Carbon nanotube–cellulose composite aerogels for vapour sensing

Electrically conductive aerogels composed of carbon nanotubes (CNTs) and cellulose were used as vapour sensors for the first time. The vapour sensing behaviours of these aerogels were investigated by monitoring the electrical resistance change upon exposure to a series of volatile organic compound (VOC) vapours such as methanol, ethanol, toluene, and others. The effects of vapour types, CNT contents and vapour concentrations on relative electrical resistance change were analyzed. The results revealed that CNT–cellulose composite aerogels exhibit rapid response, high sensitivity and good reproducibility to both polar and nonpolar vapours. The dominant mechanism for these aerogels as vapour sensors is the resistance change from chemical molecule absorption by both CNT networks and cellulose matrix. This is mainly due to the unique three-dimensional (3D) porous structure of materials, which also broadens the scope of analytes to be detected. This work provides a novel concept for developing a new class of chemical sensors by combining the nature of CNTs with the 3D porous matrix.