Abstract: An arachidic acid(AA)/poly(3,4-ethylenedioxythiophene)(PEDOT) multilayer LB film was prepared via a modified LB film method. The theories were utilized to explain the effects of HCl gas on the gas sensitivity of PEDOT LB film. The gas sensitivity mechanism of PEDOT multilayer film can be explained by the charge transfer between π system of PEDOT and oxidization HCl system. The gas sensitivity of PEDOT LB film deposited interdigital electrode to HCl was tested. The results show that film thickness, treating temperature, deposition speed have different influences on the film gas sensitivity. The AA/PEDOT film deposited device exhibited nonlinear behavior to HCl gas at a lower volume fraction(20—60 μL/L) and linear response behavior at a higher gas concentration was observed. The time of the compound LB film of the AA/PEDOT responding to the 30 μL/L HCl gas is about 20 s, it is far quicker than that of the PEDOT-PRESS film(is about 80 s). When the film press attains the 45 mN/m, the sensitivity of the AA/PEDOT film descends on the contrary.

Key words: Poly(3,4-ethylenedioxythiphene)(PEDOT), LB film method, Gas sensitivity