Receptor-free poly(phenylenevinylene) fibrous membranes for cation sensing: high sensitivity and good selectivity achieved by choosing the appropriate polymer matrix.

Poly(phenylenevinylene)/polyimide (PPV/PI) and poly(phenylenevinylene)/ polymethylmethacrylate (PPV/PMMA) fibrous membranes without any deliberately introduced receptors were prepared as fluorescence sensing materials through electrospinning, followed by thermal treatment. Both of these membranes displayed higher sensitivity toward most cations compared to the corresponding spin-coated films. PPV/PMMA membranes were more sensitive than PPV/PI membranes toward Cu(2+) and Fe(3+). About 4.5 fold of intensity enhancement upon 20 nM of Cu(2+), 80% of quenching upon 20 nM of Fe(3+) with fast response and simple regeneration were realized for PPV/PMMA membrane. The preliminary investigation into the mechanism revealed that the properties of the polymer matrix and thermal treatment of the membrane played important roles in the sensing performance.