Indication of critical micelle concentration of nonionic surfactants with large emission change using water-soluble conjugated polymer as molecular light switch

► Investigated the interaction of a new water-soluble conjugated polymer with surfactants. ► The dramatic fluorescence enhancement and emission blue-shift were observed at the CMC. ► The obvious emission color change could be observed with naked-eyes under UV-lamp. ► Gave a direct indication for the micelle forming process. ► Provided a simple method for the CMC determination of the nonionic surfactants.