Recent advances in the fabrication of nanostructured barrier films.

The fabrication of barrier packaging films has gained significant momentum in recent years. Besides its dominance in the food industry as a means to extend the shelf-life of perishable goods and facilitate ease of handling and transportation, the use of barrier films to protect semiconductor and flexible electronics from dust, oxidation and moisture has generated considerable interest in recent years. This has ushered in new challenges for researchers to design and develop novel thin film barrier coatings that could be made available at a fraction of the cost. The emergence of the multidisciplinary field of nanotechnology has provided innovative solutions in the fields of medicine, catalysis and energy. In this review, we will be examining the integration of nanoscience driven techniques with barrier film technology with applications in both food and electronics industry. Details regarding permeation theory, some key parameters governing gas/moisture barrier properties and the market potential of nanostructured barrier films have been included. This review also explores several past and current examples of successful inclusion of functional nanostructured or colloidal materials to fabricate tailor-made barrier films. Finally a brief discussion regarding novel emerging trends for this industry has been included.

Conductive oxygen barrier films using supramolecular assembly of graphene embedded polyelectrolyte multilayers.

The supramolecular self-assembly of polyelectrolyte multilayers (PEMs) provides robust bottom-up strategies to assemble a broad spectrum of nanostructures on the host substrates. In this study, we discuss the formation of graphene nanoplatelet (GNP) embedded polyelectrolyte films to enhance the oxygen barrier properties of poly(ethylene terephthalate) (PET) films. Despite cheaper costs and high mechanical strength, the diffusion of small gas molecules such as oxygen through PET films remains a matter of great concern. The simple yet robust supramolecular deposition of GNP/polyelectrolyte on PET substrates significantly increases the tortuous path the oxygen molecule has to travel, making it harder to diffuse through the PET film. With permeability coefficients in the range of 10-18 cc cm/cm(2) s Pa, the coatings developed in this study show three orders of magnitude reduction as compared to the permeability coefficient of the bare PET film, significantly lower than that of ethylene vinyl alcohol (EVOH) and comparable to silicon oxide thin films used in commercial gas barrier foils. The use of GNPs in the multilayered films also helped reduce the electrical sheet resistance to about 1MΩ which is five orders of magnitude lower than the original PET substrate opening up promising opportunities for future use in semiconductor and electronics industry. Making suitable modifications in the deposition process, three configurations of GNP embedded PEM multilayers namely hydrogen bonded, electrostatic, and composite films were developed and their effect on oxygen barrier property and sheet resistance was monitored. Oxygen permeability of films was tested in accordance with ASTM D-3985 using a MOCON 2/21 ML instrument, whereas electrical sheet resistance was quantified using a Gamry Femtostat Electrochemical Impedance station.

Identification of a novel benzimidazole that inhibits bacterial biofilm formation in a broad-spectrum manner.

Bacterial biofilm formation causes significant industrial economic loss and high morbidity and mortality in medical settings. Biofilms are defined as multicellular communities of bacteria encased in a matrix of protective extracellular polymers. Because biofilms have a high tolerance for treatment with antimicrobials, protect bacteria from immune defense, and resist clearance with standard sanitation protocols, it is critical to develop new approaches to prevent biofilm formation. Here, a novel benzimidazole molecule, named antibiofilm compound 1 (ABC-1), identified in a small-molecule screen, was found to prevent bacterial biofilm formation in multiple Gram-negative and Gram-positive bacterial pathogens, including Pseudomonas aeruginosa and Staphylococcus aureus, on a variety of different surface types. Importantly, ABC-1 itself does not inhibit the growth of bacteria, and it is effective at nanomolar concentrations. Also, coating a polystyrene surface with ABC-1 reduces biofilm formation. These data suggest ABC-1 is a new chemical scaffold for the development of antibiofilm compounds.