Humidity sensors based on MCM-41/polypyrrole hybrid film via in-situ polymerization

Inorganic zeolites, such as MCM (Mesoporous Crystalline Material), are widely used as skeleton to load humidity sensitive materials for constructing high-performance humidity sensor. In this work, an in-situ preparation method was developed to prepare MCM-41/polypyrrole (PPy) humidity sensors, by inducing the polymerization of pyrrole vapor inside MCM-41 film that was coated on the ceramics substrate with carbon interdigital electrodes. MCM-41/PPy sensors with different polymerization times were fabricated, and their capacitance humidity sensing properties demonstrate much better performance than individual MCM-41 sensor or PPy sensor, with high sensitivity and a wide humidity sensing range. The sensing properties of MCM-41/PPy sensors were further optimized by controlling the polymerization time. In addition, a humidity sensing mechanism explanation is discussed at the end of this paper.