Preparation of conducting polyaniline/protoporphyrin composites and their application for sensing VOCs.

Polyaniline/protoporphyrin nanocomposites were prepared via a simple chemical method in the acidic suspension of protoporphyrin. The scanning electron microscope images revealed that the polyaniline/protoporphyrin composites exhibited an interesting nanosheet structure decorated with nanoparticles, which is rather different with the usual nanofiber morphology of polyaniline. The formation of the nanosheet structure is because protoporphyrin molecules may exist as a bilayer form at low pH, which is similar with the phospholipid bilayer in membranes of cells. To demonstrate the application potential of the composites, the sensing performance of the composites was tested when exposed to four volatile organic compounds, including trimethylamine, triethylamine, ethanol, and ethyl acetate. The composites exhibited highest response value (S) of 39.482 toward trimethylamine, and fast response time of 2-4 s toward trimethylamine and triethylamine. The outstanding sensing performance showed that the prepared composites had great application potential in electronic noses system in further work.