Development of a Colorimetric Polydiacetylene Nanocomposite Fiber Sensor for Selective Detection of Organophosphate Pesticides.

Exposure to organophosphate (OP) pesticides is highly hazardous to human health and well-being. It has been linked to over 250,000 annual deaths connected to various chronic diseases, including cancer, Parkinson's, Alzheimer's, depression, etc. In the absence of any solid-state sensing system suitable for integration into a clothing system, an equipment-free on-site detection system for OP insecticides is essential for mitigating the severe health risks from OP exposure. This work demonstrates the synthesis, fabrication, and naked-eye and quantitative detection of OP insecticides with a polydiacetylene (PDA) ester containing the nanocomposite fiber sensor. Ester of PDA (PDA-HBA) was synthesized via facile green chemical synthesis and incorporated into a cellulosic nanocomposite fibrous assembly via the electrospinning technique. The solid-state soft sensor exhibited a blue-to-pink/red color transition within seconds of exposure to OP pesticide diisopropylfluorophosphate (DFP), and the color change was visible to the naked eye. Nanocomposite fibers containing 10% PCDA-HBA were found to be the optimum composition for DFP detection. The limit of DFP detection was 63 ppm. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, wide-angle X-ray diffraction (XRD), small-angle XRD, nuclear magnetic resonance, and Fourier-transform infrared spectroscopy were employed for characterization. This research is a landmark study in the development of a highly sensitive and selective OP sensing system.