Blue-emitting self-assembled polymer electrolytes for fast, sensitive, label-free detection of Cu(II) ions in aqueous media.

Abstract

We have developed a light-emitting material based on nonconjugated block copolymers that contain polystyrene sulfonate (PSS) chains. The confinement of the PSS chains within nanosized domains appeared to be a powerful means of achieving enhanced fluorescence signals. High fluorescence quantum yield, with a maximum value of 37%, was obtained by adjusting the types of self-assembled morphologies of PSS-containing block copolymers; in contrast, the fluorescence quantum yield was merely 5% for the PSS homopolymer lacking organization. The wavelength of fluorescence emission was tunable by rational molecular design. In addition, significant self-quenching behavior was not noticed in diverse forms of this material such as solutions, thin films, and free-standing membranes. Notably, the light-emitting self-assembled block copolymer electrolytes exhibited high sensitivity toward Cu(2+) ions, with a detection limit of parts per billion levels, rapid response time of ≤1 min, and insignificant interference of other competitive metal ions.