Preparation of polyaniline–TiO2 composite film with in situ polymerization approach and its gas-sensitivity at room temperature

Polyaniline composite was prepared with chemical oxide method by adding a small amount of TiO2 sol–gel. This film on the interdigital electrodes of carbon paste was formed via spin-coating or immersion method with in situ polymerization approach. And its gas-sensitivity to trimethylamine was examined at room temperature. The results indicated that, the heat stability of polyaniline film was improved obviously by adding 10 wt% TiO2. Meanwhile, this film still showed excellent gas-sensitivity to trimethylamine of 5.14 × 10−7 mol mL−1, its value of gas-sensitivity was up to three to five orders of magnitude within 3 min, and had good selectivity to analogy gases. The film also exhibited good reproducibility and stability, and easily recovered with high-purity N2 at room temperature.