Electrostatically Functionalized Multiwalled Carbon Nanotube/PMMA Composite Thin Films for Organic Vapor Detection

Thin-film composites of polymethylmethacrylate (PMMA) with multiwalled carbon nanotubes (MWCNTs) and corona based electrostatically functionalized multiwalled carbon nanotubes (f-MWCNTs) were drop cast for organic vapor detection. The electrical responses of the composite films were investigated for different organic vapors such as dichloroethane, toluene, chloroform, methanol and benzene at concentrations as low as 100 ppm (parts per million) with average percentage sensitivity as high as 49% for f-MWCNT/PMMA composites. The selectivity of the composite films for different organic vapors was defined based on the response time and percentage sensitivity. Detection with these composite films did not require high temperatures. It is proposed that the sensing mechanism of composite films is based on matrix swelling of the polymer and polar interaction of various vapors with f-MWCNTs.