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Amphiphilic Conjugated Block Copolymers: Synthesis and Solvent‐Selective Photoluminescence Quenching
Author(s) -
Tu Guoli,
Li Hongbo,
Forster Michael,
Heiderhoff Ralf,
Balk Ludwig J.,
Sigel Reinhard,
Scherf Ullrich
Publication year - 2007
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200600351
Subject(s) - copolymer , amphiphile , conjugated system , photoluminescence , quenching (fluorescence) , materials science , solvent , block (permutation group theory) , photochemistry , polymer chemistry , organic chemistry , chemistry , fluorescence , polymer , optoelectronics , physics , quantum mechanics , geometry , mathematics , composite material
A novel, amphiphilic, conjugated block copolymer is described, which was prepared by a Suzuki‐type cross‐coupling of 2‐bromo‐[9,9‐bis(2‐ethylhexyl)fluorene]‐7‐pinacolato boronate as an AB‐type monomer and monobromo‐substituted poly[3‐(6‐bromohexyl)thiophene] ( Br‐P3BrHT ) as a polymeric end capper in the key step. PF‐P3PHT ( P2 ; PF =poly(9,9‐dialkylfluorene); P3PHT =poly[3‐(6‐diethylphosphonato‐hexyl)thiophene]) as the amphiphilic target polymer was then generated in a polymer‐analogous conversion of the alkyl bromide side chains of the PF‐P3BrHT ( P1 ) precursor into polar alkyl phosphonate groups by reaction with triethyl phosphite. P2 shows a strong influence of the solvent polarity on the optical spectra (absorption, emission). Treatment of solutions of P2 in tetrahydrofuran (THF), a nonselective solvent, with increasing amounts of solvents that are selective for the polar polythiophene blocks (water) or the nonpolar polyfluorene blocks (hexane), respectively, results in the formation of two different types of core–shell aggregates, which show rather different optical properties (photoluminescence quenching, excitation energy transfer).