received by the International Bureau on 4 February 2014 (04.02.2014)

We claim

1. A process for preparation of a polymer composition with tunable fluorescence comprising the steps of: i. adding 37 mg/ml of silk solution to 10^'2 M aqueous solution of KMn0₄, 10^"2 M oxalic acid and 0.17 M H₂S0₄ in 1 : 1 : 1 : 1 v/v ratio followed by stirring and heating at a temperature in the range of 55 to 60°C until the solution becomes colourless; ii. adding 0.1 to 30 % of one or more monomer(s) selected from the group consisting of methacrylates, acrylates, vinyl groups, pyrene, perylene, oligophenylene vinylene, oligothiophene, and combinations thereof provided with fluorophore solution in DMF (dimethyl formamide) to the colourless mixture as obtained in step (i) in a ratio ranging between 0.02 to 0.8 w/w and heating at the same temperature to obtain a mixture; iii. cooling the mixture as obtained in step (ii), extracting the precipitate formed with organic solvent and water to remove all unreacted monomer and homopolymer, filtering under vacuum and drying to obtain a dried mixture; iv. soxhlating the dried mixture as obtained in step (iii) in organic solvent for 2 days to obtain pure polymer composition with tunable fluorescence.

2. The process as claimed in claim 1, wherein the silk used in step (i) is obtained from Bombyx mori silk worm having functional group selected from the group consisting of tryptophan, serine, glycinyl, and alanyl.

3. The process as claimed in claim 1, wherein the organic solvent used in step (iii) is selected from the group consisting of Tetrahydro furan (THF), and chloroform.

4. The process as claimed in claim 1 , wherein said polymer composition with tunable fluorescence comprises silk with PEG-PBA ester (ester of polyethyleneglycol methacrylate and 1 -pyrene butyric acid).

5. The process as claimed in claim 1, wherein said polymer composition with tunbale fluorescence comprises silk with perylene containing monomer.

6. The process as claimed in claim 1, wherein said polymer composition with tunable fluorescence comprises silk with oligophenylenevinylene (OPV) containing monomer.

7. The process as claimed in claim 1, wherein said polymer composition with tunable fluorescence comprises silk together with pyrene and perylene containing monomers, oligophenylenevinylene (OPV) and perylene containing monomers, pyrene, oligophenylenevinylene (OPV) and perylene containing monomers pyrene monomer, Perylene monomer and oligophenylene vinylene monomer randomly.

8. A polymer composition with tunable fluorescence prepared by the process as claimed in claim 1, wherein said polymer composition comprises silk and one or more monomer(s) selected from the group consisting of methacrylates, acrylates, vinyl groups, pyrene, perylene, oligophenylene vinylene, oligothiophene, and combinations thereof provided with fluorescent probe, characterized in that the monomer(s) provided with fluorescent probe is grafted onto a silk backbone.

9. The polymer composition with tunable fluorescence as claimed in claim 8 for use in optoelectronics and tracing the chain dynamics of silk as well as its self -organization properties in solution.

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