Colorimetric sensing of non-ionic and cationic surfactants using a versatile anionic poly(3,4-propylenedioxythiophene) derivative

A novel anionic water-soluble poly(3,4-propylenedioxythiophene) derivative (WSPProDOT) has been prepared through FeCl3 oxidative polymerization with a subsequent post-polymerization defunctionalization process, and applied as a colorimetric sensor to determine and discriminate non-ionic and cationic surfactants in aqueous solutions. The de-aggregation, conformation change of WSPProDOT and its colorimetric and fluorescent responses toward non-ionic and cationic surfactants have been studied by absorption and emission spectroscopy. The solution color of WSPProDOT changes from purple to blue upon addition of a non-ionic surfactant and from purple to black for a cationic surfactant. Therefore, non-ionic and cationic surfactants can be discriminated and detected using this versatile sensing platform.