Carbon nanotube/PMMA composite thin films for gas-sensing applications

The design and development of composite thin films of polymethylmethacrylate (PMMA) with multiwalled carbon nanotubes (CNTs) and surface-modified multiwalled carbon nanotubes (f-CNTs) for gas-sensing applications are presented in this paper. The responses of these composites for different organic vapors were evaluated by monitoring the change in the resistance of thin films of composite when exposed to gases like dichloromethane, chloroform, acetone, methanol, ethyl acetate, toluene and hexane. It was observed that the f-CNT/PMMA composite showed a higher response. There was an increase in resistance of the order of 10(2)-10(3), due to surface modification, when exposed to dichloromethane, chloroform and acetone. The sensing mechanism is explained on the basis of volume expansion and polar interaction of various vapors on the CNT surface.