▎ 摘　　要

The nitrogen dioxide (NO2) is a typical hazardous gas and there is an urgent demand to develop effective, sensitive and reproducible sensing materials for NO2 gas detecting. In this paper, [poly-(sodium4-styrenesulfonate) stabilized reduced graphene oxide/poly-(allylamine hydrochloride)](n) nanocomposite film are prepared via layer-by-layer assembly technique. The assembled process was monitored by UV-Vis spectroscopy in the range from 200 nm to 800 nm. Absorption peaks located at 233 nm and 271 nm,-and the optical energy band-gap was estimated as 4.57 eV. The film thickness was tested about 95 nm by AFM with 0.95 nm for each assembled circle, and it was featured 975 +/- 10 MPa, 28 +/- 2 GPa, 10(5)-10(6) Omega/sq. in modulus, hardness and sheet resistance respectively. The assembled films were extremely sensitive to NO2 with response (Delta R/R-a) above 66% with a linear relationship ranged from 2 to 8 ppm and independent on thickness. The impact of relative humidity was also considered for the film towards 5 ppm of NO2 gas at a room temperature, presenting a decreasing response from 1.8 to 0.89 when the relative humidity reaches 80%. The polyelectrolytes/reduced graphene oxide composite films are promising for application as gas sensing materials.