Super gas barrier thin films, fabricated with layer-by-layer assembly of polyethylenimine and graphene oxide, exhibit significantly reduced oxygen and carbon dioxide transmission rates. This thin film's nanobrick wall structure also provides high gas selectivity for hydrogen.

Thin films of polyethylenimine (PEI) and poly(acrylic acid) (PAA), deposited using layer-by-layer assembly, were studied to understand the influence of various crosslinking methods on their oxygen and water vapor barrier. Glutaraldehyde (GA), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide methiodide (EDC) and thermal crosslinking were evaluated with respect to film thickness and barrier properties. The thickness of an 8 bilayer PEI/PAA assembly decreased from 640 to 551 nm after crosslinking with a 0.1 M aqueous GA solution and obtained an oxygen permeability one order of magnitude better than an SiO x thin film (,5.9 6 10 221 cm 3 cm cm 22 s 21 Pa 21 ) This same crosslinking treatment reduced the oxygen transmission rate (OTR), measured at 23 uC and 100% RH, from 0.61 to 0.09 (cm 3 m 22 day 21 ). Increasing the number of bilayers and heating time with thermal crosslinking also reduces the water vapor transmission rate (WVTR). These nanocoatings are a promising alternative to currently used barrier layers for flexible electronics and food packaging.

Single bilayer polymer/clay nanobrick wall self-assembled thin films, deposited as a continuous coating on open-celled polyurethane foam, cut peak heat release rate in half with only 3.2 wt% addition.