26 - High gas barrier polymer-clay nano brick wall thin films as foil replacement technology for food packaging
Prof. Jaime C. Grunlan Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States; Department of Chemical Engineering, Texas A&M University, College Station, TX, United States; Materials Science and Engineering Program, Texas A&M University, College Station, TX, United States
Thin films of sodium montmorillonite clay and weak polyelectrolytes were prepared, using the layer-by-layer (LbL) assembly process, by alternately dipping a PET substrate into four different dilute aqueous mixtures (polyethylenimine, poly(acrylic acid), polyethylenimine, and montmorrilonite clay). After depositing four of these quadlayers (QL), the resulting transparent film exhibits an oxygen transmission rate below the detection limit of commercial instrumentation (< 0.005 cm3/m2·day). This level of oxygen barrier, which is unprecedented for a clay-filled polymer composite, is believed to be due to a nano-brick wall microstructure comprised of completely exfoliated clay bricks in polymeric mortar and clay layer spacing on the order of tens of nanometers. This 4 QL film has a thickness of only 51 nm and an optical transparency of 95%. When multiplying OTR by film thickness to achieve oxygen permeability, we find that these films are a better barrier than SiOx and also rival metalized plastic film. These thin film composites could be a microwaveable foil replacement for a variety of food packaging applications. This same LbL process can be used to impart UV-resistance or antimicrobial behavior by placing the appropriate ingredients in water along with the barrier film ingredients.
Sunday, March 27, 2011 02:00 PM
Nanotechnology for Food and Agriculture (01:30 PM - 04:25 PM)
Location: Anaheim Marriott
Room: Orange County IV