Permeation Of Sodium Chloride Through Polyaniline-epoxy Composite Membrane

Polyaniline has many advantages including cost effective, facile synthesis, redox reversibility, and unique doping mechanism, high chemical and environmental stability. Membranes containing polyaniline used for water and gas separation, proton-exchange membrane fuel cells, metal anti-corrosion and some other applications have been reported in recent years. Here, ployaniline-epoxy composite membranes were prepared, during which polyaniline with different morphologies were used as filling materials, and epoxy resin as matrix. Scanning electronic microscopy (SEM) was used to characterize the surface and cross-section of the membranes, UV-Vis Spectrophotometer was also used to characterize membranes. No polyaniline was found at the membranes surface. The cross-section SEM image indicates that dispersion of polyaniline is very well and there a few aggregations. UV-Vis Spectroscopic measurements indicate that PANI-epoxy composite membranes containing PANI nanoparticles and PANI nanosheets have different ultraviolet spectra from composite membranes containg PANI nanowires.Chloride ion has great effect on metallic electrochemical corrosion. Here, permeation behavior of sodium chloride in PANI-epoxy composite membranes was studied. The permeation of sodium chloride through composite membranes was recorded according to the change of conductivity of solutions. Diffusion coefficients of sodium chloride in PANI-epoxy composite membranes were calculated. The obtained diffusion coefficients calculated with data at t=20 hours demonstrate that the content and morphologies of PANI have significant effect on chloride ion diffusion, and were lower about one order of magnitude in PANI-epoxy composite membranes than that of epoxy resign membrane.This experimental results offer an optimized method to prepare polyaniline-epoxy composite membrane, and offer a novel insight in researching PANI anti-corrosion coatings.