Recent advances in gas barrier thin films via layer-by-layer assembly of polymers and platelets
Layer-by-layer (LbL) assembly has emerged as the leading non-vacuum technology for the fabrication of transparent, super gas barrier films. The super gas barrier performance of LbL deposited films has been demonstrated in numerous studies, with a variety of polyelectrolytes, to rival that of metal and metal oxide-based barrier films. This Feature Article is a mini-review of LbL-based multilayer thin films with a ‘nanobrick wall’ microstructure comprising polymeric mortar and nanoplatelet bricks that impart high gas barrier to otherwise permeable polymer substrates. These transparent, water-based thin films exhibit oxygen transmission rates below 5 × 10-3 cm3 m-2 day-1atm-1 and lower permeability than any other barrier material reported. In an effort to put this technology in the proper context, incumbent technologies such as metallized plastics, metal oxides, and flake-filled polymers are briefly reviewed.