Colorimetric detection of anionic surfactant using polydiacetylene/zinc (II)/zinc oxide nanocomposites with unique yellow-to-red color transition

Polydiacetylenes (PDAs) have extensively received attention as colorimetric sensors because of their stimulus-responsive properties. This contribution presents a simple technique to modify polydiacetylene/zinc (II) ion/zinc oxide (PDA/Zn²⁺/ZnO) nanocomposites for colorimetric detection of an anionic surfactant. Incorporation of cetyltrimethylammonium bromide (CTAB) into the nanocomposite structure is achieved through a simple mixing process in an aqueous medium. Interestingly, the resultant PDA/Zn²⁺/ZnO-CTAB sensors exhibit a unique yellow-to-red color change in response to the anionic surfactant, sodium dodecyl sulfate (SDS). Furthermore, the colorimetric detection of SDS at different concentrations can be achieved by varying the added CTAB concentrations. The detectable concentration range of SDS in this study extends from 0.3 to 7 mM. Our study offers a simple and low-cost method to fabricate colorimetric sensors for anionic surfactant detection using PDA materials.