fixing a colloidal crystal, and a gel-immobilized colloidal crystal precursor that behaves as a gel-immobilized gel. The present invention relates to a gel-immobilized colloidal crystal and a gel-immobilized colloidal crystal.
The gel-immobilized colloidal crystal and the gel-immobilized colloidal crystal of the present invention are particularly preferably used as an optical element.

Particles collectively called ionic colloid particles such as ionic polymer latex particles and silica particles have a dissociating group on the surface. Specifically, the ionic polymer latex particles have a sulfone group, a sulfuric acid group, a carboxyl group or the like introduced during particle synthesis, and the silica particles have a weakly acidic silanol group on the particle surface.
When these particles are dispersed in a polar solvent such as water, the surface of the particles is charged and electrostatic interaction occurs between the particles, and the particles are stably dispersed without aggregating in the medium. When electrostatic interactions are weak, the spatial distribution of particles is relatively disordered, but with increasing electrostatic interactions, this system is known to form colloidal crystals with regularly arranged particles. (For example, refer nonpatent literature 1.).
In this case, the magnitude of the electrostatic interaction is mainly determined by the particle concentration in the dispersion, the low molecular ion concentration in the dispersion medium, the charge density and particle size of the particle surface, and the like.

Among the above parameters, as for the low molecular ion concentration in the dispersion medium, the electrostatic interaction between particles becomes weaker as the concentration increases (Non-Patent Document 1). This is because electrostatic interactions are shielded by the presence of low molecular ions. Therefore, crystallization is hindered by increasing the low molecular ion concentration.
The upper limit of the low molecular ion concentration that can be crystallized depends on the values of the above parameters other than the low molecular ion concentration, but in many cases, the low molecular ion concentration is a very low low molecular ion concentration of several μM (Non-Patent Document 1 and Non-Patent Document 1). (See Patent Document 2).

Further, the particles to be used in the production of colloidal crystals have a diameter of several tens of nm to several μm and a particle size distribution of about 10% or less. Using these particles, it is possible in principle to create practically useful colloidal crystals by selecting parameters such as particle concentration, salt concentration in the dispersion medium, and the number of charges on the particle surface. The material is not particularly limited.
Conventionally, those that are easily synthesized and obtained are polymer latex particles mainly composed of polystyrene, polymethyl methacrylate, and the like, and silica particles, but other metal oxide particles and metal particles can also be used.

  By using the above-mentioned particles and selecting the particle size and particle concentration, the lattice constant of the colloidal crystal can be set in the range of about 100 nm to several μm, and when the diffraction wavelength of the colloidal crystal is in the visible light region, A red color is observed by Bragg diffraction of visible light. Therefore, the development of red color also serves as a means for confirming the formation of colloidal crystals.

As described above, the lattice constant of the colloidal crystal can be set in the range of about 100 nm to several μm, but this range is on the order of wavelengths of near-ultraviolet, visible, and infrared light, and therefore the corresponding light is diffracted. .
In addition, colloidal crystals have a periodic structure with a spatial dielectric constant that is spontaneously and easily formed. Recently, colloidal crystals have attracted attention for application to optical elements such as photonic elements (see, for example, Non-Patent Document 3). ing.

However, a charged colloidal crystal (ionic colloidal crystal) is a structure formed in a liquid medium, and is easily broken by a minute external force such as shaking. Moreover, even if it is allowed to stand under conditions without external force or flow, it has the principle instability that it is destroyed when a very small amount of impurity ions are mixed. Therefore, in the application, it is necessary to fix the crystal structure in some matrix having a mechanical strength that can withstand practical use.
For this reason, a method for immobilizing colloidal crystals using a polymer hydrogel (see, for example, Patent Document 1, Non-Patent Documents 4 and 5) has been developed.

Here, the conventional method relating to the immobilization of crystals by the polymer gel is roughly as follows.
A solution containing a monomer, a crosslinking agent and a polymerization initiator is used as a gelling reaction solution, and ionic colloid particles are dispersed using this reaction solution as a medium to form a crystal structure. Next, polymerization is started and the colloidal crystal structure is fixed by gelling the medium.

At this time, a method using a radical polymerization method using a vinyl monomer such as acrylamide (AAm) as a monomer and methylene bisacrylamide (Bis) having two vinyl groups as a crosslinking agent is generally used.
In addition, radical polymerization initiators used for gel samples for acrylamide gel electrophoresis are usually ionic, but as described in paragraph [0003], colloidal crystals form their structures due to the presence of low molecular ions. Cannot be used.
Therefore, conventionally, a nonionic polymerization initiator is used and gelation is performed by irradiation with light (ultraviolet or visible light) corresponding to the absorption wavelength of the initiator.
US Pat. No. 5,330,685 A. K. Wood, Solid State Phys. 45, 1991, 1: K. S. Schmitz, Macroions in Solution and Colloidal Dispersion, VCH Inc. , New York (1993). J. et al. Yamanaka, H .; Yoshida, T .; Koga, N .; Ise and T. Hashimoto, Phys. Rev. Lett. 80, 1998, 5806 “Photonic Crystal”, J.A. D. Joannopoulous et al., Corona, Fujii, Inoue (2000) E. A. Kamenetzky, L .; G. Mangliocco, H.M. P. Panzer, Science 263, 1994, 207 Y. Iwayama, J. et al. Yamanaka, Y. et al. Takiguchi, M .; Takasaka, K .; Ito, T .; Shinohara, T .; Sawada, M .; Yonese, Langmuir, 19, 2003, 977.

However, as a result of studies on gelation and fixation of conventional colloidal crystals using acrylamide gel, the present inventors have found that there are the following problems.
That is, AAm as a monomer is hydrolyzed under acid / base conditions to become ionic acrylic acid and ammonium ion. In preparation of the charged colloidal crystal, the sample aqueous solution is usually sufficiently desalted and purified by coexisting ion exchange resin. However, since the ion exchange resin surface has many acids and bases, AAm is hydrolyzed, On the contrary, the ion concentration increases, and treatment with an ion exchange resin is not necessarily effective.

For example, if the electrical conductivity (κ) of the solution is used as an indicator of ion concentration, the κ value of the 1.33M aqueous solution is about 1 μS / cm at the time of preparation, and the interaction is strong (that is, the salt concentration is high). (Although it can also be a crystal), it is possible to fix the colloidal crystal, but it is desirable to carry out desalting purification since the crystal is destroyed by the slight contamination of impurities during the synthesis.
However, it was found that the κ value increased to about 2 μS / cm when the above-described ion exchange resin was coexisted therewith and purified by shaking for about 10 minutes.
On the other hand, it can be said that it is better to use it without purification, but if it is used without purification, a considerable amount of impurity ions will remain.

The κ value of ultrapure water (Milli-Q: trade name; manufactured by Millipore) used in the above purification is 0.3 to 0.3 when water is taken from a device into a clean container and immediately measured in air. Although it is 0.4 μS / cm, it is extremely difficult to obtain water having a lower κ value under normal conditions.
Furthermore, as described in paragraph [0002], acidic groups exist on the surface of the colloidal particles, and the particles themselves act as acids, so that acrylamide is gradually hydrolyzed. In fact, as a result of investigations by the present inventors, when colloidal crystals containing acrylamide are stored for a period of several days to several weeks or more, the concentration of ions in the solvent may increase and the colloidal crystals may be destroyed. I understood.

As described above, employing acrylamide as a monomer for gelation and fixation of colloidal crystals is disadvantageous in terms of ion concentration.
In the production of colloidal crystals, it is a general requirement that the concentration of unintentional ions such as ions derived from monomers be as low as possible, but it is essential to reduce the ion concentration of the solution. In some cases it is particularly serious.
As such a case, for example, there is gel immobilization of colloidal crystals having a very low particle concentration such that the volume fraction concentration is less than 5%. In this case, since the upper limit of the ion concentration at which colloidal crystals can exist is several μM, colloidal crystals cannot be formed in a solvent containing acrylamide.
Another example is the gel immobilization of colloidal crystals when a visible light initiator is used.
Recently, a method for fixing a gel of colloidal crystals using camphorquinone or riboflavin as a visible light initiator has been proposed (currently unpublished, but Japanese Patent Application No. 2003-18546), but both initiators were dissolved in water. When the state shows a certain electric conductivity and there is an increase in the ion concentration derived from the initiator, and the ion concentration derived from the monomer is added to this, visible light gelation cannot be applied to a colloidal crystal having a very low particle concentration.

The phenomenon that acrylamide is hydrolyzed into colloidal particles themselves and the ionic concentration gradually increases is very inconvenient for the case where the ionic concentration of the colloidal crystal needs to be kept stable.
A specific example of this is gel fixation of colloidal crystals formed under conditions near the phase boundary. From the viewpoint of application to an optical element, it is desired to construct a colloidal crystal having a size of several mm or more to several centimeters. However, as described above, such a large crystal is formed under conditions near the phase boundary (H. (See Yoshida, J. Yamanaka, Ta. Koga, Tu. Koga, N. Ise and T. Hashimoto, Langmuir, 15, 1999, 4198). The formation of such large crystals often requires a long time such as days or weeks, but the change in ion concentration over time due to hydrolysis of acrylamide is very inconvenient in controlling such processes. .
Or, even if it is not such a delicate process, the low molecular ion concentration is an important parameter of the colloidal system that influences the interaction between particles, and that the ion concentration changes with time is the crystallization condition, viscosity, etc. This is generally inconvenient in the production of colloidal crystals.
For the crosslinking agent, the concentration in the reaction solution is very small (about 1/100 of that of the monomer), and even if an ionic impurity is generated by hydrolysis, the effect is small, so it is not a big problem. .

The present invention has been made in view of the above-mentioned findings of the present inventors. The object of the present invention is to facilitate the fixation of colloidal crystals and to form gel-immobilized colloidal crystals having excellent stability. the gel immobilized colloidal crystals using a monomer, Ru near to provide a gel immobilized colloidal crystals.

  As a result of intensive studies to solve the problems based on the above findings, the present inventors have found that the above problems can be solved by using a predetermined monomer, and have completed the present invention.

（式中のＲ_１はアクリル酸残基又はメタクリル酸残基、Ｒ_２は炭素数Ｃ１〜Ｃ３のアルキロール基、炭素数Ｃ２〜Ｃ６のアルコキシアルキル基又は炭素数Ｃ２〜Ｃ６のアルコキシアルキロール基から成るアミノ基保護基を示す。）で表される構造を有するゲル固定化コロイド結晶形成用モノマーと架橋剤と光重合開始剤を含む溶液を媒体とするコロイド結晶から成り、光照射によってゲル固定化されることを特徴とする。 The gel-fixed colloidal crystal of the present invention has the following formula A

(In the formula, R ₁ is an acrylic acid residue or a methacrylic acid residue, R ₂ is a C1-C3 alkylol group, a C2-C6 alkoxyalkyl group or a C2-C6 alkoxyalkylol group. consists colloidal crystals to the medium a solution containing a gel immobilized colloidal crystals forming monomer crosslinking agent and a photopolymerization initiator having a structure represented by an amino protecting group.) consisting of a gel fixed by light irradiation It is characterized by being made.

  In a preferred form of the gel-immobilized colloidal crystal of the present invention, the photopolymerization initiator is azobis [2-methyl-N- (2-hydroxyethyl) propionamide] and / or azobis {2-methyl-N. -[2- (1-hydroxybutyl)] propionamide.

  Furthermore, another preferred embodiment of the gel-immobilized colloidal crystal of the present invention is characterized in that the photopolymerization initiator is camphorquinone and / or riboflavin.

Furthermore, in another preferred embodiment of the gel-immobilized colloidal crystal of the present invention, the colloidal crystal can be prevented from being destroyed by storing or growing it in an inert gas atmosphere in a container in which ions do not exude. It is characterized by.

The gel-immobilized colloidal crystal of the present invention is a gel-immobilized colloidal crystal obtained by gel-immobilizing a colloidal crystal using a solution containing a monomer, a crosslinking agent, and a photopolymerization initiator by light irradiation. ,
The monomer is represented by the following formula A

(In the formula, R ₁ is an acrylic acid residue or a methacrylic acid residue, R ₂ is a C1-C3 alkylol group, a C2-C6 alkoxyalkyl group or a C2-C6 alkoxyalkylol group. And an amino group-protecting group consisting of:

Further, another preferred form of a gel immobilized colloidal crystals of the present invention, the monomers, N- methylol methacrylamide, N- methylolacrylamide and N- methoxymethyl acrylamide or we made at least one selected from the group It is characterized by being.

  In a preferred embodiment of the gel-immobilized colloidal crystal of the present invention, the photopolymerization initiator is azobis [2-methyl-N- (2-hydroxyethyl) propionamide] and / or azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide.

  Furthermore, still another preferred embodiment of the gel-immobilized colloidal crystal of the present invention is characterized in that the photopolymerization initiator is camphorquinone and / or riboflavin.

Furthermore, another preferred form of a gel immobilized colloidal crystals of the present invention is characterized in that the colloidal crystals all SANYO was optically uniform growth, its optical properties are homogeneous regardless of the site .

The multi-structure colloidal crystal of the present invention is a multi-structure colloid crystal including the gel-immobilized colloid crystal as described above,
The gel immobilized colloidal crystals formed SQLDESC_BASE_TABLE_NAME This surrounded by gelling material gelling material the same as or different forming this gel immobilized colloidal crystals,
The same type of gelling material includes the monomer as described above, a crosslinking agent, and a photopolymerization initiator, and is gel-fixed by light irradiation.
The dissimilar gelling material is a synthetic polymer gel, a polysaccharide gel, or a protein gel.
It is characterized by that.

According to the present invention, since the like using a predetermined monomer, to facilitate immobilization of the colloidal crystal, stability excellent gel immobilized colloidal crystal monomer over that capable of forming a target gel immobilized colloidal crystal used, Gel-immobilized colloidal crystals can be provided.
That is, the present invention succeeds in suppressing the generated ion concentration to a very small amount when the colloidal crystal is immobilized by gelation. Compared with conventional methods, it is possible to immobilize colloidal crystals with low particle concentration, immobilize large colloidal crystals formed near the phase boundary, and immobilize colloidal crystals using a visible light initiator under a wide range of conditions. The effect is remarkable.
Furthermore, it is expected that the present invention opens up a way to construct high-performance optical elements using colloidal crystals and greatly contributes to the optical industry field.

Hereinafter will be described in detail gel immobilized colloidal crystals forming monomers. In the present specification, “%” represents mass percentage unless otherwise specified.
As described above, the gel-immobilized colloidal crystals forming monomers, the following formula A

(Wherein R ₁ represents an acrylic acid residue or a methacrylic acid residue, and R ₂ represents an amino group protecting group).
Here, examples of the amino group protecting group of R _2, hydrolysis, in particular functional groups der to protect an amino group against hydrolysis under acidic conditions is, alkylol group having a carbon number is C1 to C3, for example, methylol Groups, ethylol groups and propirol groups, C2-C6 alkoxyalkyl groups, such as alkoxyalkyl groups in which the alkyl moiety is methyl, ethyl, propyl or isopropyl and the alkoxy moiety is methoxy, ethoxy, propoxy or isopropoxy, and the number of carbons Mention may be made of C2-C6 alkoxyalkylol groups, for example alkoxyalkyloxy groups in which the alkoxy moiety is methoxy, ethoxy, propoxy or isopropoxy and the alkylol moiety is methylol, ethylol and propirol.

As typical examples of the gel immobilized colloidal crystals forming monomers, N- methylol methacrylamide, N- methylolacrylamide, N- methoxymethyl acrylamide, N- acryloyl amino ethoxy ethanol, N- acryloyl amino propanol or a derivative thereof However, these may be used alone or arbitrarily mixed. The chemical formulas of these monomers are shown in the following formulas (1) to (5).

  Examples of such monomer derivatives include various compounds such as these esters. For example, a terminal hydroxyl group (- Examples of the monomer having an (OH group) include these methyl esters and ethyl esters.

The monomers for forming a gel-immobilized colloidal crystal are monomers that can lower the ion concentration of these aqueous solutions to a sufficiently low level by purification with an ion exchange resin.
Specifically, when 10 ml of an ion exchange resin coexist in 15 ml of a 10% aqueous solution of each monomer and shaken for 10 minutes, the electrical conductivity (κ) of the aqueous solution is less than 1 μS / cm, particularly 0.3 to 0.6 μS. Deionization purification is possible up to about / cm. This electrical conductivity is comparable to that of ion-exchanged water, and is close to the limit of deionization by ion-exchange resin.
Thus, the fact that the monomer can be purified by coexistence with an ion exchange resin means that it is a monomer that is difficult to generate ions due to hydrolysis with an acid / base. As will be described later, even when colloidal crystals containing these monomers are stored for a long period of time, the crystals were not destroyed like acrylamide.

In addition, the said monomer can be synthesize | combined by a conventionally well-known method, and can be obtained on the market.
Specifically, the monomers represented by the above formulas (1) to (3) can be obtained from Kasano Kosan Co., Ltd. under the trade names MM90, N-MAM60, and Wasmer-EMA.

On the other hand, the monomer (N-acryloylethoxyethanol (AAEE)) represented by the formula (4) is stirred by adding acryloyl chloride to aminoethoxyethanol and sodium hydroxide, and the resulting reaction solution is neutralized with hydrochloric acid. A polymerization inhibitor is added. This solution can be distilled and concentrated, filtered to remove inorganic salts, re-concentrated, and purified by column (M. Chiari et al Electrophoresis 16 1995, 1815: E. Simo- Alfonso et al Electrophoresis 17 1996, 723: M. Chiari et al Electrophoresis 15 1994, 177: M. Chiari et al Electrophoresis 15 1994, 616).
In addition, the monomer represented by the formula (5) (N-acryloylaminopropanol (AAP)) is also mixed with acryloyl chloride and ethanol cooled in an inert gas atmosphere in accordance with the above document, and 3-amino-1 Add dropwise ethanol solution of propanol and stir. The reaction solution obtained can be synthesized by concentrating under reduced pressure and further purifying with a column.

Next, the gel-fixed colloidal crystal of the present invention will be described.
As described above, the gel-immobilized colloidal crystal of the present invention comprises a colloidal crystal using a solution containing the above-mentioned monomer for forming a gel-immobilized colloidal crystal, a crosslinking agent, and a photopolymerization initiator as a medium. This gel-immobilized colloidal crystal is gel-immobilized by light irradiation, and functions as a precursor of the gel-immobilized colloidal crystal of the present invention described later.

Here, the photopolymerization initiator is not particularly limited as long as it has a function capable of initiating the photopolymerization reaction of the monomer. However, from the viewpoint of the gel stability described above, the photopolymerization initiator has a small ion concentration. Preferably, when a lot of candidate substances were experimentally examined, azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide represented by the following formulas (6) and (7), and azobis [2-Methyl-N- (2-hydroxyethyl) propionamide] was found to be one of the chemical species with the lowest generated ion concentration.
Therefore, these photopolymerization initiators are suitable for use in combination with the above-mentioned monomers, and by using this combination, the ion concentration derived from the gelling agent is extremely reduced and is extremely suitable for fixing colloidal crystals. Gelation can be realized.
In addition, the photoinitiator shown to (6) and (7) type | formula can be used individually or in combination, and the product names "VA-085" and "VA-086" manufactured by Wako Pure Chemical Industries, respectively. Available.

In addition, an initiator containing an azo group such as the photopolymerization initiator shown in the formulas (6) and (7) has a property that nitrogen gas is liberated at the start of polymerization. It is known to accompany outbreaks.
In application of the gel-immobilized colloidal crystal as a photonic element, the presence of bubbles should be avoided because it causes optical defects.
The inventors of the present invention have confirmed that by reducing the concentration of the photopolymerization initiator to a very low level, the amount of nitrogen gas generated can theoretically be less than the solubility in water, and the problem of bubble generation can be avoided. ing.

On the other hand, camphorquinone has advantages such as having a photopolymerization start wavelength in the visible light region and no generation of nitrogen gas at the start of polymerization, but the concentration of ionic impurities generated at the time of photopolymerization is higher than that of VA-086. And an initiator that exhibits its characteristics under conditions such as high colloid particle concentration.
However, if the generation of impurity ions derived from the monomer is small, it can be used under a wider range of conditions. Therefore, when the monomer of the present invention is used, camphorquinone can be used effectively as an initiator. In the gel-fixed colloidal crystal of the present invention, camphorquinone can be appropriately used as a constituent component.
Similarly, riboflavin having a photopolymerization initiation wavelength in the visible light region but also having a higher impurity ion concentration than that of VA-086 can be used effectively according to the present invention.

  Moreover, as a crosslinking agent, although it can change suitably according to the kind and quantity of a monomer to be used, or a photoinitiator, typically, N, N'- methylenebis shown to following (8) Formula is used. Acrylamide can be used.

The gel-immobilized colloidal crystal of the present invention uses a solution containing the above monomer, crosslinking agent and photopolymerization initiator as a medium (dispersion medium), and colloidal particles are regularly arranged in this medium like crystals. It has a (dispersed) form.
In the present invention, the solution is typically an aqueous solution, but may be a non-aqueous solution. For example, ethylene glycol, alcohols, dimethylformamide, and a mixed solution of these with water are applicable.
In addition to the above-described components, various additives can be added to the gel-fixed colloidal crystal of the present invention.
The gel-immobilized colloidal crystal functions as a precursor of the gel-immobilized colloidal crystal of the present invention as described above. However, the storage and growth of ions are performed under an inert gas atmosphere such as argon. It is preferable to carry out in a container that does not exude.

Next, the gel-immobilized colloidal crystal of the present invention will be described.
As described above, the gel-immobilized colloidal crystals of the present invention, the above gel immobilized colloidal crystals forming monomer, a crosslinking agent and gel immobilized by light irradiation colloidal crystals to the medium a solution containing a photopolymerization initiator Is.
The gel-immobilized colloidal crystal of the present invention is also obtained by irradiating the aforementioned gel-immobilized colloidal crystal of the present invention with light.
Note that the gel-immobilized colloidal crystal of the present invention is preferably optically uniformly grown, and such a colloidal crystal is excellent in applicability to optical applications. “Grown optically uniformly” means that the optical properties such as light transmittance are grown so as to be uniform regardless of the part.

  Here, the light irradiation for promoting fixation by gelation can be appropriately changed according to the type of the monomer used or the polymerization initiator, but typically, azobis [2-methyl-N- (2 -Hydroxyethyl) propionamide] may be irradiated with ultraviolet rays for 5 to 30 minutes.

Furthermore, as unexpectedly, it is clear that the use of methylolacrylamide, which is the main monomer in the present invention, yields a gelled colloidal crystal having a higher mechanical strength than when acrylamide (AAm) is used. became.
Specifically, the gel-immobilized colloidal crystal obtained with 0.67 M methylolacrylamide had a mechanical strength equivalent to that obtained with 1.33 MAAm in the conventional method.
That is, according to the preferred embodiment of the present invention, the monomer concentration to be used can be reduced to ½ of AAm, and thereby the ionic impurity concentration can be further reduced.

In the actual use of the gel-immobilized colloidal crystal of the present invention, it is preferable to use the gel-immobilized colloidal crystal in a state in which the surface is protected from environmental factors. Is preferably used in the form of a three-dimensionally polymerized polymer or a multi-structure colloidal crystal obtained by surrounding the colloidal crystal with a different gelling material.
By using such a multi-structure colloidal crystal, it is possible to easily protect elements for various applications obtained by appropriately cutting the colloidal crystal.
Examples of usable different gelling materials include various synthetic polymer gels such as polyacrylamide and polyacrylic acid, polysaccharide gels such as agar, and protein gels such as gelatin. .

The gel-immobilized colloidal crystal of the present invention can be applied to various optical elements, and various optical elements can be produced using the gel-immobilized colloidal crystal of the present invention.
In this case, if a trigger material that induces a change in the Bragg diffraction wavelength of the colloidal crystal is contained in the gel-immobilized colloidal crystal, a sensor of an object to which the trigger material is sensitive can be created. .
An enzyme can be used as such a trigger material, and the enzyme can be used by being immobilized on the gel network of this gel-immobilized colloidal crystal.

It will now be described ion-releasing inhibiting gel material.
As described above, this gel material is a gel obtained by irradiating the solution containing the monomer, the crosslinking agent, and the photopolymerization initiator described above with light.
This gel has a feature that the concentration of ionic impurities contained in the inside immediately after synthesis is smaller than that of AAm gel, and therefore, the ion releasing property is suppressed even with time. It has the feature that the influence of elution on can be reduced.
In order to remove the ionic impurities in the gel to several μM or less, it is necessary to wash with water very carefully. However, if this gel is used, this operation can be reduced.
Therefore, in the present invention, not only when fixing colloidal crystals but also as a gel material that does not contain colloidal crystals, (1) the gel is placed in contact with the solution (or inside the solution), and (2) the solution is brought into solution. This is useful when it is desirable to avoid elution of several μM ions.
For example, as described in JP-A-2004-089996, through a gel film by diffusing the base, also the gel material in the case of growing a colloidal crystal in one direction is useful.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

(Example 1)
Using ultrapure water “Milli-Q water” (Millipore, manufactured by trade name “Milli-Q system”), methylolacrylamide (6M), Bis (0.5 mM) and VA-086 (8 mg / ml) An aqueous solution was prepared and purified by deionization in the presence of an ion exchange resin. The silica particle (KE-W10) dispersion was sufficiently purified by dialysis and ion exchange.
Using these, from methylol acrylamide (0.67M), N, N′-methylenebisacrylamide (Bis) (10 mM), VA-086 (0.05 mg / ml) KE-W10 (particle concentration 3.2 vol%) A dispersion was prepared. For sample preparation, a polystyrene or polytetrafluoroethylene container sufficiently washed with Milli-Q water was used to prevent contamination by ionic impurities.

NaOH was added to the dispersion to a concentration of 20 μM. After bubbling with argon gas for 10 minutes through an injection needle, 4 ml of the dispersion was placed in a 1 × 1 × 4.5 cm polymethylmethacrylate cell and allowed to stand. Crystals formed.
Next, using a 400 W mercury lamp (HP-400 type, manufactured by Toshiba) and irradiating with UV light for 20 minutes at a distance of 30 cm from the sample, the crystals were fixed by gelation without being destroyed.
From the crystallization phase diagram shown in FIG. 1, it can be seen that at the NaOH concentration (20 μM) in this example, the crystals are destroyed by the presence of about 2 μM salt (ion concentration is 4 μM). The fact that the crystals could be fixed without being broken in this example indicates that the ionic impurity concentration was 4 μM or less throughout the gelation process.
When acrylamide was used as the monomer, colloidal crystals could not be formed in the gelation reaction solution under the condition of NaOH concentration of 20 μM.

(Example 2)
In the same manner as in Example 1, a dispersion composed of methylolacrylamide (0.67M), Bis (10 mM), VA-086 (0.05 mg / ml), and KE-W10 (particle concentration: 3.2 vol%) was prepared. For sample preparation, a polystyrene or polytetrafluoroethylene container sufficiently washed with Milli-Q water was used to prevent contamination by ionic impurities.
After bubbling with argon gas for 10 minutes through an injection needle, 4 ml of the dispersion was placed in a 1 × 1 × 4.5 cm polymethylmethacrylate cell, and then 10 μL of 0.1 M pyridine, a weak base, was added dropwise to the material. However, a large 5 mm square colloidal crystal was formed.
When a 400 W mercury lamp (HP-400 type, manufactured by Toshiba) was used and irradiated with UV light for 20 minutes at a distance from the sample, the crystals were fixed by gel without being destroyed.

(Example 3)
A 6 mm diameter hole was provided in the bottom of a 1 × 1 × 4.5 cm polymethylmethacrylate cell, which was once closed with a film, and then deionized and purified gelation reaction solution (methylolacrylamide (0.67M ), Bis (10 mM) and 0.4 ml of VA-086 (0.4 mg / ml)) were poured and gelled by irradiating with UV light, and then the film was removed and a gel film (film thickness = 4 mm at the bottom). ).
Subsequently, a mixture solution consisting of KE-W10 (particle concentration: 3.2 vol%), methylolacrylamide (0.67 M), Bis (10 mM) and VA-086 (0.1 mg / ml) was deionized and purified. Thereafter, argon gas was bubbled through the injection needle for 10 minutes, collected in the cell, and the upper part of the cell was sealed with a film.
Next, 50 ml of a solution consisting of methylolacrylamide (0.67 M), Bis (10 mM), VA-086 (0.1 mg / ml) and NaHCO ₃ (60 μM) was added (after deionization and bubbling for 10 minutes). The reservoir was brought into contact via the gel membrane of the cell and held as it was. As time passed, NaHCO ₃ diffused from the reservoir into the cell, increasing the surface charge of silica as in the case of NaOH addition, and a colloidal crystal having a height of several centimeters was formed in 7 days.
Using a 400 W mercury lamp (HP-400 type, manufactured by Toshiba Corporation), when irradiated with UV light for 30 minutes at a distance of 30 cm from the obtained colloidal crystal sample, the colloidal crystal is not destroyed and is columnar by gelation. Crystals were immobilized.

(Example 4)
Methylolacrylamide (6M), Bis (0.1M), and riboflavin (0.29 mM) aqueous solutions were prepared, and each was subjected to deionization purification in the presence of an ion exchange resin. As a colloidal sample, an aqueous dispersion of polystyrene particles (particle size: about 200 nm, manufactured by Duke Scientific) was sufficiently purified by dialysis and ion exchange.
These were mixed to prepare a dispersion composed of methylolacrylamide (1.18 M), Bis (10 mM), riboflavin (0.058 mM), and polystyrene particles (particle concentration 10 vol%). For sample preparation, a polystyrene or polytetrafluoroethylene container sufficiently washed with Milli-Q was used to prevent contamination by ionic impurities. After bubbling with argon gas for 10 minutes through an injection needle, about 0.5 ml of the reaction solution was injected into a thin quartz cell having a thickness of 0.1 mm (inner) × 1 × 5 cm, and colloidal crystals were formed.
A blue LED (light source: MBARB-5015 type, power supply unit: MLED-A12010L type, both manufactured by Moritex Corporation) was used as the light source, the distance from the cell surface was 2 cm, and the two light sources were irradiated with light from both sides for 20 minutes. However, the crystals were gel-fixed without being destroyed.
Even when camphorquinone was used as the photopolymerization initiator, gel fixation was possible by the same method as described above. However, at this time, a 15 mM aqueous camphorquinone solution was used without deionization purification, and the concentration of camphorquinone in the reaction solution was 0.4 mM.

FIG. 4 is a crystallization phase diagram of silica colloid (Nippon Shokubai KE-W10, particle size 110 nm, particle concentration 3.2 vol%).

Claims (12)

Formula A

(In the formula, R ₁ is an acrylic acid residue or a methacrylic acid residue, R ₂ is a C1-C3 alkylol group, a C2-C6 alkoxyalkyl group or a C2-C6 alkoxyalkylol group. consists colloidal crystals to the medium a solution containing a gel immobilized colloidal crystals forming monomer crosslinking agent and a photopolymerization initiator having a structure represented by an amino protecting group.) consisting of a gel fixed by light irradiation Gel-fixed colloidal crystal, characterized in that The gel immobilized colloidal crystals forming monomers, wherein characterized in that it consists of N- methylol methacrylamide, N- methylolacrylamide and at least one thing selected from N- methoxymethyl-acrylamide or al the group consisting Item 2. The gel-fixed colloidal crystal according to Item 1.   The gel-immobilized colloidal crystal-forming monomer is characterized in that the electric conductivity of an aqueous solution after purification by an ion exchange method is less than 1 μS / cm, and it is difficult for ions to be generated by acid / base hydrolysis. The gel-fixed colloidal crystal according to claim 1 or 2.   The photopolymerization initiator is azobis [2-methyl-N- (2-hydroxyethyl) propionamide] and / or azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide. The gel-immobilized colloidal crystal according to any one of claims 1 to 3, wherein:   The gelled immobilized colloidal crystal according to any one of claims 1 to 3, wherein the photopolymerization initiator is camphorquinone and / or riboflavin.   6. The gel to be coated according to any one of claims 1 to 5, wherein the colloidal crystal is prevented from being destroyed by being stored or grown in a container in which ions do not exude under an inert gas atmosphere. Immobilized colloidal crystals. A gel-immobilized colloidal crystal obtained by gel-immobilizing a colloidal crystal using a solution containing a monomer, a crosslinking agent, and a photopolymerization initiator as a medium,
The monomer is represented by the following formula A

(In the formula, R ₁ is an acrylic acid residue or a methacrylic acid residue, R ₂ is a C1-C3 alkylol group, a C2-C6 alkoxyalkyl group or a C2-C6 alkoxyalkylol group. A gel-immobilized colloidal crystal having a structure represented by the following formula: The monomer is, N- methylol methacrylamide, gel fixation according to claim 7, characterized in that the at least one selected from N- methylolacrylamide and N- methoxymethyl acrylamide or al the group consisting Colloidal crystals.   The photopolymerization initiator is azobis [2-methyl-N- (2-hydroxyethyl) propionamide] and / or azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide. The gel-immobilized colloidal crystal according to claim 7 or 8.   The gel-immobilized colloidal crystal according to claim 7 or 8, wherein the photopolymerization initiator is camphorquinone and / or riboflavin.   The gel-immobilized colloidal crystal according to any one of claims 7 to 10, wherein the colloidal crystal is optically uniformly grown, and the optical characteristics thereof are uniform regardless of the site. . A multi-structure colloidal crystal comprising the gel-immobilized colloidal crystal according to any one of claims 7 to 11,
The gel-immobilized colloidal crystal is surrounded by the same or different type of gelling material as the gelling material forming the gel-immobilized colloidal crystal,
The same kind of gelling material includes the monomer according to any one of claims 7 to 11, a crosslinking agent, and a photopolymerization initiator, and is gel-fixed by light irradiation.
The dissimilar gelling material is a synthetic polymer gel, a polysaccharide gel, or a protein gel.
A multi-structure colloidal crystal characterized by that.

Images