Molecularly ordered structure and permeability properties of amphiphilic polyacetylene-multilayer nanocomposites

Nanocomposite films consisting of amphiphilic ionic polyacetylenes (P2EPy-R) and layered aluminosilicates (saponite) have been prepared through electrostatic layer-by-layer assembly. The water vapor barrier properties of the nanocomposite films coated on Nafion™ film have been studied. The Nafion film coated with poly(N-octadecyl-2-ethynylpyridinium bromide) (P2EPy-C18) and aluminosilicates showed 22 times higher diffusion resistance to water vapor and 95% reduction in water vapor permeability when compared with the pristine Nafion control film. The X-ray diffraction data, UV–vis absorption spectroscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM) suggest a strong tendency of micellization of P2EPy-C18 polymer and ordered structure on the surface of aluminosilicate nanosheets compared to short alkyl side chains, C12, C6, and C0. The micellized and ordered structure of P2EPy-C18 between aluminosilicate could explain the improved hydrophobic barrier properties of P2EPy-C18/aluminosilicate nanocomposites.