KR101544261B1 - Sulfonated polystyrene fluorescent polymers and copper ion sensors using thereof - Google Patents

Abstract

The present invention relates to a method for measuring a copper ion by fluorescence of sulfonated polystyrene and more particularly to a method for fluorinating a block copolymer containing a sulfonated polystyrene, And more particularly, to a method and an apparatus for measurement.
The present invention provides a fluorescent material comprising a block copolymer fluorescent material comprising a sulfonated polystyrene block.
A novel fluorophore based on a block copolymer comprising a sulfonated polystyrene block has been proposed by the present invention. The fluorescent material according to the present invention can control the fluorescence wavelength and intensity according to necessity through various methods. The fluorescent material according to the present invention does not require a label and therefore does not exhibit cohesion and quenching problems due to the adherence of the label.
The fluorescence agent according to the present invention can be utilized as a new sensor capable of effectively detecting and measuring copper ions without labeling due to the selective binding of copper ions to fluorescence properties.
Further, the fluorescent agent according to the present invention may exist in various forms and can be used in various light emitting devices.

Description

TECHNICAL FIELD [0001] The present invention relates to a sulfonated polystyrene fluorescent substance, and a copper ion sensor using the same. BACKGROUND ART [0002]

The present invention relates to a method for measuring a copper ion by fluorescence of sulfonated polystyrene and more particularly to a method for fluorinating a block copolymer containing a sulfonated polystyrene, And more particularly, to a method and an apparatus for measurement.

Light-emitting materials have received much attention in recent decades, from electronics (displays, photovoltaic cells) to chemical and biological sensors.

Conjugated polymers are also a category of luminescent materials, and recent developments in the field of conjugated polymers have led to the development of light-emitting polymers that can be dissolved in a variety of solvents, Solution processability that enables the fabrication of scale devices.

Methods for detecting heavy metal ions in an aqueous solution using such conjugated polymers as chemical sensors have been developed. Extensive research has been conducted to develop an efficient sensor that exhibits a fast response time based on a conjugated polymer and a highly selective recognition of target ions.

By introducing ionic components such as carboxylates, sulfonates, and quaternary ammonium salts into the conjugated polymer, the sensor efficiency of the conjugated polymer can be improved. However, such functional conjugated polymers often exhibit low luminous efficiency due to self-quenching or intermolecular energy transfer caused by aggregation of chromophores in an aqueous liquid or film state.

Accordingly, there is a continuing need for new chemical sensors using non-conjugated polymers. In particular, to overcome self-extinguishing effects by polymer aggregation, label-free amorphous, non-conjugated, There is a continuing need for non-conjugated amorphous light emitting polymers.

A problem to be solved by the present invention is to provide a phosphor using a new non-conjugated, amorphous, and luminescent polymer.

Another object of the present invention is to provide a novel phosphor capable of preventing flocculation due to introduction of an ionic component and self-quenching effect due to the flocculation.

Another problem to be solved by the present invention is to provide a novel phosphor capable of being dissolved in water to perform a solution process.

Another object of the present invention is to provide a novel luminescent polymer capable of selectively reacting with copper ions.

In order to solve the above problems, the present invention provides a fluorescent material comprising a block copolymer fluorescent substance comprising a sulfonated polystyrene block.

In the present invention, the sulfonated polystyrene block can be represented by the following formula.

Here, n is the degree of polymerization of styrene which is a repeating unit in the polystyrene block of the block copolymer, preferably 10 to 500, more preferably 50 to 200, and x is an integer, expressed as (x / n) * 100 The degree of sulfonation is from 1 to 99, preferably from 50 to 90.

In the present invention, the block copolymer may be a di-block copolymer or a tri-block copolymer, and preferably a sulfonated polystyrene block and a hydrophobic block such that hydrophilic sulfonated polystyrene blocks can self- Is preferable.

In the practice of the present invention, the block copolymer may be represented by the following formula (2)

Here, n is the degree of polymerization of styrene which is a repeating unit in the polystyrene block of the block copolymer, preferably 10 to 500, more preferably 50 to 200, and x is an integer of (x / n) * 100 Is in the range of 1 to 99, preferably 50 to 90, and m is the degree of polymerization of methylbutylene, preferably 10 to 500, and more preferably 50 to 200. [

The block copolymer according to the present invention absorbs ultraviolet light and exhibits green fluorescence in visible light, preferably blue. Although not to be bound by theory, it is believed that non-luminescent amorphous polystyrene (PS) can be converted to a benzene ring of PS (s) by introducing a sulfonic acid group at the para- benzene ring) and sulfonic acid (anti-bonding).

In the present invention, the phosphor may exist in various forms such as a solution, a thin film, or a bulk phase.

In the present invention, the solution type fluorescent substance is obtained by dissolving the fluorescent substance according to the present invention in a solvent, and is a solvent capable of dissolving the block copolymer according to the present invention, preferably a polar solvent, more preferably water , And can exhibit fluorescence properties at a low concentration, for example, a concentration of 0.1 to 5% by weight, preferably 1% by weight.

In the present invention, the fluorescent agent can control the wavelength to be fluoresced by various methods.

In the present invention, the fluorescent agent can change the fluorescence wavelength through crosslinking of the block copolymer. The crosslinking may be carried out by photo-crosslinking, and may be carried out in such a range that the block copolymer can be dissolved in the solution. Preferably, the fluorescence wavelength can be effectively changed from blue to green at a degree of crosslinking ranging from 0.1 to 1.0%.

In the present invention, the fluorescent material can control the fluorescence wavelength by controlling the molecular weight. Preferably, through the control of the molecular weight of the partially sulfonated polystyrene block, a blue shift occurs at the peak of the fluorescence wavelength as the molecular weight increases.

In the present invention, the fluorescent material can control the fluorescence wavelength by controlling the degree of sulfonation. Redshift may occur at the peak of the fluorescence wavelength, preferably through an increase in the degree of sulfonation.

In the present invention, the fluorescent agent can change the fluorescence property through self-assembly. Preferably, the block copolymer can be assembled into a core-shell form to improve the fluorescence property. The assembly into the core-shell form can be accomplished through the control of the polarity of the solvent, and preferably when a non-polar solvent such as toluene is used to form the core of the sulfonated polystyrene block, By being isolated in the scale region, the fluorescence quantum efficiency can be maximized.

In the present invention, the fluorescent agent may form a solution, a coating film, or a bulk phase, for example, a pre-stained film.

In the practice of the present invention, the solution can be prepared by dissolving the fluorescent agent in various solvents. In the case of the PSS-b-PMB block copolymer, water, a polar solvent such as methanol, tetrahydrofuran It can be dissolved in various solvents such as neutral solvents and non-polar solvents such as toluene.

In the practice of the present invention, the film or the coating film can be formed by solution processing of the fluorescent agent solution, and the micropatterned surface can be produced by a capillary method using, for example, micromolding. In another embodiment of the present invention, the fluorescent agent can be emitted by being fluorescent in a bulk state, for example, in the form of a pre-stenting film, without self extinguishing.

In one aspect, the present invention provides a method of irradiating a block copolymer containing a sulfonated polystyrene block with light to perform fluorescence.

In another aspect, the present invention provides a method for selectively measuring copper ions using a solution of a block copolymer fluorophore comprising a sulfonated polystyrene block. The block copolymer according to the present invention has the ability to detect copper ions (Cu ²⁺ ), and in the case of Cu ^{2 +} ions, it is the main pollutant in the wastewater stream. When the excess is present in the body, It is a substance that can cause serious damage to the product. Sensor according to the present invention is the detection limit of ppb level without significant interference from other metal ions in an aqueous solution do not detect the Cu ^{2 +} in one minute.

In the practice of the present invention, the fluorescent agent solution may be prepared by diluting the diluted block copolymer at a concentration of 1x10 ^-3 ~ 5x10 ^-3% by weight, preferably may be prepared by dissolving in water. Copper ions of 40 μM or less can be selectively measured in the fluorescent agent solution, and the fluorescence intensity is reduced by the presence of copper.

A novel fluorophore based on a block copolymer comprising a sulfonated polystyrene block has been proposed by the present invention. The fluorescent material according to the present invention can control the fluorescence wavelength and intensity according to necessity through various methods. The fluorescent material according to the present invention does not require a label and therefore does not exhibit cohesion and quenching problems due to the adherence of the label.

The fluorescence agent according to the present invention can be utilized as a new sensor capable of effectively detecting and measuring copper ions without labeling due to the selective binding of copper ions to fluorescence properties.

Further, the fluorescent agent according to the present invention may exist in various forms and can be used in various light emitting devices.

1 is a molecular structural formula of a partially sulfonated poly (styrene) (PSS) homopolymer and partially sulfonated poly (styrene-b-methylbutylene) (PSS-PMB) block copolymer, UV-vis absorption spectra (dotted line) and fluorescence intensity (solid line, excited at 330 nm) of S ₅₉ (82) and (c) 1 wt% S ₅₀ MB ₇₃ (66). The photograph of the solution photographed by irradiating ultraviolet light of 365 nm was also shown in the picture.
Figure 2 is a graphical representation of the density functional theory Ab (a) HOMO and LUMO forms of (a) styrene and (b) sulfonated styrene calculated by initio calculation.
3 shows spectroscopic peak shifts of normalized fluorescence intensities of (a) different polymerization degrees, (b) a 1 wt% S _n MB _m (SL) block copolymer aqueous solution having different sulfonation levels (SL) Respectively. (c) normalized fluorescence intensity of a 1 wt% S ₅₀ MB ₇₃ (66) copolymer aqueous solution after cross-linking (excited at 390 nm with a solid line, excited at 330 nm) to be.
Figure 4 shows (a) the fluorescence quantum yield of 1 wt% S ₈₉ MB ₁₃₀ (49) in various solvents. Different types of micelles are shown in the illustrations. (b) TEM image of micelles in THF / toluene and MeOH / water solution to determine the different core-shell morphology of the micelles according to the solvent.
Figure 5 is a fluorescence microscope image of micro-patterned surfaces of a non-crosslinked (blue) S ₅₀ MB ₇₃ (66) copolymer and a crosslinked (green) S ₅₀ MB ₇₃ (66) copolymer in a LED illumination. The internal photograph shows fluorescence in the free-standing membrane state of a 500 탆 thick S ₅₀ MB ₇₃ (66) copolymer that is not crosslinked.
Figure 6 shows (a) fluorescence quenching (excitation at 330 nm) of an aqueous solution of 0.002 wt% S ₅₀ MB ₇₃ (66) as evidenced by the addition of various concentrations of Cu ^{2 +} ions. For the sake of comparison, the internal figure shows the result in the aqueous S ₅₉ (82) solution. (b) a stepwise change in the sensing signal as the specific amount of Cu ^{2 +} ions shown in the figure is entered. (c) The effect of various other metal ions on I ₀ / I of the sensor when the metal ion concentration is fixed at 20 μM. Volumetric plot of Stern-Volmer plot between I ₀ / I and Cu ^{2 +} concentrations at Cu ²⁺ ion concentration 0-40 μM.
7 is a schematic view illustrating a mechanism for Cu ^{2 +} ion sensing of a light emitting PSS-PMB block copolymer electrolyte. Spherical micelles PMB is located in the core in an aqueous solution striking the negative PSS is composed of a shell is, Cu ^{2 +} led to appropriate spatial match for the ion, and sulfonate ion and a high binding affinity of Cu ^{2 +} ions and with the Of the collision speed.

Hereinafter, the present invention will be described in detail with reference to examples. It should be noted that the following examples are intended to illustrate the invention and are not intended to limit the scope of the invention.

Example

Synthesis of Emissive Polymer Electrolyte.

A set of poly (styrene-b-methylbutylene) (PS-PMB) block copolymers were synthesized by sequential anionic polymerization of styrene and isoprene followed by hydrogenation of an optional isoprene unit.

The molecular weight and molecular weight distribution of PS-PMB copolymer also (molecular weight distribution) is ¹ H- nuclear magnetic resonance ^{(1 H Nuclear Magnetic Resonance, 1} H-NMR, Bruker AVB-300) and gel permeation chromatography (gel permeation chromatography, GPC, Waters Breeze 2 HPLC).

The polydispersity indices (PIs) of PS-b-PMB polymers were smaller than 1.05. The styrene chains of PS-PMB block copolymers are described in Kim, SY; Kim, S .; Park, MJ Enhanced Proton Transport in Nanostructured Block Copolymer Electrolyte / Ionic Liquid Membrane under Water Free Conditions. Nat . Commun . , 2010 , 1:88. The PSS-PMB block copolymer was obtained by partial sulfonation.

Partially sulfonated polystyrene (PSS) single polymers were synthesized by sulfonation of PS monomers synthesized with anions of PIs less than 1.02 through anionic polymerization. The sulphonation level (SL) of each sample was varied by adjusting the reaction time.

Measurement of fluorescence properties.

The UV-visible spectra of the PSS general polymer and the PSS-PMB block copolymer were measured using an Agilent 8453 UV-visible spectrophotometer. Fluorescence spectra of the polymer solution were measured using a QuantaMaster ^TM40 fluorescence spectrometer. Fluorescence microscopy images of the patterned thin films were taken using ZEISS Axioplan 2 under LED illumination.

Morphology ( Morphology ) analysis

The micellar morphology of the PSS-PMB block copolymer solution was analyzed by synchrotron small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and dynamic light scattering Model Zetasizer, Nano-ZS). SAXS experiments were performed using the MAR345 imaging plate detector in a 4C beamline of the Pohang Accelerator Light Source (PAL). Wavelength (λ) of the X-ray beam is incident is 0.15 nm (△ λ / λ = 10 -4) , and the sample and the distance between the detectors by 2.0 m, 0.1 ~ 2.0 nm in the range ^-1 scattering wave vector q (q = 4? Sin (? / 2) /?, Where? Is the scattering angle). TEM images of drop-coated samples on a TEM grid were obtained using a Hitach H-800 microscope at 100 kV. The electrical contrast and contrast of the samples were improved by staining the samples exposed to ruthenium tetroxide (RuO ₄ ) vapor for 50 minutes.

Photo-crosslinking reaction Photo - crosslinking reaction )

Benzophenone (99.9% purity) was purchased from Sigma-aldrich and used without further purification. Benzophenone solution and PSS-PMB block copolymer solution were vigorously mixed for 1 hour and irradiated with ultraviolet rays using a portable germicidal lamp (15 W; G 15 T8 UV-C, Phillips, Holland) at room temperature under argon To crosslink the main chain portion of the PSS portion [Chen, S.-L .; Benziger, JB; Bocarsly, AB; Zhang, T. Photo-Cross-Linking of Sulfonated Styrene-Ethylene-Butylene Copolymer Membranes for Fuel Cells. Ind . Eng . Chem . Res . 2005 , 44 , 7701-7705. Optimum irradiation time was determined based on the crosslink density analyzed by Fourier Transform InfraRed (FT-IR) experiments.

Metal ion detection.

NaCl (= 99.0%), KCl (= 99.0%), CaCl _{2 (= 97.0%), ZnCl 2} (= 98.0%), MgSO 4 · 6H 2 O (= 99.0%), MnCl 2 · 4H 2 O (= 98.0%), HgCl 2 (= 99.5%), Pb (NO 3 ) ₂ (= 99.0%), CuCl ₂ (= 98.0%), and FeCl ₃ (= 97.0%) reagents were purchased from Sigma-aldrich and used without further purification. The metal ion sensing experiments were carried out by observing the varying fluorescence intensity (excitation at 330 nm) while injecting metal ions at various temperatures into the PSS-b-PMB block copolymer aqueous solution at room temperature.

radiation Unofficial  Polymer Electrolyte Light - emitting non - conjugated 중합체  electrolytes).

FIG. 1A shows the molecular structure of a partially sulfonated poly (styrene) (PSS) homopolymer and partially sulfonated poly (styrene-b-methylbutylene) (PSS-b-PMB) block copolymer. Covalently bonded hydrophobic PMB chains are chains intended to make self-assembled forms in aqueous solution. The degree of polymerisation (n, m) and the degree of sulfonation (defined as x / n, SL) of the polymer varied to control the self-assembled structure and ultimately to control the fluorescence properties of the polymer. Hereinafter, the PSS single polymer and the PSS-PMB block copolymer are represented by S _n (SL) and S _n MB _m (SL), respectively.

Figures 1b and 1c show UV-visible absorption spectra (dotted line) fluorescence intensities (solid lines) of 1 wt% S ₅₉ (82) and 1 wt% S ₅₀ MB ₇₃ (66) in aqueous solution, respectively. The UV-vis absorption spectra of both samples were qualitatively the same for both broad shoulders at approximately 330 nm. When the samples were excited at 330 nm, there was a significant difference between the homopolymer and the block copolymer. In the case of S ₅₀ MB ₇₃ (66), strong fluorescence with maximum emission at 392 nm was observed, whereas S ₅₉ 82) produced very weak fluorescence with center at 385 nm. Photographs of the solutions shot with 365 nm ultraviolet lamps are shown in the internal illustrations of Figures 1b and 1c, respectively. In the photograph, S ₅₀ MB ₇₃ (66) shows more intense blue fluorescence in the aqueous solution. The fluorescence quantum yields (QY) of 1 wt% S ₅₉ (82) and 1 wt% S ₅₀ MB ₇₃ (66) in aqueous solution were 5% and 26%, respectively. In the case of S ₅₀ MB ₇₃ (66), which has amphiphilic properties in aqueous solution, the negatively charged PSS has a spherical micellar form surrounding the PMB core with a shell. As a result of dynamic light scattering (DLS) and electrophoresis experiments, the hydrodynamic radius and zeta potential of micelles were measured to be 11.6 nm and -65 mV, respectively.

A distinct redshift peak shift of up to 80 nm was observed compared to PS, a non-fluorescent polymer. As shown in FIG. 2, anti-bonding between sulfonic acid and benzene ring was observed, .

Control of fluorescence wavelength.

A set of S _n MB _m (SL) copolymers were synthesized by varying n, m, and SL values, and the fluorescence intensities of 1 wt% of the micelle solution of these copolymers were used for comparison and experiment.

As shown in FIG. 3A, as the molecular weight of S _n MB _m (SL) increases while maintaining the SL level, a blue-shift of a small but clearly visible emission wavelength peak is observed.

As shown in FIG. 3B, as the SL level is increased with the same degree of polymerization, a remarkable red-shift of the emission wavelength peak is observed.

As shown in FIG. 3c, only a small amount (0.5 mol%) of the PSS main chain (backbone) was chemically crosslinked through a photo-crosslinking reaction to change the fluorescence wavelength very greatly. The crosslinking reaction shifts the fluorescence color from blue to green without significantly changing the solubility of the polymer or the size of the micelle. The cross-linking reaction shows that the S ₅₀ MB ₇₃ (66) copolymer fluorescence in aqueous solution redshifts distinctly the peak at 392 nm to 485 nm.

Solvent and On morphology  Fluorescence characteristics change due to

The quantum yield (QY) of fluorescence intensity is sensitive to the solvent used. Representative data obtained using 1 wt% S ₈₉ MB ₁₃₀ (49) solution are shown in Figure 4A.

THF  Use of solvents

The QY value was 12% when THF (tetrahydrofuran) was used as a neutral solvent in both PSS and PMB chains to prevent formation of micelles.

THF / Toluene  Use of solvents

When toluene was added to THF (50/50 vol%), the maximum value of QY of 37% was obtained. This is because toluene has a high selectivity to PMB as compared to PSS, so that PSS is spontaneously formed in the core and PMB is surrounded by shell. The core-shell form factor analysis and dynamic light scattering (DLS) of X-ray small angle X-ray scattering (SAXS) experiments were carried out with PSS core radius and PMB shell thickness of 4.0 nm and 3.0 nm, Respectively.

Methanol / water  ( MeOH / water ) Use of Solvent

The structure of the micelle is illustrated in FIG. 4A. The polymer formed spherical micelles composed of a PSS shell with a thickness of 10.0 nm on a PMB core of 8.6 nm in radius. The change of the QY value according to the solvent showed no change in the position of the maximum fluorescence wavelength.

Change in form

Core-shell micelles according to the solvent were confirmed by transmission electron microscopy (TEM) image observation of drop-coated samples. As shown in FIG. 4B, formation of spherical micelles of uniform size was confirmed in both of THF / toluene and MeOH / water mixed solutions. In the case of MeOH / water, PSS appeared in shell, whereas in THF / toluene, PSS was composed of core. In the TEM micrograph, the PMB area is not visible, only the PSS area is RuO ₄ It looks dark because it has been stained by. The TEM and SAXS results agree well with the size of the core and shell regions.

Manufacture of fluorescent film

MB _n S _m (SL) on the basis of excellent solubility and well not broken advantages of the copolymer, a surface micro-patterned to prepare a material with a capillary method using the micromolding. This surface provides a convenient and economical way to design the luminescent film in a variety of device formats with only a minimal amount of sample. A 1 wt% copolymer solution using methanol as a solvent was made by passing it through a capillary tube to a poly (dimethyl siloxane) stamp.

Figure 5 shows a fluorescence microscope photograph of the patterned surface taken under LED illumination. Micropatterns of various sizes and shapes were obtained for both blue fluorescent samples (excited at 330 nm, unbridged) and green fluorescent samples (cross-linked, excited at 390 nm).

In addition, as shown in the photograph shown in Fig. 5, strong blue fluorescence was well preserved even in free-standing membranes with a thickness of 500 mu m. Therefore, regardless of the final form of the S _{m n} MB (SL) copolymers, self-quenching phenomenon of the S _{m n} MB (SL) copolymer is negligible.

High selectivity without labeling and fast reaction rate Cu ^{2 +}  Ion detection.

_{Finally, S n MB m (SL)} 10 of different metal ions in the copolymer ^{(Na +, K +, Ca} 2 +, Mg 2+, Mn 2 +, Zn 2 +, Hg 2 +, Pb 2 +, Cu ^{2 +} , and Fe ^{3 +} ). In order to demonstrate the high sensitivity (sensitivity) for a very small amount of material was used in which _{^{(2x10 -3 wt%) S n}} MB m (SL) copolymer solution diluted in water.

When the fluorescence intensity of the solution was observed while adding various concentrations of metal ions, a distinct fluorescent signal change was observed only in the Cu ^{2 +} ion. As can be seen in FIG. 6A, the fluorescence intensity was reduced by 38% compared with the initial state, as Cu ^{2 +} ions were added to the S ₅₀ MB ₇₉ (66) aqueous solution of ² x 10 ^-3 wt% from 0 to 40 μM .

As can be seen from the illustrated figure of Figure 6a, this behavior is not seen in the PSS single polymer (S ₅₉ (82)) under the same conditions.

Detection reaction rate

As shown in FIG. 6B, as the target amount of Cu ^{2 +} ion was added, the sensing signal of the solution of S ₅₀ MB ₇₉ (66) changed drastically. Here, the signal change of each step was continued for 1 minute It was not. I ₀ / I value represents the ratio of fluorescence intensity when Cu ^{2 +} ion is present and when it is not present. The Cu ^{2 +} ion sensor according to the present invention has a low detection limit of 500 nM (concentration corresponding to 32 ppb), enabling operation over a wide range of concentrations from nanomolar to micromolar levels.

Selective detection characteristics

6C shows that there is a high selective sensing capability without labeling the sensor for Cu < ^{2 + &} gt ^; ions. Regardless of the concentration, other metal ions did not show a clear disturbance to the fluorescence quenching phenomenon of the polymer.

Claims (22)

A fluorescent substance comprising a block copolymer fluorescent substance comprising a sulfonated polystyrene block. The phosphor according to claim 1, wherein the phosphor is a solution, a thin film, or a bulk phase. The phosphor according to claim 1, wherein the block copolymer is self-assembled. The phosphor according to claim 1, wherein the phosphor is assembled in a core-shell form. The phosphor according to claim 4, wherein the sulfonated polystyrene block forms a core. The phosphor according to claim 1, wherein the sulfonated polystyrene block is represented by the following formula (1).

Here, n is an integer of 10 to 500, x is an integer, and the degree of sulfonation represented by (x / n) x100 is 1 to 99. The fluorescent substance according to claim 1, wherein the block copolymer is represented by the following formula (2).

Here, n is an integer of 10 to 500, m is an integer of 10 to 500, x is an integer, and the degree of sulfonation represented by (x / n) x100 is 1 to 99. The phosphor according to claim 1, wherein the block copolymer is a partially sulfonated polystyrene-polymethylbutylene block copolymer. The phosphor according to claim 1, wherein the block copolymer is a cross-linked block copolymer. 10. A method of irradiating a fluorescent material according to any one of claims 1 to 9 with light to cause fluorescence. 11. The method of claim 10, wherein the light is ultraviolet. 11. The method of claim 10, wherein the molecular weight of the block copolymer is increased to blue-shift the fluorescence. 11. The method of claim 10, wherein the degree of sulfonation of the block copolymer is increased to red-shift the fluorescence. The method according to claim 10, wherein the block copolymer is crosslinked to fluoresce green. A method for measuring metal ions by detecting fluorescence change of a solution containing a block copolymer comprising a sulfonated polystyrene block. The measuring method according to claim 15, wherein the metal ion is Cu ^{2 +} . 16. The method of claim 15, wherein the block copolymer is assembled in a core-shell form. The measuring method according to claim 17, wherein the sulfonated polystyrene block comprises a shell. The measuring method according to claim 15, wherein the solution is an aqueous solution. 17. The measuring method according to claim 16, wherein the concentration of the copper ions is in a concentration of ppb. 17. The method according to claim 16, wherein the time for detecting the copper ions is within one minute. 16. The method according to claim 15, wherein copper ions are selectively detected under the coexistence of various metal ions.

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