Combined High Stretchability and Barrier in Hydrogen-Bonded Nanobrick Wall Thin Films

Hydrogen-bonded multilayer thin films are very stretchable, but their gas barrier properties are modest compared to more traditional ionically-bonded assemblies. In an effort to improve the gas barrier of poly(ethylene oxide) (PEO) – poly(acrylic acid) (PAA) multilayer films, without sacrificing stretchability, montmorillonite (MMT) clay platelets were combined with PAA and alternately deposited with PEO. A ten bilayer PEO/PAA+MMT film (432 nm thick), deposited on a 1 mm PU substrate, resulted in a 54X reduction in oxygen transmission rate after exposure to a 20% strain. This system is the best combination of stretchability and gas barrier ever reported. This same concept can be converted into a single polyelectrolyte complex solution to achieve relatively good barrier in a single step. If there’s time, I’ll briefly describe how these types of polyelectrolyte thin films can be used to prepare insulation layers with high dielectric breakdown strength.