Ion sensor

1. A copolymer, comprising a repeating unit (A) comprising a carboxyl group on a side chain thereof, and a repeating unit (B) comprising a carboxylate group having an ester residue exhibiting an aggregation-induced emission capability on a side chain thereof,

wherein the repeating unit (A) is a repeating unit derived from a monomer selected from the group consisting of acrylic acid, methacrylic acid and styrenecarboxylic acid;

wherein the repeating unit (B) is a repeating unit derived from at least one monomer selected from the group consisting of an acrylate, a methacrylate and a styrenecarboxylate; and

wherein the ester residue is derived from 1-methyl-1,2,3,4,5-pentaphenylsilole, 2,3,4,5-tetraphenyl-1,1-dimethylsilole or tetraphenylethylene, each of which optionally have 1 to 5 hydrophilic groups substituted on a phenyl group thereof, wherein the hydrophilic groups are independently selected from the group consisting of hydroxy group, an amino group, an alkylamino group, a dialkylamino group, a thiol group, a polyoxyethylene group, a polyoxypropylene group and a sulfinyl group.

2. The copolymer according to claim 1 , wherein the copolymer has a molar ratio of the repeating unit (A) to the repeating unit (B), (A:B) 4:1 to 1000:1.

3. The copolymer according to claim 1 , wherein the copolymer has a number-average molecular weight of 10,000 to 1,000,000.

4. The copolymer according to claim 1 , wherein the copolymer is a copolymer adapted to function as a polymer for detecting polyvalent metal ion fluorescence.

5. The copolymer according to claim 1 , further comprising a repeating unit (C) derived from a polyfunctional monomer.

6. The copolymer according to claim 5 , wherein the copolymer comprises 0.1 to 10 mol % of the repeating unit (C).

7. The copolymer according to claim 5 , wherein the repeating unit (C) is a repeating unit derived from a monomer having two or more polymerizable vinyl groups.

8. A device for detecting a polyvalent metal ion, the device comprising the copolymer according to claim 1 .

9. The device of claim 8 , wherein the copolymer is immobilized on a solid base material.

10. The device of claim 9 , wherein the copolymer is immobilized on the solid base material by covalent bonding to the solid base material.

11. A method for quantifying a polyvalent metal ion concentration in a sample, the method comprising contacting the sample with the device of claim 8 , and measuring a fluorescence intensity.

12. The copolymer according to claim 1 , wherein the hydrophilic groups are independently selected from a C 1 to C 6 alkylamino group and a di(C 1 to C 6 alkyl)amino group.

13. The copolymer according to claim 1 , wherein the ester residue is derived from 1-methyl-1,2,3,4,5-pentaphenylsilole.

14. The copolymer according to claim 1 , wherein the ester residue is derived from 2,3,4,5-tetraphenyl-1,1-dimethylsilole.

15. The copolymer according to claim 1 , wherein the ester residue is derived from tetraphenylethylene optionally having 1 to 5 hydrophilic groups substituted on a phenyl group thereof, wherein the hydrophilic groups are independently selected from the group consisting of hydroxy group, an amino group, an alkylamino group, a dialkylamino group, a thiol group, a polyoxyethylene group, a polyoxypropylene group and a sulfinyl group.

16. The copolymer according to claim 1 , wherein a carboxyl group in the repeating unit (A) on a side chain is a hydrophilic group having bonding site that can bind to the target polyvalent metal ions.

17. The copolymer according to claim 1 , wherein the repeating unit (A) is acrylic acid.

18. The copolymer according to claim 1 , wherein the repeating unit (A) is methacrylic acid.

19. The copolymer according to claim 1 , wherein the repeating unit (A) is styrenecarboxylic acid.