The topic of this newly published journal paper, lead author Morgan A. Priolo, discusses the latest progress in gas barrier technology from the PNC Lab. A 51 nm thick, fully transparent film provides super gas barrier properties that are potentially applicable in food, electronic and pharmaceutical packaging.
These transparent, flexible thin films are fabricated with layer-by-layer assembly (LbL), which is a dipping cycle consisting of a substrate being dipped into alternating cationic and anionic deposition solutions, with spray-rinsing and drying between each deposition. This paper highlights a new quadlayer (QL) system composed of three polymers and a capping clay layer – catioinic polyethylenimine (PEI) and anionic montmorillonite clay (MMT) and poly(acrylic acid) (PAA) – in the dipping sequence PEI/PAA/PEI/MMT.
LbL assembly of polymer and clay creates a nano brick wall structure that forms a highly tortuous path, resulting in a transparent, super gas barrier exhibiting an oxygen permeability orders of magnitude lower than EVOH and SiOx.
Lowest oxygen permeability ever reported for any thin film material! (≤ 5 x 10-22 cm3(STP)·cm/cm2·s·Pa).