Sensors for organic vapor detection based on composites of carbon nonotubes functionalized with polymers

Composites of multi-walled carbon nanotubes (MWCNTs) grafted with polystyrene, poly(4-vinylpyridine), poly(styrene-b-4-vinylpyridine) and poly(styrene-co-4-vinylpyridine) were prepared by a nitroxide mediated “living” free radical polymerization. The electrical responses of the composites towards organic vapors of methanol, chloroform and tetrahydrofuran were investigated at room temperature. It was found that the gas sensitive properties of the composites towards the organic vapors depended on both the compositions of the polymers and the nature of the vapors. Based on the observations of the morphology of the composite films by scanning electron microscopy and transmission electron microscopy, the sensing mechanism was explored and the different sensing behaviors were proposed to relate to the varied morphologies of the composites with different compositions. The varying sensing characteristics of the composites with different polymer compositions may be a basis for constructing sensor arrays with good selectivity towards organic vapors at room temperature.