pH-Controlled "off-on-off" switch based on Cu(2+)-mediated pyrene fluorescence in a PAA-SDS micelle aggregated...

We report herein the fluorescence response of pyrene in the presence of sodium dodecyl sulfate (SDS) micelle and poly(acrylic acid) (PAA) with Cu(2+) as an ionic quencher. Pyrene present in the PAA-SDS complex is quenched by Cu(2+) at pH approximately 2 ("off" state). Quenched pyrene emission is recovered at pH approximately 8 ("on" state). Due to easy protonation and deprotonation of the PAA chain in aqueous solution, this pH-controlled micellar ternary system exhibits a highly reversible "off-on-off" switch of the pyrene emission.