Water-Based Elastomeric Gas Barrier Nanocoatings

While ionically bonded and/or clay loaded gas barrier thin films tend to crack easily when moderately stretched, hydrogen-bonded polyacrylic acid (PAA)/polyethylene oxide (PEO) multilayer thin films remain crack-free. Even after 100% strain, these nanocoatings provide more than a 5x reduction in oxygen transmission rate. This study shows that the lowest modulus PAA/PEO thin film, assembled at pH 3, is stretchable and maintains high gas barrier. 20 PAA/PEO bilayers (367 nm thick) on 1.58 mm rubber reduce the oxygen transmission rate by one order of magnitude. The film exhibits plastic deformation and reduced oxygen barrier when stretched from 25-100%, but the oxygen transmission rate remains at least five times lower than the uncoated rubber. The ability to prevent cracking and preserve gas barrier up to 100% strain provides a tremendous opportunity for reducing weight and improving barrier of elastomeric materials.