Electrical Conductivity in Nylon 66 Thin Films Prepared by Alternating Vapor Deposition Polymerization

Electrical conductivity of Nylon 66 thin films prepared by alternating vapor deposition polymerization (AVDP) and interfacial polymerization (IFP) were measured as a function of temperature and humidity. AVDP films had highly ordered structures with the molecular orientation normal to the substrate with the tilting angle of about 54°. Electrical properties of AVDP and IFP films were made along the film thickness direction and parallel to the film surface. The conductivity of AVDP film was anisotropic over temperature ranges of 50–200°C. The conductivity of AVDP film perpendicular to the film thickness was larger than that along the film thickness direction. Temperature dependence of the conductivity showed three temperature ranges: (1) below Tg, (2) Tg∼100°C, (3) above 100°C. The activation energy for the conductivity decreased with humidity in the range of Tg∼100°C but was almost constant above 100°C. Carriers were supposed to be impurities, such as hydrochloric acid in AVDP films and sodium chloride in IFP films. The ionic jump distance was estimated to be about 3.5 nm above Tg.