(80b) Control of Oxygen Permeability of Polyethylene Terephthalate Films by Supramolecular Assembly of Charged Carbon Nanostructures

Supramolecular self-organization is a branch of chemistry that studies the interplay of noncovalent interactions and their effects on self-assembly of an ensemble of discrete atoms, ions and molecules. In recent years, there has been increased focus on using supramolecular techniques for stabilization and functionalization of a number of nanomaterials. These techniques provide for robust bottom-up strategies to assemble a broad spectrum of nanostructures on the host substrates. Multifunctional tailor-made substrates fabricated using this route, have found applications in catalysis, sensing, and drug delivery.  Using a similar approach, we show enhanced oxygen barrier properties of polyethylene terephthalate (PET) films when coated with polymer modified carbon nanostructures. PET has gained significant prominence in recent years due to cheaper costs and high mechanical strength. However, the diffusion of small gas molecules such as oxygen remains a matter of great concern. The simple yet robust deposition of carbon nanostructures on PET substrates increases the tortuous path the oxygen molecule has to travel making it harder to diffuse through the PET film. Our preliminary results indicate a reduction of almost 20-25% in the oxygen transmission rate (OTR) after the deposition of a carbon composite film which is at least one hundred times thinner than the original PET film. Charge overcompensation, the driving force for constructing supramolecular self-assembled structures has a significant effect on packing density and surface coverage of carbon nanostructures. The effect of these parameters on barrier properties would be shown. Barrier properties of films were tested in accordance with ASTM D-3985 using  a MOCON 2/21 ML instrument.