The preparation and vapor sensitivity of a novel PAAm-g-CB/Al2O3 gel hybrid material with smart responsiveness prepared by the sol-gel process of isopropoxide (AIP) in the presence of PAAm-g-CB were investigated. The polyacrylamide grafted carbon black was synthesized by a redox system of ammonium cerium (Ⅳ) nitrate in the presence of carbon black containing alcoholic hydroxyl groups. The introduction of alcoholic hydroxyl groups onto carbon black surface was achieved by the reaction of carbon black with alcoholic hydroxyl radicals formed by the reaction of alcohols with benzoyl peroxide. The results showed that the electric resistance of the hybrid material rapidly decreased in good solvent vapors for the hybrid material, presenting a negative vapor coefficient phenomenon (NVC). However, the same effect was not observed in poor solvent vapors. The responsiveness is related to the graft percentage and the hydrogen bond between carbonyl groups of the grafted polymer and the residual hydroxyl groups in the alumina gel.

polyacrylamide grafted carbon black; isopropoxide; hybrid material; vapor and humidity sensitivity; sol-gel process