Development of a carbon aerogel composite film for gas sensors

Abstract

New organic aerogel was synthesized via thermal curing reaction of a novel type of phenolic resin called polybenzoxazine. The subsequent carbon aerogel (CA) was generated by pyrolysis of the organic aerogel at high temperature under inert atmostphere. Further activation of CA resulted in an activated CA. The CA and activated CA have surface area of 466 m²/g and 917 m²/g with uniform mesopore radius of 2.4 nm and 2.5 nm, respectively. New gas sensing conductive polymer composites, fabricated from poly (vinyl alcohol) and polybutadiene filled with polybenzoxazine-based CA, have been investigated for organic vapor detection. The experimental results showed that high polar poly (vinyl alcohol) gave a higher response to high polar solvent, ie. water, and moderate polar solvent, ie. Acetone, but a lower response to low polar solvent, ie. n-hexane and toluene. On the other hand, the response of non-polar polybutadiene was excellent to n-hexane and toluene but not to water and acetone. Moreover, CA polymer composites showed better gas response compared to graphite polymer composites since CA is a nano-porous material, which has a high adsorption capacity . Moreover, CA polymer composites showed good reproducibility as the electrical resistance came back to the original value when they were exposed to N₂ gas. This study shows that CA composite films have potential to be used as gas sensors.