A flexible polypyrrole/silk-fiber ammonia sensor assisted by silica nanosphere template

Flexible polypyrrole (PPy)@silk-fiber and [email protected] sensors were fabricated using the silica nanosphere (SiO2 NS) template via a facile in situ chemical oxidation polymerization method. Exposed to 100 ppm NH3 gas at room temperature in 68 ± 5 % relative humidity (RH), the response of the PPy/[email protected] sensor (73.25 %) was five-fold higher than that of the PPy/[email protected] sensor (14.51 %). Meanwhile, the recovery time (69 s) of the PPy/[email protected] sensor was reduced to two-thirds of that (98 s) of the PPy/[email protected] sensor for 100 ppm NH3. Additionally, the PPy/[email protected] sensor exhibited excellent reproducibility, flexibility, selectivity, and long-term stability to NH3 at room temperature. The improved gas-sensing properties can be attributed to the high surface area of the flexible PPy/[email protected] with relative rough hill-like shapes. This investigation indicated that the PPy/[email protected] is promising sensing material for developing flexible and wearable NH3 sensors.