Gas-permeation properties of sandwich-like polyaniline/poly(ethylene vinyl acetate) nanocomposite membranes

The effect of the use of sandwich-like polyaniline (S-PANI) nanocomposites in CO2 gas-separation membranes was investigated. S-PANI nanocomposites were synthesized via a two-step dispersion polymerization method. The first step was to manufacture a leaf-like polyaniline (L-PANI), which was used in the next step as a 2D template to synthesize the S-PANI. SEM images show that a three-layer sandwich-like structure of the S-PANI was successfully synthesized. ATR-FTIR measurements revealed that the S-PANI has a structure with conductive PANI layers on both sides of the L-PANI template. Furthermore, the N2 and CO2 adsorption isotherms illustrate that S-PANI is much more attractive to CO2 than N2 because of the amine functional groups of S-PANI. Hence, the CO2/N2 separation performance of the ethylene vinyl acetate (EVA) copolymer membrane was successfully enhanced by the addition of the S-PANI nanocomposite. The CO2/N2 selectivity of the membrane increased from 6.8 to 32.5 with a 3-wt% loading of S-PANI within the EVA matrix. The results show that 2D S-PANI could feasibly be used for CO2 gas membrane separation.