Polyelectrolyte-carbon nanotube composite film humidity sensor

The invention relates to a humidity sensor based on nano material film. The humidity sensor comprises a flexible polymer substrate, a comb-like interdigital electrode, a polyelectrolyte-carbon nanotube composite film, a humidity sensitive film resistor pickup circuit board, a circuit signal line and an air hole casing. An electrostatic self-assembly method is employed to construct the polyelectrolyte-carbon nanotube composite film as a humidity sensing element on the surfaces of the flexible polymer substrate and the comb-like interdigital electrode; the film resistor pickup circuit and the humidity sensitive element are electrically connected together through a contact pin mode; the humidity sensitive element and the signal pickup circuit board are fixed through screws and nuts, and arranged in air hole plastic casing; and the circuit signal line is lead out through a casing lead hole to realize functions of data acquisition, storage, display and alarm. The sensor employs humidity sensitive and electrical characteristics of the polyelectrolyte-carbon nanotube film, and has the advantages of simple and compact structure, low cost, high linearity, good repeatability, and high speed of humidity sensitive response and recovery, etc.