A first time report on the reactive sensing capabilities of polyaniline (PANI) is presented. Microfibrous silk fibroin mats were coated with polyaniline (PANI) through in situ chemical polymerization. The mat gives closed coulovoltammetric responses in acidic aqueous solution, indicating that only reversible PANI oxidation/reduction reactions occur. Inside the reversible range the chronopotentiometric responses change with (sense) the reaction variables: electrolyte concentration, pH, temperature and driving current. The potential of the materials, or the consumed electrical energy, for a constant reaction time follow the linear or semilogarithmic relationships with each of the experimental variables predicted by the electrochemical kinetics. The reversible charge from the closed coulovoltammetric loop also senses the chemical or thermal energetic conditions of the reaction acting on the conformational movements getting deeper oxidation states for rising energetic working conditions.