AMPHIPHILIC BLOCK CO-POLYMER OF 9-VINYLPHENANTHRENE AND METHACRYLIC-ACID - FLUORESCENCE QUENCHING OF PHENANTHRENE RESIDUE IN AQUEOUS-MEDIUM

In the reported experiments, amphiphilic block copolymers of 9-vinylphenanthrene (VPh) and methacrylic acid (MA) were prepared by a two-step living anionic polymerization of VPh and trimethylsilyl methacrylate followed by hydrolysis of the trimethylsilyl ester groups. Bis(2-hydroxyethyl) terephthalate, an oxidative quenching agent with amphiphilic nature, strongly quenched the fluorescence of phenanthrene groups in the block copolymer in aqueous solution. Apparent second-order rate constants kappa //q for the quenching ranged in the magnitude of 10**1**1 minus 10**1**2M** minus **1s** minus **1 in the borate (pH9) and phosphate (pH 7) buffers, whereas those in DMF solution were found to be similar 10**9M** minus **1s** minus **1. Fumaric acid (FA), an anionic quencher, did not quench the fluorescence of the copolymer at pH 9 and 7, presumably because of the lack of accessibility of the quencher to the copolymer due to electrostatic repulsion.