Super Stretchy Polymer Multilayer Thin Film with High Gas Barrier.

Unlike ionically bonded or clay-loaded gas barrier thin films, which easily crack when moderately stretched, hydrogen-bonded poly(acrylic acid) (PAA)/poly(ethylene oxide) (PEO) multilayer thin films remain crack-free. Even after 100% strain, these nanocoatings provide more than a 5× reduction in oxygen transmission rate. This study shows that the lowest modulus PAA/PEO thin film is obtained at pH 3, but maintains a high barrier. A total of 20 PAA/PEO bilayers (367 nm thick) on 1.58 mm rubber reduced the oxygen transmission rate by 1 order of magnitude. Stretching from 25-100% caused plastic deformation and reduced gas barrier, but the oxygen transmission rate remained at least 5× lower than the uncoated rubber. The ability to prevent cracking and preserve the gas barrier up to 100% strain provides a tremendous opportunity for reducing weight and improving the barrier of elastomeric materials.