JP2018095828A - Surface modification agent for solid polyvinyl alcohol, surface modification method for solid polyvinyl alcohol and surface modified vessel of solid polyvinyl alcohol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface modification agent for solid polyvinyl alcohol that can modify the surface of solid polyvinyl alcohol under moderate conditions, to provide a surface modification method and to provide a surface modified vessel.SOLUTION: The surface modification agent for solid polyvinyl alcohol comprises a polyvinyl alcohol produced by dissolving a boronic acid derivative in a solvent and having a saponification degree of 40 to 99. The surface modification method for solid polyvinyl alcohol comprises allowing a surface modification agent produced by dissolving a boronic acid derivative in a solvent to act on solid polyvinyl alcohol comprising polyvinyl alcohol having a saponification degree of 40 to 99. The surface modified vessel has a holding part for holding with hands of a user, a solution storage part provided in the holding part for storing a solution and a discharge part for applying the solution to an object by communicating with the solution storage part in which the solution includes the surface modification agent for solid polyvinyl alcohol as mentioned above.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for chemically modifying the surface of a solidified polyvinyl alcohol, specifically to a surface modifying agent for solid polyvinyl alcohol, a surface modifying method for solid polyvinyl alcohol, and a surface modifier for solid polyvinyl alcohol.

Polyvinyl alcohol (PVA) is widely used as a base material for fiber materials, packaging materials, optical films, and the like. Recently, development of catalysts, adsorbents, sensors, fuel cells, medical materials, and the like based on the functionalization of PVA has been studied, and has attracted attention in the environment, energy, medical fields, and the like.
Since the surface of a solid material plays an important role in various physicochemical phenomena such as chemical reaction, separation, and adsorption, the development of a method for chemically modifying the surface of a solid PVA is useful for deriving a material having a desired function. Means.
So far, there have been reported examples of chemical modification of PVA, but there are very few examples of direct chemical modification of the surface of solid PVA. Even in the reported examples, even under severe conditions such as strong base conditions and high-temperature heating. Most are chemical modifications.
For example, as one surface modification method for solidified polyvinyl alcohol (Poval), there is a method of immobilizing a chemical modifier on the surface of the solidified polyvinyl alcohol, and this method has an advantage that a desired function can be imparted to the surface. Specifically, after the surface of solidified polyvinyl alcohol is treated with an activator such as paratoluenesulfonic acid, trialkoxysilane, succinic anhydride, isocyanate, or peroxide, the surface is reacted with a chemical modifier. is there. In addition, a technique for chemically modifying the surface of the solidified polyvinyl alcohol by using a chemical modifier introduced with acid chloride, isocyanate, or trichlorosilane group has been proposed.
However, with this method, the company has poor reactivity with the alcoholic hydroxyl group present on the surface of the solidified polyvinyl alcohol, so in many cases the hydroxyl group is replaced with paratoluenesulfonic acid, trialkoxysilane, succinic anhydride, isocyanate, peroxide. It is necessary to treat with an activator, and a multi-step process is required for its execution. In addition, since the activator is highly reactive with water and the like, the solvent used for activation and surface modification of the polyvinyl alcohol after activation is limited, and it is necessary to dehydrate the solvent in advance. , Accompanied by complicated operations.
In addition, by introducing highly reactive functional groups such as acid chlorides, isocyanates, and trichlorosilane groups into chemical modifiers, methods have been proposed to chemically modify the surface of solidified polyvinyl alcohol in one step. The functional group is highly reactive and reacts violently with water, alcohol, etc., so dehumidifying conditions are required for storage and handling of chemical modifiers, and alcohol solvents cannot be used as solvents. However, in order to prevent reaction decomposition of these functional groups, there is a problem that complicated operations are involved, for example, it is necessary to remove moisture from the solvent used.
Patent Document 1 proposes that polyvinyl alcohol can be modified by reacting polyvinyl alcohol and boronic acid.

JP 2007-217613 A

However, in the modification method of polyvinyl alcohol according to the above-mentioned proposal, only the boronic acid compound is introduced into the side chain of polyvinyl alcohol dissolved in a solvent, and the surface of solid polyvinyl alcohol cannot be modified.
Accordingly, an object of the present invention is to provide a solid polyvinyl alcohol surface modifier, a surface modification method and a surface modifier capable of modifying the surface of the solid polyvinyl alcohol under mild conditions.

In order to achieve the above object, as a result of intensive studies, the present inventors have found that solid polyvinyl alcohol having a specific saponification degree and a boronic acid compound can be reacted under mild conditions. The present invention has been completed.
That is, the present invention provides the following inventions.
1. A surface modifying agent for solid polyvinyl alcohol comprising polyvinyl alcohol having a saponification degree of 40 to 99% obtained by dissolving a boronic acid derivative in a solvent.
2. A surface modification method for solid polyvinyl alcohol,
A surface modification method characterized by causing a surface modifier formed by dissolving a boronic acid derivative in a solvent to solid polyvinyl alcohol comprising polyvinyl alcohol having a saponification degree of 40 to 99%.
3. A holding unit for holding by a user's hand, a liquid agent storage unit provided in the holding unit for storing a liquid agent, and a discharge unit that communicates with the liquid agent storage unit and applies the liquid agent to an object. A solid polyvinyl alcohol surface modifier, comprising the solid polyvinyl alcohol surface modifier according to 1.

  The surface modifier for solid polyvinyl alcohol of the present invention is capable of modifying the surface of solid polyvinyl alcohol under mild conditions. In particular, since the surface of the solidified polyvinyl alcohol can be chemically modified in one step, does not react with water or alcohol, and is stable, dehumidifying conditions are not required for storage and handling of the chemical modifier. In addition, the solvent used for the chemical modification can be an alcohol solvent, a solvent having a hydroxyl group or an amino group, and it is not necessary to remove moisture from the solvent used for the chemical modification, so that handling is easy. It is.

FIG. 1 is a SEM photograph (drawing substitute photograph) of PVA particles used in Example 1. FIG. 2 is an explanatory diagram showing the flow of surface modification in Example 1 and Comparative Example 1. 3a to 3d are photographs (drawing-substituting photographs) obtained by conducting a test for determining whether or not there is fluorescence emission by irradiating the surface state when the surface treatment is performed using the compound 1a or 1b, respectively. ). FIG. 4 is a chart showing the fluorescence spectrum measurement results of the solid PVA surface-modified in Example 1 and Comparative Example 1. FIG. 5 is a fluorescence micrograph (drawing substitute photograph) of the solid PVA surface-modified in Example 1. FIG. 6 is a confocal laser fluorescence micrograph (drawing substitute photograph) of the solid PVA surface-modified in Example 1. FIG. 7 is a chart showing an XPS spectrum of the solid PVA surface-modified in Example 1. FIG. 8 is a chart showing an FT-ATR-IR spectrum of solid PVA surface-modified in Example 1. FIG. 9 is a chart showing the curve fitting results of the solid PVA surface-modified in Example 1 and Comparative Example 1. FIG. 10 is a chart showing a curve fitting result and an equation for performing curve fitting in the first embodiment. FIG. 11 is a chart showing the time dependency of the amount of adsorption during the surface modification in Example 1. FIG. 12 is a graph showing the solvent stability of the solid PVA surface-modified in Example 1. 13a to 13c are photographs (drawing substitute photographs) showing the PVA film used in Example 1 before and after the surface treatment, respectively. 14a and 14b are photographs (drawing substitute photographs) showing the PVA nanofiber mat used in Example 1 before and after the surface treatment, respectively. FIGS. 15a to 15h are photographs when a test was performed to determine whether the surface treatment was performed using compounds 3a, 3b, 4a, and 4b, respectively, by irradiating with ultraviolet rays and whether there was fluorescence emission. (Drawing substitute photo). FIG. 16 is a chart showing fluorescence spectrum measurement results of solid PVA surface-modified in Example 2 and Comparative Example 2, Example 3 and Comparative Example 3. FIG. 17 is a fluorescence micrograph (drawing substitute photo) of the solid PVA surface-modified in Examples 2 and 3. 18A and 18B are both SEM image photographs (drawing substitute photographs) of PVF sponge. FIGS. 19 (a) to 19 (c) are photographs (drawing substitute photographs) each showing the degree of luminescence with respect to compound 1a, and (d) and (e) are photographs (drawing substitute photographs) showing the degree of luminescence with respect to compound 1b. . FIG. 20 is a fluorescence spectrum chart. FIG. 21 is an FT-IR chart. FIG. 22 is a chart in which the adsorption amount is plotted against the equilibrium concentration. FIG. 23 is a diagram showing calculation formulas for obtaining a chart showing curve fitting for the obtained saturation curve. FIG. 24 is a photograph (drawing substitute photograph) showing the state of the sponge at various pHs. FIG. 25 is a partially broken perspective view showing an embodiment of the surface modifier of the present invention.

Hereinafter, the present invention will be described in more detail.
The surface modifying agent for solid polyvinyl alcohol of the present invention is a boronic acid derivative solution obtained by dissolving a boronic acid derivative in a solvent.
<Solid polyvinyl alcohol>
The solid polyvinyl alcohol (hereinafter sometimes referred to as PVA) that is the target of surface modification in the surface modifier of the present invention is not particularly limited as long as it is a solid substance made of polyvinyl alcohol, and various forms such as a film, Various shapes such as a fibrous shape, a non-woven fabric shape, and a spherical shape can be used.
The polyvinyl alcohol used in the present invention has a saponification degree of 40% to 99%. If the degree of saponification is less than 40%, PVA dissolves in methanol or the like, so surface modification cannot be performed. If the degree of saponification exceeds 99%, the adsorption of boronic acid is not confirmed, so it is necessary to be within the above range. Further, the degree of saponification can be changed depending on the form of the solid polyvinyl alcohol, and in particular when the solid polyvinyl alcohol is a nanofiber, the degree of saponification can be set within the above range, but other forms In this case, the range of 40 to 94% is preferable from the viewpoint of sufficiently exerting the surface modification effect by boronic acid, and more preferably 85 to 94%.
Moreover, as said solid polyvinyl alcohol, a sponge-like thing can also be used. In that case, it is not pure polyvinyl alcohol, Polyvinyl formal (PVF) formed by modifying a part of hydroxyl groups of polyvinyl alcohol. It can also be used as a sponge. In this case, the saponification degree of the polyvinyl alcohol as a raw material to be used (that is, the number of polymerized units including hydroxyl groups / total number of polymerized units × 100) needs to be within the above-mentioned range of the saponification degree.

<Boronic acid derivative>
The boronic acid derivative used in the present invention is not limited as long as it is a compound having a boronic acid skeleton, and various compounds can be used, but other skeletons according to various uses, such as a fluorescent skeleton, can be used simultaneously. It is preferable to have it. Specifically, boron dipyrromethene (BODIPY), diphenylanthracene, rhodamine and the like can be given as boronic acid derivatives having a fluorescent skeleton together with a boronic acid skeleton. A boronic acid derivative having a porphyrin skeleton, a coumarin skeleton, a dimethylaminonaphthalenesulfonamide skeleton, or a naphthalene bisimide skeleton can also be used.
Since boronic acid has a property of forming a boronic acid ester bond in a short time at room temperature without adding an additive or the like, a covalent bond under mild conditions with PVA having a diol skeleton as a partial structure. And is fixed on the surface of the solid polyvinyl alcohol.
Specific examples of the boronic acid derivative include the following compounds.
Since each of the above boronic acid derivatives is a known compound, it can be obtained by a known production method.

<Solvent>
Examples of the solvent that can be used in the present invention include alcohol solvents, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, and the like. Examples of the alcohol solvent include methanol and ethanol.
<Concentration>
The boronic acid derivative concentration in the boronic acid derivative solution is preferably 1.0 × 10 ⁻⁷ M (molar concentration of the boronic acid derivative in the solution) to 5.0 × 10 ⁻⁴ M, More preferably, it is 1.0 × 10 ⁻⁷ M to 7.0 × 10 ⁻⁵ M. When the concentration is outside the lower limit of the above range, the reaction between the boronic acid derivative and the PV may be insufficient, and the surface modification of PVA may not proceed. Even when the upper limit is exceeded, the reactivity is good. However, it is not preferable because the surface modification may be inhibited and the reaction may be uneven.
The viscosity of the boronic acid derivative solution is arbitrary depending on the method of use and application. When using the immersion method, inkjet printing, marker pen method (method using a surface modifier described later), micro contact printing, In the case of using the stamp method, the optimum values are different from each other, but it is preferably 0.5 to 30 cP as a whole. Specifically, it is as follows. Then, the viscosity shown below is the optimum viscosity.
Immersion method: preferably 3 cP or less.
Inkjet printing marker pen: preferably 0.5 to 10 cP Microcontact printing / stamping method: preferably 30 cP or less <Third component>
In the present invention, various components can be added in addition to the boronic acid derivative and the solvent as long as the desired effects of the present invention are not impaired.
Specifically, ethylene glycol, glycerin, polyethylene glycol, or the like can be added to adjust the viscosity of the ink and the volatilization rate of the ink solvent.

The surface modifier of the present invention can be used by the following surface modification method or by using the following surface modifier.
<Surface modification method>
The surface modification method of the present invention comprises:
A surface modification method for solid polyvinyl alcohol, comprising:
The surface modification agent formed by dissolving a boronic acid derivative in a solvent is allowed to act on solid polyvinyl alcohol composed of polyvinyl alcohol having a saponification degree of 40% to 99% (hereinafter, this step is referred to as “action step”). can do.
Details will be described below.
[Pre-process and post-process]
In the present invention, various pre-processes such as cleaning the PVA surface prior to the above-described operation process can be performed. About this pre-process, the technique normally used in the surface treatment of this kind of polymer solid can be carried out without particular limitation.
Moreover, various post-processes, such as washing | cleaning, can be performed after completion | finish of the said operation | movement process. About this post process, the method normally used in the surface treatment of this kind of polymer solid can be carried out without particular limitation.
[Operation process]
The solid polyvinyl alcohol to be modified in the above-mentioned action step, and the surface modifier that acts on this solid polyvinyl alcohol are the same as the solid polyvinyl alcohol and the surface modifier described in the above-mentioned column of the surface modifier of the present invention, respectively. is there.
The operating conditions are not particularly limited, and can be performed by bringing the surface modifier into contact with the surface of the solid PVA under conditions such as normal temperature and pressure. As temperature conditions, what is necessary is just the temperature which a solvent does not freeze, Preferably it can carry out in the range of 10-50 degreeC. The pressure at the time of making it act is not restrict | limited. The time for the action is arbitrary depending on the form of the PVA and the means for the action, but it is preferably 1 minute to 330 hours.
Examples of the method for bringing the surface modifier into contact with the solid PVA surface used in the action step include an immersion method, an ink jet printing method, a marker pen method, a micro contact printing method, and a stamp method.
The immersion method is a method of immersing solid PVA in the surface modifier, and is particularly effective when the solid PVA is in the form of particles, fibers, nonwoven fabrics, or sheets. The ink jet printing is a system in which a solid PVA sheet is filled with the surface shrinkage material as an ink in a normal ink jet printer and applied, and is effective for a solid or non-woven solid PVA. This is useful when drawing symbols, characters, etc. The marker pen method is a method of drawing an arbitrary figure or character by applying a surface modifier to the surface of the solid PVA in a desired shape using a surface modifier described later, and is a sheet-like or non-woven solid. Effective for PVA. Microcontact printing is a kind of nanostructure construction method called soft lithography, which is a technique detailed in A. Kumar, GM Whiteside et al. Langmuir 10 (1994) 1498, etc. A predetermined fine pattern can be formed on the surface of the solid PVA by using the surface modifier as the ink transferred by the above method. The form of the solid PVA used at this time is not particularly limited. The stamp method is a method using the surface modifier as an ink in a normal stamp, and is particularly effective for transferring an arbitrary pattern to a sheet-like or nonwoven fabric-like solid PVA.
As described above, by using the surface modifier of the present invention, substances having various characteristics are introduced into the surface of the solid PVA in various forms via the boronic acid derivative, and various characteristics are imparted in addition to coloring and fluorescence action. It is possible.

<Surface modifier>
As shown in FIG. 25, the surface modifier 1 of the present invention includes a rod-shaped holding unit 10 for holding by a user's hand A, and a liquid agent storage unit 20 that is provided in the holding unit 10 and stores a liquid agent. And a discharge unit 30 that communicates with the liquid agent storage unit 20 and applies the liquid agent to the object. And the liquid agent accommodated in the liquid agent accommodating part 20 is the above-mentioned surface modifier of this invention.
As shown in FIG. 25, the surface modifier 1 of the present embodiment has a structure similar to that of a normal marker pen, the liquid agent container 20 is a hydrophobic hollow, and one end is open. , A non-woven material having a liquid retaining property is accommodated in a cylindrical container, and the surface modifier is accommodated by impregnating the non-woven material with the surface modifier of the present invention as a liquid agent (see FIG. Not shown). Moreover, the discharge part 30 consists of felt materials, and one end is inserted in the said opening, and is connected with the said nonwoven fabric material, and the other end is distribute | arranged so that it may be located outside a holding | maintenance part. Thereby, the surface modifier can be transferred to the desired solid PVA sheet B from the other end.
The surface modifier of the present invention is not limited to the above-described form, and can be variously modified without departing from the spirit of the present invention. For example, it is possible to configure the ejection unit 30 as a ball-point pen type so that ink is ejected using a ball material.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not restrict | limited to these.
[Synthesis Example] Synthesis of BODIPY-derived boronic acid (1a) and reference compound (1b) First, boron dipyrromethene (BODIPY) -derived boronic acid (1a) and boronic acid group as a surface modifying agent for solid polyvinyl alcohol of the present invention Synthesis with a reference compound (1b) having no.
That is, a compound (1a) in which boronic acid was introduced into boron dipyrromethene (BODIPY) having a high molar extinction coefficient and high photostability was synthesized as a surface modifier of the present invention. By using a boronic acid having a fluorescent chromophore in this way, its adsorption behavior can be traced by UV-visible spectroscopy or fluorometry, and its quantification becomes possible. These synthetic routes are shown in the following formula.

The above reaction will be briefly described.
Dipyromethanation of 4-hydroxybenzaldehyde and 2,4-dimethylpyrrole with trifluoroacetic acid was performed. Subsequently, dipyrination by oxidation reaction using 2,3-dichloro-5,6-diaminobenzoquinone, and boronation with boron trifluoride diethyl ether complex in the presence of triethylamine as an acid trap, A BODIPY compound (2 in the above formula, hereinafter simply indicated as 2) was obtained as a precursor.
Next, in the presence of the base, the BODIPY-derived boronic acid as the target compound (1a in Chemical Formula 1, hereinafter simply referred to as the target compound) is obtained by nucleophilic substitution reaction between the precursor BODIPY compound (2) and 3-bromomethylphenylboronic acid 1a) was obtained.
Similarly, in the presence of a base, a nucleophilic substitution reaction between the precursor BODIPY compound (2) and benzyl bromide results in a reference compound having no boronic acid group (1b in the above formula as a reference compound for the target compound). , Hereinafter referred to simply as 1b).
Hereinafter, Example 1 and Comparative Example 1 will be described in detail.

[Example 1]
-Synthesis | combination of precursor (2) First, in order to synthesize | combine the target compound BODIPY derivative | guide_body boronic acid (1a), the BODIPY compound (2) used as the precursor of 1a was synthesize | combined by reaction shown by a following formula.
The reaction shown in Formula 2 was performed as follows.
4-Hydroxybenzaldehyde (0.64 g, 5.2 mmol) and 2,4-dimethylpyrrole (1.1 g, 11.6 mmol) are dissolved in tetrahydrofuran (THF, 90 mL), 8 drops of trifluoroacetic acid are added, And dipyrromethanation was carried out for 5 hours to obtain a reaction intermediate solution A. To the obtained reaction intermediate solution A, a solution of 2,3-dichloro-5,6-diaminobenzoquinone (1.2 g, 5.3 mmol) in THF (120 mL) was added and stirred at room temperature for 4 hours. The reaction intermediate solution B was obtained. Subsequently, triethylamine (16 mL, 0.12 mol) was added as an acid trap to the obtained reaction intermediate solution B, cooled in an ice-water bath, and boron trifluoride diethyl ether complex (16 mL, 0.12 mmol) was added dropwise to react. Intermediate liquid C was obtained. The resulting reaction intermediate C was stirred overnight at room temperature, and the solvent was distilled off under reduced pressure to obtain a reaction product D containing the final product. Dichloromethane (100 mL) was added to the resulting reaction product D, and the mixture was washed twice with 5% NaHCO ₃ aqueous solution (100 mL) to obtain a mixture E. The organic phase of the obtained mixed liquid E was dehydrated with anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and then purified by silica gel column chromatography using the developing solvent as dichloromethane. Finally, reprecipitation was performed using a dichloromethane / hexane system, and an orange solid was recovered. This orange solid was confirmed to be BODIPY compound (2) by ¹ H-NMR, and the yield was 0.80 g and the yield was 45%.
The silica gel column chromatography was performed using a trade name “Wakogel C300” as a silica gel column, and the solvent as dichloromethane at room temperature. Further, ¹ H-NMR is as described later.

Synthesis of BODIPY-derived boronic acid (1a) Subsequently, the reaction shown in the following formula is carried out from the obtained precursor BODIPY compound (2) to obtain BODIPY-derived boronic acid (1a) (surface modifying agent of the present invention). Was synthesized.
The above reaction was performed as follows.
BODIPY compound (2) (0.30 g, 0.88 mmol) was dissolved in THF (30 mL), cesium carbonate (1.44 g, 4.4 mmol) was added, and reaction intermediate solution F was obtained. 3-Bromomethylphenylboronic acid (0.22 g, 1.0 mmol) was added to the obtained reaction intermediate solution F, stirred at room temperature for 6 hours, the solvent was distilled off under reduced pressure, and a reaction product containing the final product G was obtained. Dichloromethane (100 mL) and water (100 mL) were added to the resulting reaction product G to obtain a mixture H. Hydrochloric acid was added to the obtained mixed solution H until the aqueous layer became neutral to neutralize the aqueous layer, and liquid separation was performed. Dichloromethane (100 mL) was added to the aqueous layer for liquid separation, and the collected organic layers were combined, dehydrated with anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure, followed by purification by silica gel column chromatography. As a developing solvent, dichloromethane was first used, and then a methanol / dichloromethane mixed solvent containing 1% by weight of methanol. Finally, reprecipitation was performed using a dichloromethane / hexane system, and an orange solid was recovered. This orange solid was confirmed to be BODIPY-derived boronic acid (1a) by ¹ H-NMR, ¹³ C-NMR, and fast atom bombardment mass spectrometry (FAB-MS), and the surface modifier of the present invention was obtained. . The yield was 0.40 g, and the yield was 96%.
The FAB-MS will be described later.
¹ H-NMR (500 MHz, DMSO-d ₆ ), δ (TMS, ppm): 8.08 (s, 2H), 7.89 (s, 1H), 7.77 (d, 1H, J = 7.4), 7.51 (d, 1H , J = 7.6), 7.37 (t, 1H, J = 7.5), 7.27 (d, 2H, J = 8.6), 7.20 (d, 2H, J = 8.7), 6.17 (s, 2H), 5.16 (s, 2H), 2.50 (s, 6H), 1.40 (s, 6H)
¹³ C-NMR (125 MHz, DMSO-d ₆ ), δ (TMS, ppm): 159.1, 154.7, 142.8, 142.2, 135.5, 133.9, 133.8, 131.1, 129.8, 129.1, 127.5, 126.2, 121.3, 115.6, 69.9, 14.2.
FAB-MS m / z = 744 [1a + 2 (m-nitrobenzylalcohol) −2H ₂ O] ⁺

-Absorption spectrum and fluorescence spectrum of compound (1a) Next, the optical properties of the obtained BODIPY-derived boronic acid (1a) were measured.
A 1.0 × 10 ⁻⁶ M methanol solution of the BODIPY-derived boronic acid (1a) was prepared, and an ultraviolet-visible absorption spectrum and a fluorescence spectrum were measured. In the absorption spectrum, a maximum absorption peak was observed at 498 nm, and the molar extinction coefficient was 8.8 × 10 ⁴ L / mol cm. In the fluorescence spectrum, a maximum fluorescence peak was observed at 506 nm. In addition, using a 1.0 × 10 ⁻⁶ M sodium hydroxide aqueous solution of fluorescein ([NaOH] = 0.1 M, φ _f = 0.90) as a reference solution, the fluorescence quantum yield was calculated from the fluorescence spectrum at λ _ex = 436 nm. The calculated value was φ _f = 0.60. These values were similar to those of a previously reported BODIPY derivative having a similar structure. Further, a 1.0 × 10 ⁻⁵ M methanol solution of BODIPY-derived boronic acid (1a) was prepared and irradiated with ultraviolet light (365 nm), and yellow-green fluorescence was observed.

-Characterization of PVA microparticles Next, PVA microparticles were characterized to confirm the surface modification properties of solid PVA.
As the solid PVA, commercially available PVA microparticles (manufactured by Aldrich, weight average molecular weight (MW) 146000-186000, saponification degree 87-89%) were subjected to size selection with a sieve shaker and washed with methanol. . In this example, PVA microparticles having a particle size of 212 to 425 μm by sieving were used.
The selected PVA microparticles were sputtered with neoosmium and observed with a scanning electron microscope (SEM), and the average particle diameter was confirmed from this SEM observation. This SEM photograph is shown in FIG. When the biaxial average diameter of the observed particles was calculated according to the following formula 1, the average particle diameter was 405 ± 95 μm.
((Maximum diameter length) + (average width in the direction perpendicular to the maximum diameter length)) / 2 (Expression 1)
Moreover, in order to investigate the surface area of PVA microparticles, nitrogen gas adsorption measurement (described later) was performed. The PVA particles were pre-dried at 110 ° C. for 5 hours and measured. The specific surface area calculated from the BET method was 0.0414 g / m ² .

-Surface modification The surface chemical modification of PVA microparticles was performed with the obtained BODIPY-derived boronic acid (1a). An explanatory diagram showing the flow of surface modification is shown in FIG.
First, 50.0 mg of PVA microparticles (the above-mentioned PVA microparticles) are weighed into a 50 mL sample bottle 101 (A in FIG. 2). Next, ⁵ mL of a 2.0 × 10 ⁻⁵ M methanol solution (viscosity 0.55 cp, the surface modifier of the present invention) of BODIPY-derived boronic acid (1a) was added thereto, and the mixture was shaken for 24 hours with a shaker. (B in FIG. 2). Thereafter, filtration was performed to collect PVA particles, and the obtained PVA particles were rinsed with methanol and dried to obtain surface-modified PVA particles. This PVA particle was designated as PVA / 1a.
As a result, PVA / 1a exhibited a yellow color, and under the ultraviolet light irradiation (365 nm), yellow-green light emission expected to be fluorescence from the BODIPY skeleton was observed. A photograph of PVA / 1a taken under visible light is shown in FIG. 3a, and a photograph taken under ultraviolet light irradiation is shown in FIG. 3b.

Solid Fluorescence Spectrum Next, the optical properties of the obtained PVA / 1a were tested. First, solid fluorescence spectrum measurement was performed, and the luminescence was quantitatively investigated.
As a result of measuring the fluorescence spectrum by adding 0.2 g of PVA / 1a into a 1 mm cell (λ _ex = 436 nm), fluorescence derived from BODIPY was observed in PVA / 1a. From this, it was found that 1a adsorbs to the PVA particles, and the boronic acid group plays an important role in the adsorption. It is shown in FIG. 4 together with the fluorescence spectrum measurement result of PVA / 1b in Comparative Example 1 described later.
-Fluorescence microscope observation Next, the fluorescence microscope observation was performed.
When PVA / 1a was observed with a fluorescence microscope, yellow-green fluorescence was observed from the entire surface of the particle, and it was found that 1a was adsorbed on the entire surface of the PVA particle. FIG. 5 shows a fluorescence micrograph of PVA / 1a.
・ Confocal laser fluorescence microscope observation Subsequently, confocal laser fluorescence microscope observation was performed.
When PVA / 1a was observed with a confocal laser fluorescence microscope, fluorescence was selectively detected from the surface of the PVA particles in the obtained cross-sectional fluorescence image. FIG. 6 shows a confocal laser fluorescence micrograph of PVA / 1a. From this, it was found that BODIPY-derived boronic acid 1a was adsorbed on the surface of the PVA particles.

XPS spectrum measurement and infrared absorption spectrum measurement Further, XPS spectrum measurement and infrared absorption spectrum (FT-ATR-IR) measurement (ATR method) of the obtained PVA / 1a particles were performed. In this measurement, PVA particles whose surfaces were modified by dipping in 2.6 × 10 ⁻⁴ M BODIPY-derived boronic acid la solution (methanol solution) were used.
When XPS spectrum was measured, in PVA / 1a, in addition to peaks derived from oxygen and carbon, peaks derived from fluorine, nitrogen and boron, which are constituent elements of BODIPY-derived boronic acid 1a, were observed. FIG. 7 shows the obtained XPS spectrum.
Next, when the FT-ATR-IR spectrum was measured, in PVA / 1a, in addition to the peak derived from PVA, peaks attributed to the CC stretching vibration of the aromatic ring were observed at 1543 cm ⁻¹ and 1508 cm ⁻¹ . the peak 1307cm ^-1 attributed to -O stretching vibration, peak attributed to C-O-C stretching vibration was observed respectively 1195cm ^-1. FIG. 8 shows the obtained FT-ATR-IR spectrum. From these results, it was found that 1a was adsorbed on the PVA particles.
PS spectrum measurement and FT-ATR-IR spectrum measurement (ATR method) will be described later.

-Concentration dependence of adsorption amount Next, the change in adsorption amount when the immersion concentration was changed was investigated, and the adsorption behavior was quantified.
First, 10 samples prepared by weighing 50.0 mg of PVA microparticles (same as the above-mentioned PVA microparticles) in 50 mL sample bottles were prepared, and methanol solutions of BODIPY-derived boronic acid 1a (concentrations were respectively 10 mL of 10 solutions adjusted to 10, 20, 40, 70, 100, 130, 160, 200, 230, and 260 μM) were added. After shaking the sample bottle with a shaker for 24 hours, the supernatant solution was recovered and diluted 20-fold with methanol. The ultraviolet-visible absorption spectrum of the obtained diluted solution was measured, and the amount of BODIPY-derived boronic acid 1a adsorbed on the PVA particles was calculated.
When the adsorption amount of BODIPY-derived boronic acid 1a was plotted against the equilibrium concentration, a typical saturation curve was obtained. This also shows that the boronic acid group becomes an anchor site and is adsorbed on PVA. It is shown in FIG. 9 together with the measurement result of the adsorption amount of PVA / 1b in Comparative Example 1 described later.

-Curve fitting Next, curve fitting was tried with respect to the saturation curve of the obtained BODIPY derivative boronic acid 1a for quantification of adsorption behavior. When curve fitting was performed using the following equation shown in FIG. 10, which was established based on an equilibrium equation assuming a 1: 1 binding between the BODIPY-derived boronic acid 1a and the diol moiety of PVA, The values agreed well with the calculated values, and it was found that the boronate ester bond was the driving force for adsorption. Further, from the calculation, the saturated adsorption amount was determined to be (7.9 ± 0.1) mg / g, and the apparent binding constant was determined to be (6.5 ± 2.4) × 10 ⁵ M ⁻¹ . Further, from this calculation, the initial concentration of the hydroxyl group of PVA was also calculated, and the value was (1.9 ± 0.02) × 10 ⁻⁶ mol (unit). This means that 0.16% of the hydroxyl groups of PVA are involved in the binding with the BODIPY-derived boronic acid 1a, and the BODIPY-derived boronic acid 1a is a PVA particle. It was found that it was adsorbed only on the surface of the PVA and not bonded to the OH group of the internal PVA.

-Time dependency of the adsorption amount In order to measure the time dependency of the adsorption amount, a methanol solution (2.0 × 10 ^-5 M) of BODIPY-derived boronic acid 1a was mixed with PVA microparticles (with the above-mentioned PVA microparticles). The amount of adsorption when the same was immersed was plotted against the immersion time. The amount of adsorption was calculated from the UV-visible absorption spectrum measurement of the supernatant solution. As a result, it was found that the adsorption amount reached saturation (80%) in about 2 hours, and it was found that the solid surface of PVA can be chemically modified in a relatively short time. FIG. 11 shows a chart showing the time dependency of the amount of adsorption during the surface modification of PVA particles in a methanol solution of BODIPY-derived boronic acid 1a.

-Solvent stability investigation When a material obtained by chemically modifying a solid surface is actually applied, it is required that the chemical modifier be stably immobilized on the surface. Therefore, when the chemically modified PVA particles were immersed in various organic solvents, whether or not BODIPY-derived boronic acid 1a was released from the particle surface was calculated from the UV-visible absorption spectrum measurement of the supernatant solution. As a commonly used organic solvent, methanol, acetone, acetonitrile, toluene, dichloromethane, and chloroform were selected, and as a result of examining the boronic acid retention rate of 1a when each of the above PVA / 1a was immersed for 24 hours, The retention was 97% or more, indicating that 1a was stably immobilized on the surface of the PVA particles. FIG. 12 is a graph showing the solvent stability when PVA / 1a is immersed in the organic solvent.

-Surface-modified PVA of PVA film (sheet-like solid PVA) has excellent processability and can be processed into a film or fiber. Then, the surface modification was examined using the film of PVA.
PVA particles (saponification degree 87-89%, 2.4 g) were dissolved in DMSO / water (7.3 v / v, 40 mL), poured into a silicon rubber frame placed on a glass plate, and left at 80 ° C. for 48 hours. By doing so, a transparent PVA film (thickness 76 μm) was prepared. The obtained PVA film was cut into 1 cm × 1 cm and used. The PVA film used is shown in FIG. 13a.
The PVA film was immersed in a 2.0 × 10 ⁻⁵ M methanol solution (5 mL) of BODIPY-derived boronic acid 1a and shaken with a shaker for 24 hours. Thereafter, the film was taken out of the methanol solution of BODIPY-derived boronic acid 1a, rinsed with methanol and dried. As a result, the film was colored yellow, and yellow-green fluorescence was observed under ultraviolet light irradiation. A photograph taken under visible light is shown in FIG. 13b, and a photograph taken under ultraviolet light irradiation is shown in FIG. 13c.
From this result, it was shown that the surface of the PVA film can be directly chemically modified with boronic acid.

-Surface modification of fiber Next, the surface modification was examined using the fiber of PVA.
A PVA nanofiber mat was prepared by electrospinning using PVA particles (saponification degree 99%). An SEM photograph of the obtained PVA nanofiber mat is shown in FIG. 14a. This nanofiber mat was prepared by requesting a company. This nanofiber mat was cut into 1 cm × 1 cm and used.
The PVA nanofiber mat was immersed in a 2.0 × 10 ⁻⁵ M methanol solution (5 mL) of BODIPY-derived boronic acid 1a and shaken for 24 hours with a shaker. Thereafter, the nanofiber mat was taken out of the methanol solution of BODIPY-derived boronic acid 1a, rinsed with methanol, and dried. When the obtained nanofiber mat was observed with a confocal laser fluorescence microscope, fluorescence derived from BODIPY-derived boronic acid 1a was observed. The fluorescence micrograph of the obtained PVA nanofiber mat is shown in FIG. 14b.
From this result, it was shown that the surface of the PVA nanofiber mat can be directly chemically modified with boronic acid.

  Further, when the surface modification was performed in the same manner by changing the degree of saponification of PVA, the degree of saponification was over 99%: PVA coloring was not recognized by visual observation. Saponification degree 94.5% to 96%: coloring was observed. Saponification degree: 94% to 85%: Remarkable coloring was observed. Saponification degree: 85% to 40%: coloring was observed. Saponification degree is less than 40%: PVA was dissolved in a solvent such as methanol, and the surface modification of the desired form of PVA was not possible.

[Comparative Example 1]
First, in order to synthesize a reference compound (1b) having no boronic acid group as a reference compound of the target compound BODIPY-derived boronic acid (1a), a method similar to the method described in Example 1 was used. The BODIPY compound (2) which becomes a precursor of was synthesized.
Subsequently, from the obtained precursor BODIPY compound (2), a reaction represented by the following formula was performed to synthesize a reference compound having no boronic acid group (hereinafter simply referred to as a reference compound) (1b).
The above reaction was performed as follows.
The BODIPY compound (2) (0.10 g, 0.29 mmol) was dissolved in THF (10 mL), and cesium carbonate (0.47 g, 1.4 mmol) was added to obtain a mixture I. Benzyl bromide (0.040 mL, 0.35 mmol) was added to the obtained mixed liquid I, stirred overnight at room temperature, and subjected to nucleophilic substitution reaction to obtain reaction liquid J containing the final product. The obtained reaction liquid J was filtered and the solvent was distilled off under reduced pressure to obtain a reaction product K containing the final product. Subsequently, the obtained reaction product K was purified by silica gel column chromatography. As a developing solvent, a mixed solvent of dichloromethane: hexane = 4: 1 (weight ratio) was used. Finally, reprecipitation was performed in a dichloromethane / hexane system, and an orange solid was recovered. This orange solid was confirmed to be the reference compound (1b) by ¹ H-NMR, ¹³ C-NMR, and FAB-MS. The yield was 0.90 g, and the yield was 71%.
¹ H-NMR (500 MHz, CDCl ₃ ), δ (TMS, ppm): 7.46 (d, 2H, J = 7.4), 7.41 (t, 2H, J = 7.4), 7.35 (t, 1H, J = 7.2) 7.18 (d, 2H, J = 8.3), 7.09 (d, 2H, J = 8.3), 5.97 (s, 2H), 5.13 (s, 2H), 2.55 (s, 6H), 1.43 (s, 6H)
¹³ C-NMR (125 MHz, CDCl ₃ ), δ (TMS, ppm): 159.3, 155.3, 143.2, 141.8, 136.4, 131.8, 129.2, 128.6, 128.2, 127.6, 127.4, 121.1, 115.6, 70.2, 14.6
FAB-MS m / z = 430 [1b] ⁺
Next, the optical properties of the obtained reference compound (1b) were measured.
The ultraviolet-visible absorption spectrum and fluorescence spectrum of the reference compound (1b) (compound represented by the following formula) in methanol were measured.
A 1.0 × 10 ⁻⁶ M methanol solution of the reference compound (1b) was prepared, and an ultraviolet-visible absorption spectrum and a fluorescence spectrum were measured. In the absorption spectrum, a maximum absorption peak was observed at 498 nm, and the molar extinction coefficient was 9.0 × 10 ⁴ L / mol cm. In the fluorescence spectrum, a maximum fluorescence peak was observed at 506 nm. In addition, using a 1.0 × 10 ⁻⁶ M sodium hydroxide aqueous solution of fluorescein ([NaOH] = 0.1 M, φ _f = 0.90) as a reference solution, the fluorescence quantum yield was calculated from the fluorescence spectrum at λ _ex = 436 nm. When calculated, φ _f = 0.58. These values were very similar to those of the BODIPY-derived boronic acid (1a) in Example 1 above. Moreover, when a 1.0 × 10 ⁻⁵ M methanol solution of the reference compound (1b) having no boronic acid group was prepared and irradiated with ultraviolet light (365 nm), yellowish green fluorescence was observed.
Next, the PVA microparticles were characterized to confirm the surface modification property of the solid PVA.
As the solid PVA, commercially available PVA microparticles (same as the above-mentioned microparticles) were subjected to size selection with a sieve shaker and washed with methanol. In the present invention, PVA microparticles having a particle size of 212 to 425 μm by sieving are used.
The average particle diameter was calculated | required like Example 1 about the selected PVA microparticle. As a result, the average particle size was 405 ± 95 μm.
Further, when the surface area of the PVA particles was determined in the same manner as in Example 1, the specific surface area by the BET method was 0.0414 g / m ² .
Subsequently, the surface chemical modification of the PVA microparticles with the reference compound (1b) was performed in the same manner as in Example 1. The obtained treated PVA particles are referred to as PVA / 1b. As a result, no coloration was observed with PVA / 1b, and almost no light emission was observed even under ultraviolet light irradiation (365 nm). A photograph of PVA / 1b taken under visible light is shown in FIG. 3c, and a photograph taken under ultraviolet light irradiation is shown in FIG. 3d.
Next, solid fluorescence spectrum measurement of the obtained PVA / 1b was performed, and the luminescence was quantitatively investigated.
As a result of adding 0.2 g of PVA / 1b to a 1 mm cell and measuring the fluorescence spectrum (λ _ex = 436 _nm ), almost no fluorescence was observed from PVA / 1b. From this, it was found that 1b was not adsorbed on the PVA particles. FIG. 4 shows the results together with the fluorescence spectrum measurement results of PVA / 1a in Example 1 above.
Next, the change in the amount of adsorption when the immersion concentration was changed was determined based on the methanol concentration of the reference compound 1b (10 types adjusted to 2, 4, 8, 12, 16, 20, 28, 52, 72, 100 μM). Except that, the adsorption behavior was quantified in the same manner as in Example 1.
When the adsorption amount of the reference compound 1b was plotted against the equilibrium concentration, almost no adsorption was observed even when the immersion concentration increased. FIG. 9 shows the results together with the measurement results of the adsorption amount of PVA / 1a in Example 1 above.

[Example 2] Boronic acid derivative of diphenylanthracene It can be seen from the results of Example 1 and Comparative Example 1 that a compound having a boronic acid group is adsorbed on various solid PVA. The PVA microparticles were surface-modified using a boronic acid derivative (3a) of diphenylanthracene having blue fluorescence, which can be obtained by a boronic acid derivative having a skeleton or represented by the following formula. The boronic acid derivative (3a) of diphenylanthracene was obtained by a generally known method and purified by a known method.

The absorption spectrum and fluorescence spectrum of the boronic acid derivative (3a) of diphenylanthracene were measured.
The measurement was performed using the surface modifier (viscosity 0.55 cp) of the present invention obtained by preparing a 2.0 × 10 ⁻⁶ M methanol solution of boronic acid derivative 3a of diphenylanthracene. The measurement was performed by measuring an ultraviolet-visible absorption spectrum and a fluorescence spectrum. In the absorption spectrum, a maximum absorption peak was observed at 372 nm, and the molar extinction coefficient was 1.2 × 10 ⁴ L / mol cm. In the fluorescence spectrum, a maximum fluorescence peak was observed at 433 nm. Further, when the fluorescence quantum yield was calculated from the fluorescence spectrum at λ _ex = 355 nm using a 2.0 × 10 ⁻⁶ M ethanol solution (φ _f = 0.98) of diphenylanthracene as a reference solution, φ _f = 0. 82.
Next, surface modification of the same PVA microparticles as used in Example 1 was performed in the same manner as described in Example 1. PVA microparticles immersed in a methanol solution of the boronic acid derivative 3a of diphenylanthracene were designated as PVA / 3a.
The PVA particles (PVA / 3a) immersed in a methanol solution of the boronic acid derivative 3a of diphenylanthracene exhibited blue light emission under ultraviolet light irradiation (365 nm). A photograph of PVA / 3a taken under visible light is shown in FIG. 15a, and a photograph taken under ultraviolet light irradiation is shown in FIG. 15b.
Moreover, the solid-state fluorescence spectrum measurement of PVA / 3a was performed by the method similar to the method described in Example 1, and the light emission was investigated quantitatively ((lambda) _ex = 355nm). As a result, fluorescence derived from diphenylanthracene was observed from PVA / 3a. It is shown in FIG. 16a together with the fluorescence spectrum measurement result of PVA / 3b in Comparative Example 2 described later.
Next, when PVA / 3a was observed with a fluorescence microscope, fluorescence was observed from the entire surface of the particle, and it was found that 3a was adsorbed on the entire surface of the PVA particle. FIG. 17a shows a fluorescent micrograph of PVA / 3a.
From these results, it was found that a boronic acid derivative of diphenylanthracene is also useful as a surface modifier for the solid PVA of the present invention.

[Comparative Example 2]
The surface modification of the PVA microparticles was performed using the diphenylanthracene-induced reference compound (3b) shown in the following chemical formula as the reference compound of the boronic acid derivative (3a) of diphenylanthracene having blue fluorescence shown in Example 2. .
First, diphenylanthracenoic acid induced reference compound (3b) was synthesized.
9-Hydroxyphenyl-10-phenylanthracene (0.10 g 0.29 mmol) was dissolved in THF (30 mL), and cesium carbonate (0.47 g 1.44 mmol) was added to obtain a mixture L. 3-Bromobenzyl bromide (0.06 g 0.35 mmol) was added to the obtained mixed solution L, and the mixture was stirred overnight at room temperature to obtain a reaction solution M. The obtained reaction solution M was filtered, and the solvent was distilled off under reduced pressure to obtain a reaction product N containing the final product. Subsequently, the obtained reaction product N was purified by silica gel column chromatography. As a developing solvent, a mixed solvent of dichloromethane: hexane = 9: 1 (weight ratio) was used, and finally a white solid was recovered. This white solid was confirmed by ¹ H-NMR, ¹³ C-NMR, and FAB-MS to be a diphenylanthracenoic acid induced reference compound (3b). The yield was 0.12 g, and the yield was 95%.
¹ H-NMR (500 MHz, CDCl ₃ ), δ (TMS, ppm): 7.76-7.68 (m, 4H), 7.62-7.55 (m, 5H), 7.49-7.32 (m, 11H), 7.22 (d, 2H , J = 8.1), 5.22 (s, 2H)
¹³ C-NMR (125 MHz, CDCl ₃ ), δ (TMS, ppm): 158.3, 139.1, 137.1, 137.0, 136.9, 132.4, 131.4, 131.1, 130.2, 129.9, 128.7, 128.4, 128.1, 127.7, 127.4, 127.1, 127.0, 125.0, 124.9, 114.8, 70.2.
FAB-MS m / z = 436 [3a] ⁺
The absorption spectrum and fluorescence spectrum of the diphenylanthracenoic acid induced reference compound (3b) were measured.
A 2.0 × 10 ⁻⁶ M methanol solution of 3b was prepared, and an ultraviolet-visible absorption spectrum and a fluorescence spectrum were measured. In the absorption spectrum, a maximum absorption peak was observed at 372 nm, and the molar extinction coefficient was 1.4 × 10 ⁴ L / mol cm. In the fluorescence spectrum, a maximum fluorescence peak was observed at 433 nm. Further, when the fluorescence quantum yield was calculated from the fluorescence spectrum at λ _ex = 355 nm using a 2.0 × 10 ⁻⁶ M ethanol solution (φ _f = 0.98) of diphenylanthracene as a reference solution, φ _f = 0. 71.
Next, surface modification of the same PVA microparticles as used in Example 1 was performed in the same manner as described in Example 1. The PVA microparticles immersed in the 3b methanol solution were designated as PVA / 3b.
The PVA particles (PVA / 3b) immersed in the 3b methanol solution showed almost no light emission even under ultraviolet light irradiation (365 nm). A photograph of PVA / 3b taken under visible light is shown in FIG. 15c, and a photograph taken under ultraviolet light irradiation is shown in FIG. 15d. Moreover, the solid-state fluorescence spectrum measurement of PVA / 3b was performed by the method similar to the method described in Example 1, and the light emission was investigated quantitatively ((lambda) _ex = 355nm). As a result, almost no fluorescence derived from diphenylanthracene was observed from PVA / 3b. It is shown in FIG. 16a together with the fluorescence spectrum measurement result of PVA / 3a in Example 2 above.

Example 3
The results of Example 1 and Example 2 show that the BODIPY-derived boronic acid (1a) and the boronic acid derivative (3a) of diphenylanthracene are adsorbed on various solid PVA. The surface modification of PVA microparticles was performed using a boronic acid derivative (4a) of rhodamine having red fluorescence, which can be seen even with boronic acid having the following formula. In addition, the boronic acid derivative (4a) of rhodamine was obtained by a generally known method and purified by a known method.
The absorption spectrum and fluorescence spectrum of the rhodamine boronic acid derivative (4a) were measured.
The measurement was performed using the surface modifier (viscosity 0.55 cp) of the present invention obtained by preparing a 5.0 × 10 ⁻⁷ M methanol solution of a rhodamine boronic acid derivative (4a). The measurement was performed by measuring an ultraviolet-visible absorption spectrum and a fluorescence spectrum. In the absorption spectrum, a maximum absorption peak was observed at 561 nm, and the molar extinction coefficient was 1.3 × 10 ⁶ L / mol cm. In the fluorescence spectrum, a maximum fluorescence peak was observed at 577 nm. Further, when a fluorescence quantum yield was calculated from a fluorescence spectrum at λ _ex = 510 nm using a 5.0 × 10 ⁻⁷ M ethanol solution (φ _f = 0.70) of rhodamine B as a reference solution, φ _f = 0. 36.
Next, surface modification of the same PVA microparticles as used in Example 1 was performed in the same manner as described in Example 1. PVA microparticles immersed in a methanol solution of the rhodamine boronic acid derivative 4a were designated as PVA / 4a.
PVA particles (PVA / 4a) immersed in a solution of rhodamine boronic acid derivative 4a in a red color exhibited red light emission under ultraviolet light irradiation (365 nm). A photograph of PVA / 4a taken under visible light is shown in FIG. 15e, and a photograph taken under ultraviolet light irradiation is shown in FIG. 15f.
Moreover, the solid-state fluorescence spectrum measurement of PVA / 4a was performed by the method similar to the method described in Example 1, and the light emission was investigated quantitatively ((lambda) _ex = 510nm). As a result, rhodamine-derived fluorescence was observed from PVA / 4a. This is shown in FIG. 16b together with the fluorescence spectrum measurement result of PVA / 4b in Comparative Example 3 described later.
Next, when PVA / 4a was observed with a fluorescence microscope, it was found that fluorescence was observed from the entire surface of the particle, and 4a was adsorbed on the entire surface of the PVA particle. FIG. 17b shows a fluorescent micrograph of PVA / 4a.
From these results, it was found that the boronic acid derivative of rhodamine is also useful as a surface modifier of the solid PVA of the present invention.

[Comparative Example 3]
As a reference compound of the rhodamine boronic acid derivative (4a) having red fluorescence shown in Example 3, the surface modification of the PVA microparticles was performed using the rhodamine acid-induced reference compound (4b) shown in the following formula. In addition, the boronic acid derivative (4a) of rhodamine was obtained by a generally known method and purified by a known method.

The absorption spectrum and fluorescence spectrum of the rhodamic acid-induced reference compound (4b) were measured.
4b of 5.0 × 10 ⁻⁷ M methanol solution was prepared, and UV-visible absorption spectrum and fluorescence spectrum were measured. In the absorption spectrum, a maximum absorption peak was observed at 561 nm, and the molar extinction coefficient was 1.3 × 10 ⁶ L / mol cm. In the fluorescence spectrum, a maximum fluorescence peak was observed at 577 nm. Further, when a fluorescence quantum yield was calculated from a fluorescence spectrum at λ _ex = 510 nm using a 5.0 × 10 ⁻⁷ M ethanol solution (φ _f = 0.70) of rhodamine B as a reference solution, φ _f = 0. 42.

Next, surface modification of the same PVA microparticles as used in Example 1 was performed in the same manner as described in Example 1. The PVA microparticles immersed in the methanol solution of 4b were designated as PVA / 4b.
The PVA particles (PVA / 4b) immersed in the methanol solution of 4b were not colored and almost no light emission was observed even under ultraviolet light irradiation (365 nm). A photograph of PVA / 4b taken under visible light is shown in FIG. 15g, and a photograph taken under ultraviolet light irradiation is shown in FIG. 15h.
Moreover, the solid-state fluorescence spectrum measurement of PVA / 4b was performed by the method similar to the method described in Example 1, and the light emission was investigated quantitatively ((lambda) _ex = 510nm). As a result, almost no fluorescence derived from rhodamine was observed from PVA / 4b. It is shown in FIG. 16b together with the fluorescence spectrum measurement result of PVA / 4a in Example 3 above.

The equipment and reagents used in the examples are as follows.
-For various NMR measurements, a Bruker AVANCE 500 type nuclear magnetic resonance apparatus (500 MHz) was used, and tetramethylsilane (TMS) was used as an internal standard.
-For fast atom bombardment mass spectrometry (FAB-MS) measurement, JEOL JMS-700 was used, and 3-nitrobenzyl alcohol (Tokyo Kasei) was used for the matrix.
-Shimadzu UV-3600 was used for the ultraviolet visible absorption spectrum measurement.
-JASCO FP-6300 was used for the fluorescence spectrum measurement.
-JEOL JSM-7500F was used for the scanning electron microscope measurement.
-Micrometric Trister was used for nitrogen gas adsorption measurement.
TS100 LED-f (λ _ex = 330-380 nm, λ _em > 420 nm) was used for fluorescence microscope observation.
• was used for confocal laser fluorescence microscope observation.
-JPS-9010MX was used for the XPS spectrum measurement.
-JASCO FT / IR-4100 was used for the infrared absorption spectrum measurement (ATR method).
Unless otherwise specified, reagents, solvents and the like used for synthesis, preparation and measurement were used as they were on the market.
-Diphenylanthracene was recrystallized from toluene and used.
-Tetrahydrofuran (THF) used what was processed by the method described below. Calcium chloride was added to commercially available THF and allowed to stir overnight. The supernatant was transferred to a heat-dried eggplant flask, sodium wire and benzophenone were added, and the mixture was heated to reflux for several hours in a nitrogen atmosphere. Distillation after the color of the solution turned blue.

[Example 4 and Comparative Example 4] PVF sponge Polyvinyl formal (PVF) sponge was prepared using the following reagents. -PVA (MW 89000-98000, saponification degree 99%)-Formaldehyde aqueous solution (36-38 wt%) was adjusted as follows. PVA (6.0 g) and distilled water (54 mL) were added to a 300 mL beaker and heated in an oil bath (95 ° C) until completely dissolved to prepare a 10 wt% PVA aqueous solution. Remove the beaker from the oil bath, add the aqueous formaldehyde solution (37%) (10 mL) and “Triton X-100” (trade name, manufactured by Aldrich, 1.5 g) before cooling, and stir at 1000 rpm for 25 minutes. Bubbles were formed. To the foam solution was added 50 wt% H2SO4 aqueous solution (30 mL), and the mixture was further stirred for 2 minutes. The mixture was heated in a dryer at 60 ° C. for 5 hours, and the resulting sponge was washed with water and dried until the weight of the PVF sponge was constant (yield: 5.72 g). -FE-SEM observation of PVF sponge Neoosmium was sputtered on the obtained PVF sponge and SEM observation was performed. The result is shown in FIG. In the surface observation, an open cell structure consisting of several tens of micro orders was observed.・ Porosity calculation Even if PVF sponge is immersed in water, the volume of the sponge does not swell due to water, so the porosity can be calculated by the immersion method, and the value is estimated to be 86 ± 12%. It was lost. Immersion method: The volume (ΔVwater) of water contained in the sample is calculated from the difference in the weight of the water when the sample is immersed in water for a certain period of time, and the porosity is calculated from the volume of the wetted PVF sponge (V _{PVF / water} ). It was determined.

-Chemical modification of the surface of PVF sponge Place the PVF sponge cut to 10 mg in a 50 mL sample bottle, and then add the methanol solution of BODIPY derivative (1a) obtained in Example 1 (20 μM (= 2.0 × 10 ⁻⁵ M), 25 mL of the surface modifier of the present invention, viscosity 0.55 cp) was added. After shaking for 15 hours with a shaker, the sponge was recovered, and the removed sponge was washed with methanol. This sponge was designated PVF / 1a (Example 4). The same operation was performed for BODIPY (1b) having no boronic acid group as a control molecule, and the resulting sponge was designated PVF / 1b (Comparative Example 4). The fluorescence spectra of the sponges obtained were measured. As a result, the PVF sponge immersed in the methanol solution of 1a was colored yellow-green due to the adsorption of 1a. The sponge emitted green light under UV irradiation (365 nm). On the other hand, PVF sponge immersed in 1b methanol solution was not colored. When fluorescence spectrum was measured, emission from BODIPY (λem = 535 nm) was observed from PVF / 1a, whereas PVF / 1b did not emit. These results indicate that boronic acid groups play an important role in dye adsorption on PVF sponge. In PVF / 1a (1a: sponge immersed in a 320 μM solution), in addition to the peak derived from PVF, the peaks attributed to aromatic CC stretching vibrations belonged to 1543, 1508 cm ⁻¹ and belong to BO stretching vibrations. These peaks were observed at 1307 cm ⁻¹ , confirming the adsorption of BODIPY to the PVF sponge surface.

-Concentration dependence of adsorption amount We investigated the adsorption mechanism by investigating the change of adsorption amount when the immersion concentration was changed and quantifying the adsorption behavior. Place PVF sponge cut to 4.0 mg in a 50 mL sample bottle, and add 5 mL of 1a methanol solution (15, 30, 45, 60, 90, 120, 160, 200, 240, 280, 320 μM) to each. It was. After shaking for 15 hours on a shaker, the supernatant solution was recovered and diluted 20-fold with methanol. The UV-Vis absorption spectrum of this solution was measured, and the amount of 1a adsorbed on the PVF sponge was calculated. As a result, when the amount of adsorption was plotted against the equilibrium concentration, a typical saturation curve was obtained at 1a, indicating that the boronic acid group was anchored to the PVF sponge.・ Curve fitting was attempted for the 1a saturation curve obtained in order to quantify the curve fitting adsorption behavior. It was established based on an equilibrium equation that assumed a 1: 1 bond between 1a and the PVF diol moiety. When curve fitting was performed using the following equation, the measured value and the calculated value were in good agreement, and it was found that the boronic acid ester bond was the driving force for adsorption. The calculated saturated adsorption amount was (114.1 ± 2.7) mg / g, and the apparent binding constant was (2.4 ± 0.3) × 10 ⁴ M ^-1 . Compared with the saturated adsorption amount (7.9 ± 0.1) mg / g in the study on the solid surface modification of PVA, the adsorption amount of the PVF sponge obtained this time was about 10 times higher.

・ PVF / 1a pH stability Prepare aqueous solutions with different pH (pH = 1, 3, 5, 7, 9, 11, 13) from 1 M hydrochloric acid aqueous solution and 0.1 M sodium hydroxide aqueous solution. 5 mL was added to each of the Petri dishes containing PVF / 1a (10 mg) prepared in the previous step, and photographs were taken 24 hours after immersion under incandescent light and UV (365 nm) irradiation. As a result, the previously reported PVA particles adsorbed with boronic acid compounds were dissolved in water, while PVF sponge was insoluble in water, and the adsorbed 1a did not change in color, quenching, etc. Furthermore, PVF / 1a showed very high stability with no change in a wide pH range. From these results, chemical modification of PVF sponges using boronic acid compounds can be expected to be applied to materials that can be used in water (adsorption / separation agents, catalysts, sensors, biomaterials).

[Example 5] Surface chemical modification of PVF sponge with various boronic acid dyes Boronic acid derivative of diphenylanthracene with blue fluorescence (3a) and its reference compound (3b), boronic acid derivative of rhodamine with red fluorescence (4a ) And its reference compound (4b) were used to chemically modify the PVF sponge.
In the same manner as in Example 1, surface modification of PVF sponge using various dyes was performed. PVF sponges immersed in methanol solutions of 4a, 4b, 3a, and 3b were PVF / 4a, PVF / 4b, PVF / 3a, and PVF / 3b, respectively. As a result, as in Example 1, significant adsorption was confirmed in 4a and 3a having boronic acid groups. When the fluorescence spectra of these sponges were measured, emission from diphenylanthracene (λem = 437 nm) and emission from rhodamine (λem = 598 nm) were observed. In other words, chemical modification of PVF sponge with boronic acid compounds is applicable to various boronic acid compounds.

・ Preparation of multicolored luminescent sponges The preparation of sponges with various luminescent colors was attempted by adjusting the mixing ratio of 1a, 2a and 3a. Various kinds of 20 μM dye (1a, 4a, 3a) solutions prepared in Example 1 and the above-described procedure were adjusted to a total concentration of 20 μM, and the sponge of Example 4 was immersed in the solution. The procedure for immersing the solution was the same as in Example 1. The obtained sponges were PVF / cyan, PVF / yellow, PVF / magenta, and PVF / white, respectively. As a result, the prepared solutions (cyan: [1a] = 1.6 μM, [3a] = 18.4 μM, [4a] = 0 μM, yellow: [1a] = 19.2 μM, [3a] = 0 μM, [4a ] = 0.8μM, magenta: [1a] = 0μM, [3a] = 4.0μM, [4a] = 16.0μM, white: [1a] = 2.4μM, [3a] = 16.0μM, [4a] = 1.6μM, The emission color was adjusted from the stereoscopic microscope image of the sponge soaked in) and the plot result on the chromaticity coordinates. From this experiment, it was shown that the fluorescent modification of boronic acid on PVF sponge can be chemically modified while fine tuning the ratio of multiple boronic acids.

The typical saturation curve obtained from the concentration dependence study of boronic acid dye adsorption on PVF sponge showed that the dye was adsorbed on PVF sponge with boronic acid group as anchor site. Next, IR analysis of the PVF sponge (PVF, PVF / 1a PVF / 1b) was performed to clarify the adsorption to the PVF sponge by instrumental analysis. In this measurement, PVF sponge immersed in 1a or 1b methanol solution (1.5 × 10 ⁻⁴ M) was used. In addition, as part of the functionalization of the sponge, an attempt was made to make a sponge that functions as a chemosensor. As a result, in the PVF sponge, a broad peak attributed to OH stretching vibration was 3200-3600 cm ⁻¹ , CH stretching vibration of alkyl chain, CH stretching vibration of aldehyde, and peak attributable to COC stretching vibration were 2863-2948, respectively. , 2777, 1009 cm ⁻¹ . In PVF / 1a soaked in methanol solution of 1a with boronic acid group, in addition to the peak derived from PVF sponge, the peak attributed to aromatic CC stretching vibration was 1547, 1509 cm ⁻¹ , and BO stretching vibration was observed. An assigned peak was observed at 1307 cm ⁻¹ , respectively. On the other hand, in PVF / 1b immersed in methanol solution of 1b without boronic acid group, the same spectrum as PVF sponge was obtained. The IR spectrum showed that 1a was adsorbed on the PVA sponge.

[Example 6] Metal ion response investigation of sponge surface-modified with boronic acid quinoline derivative (5 in the above formula) PVF sponge cut to 10 mg was put into a 50 mL sample bottle, and boronic acid of quinoline was put there. 25 mL of a methanol solution of the derivative (5) (20 μM (= 2.0 × 10 ⁻⁵ M), surface modifier of the present invention, viscosity 0.55 cp)) was added. After 15 hours of shaking on a shaker, the resulting sponge was removed and washed with methanol. This sponge was PVF / 5 and stored in HEPES buffer (5.0 × 10 ⁻³ M, pH 7.0). <Immersion in metal ion solution> HEPES buffer (5.0 × 10 ⁻³ M, pH 7.0, [Mn +] = 3.0 × containing 2 equivalents of various metal ions to 5 adsorbed on sponge in a 50 mL sample bottle. ^10-5 M) was added, and then PVF / 5 was added and shaken for 30 minutes. PVF / 5 immersed in a metal ion solution is taken out of the sample bottle, measured for emission spectrum, calculated for absolute quantum yield using an integrating sphere, and photographed with UV (365 nm) light in the dark field. It was. We also investigated the time course of fluorescence increase when PVF sponge was immersed in HEPES buffer containing zinc ions. As a result, the molar extinction coefficient of 5 in methanol and the amount of adsorption on the sponge were calculated from the absorbance at 307 nm. The molar extinction coefficient was calculated to be 6.3 × 10 ⁻³ M ⁻¹ cm ⁻¹ according to the Lambert-Beers law. It was done. The adsorption amount q (mg / g) of 5 to PVF sponge was calculated to be 5.67 mg / g. This figure shows that 1.56 × 10 ⁻⁷ mol of 5 is adsorbed to 10 mg of sponge. Show. From these results, it was considered that a HEPES buffer solution (5.0 × 10 ⁻³ M, pH 7.0, [Mn +] = 3.0 × 10 ⁻⁵ M) containing 2 equivalents of metal ions relative to the dye was appropriate.・ Responsiveness to metal ions Metal ions used: Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ , Cd ²⁺ , Hg The fluorescence intensity derived from quinoline group was greatly increased only in PVF sponge immersed in aqueous solution of zinc ion of perchloric acid hydrate of ²⁺ , Al ²⁺ , Pb ²⁺ . In addition, in observation under UV (365 nm) irradiation, only PVF sponge immersed in zinc ions emitted blue light, indicating that PVF / 5 selectively responds to zinc ions. . This increase in fluorescence is thought to be due to the fact that the photoinduced electron transfer at the aminoquinoline moiety is hindered by the coordination of zinc ions to the aminoquinoline moiety. In other words, it was shown that the function of the PVA surface is significantly improved by chemically modifying molecules with adsorption properties. The absolute quantum yield was calculated as φ _FL (no metal) = 0.05 and φ _FL (Zn2 +) = 0.32. Moreover, the fluorescence intensity of PVF / 5 with respect to zinc ions increased with time, and the increase in fluorescence was visually judged in about 30 minutes, indicating its usefulness as a chemosensor.・ Measurement of nitrogen gas adsorption on PVF sponge PVF sponge was dried at 100 ℃ for 2 hours before measurement. The specific surface area was calculated to be 1.69 m ² g ⁻¹ by the BET method. The classification of isotherms was type II.

[Example 7 and Comparative Example 7] PVF sponge was cut to 10 mg and added to a solution of boronic acid dye (1a, 3a, and 4a) in methanol (20 μM, 25 mL) at room temperature for 15 hours. Soaked. The resulting sponges were designated PVF / 1a, PVF / 3a, and PVF / 4a, respectively. The sponges obtained in the same experiment using dyes without boronic acid groups (1b, 3b, and 4b) as control molecules were PVF / 1b, PVF / 3b, and PVF / 4b, respectively.

PVF / 1a and PVF / 4a were colored in each pigment color, yellowish green and pink. Under UV irradiation (365 nm), PVF / 1a, PVF / 4a, and PVF / 3a emitted green, red, and blue, respectively. In addition, in the fluorescence measurement using an integrating sphere, each sponge emitted luminescence from BODIPY (λem = 535 nm, φFL = 0.42), luminescence from rhodamine (λem = 598 nm, φFL = 0.26) and luminescence from diphenylanthracene ( λem = 437 nm, φFL = 0.72). On the other hand, PVF / 1b, PVF / 3b, and PVF / 4b were not colored and did not emit light. These results indicate that boronic acid groups play an important role in dye adsorption on PVF sponge. The surface modification was verified by instrumental analysis. The obtained PVF sponge (PVF, PVF / 1a PVF / 1b) was subjected to ¹³ C CP-MAS NMR and IR measurement. In this measurement, a sample obtained by immersing PVF sponge (100 mg) in 1a, 1b methanol solution (1.5 × 10 ⁻⁴ M, 250 mL) for 15 hours was used. When the ¹³ C CP-MAS NMR spectrum of PVF sponge was measured, the peaks derived from methylene carbon (C) and methine carbon (B) at the PVA site were 25.6-52.1 ppm and 59.4-83.6 ppm. A peak derived from (A) was observed at 84.4-101.0 ppm. In PVF / 1a, in addition to the peaks observed for PVF sponge, small peaks derived from methyl carbon and aromatic carbon of BODIPY skeleton were observed at 6.2-20.9 ppm and 111.5-148.8 ppm. On the other hand, PVF / 1b only had the same peak as PVF sponge. In PVF sponge, broad peaks attributed to OH stretching vibration are 3200-3600 cm ⁻¹ , CH stretching vibration of alkyl chain, CH stretching vibration of aldehyde, and peaks attributed to COC stretching vibration are 2863-2948, 2777, respectively. Observed at 1009 cm ⁻¹ . In PVF / 1a soaked in methanol solution of 1a with boronic acid group, in addition to the peak derived from PVF sponge, the peak attributed to aromatic CC stretching vibration was 1547, 1509 cm ⁻¹ , and BO stretching vibration An assigned peak was observed at 1307 cm ⁻¹ , respectively. On the other hand, in PVF / 1b immersed in 1b methanol solution without boronic acid group, the same spectrum as PVF sponge was obtained. Analysis by NMR and IR spectra showed that 1a was adsorbed on PVF sponge.

The amount of adsorption when 4.0 mg of PVF sponge was immersed in 1a methanol solution (20 μM, 10 mL) was plotted against the immersion time. The amount of adsorption was calculated from the UV-Vis absorption spectrum measurement of the supernatant solution. The results showed that the adsorption amount reached saturation (> 90%) in about 15 hours. The amount of adsorption when the immersion concentration was changed was measured, and the adsorption behavior was quantified to investigate the adsorption mechanism. In this experiment, the adsorption amount was calculated when 4.0 mg of PVF sponge was immersed in methanol solution of 1a (15, 30, 45, 60, 90, 120, 160, 200, 240, 280, 320 μM) for 15 hours. . The experiment using 1b was conducted at 7.5, 15, 25, 30, 50, 70, 130, and 150 μM in consideration of the equilibrium concentration. When the amount of adsorption was plotted against the equilibrium concentration, a typical saturation curve was obtained at 1a. On the other hand, with 1b, even though the immersion concentration was increased, almost no adsorption was observed, indicating that the boronic acid groups were anchor sites and adsorbed on the PVF sponge. Curve fitting was performed on the saturation curve of 1a obtained this time. When curve fitting was performed using a formula assuming a 1: 1 bond between the diol moiety of the PVF sponge as an internal structure and 1a, the measured value and the calculated value agreed well. It was found to be an acid ester bond. The calculation showed that the saturated adsorption amount was (114.1 ± 2.7) mg / g, and the apparent binding constant was (2.4 ± 0.3) × 10 ⁴ M ⁻¹ . This value was about 10 times larger than that of the saturated adsorption amount (7.9 ± 0.1) mg / g in the study on the solid surface modification of PVA. This was considered to be due to the large specific surface area inherent to the sponge.

In order to investigate the stability and pH stability of surface-modified PVF sponge in water, aqueous solutions with different pH (pH = 1, 3, 5, 7, 9, 11, and 13), add 5 mL each to the Petri dish containing PVF / 1a (10 mg) prepared in the procedure 2-1 and photograph each sponge under UV (365 nm) irradiation 24 hours after immersion. Photographing and fluorescence spectrum measurement were performed. PVA was soluble in water, while PVF sponge was insoluble in water. Furthermore, PVF / 1a maintained its fluorescence characteristics in a wide pH range and showed high stability. From these results, PVF sponge chemically modified with boronic acid compounds is expected to be applied to materials that can be used in water (adsorption / separation agents, catalysts, sensors, biomaterials).

From the above experiment, it was found that PVA sponge can be chemically modified with boronic acid under mild conditions. Therefore, we tried to adjust the emission color of the fluorescent PVA sponge by adjusting the mixing ratio of dyes 1a, 2a and 3a. Various sponge (1a, 2a, 3a) solutions of 20 μM prepared in Example 5 were adjusted to a total concentration of 20 μM, and sponges were immersed. The solution immersion procedure was the same as in 2-1. The obtained PVF sponges were PVF-cyan, PVF-magenta, PVF-yellow, and PVF-white, respectively. Each prepared solution (cyan: [1a] = 1.6μM, [4a] = 0 μM, [3a] = 18.4 μM, yellow: [1a] = 19.2μM, [4a] = 0.8μM, [3a] = 0μM, magenta: [1a] = 0μM, [4a] = 16.0μM, [3a] = 4.0μM, white: [1a] = 2.4μM, [4a] = 1.6μM, [3a] = 16.0μM) The stereomicroscopic image of the sponge and the plot to the chromaticity coordinates showed the adjustment of the emission color. From this experiment, it was shown that several boronic acids can be chemically modified on PVA sponge while fine-tuning the ratio.

We investigated the possibility of applying PVA sponge as a chemosensor material by chemically modifying molecules that respond to fluorescence with metal ions. In this investigation, the boronic acid quinoline derivative was used. Dye 5 is adsorbed on PVF sponge (PVF / 5), and HEPES buffer solution (5.0 × 10 ⁻³ M, pH 7.0, containing 2 equivalents of various metal ions to the adsorption amount of 5 adsorbed on sponge. 10 mL of [M ^{n +} ] = 3.0 × 10 ⁻⁵ M) was added and shaken for 30 minutes. PVA / 4 immersed in a metal ion solution was removed from the sample bottle, measured for fluorescence spectrum, calculated for absolute quantum yield using an integrating sphere, and photographed under UV (365 nm) light irradiation in the dark field. It was. The speed of fluorescence response to PVF / 5 zinc ions was also investigated. As a result, the metal ions used were: Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ , Cd ²⁺ , Hg ²⁺ , The fluorescence intensity derived from quinoline was greatly increased only in the sponge immersed in the zinc ion aqueous solution of perchlorate hydrate of Al ³⁺ and Pb ²⁺ . Also, in observation under UV (365 nm) irradiation, we found that zinc ions could be easily detected visually using PVF / 5 because only the sponge immersed in zinc ions emitted blue light. The increase is thought to be due to the fact that the photoinduced electron transfer of the quinoline moiety is hindered by the coordination of the zinc ion to the aminoquinoline moiety). The absolute quantum yield of the sponge before and after zinc ion addition was determined to be φFL (no metal) = 0.05 and φFL (Zn ²⁺ ) = 0.32, respectively, by fluorescence measurement using an integrating sphere. The fluorescence intensity of PVF / 5 for zinc ions increased with time, indicating that the fluorescence response was almost complete in about 30 minutes. The first-order rate constant of the reaction between zinc ions and PVF / 5 was calculated as k = 7.21 × 10 ⁻² min ⁻¹ .

・ Time variation of fluorescence intensity with respect to zinc ions of PVF / 5 (remeasurement) Applying the separation method, and setting the concentration of zinc ions to a large excess (10 eq.), Conditions that approximate the system to a first-order reaction The measurement was performed again, and a pseudo first-order rate constant was calculated. In the prepared sponge PVF / 5 (PVF sponge: 10.0 mg, the amount of an immersed methanol solution of 5: 25 mL, 2.0 × 10 ⁻⁵ M), 10 equivalents of zinc to the adsorption amount of 5 adsorbed on the sponge. 10 mL of HEPES buffer containing ions (5.0 × 10 ⁻³ M, pH 7.0, [Zn ²⁺ ] = 1.5 × 10 ⁻⁴ M) was added and shaken. The PVA / 5 soaked in the solution was removed from the sample bottle, and the fluorescence response rate of PVA / 4a to zinc ions was investigated. As a result, a rapid increase in fluorescence was observed after 0-10 minutes of immersion in an aqueous zinc ion solution, after which the fluorescence intensity was almost flat. The first-order rate constant of the reaction between zinc ions and PVF / 5 was calculated as k = 1.44 × 10 ⁻¹ min ⁻¹ .

[Reference Example] In order to see the importance of boronic acid groups in the surface chemical modification of PVF sponge, the chemical modification methods of the functional groups usually used for chemical modification of PVA were investigated. Chemical modification of PVA with other substituents We investigated formyl groups, isocyanate groups, acid chlorides, and alkyl halides as functional groups that could modify the hydroxyl groups of PVA. The reaction temperature does not differ for any functional group, but formyl groups and alkyl halides require an acid as a catalyst or a base as a counter for the acid generated in the reaction. In addition, acid chlorides and isocyanates do not require the addition of acids or bases, but because they are highly reactive, they also react with water and alcohol, so dehydration conditions are indispensable to chemically modify them. On the other hand, boronic acid does not use acid or base, alcohol can be used as a solvent, and dehydration conditions are not required. Therefore, in the functional groups listed here other than boronic acid, the addition of acid and base and dehydration conditions are essential. Therefore, it was considered that boronic acid is optimal for the functionalization of solid PVA.

[Comparison example] ・ Investigation of adsorption characteristics to PVA sponge using dyes with formyl group as anchor site Adsorption experiment similar to adsorption of 1a with boronic acid group using BODIPY derivative (1c) with formyl group The usefulness of using boronic acid groups as anchor sites was investigated. The PVA sponge was cut to 10 mg and immersed in a methanol solution of each dye (20 x 10 ^-6 M, 25 mL) at room temperature for 15 hours. They were PVF / 1a and PVF / 1c, respectively.
From the fluorescent light of the obtained sponge and UV light (365 nm) irradiation, and the results of the fluorescence spectrum of the sponge, it was found that formyl groups, that is, aldehydes, could not be adsorbed under conditions where boronic acid was adsorbed on the PVA sponge. XPS measurement of PVF / 1a (part of characterization) PVF sponge (100 mg) was immersed in 1a or 1c methanol solution (1.5 × 10 ⁻⁴ M, 250 mL) for 15 hours to obtain a measurement sample. As a result, in the PVF sponge immersed in 1c methanol solution, the peak derived from oxygen and carbon (O1s: 532
eV, C1s: 284 eV) only. On the other hand, in PVF / 1a, in addition to the peaks derived from oxygen and carbon (O1s: 532 eV, C1s: 284 eV), the peaks derived from fluorine, nitrogen and boron, which are constituents of 1a (F1s: 686 eV, FKLL) : 599 eV, N1s: 399 eV, B1s: 191 eV).

・ Surface coverage From the results so far, the saturated adsorption amount of 1a to PVA q = 114.1 mg / g and the specific surface area of PVA VPVA = 1.69 m ² / g ^-1 were calculated. On the other hand, the volume of 1a was calculated as 423.579 ³ from the optimized structure of theoretical calculation. Here, assuming that 1a is a sphere, the cross-sectional area (V1a) was obtained from the radius (Onsager radius). r = [(3 × 423.579) ÷ (4π)] ^{1 ÷ 3} = 4.66 (Å) ∴V1a = πr ² = π × (4.66) ² = 68.22 (Å) = 0.68 (nm ² / molecule) From these values The surface coverage of 1a during saturated adsorption was calculated. 114.1 (mg / g) × 10 ^-3 ÷ 474.12 (g / mol) × 6.02 × 10 ²³ (molecule / mol) = 1.45 × 10 ²⁰ (molecule / g) 1.69 (m ² / g) × 10 ¹⁸ = 1.69 × 10 ¹⁸ (nm ² / g) ∴ 0.68 (nm2 / molecule) × 1.45 × 10 ²⁰ (molecule / g) ÷ 1.69 × 10 ¹⁸ (nm ² / g) × 100 (%) = 5.8 × 10 ⁴ (%) surface The reason why the coverage ratio exceeded 100% is not obvious, but some of the dye solution penetrated into the PVA solid, and the internal PVA was slightly modified, or the PVA chain appeared on the surface like a brush. It is thought that the pigment was modified there.

[Test Example] Cell culture experiment 1a (2.0 × 10 ⁻⁵ M) and methanol solution (25 mL) of lysine derivative 6 (2.0 × 10 ⁻⁴ M) having a boronic acid group were added to a PVA sponge (10 mg). Soaked for hours. The obtained sponge (PVA / 1a / 6) was taken out of the solution and washed with methanol, ethanol and distilled water. Place the PVA / 1a / 6 (2 mm x 2 mm x 1 mm) on a microplate and add 200 microL of cell suspension (5 x 10 ⁵ cell / mL phenol red-free D-MEM solution). The cells were cultured for 1, 3, 7 days under the conditions of 5% CO2, 37 ℃. The cultured sponges were washed with PBS (phosphate buffered saline) and incubated with Hoechst (1 mM), a live cell stain, for 30 minutes. After washing the sponge again with PBS, it was placed on a 14 mm glass bottom dish using phenol red-free D-MEM and observed with a confocal laser microscope. As a control experiment, the same operation was performed for PVA / 1a. Cell adhesion was observed in PVA / 1a / 6, and the proliferation of cells on the sponge surface was confirmed over time. This adhesion is thought to be caused by the positive charge caused by lysine immobilized on the sponge surface by electrostatic interaction with the cells. On the other hand, almost no cells were attached to PVA / 1a. The results showed that the obtained surface-modified sponge could be applied as a base material for three-dimensional culture.

[Example 8] Chemical modification of polyvinyl alcohol thin film surface using various boronic acid dyes as inks A silicon mold (inside frame: 8 mm x 34 mm x 1 mm) is placed on a slide glass, and red fluorescence is emitted into it. A marker pen as a surface modifier shown in FIG. 25 was filled with a solution of rhodamine boronic acid derivative (4a) in methanol (surface modifier of the present invention, concentration 0.5 × 10 ⁻⁴ M, viscosity 0.55 cp). . The obtained surface modifier was applied to the surface of a polyvinyl alcohol (PVA) thin film using a marker pen in which the liquid modifier was housed. In this example, a colorless transparent thin film having a thickness of 36 μm obtained by casting a PVA aqueous solution (5.66 wt%, 0.3 mL) and drying by heating was used as the PVA thin film. The thin film after application | coating was left still in air | atmosphere at room temperature. After 5 minutes, the thin film was washed with methanol (25 mL), and the washed thin film was dried with a dryer. Using the absorbance at 571 nm obtained from the UV-visible absorption spectrum of the obtained thin film and the molar extinction coefficient in methanol of 4a (1.3 × 10 ⁵ Lmol ^-1 cm ^-1 ), Meyer's method (Γ = Abs / ε × 10 ^-3 ), the immobilized amount of 4a was determined to be 2.20 × 10 ^-9 mol / cm ² (1.32 × 10 ¹⁵ pieces / cm ² ). A marker pen as a surface modifier shown in FIG. 25 was filled with a methanol solution of the reference compound 4b having no boronic acid group (surface modifier of the present invention, concentration 0.5 × 10 ⁻⁴ M, viscosity 0.55 cp). . The obtained surface modifier was applied to the surface of a polyvinyl alcohol (PVA) thin film using a marker pen in which the liquid modifier was housed. The thin film after application | coating was left still in air | atmosphere at room temperature. After 5 minutes, the thin film was washed with methanol (25 mL), and the washed thin film was dried with a dryer. When the ultraviolet-visible absorption spectrum of the obtained thin film was measured, no peak at 571 nm due to 4b was detected, indicating that 4b did not bind to the surface. Similarly, the surface modification of PVA thin films using various dyes was performed. A marker pen as a surface modifier shown in FIG. 25 was filled with a methanol solution of 1a, 1b, 3a, 3b (surface modifier of the present invention, concentration 0.5 × 10 −4 M, viscosity 0.55 cp). The obtained surface modifier was applied to the surface of a polyvinyl alcohol (PVA) thin film using a marker pen in which the liquid modifier was housed. As a result, significant adsorption was confirmed in 1a and 3a having boronic acid groups. On the other hand, 1b and 3b having no boronic acid group were not adsorbed. That is, it was found that the chemical modification of the PVA thin film using the marker pen in which the surface modifier is accommodated as a liquid agent can be applied to various boronic acid compounds.

[Example 9] Water-repellent property of polyvinyl alcohol thin film surface using boronic acid having fluoroalkyl group as ink Methanol solution of boronic acid having fluoroalkyl group (7) (surface modifier of the present invention, concentration 0.5) The marker pen as a surface modifier shown in FIG. 25 was filled with × 10 ⁻³ M, viscosity 0.55 cp). The obtained surface modifier was applied to the surface of a polyvinyl alcohol (PVA) thin film using a marker pen in which the liquid modifier was housed. In this example, a thin film obtained by crosslinking PVA with benzene-1,4-diboronic acid was used. The thin film after application | coating was left still in air | atmosphere at room temperature. After 5 minutes, the thin film was washed with methanol (25 mL), and the washed thin film was dried with a dryer.
The contact angle of water was measured for the thin film (7 / PVA film) thus obtained and the untreated PVA thin film (PVA film). When the untreated PVA thin film (PVA film) was used, the contact angle was 38 degrees, indicating that the PVA film is hydrophilic. On the other hand, the thin film coated with 7 (7 / PVA film) had a contact angle of 85 degrees, indicating that the surface had water repellency. Thus, it was found that the surface of the polyvinyl alcohol thin film can be easily made water-repellent by using a boronic acid having a fluoroalkyl group in the ink.

Claims (3)

  A surface modifier for solid polyvinyl alcohol comprising a boronic acid derivative dissolved in a solvent and comprising polyvinyl alcohol having a saponification degree of 40 to 99%. A surface modification method for solid polyvinyl alcohol, comprising:
A surface modification method characterized by causing a surface modifier formed by dissolving a boronic acid derivative in a solvent to solid polyvinyl alcohol comprising polyvinyl alcohol having a saponification degree of 40 to 99%. A holding unit for holding by a user's hand, a liquid agent storage unit provided in the holding unit for storing a liquid agent, and a discharge unit that communicates with the liquid agent storage unit and applies the liquid agent to an object. A surface modifier for solid polyvinyl alcohol, comprising the surface modifier for solid polyvinyl alcohol according to claim 1.