title: Thick growing multilayer nanobrick wall thin films: super gas barrier with very few layers.
abstract: Recent work with multilayer nanocoatings composed of polyelectrolytes and clay has demonstrated the ability to prepare super gas barrier layers from water that rival inorganic CVD-based films (e.g., SiOx). In an effort to reduce the number of layers required to achieve a very low oxygen transmission rate (OTR (<0.01 cc/m(2)·day·atm)) in these nanocoatings, buffered cationic chitosan (CH) and vermiculite clay (VMT) were deposited using layer-by-layer (LbL) assembly. Buffering the chitosan solution and its rinse with 50 mM Trizma base increased the thickness of these films by an order of magnitude. The OTR of a 1.6-μm-thick, six-bilayer film was 0.009 cc/m(2)·day·atm, making this the best gas barrier reported for such a small number of layers. This simple modification to the LbL process could likely be applied more universally to produce films with the desired properties much more quickly.
authors.affiliation: Department of Chemical Engineering and ‡Department of Mechanical Engineering, Texas A&M University , College Station, Texas 77843, United States.
authors.forename: Tyler
authors.initials: T
authors.lastname: Guin
authors.forename: Michelle
authors.initials: M
authors.lastname: Krecker
authors.forename: David Austin
authors.initials: DA
authors.lastname: Hagen
authors.forename: Jaime C
authors.initials: JC
authors.lastname: Grunlan