A superhydrophobic polyaniline (PANI)‐coated fabric was prepared by in‐situ doping polymerization in the presence of perfluorosebacic acid (PFSEA) as the dopant. It is found that the PANI‐coated fabric undergoes a change in wettability from superhydrophobic (doped state) to superhydrophilic (de‐doped state) when it is exposed to ammonia gas. In particular, a reversible wettability of the PANI‐fabric is observed when it is doped with PFSEA and de‐doped with ammonium gas. It is proposed that the coordination effect of the pore structure of the polyester fabric, low surface energy of the PFSEA dopant, and reversible doping/dedoping characteristics of PANI results in the reversible wettability of the PANI‐coated fabric from superhydrophobicity to superhydrophilicity. Moreover, the tactic used here may provide a new method to monitor the toxic gas.
