Olive-Structured Nanocomposite Based on Multiwalled Carbon Nanotubes Decorated with an Electroactive Copolymer for Environmental Nitrite Detection

A high-performance nitrite sensor based on a unique olive-structured electroactive copolymer/multiwalled carbon nanotube (MVVCNT) nanocomposite is demonstrated for nitrite monitoring in the environmental system. An electroactive, amphiphilic copolymer was designed to noncovalently functionalize MWCNTs. The copolymer and MWCNTs were co-assembled to form a water-dispersed copolymer/MWCNT nanocomposite with an olivelike appearance. A simple drop-casting method was utilized to fabricate the nitrite sensor. After electrochemical postpolymerization of the copolymer, an interpenetrating electroactive network was established: a macro entanglement of MWCNTs and a molecular-level conjugated structure of polycarbazole. Such an electroactive internetwork with different scales is expected to enhance the electrochemical signal from the molecular level to the microscale. The electrochemical properties of the sensor indicated that electropolymerized nanocomposites exhibited an improved electrocatalytic activity for nitrite detection with a linear response range of 0.01-25 mu M. The excellent sensing performance demonstrated that it was an effective candidate for practical monitoring of nitrite in various real samples.