Barrier properties of Al2O3 and alucone coatings and nanolaminates on flexible biopolymer films

Thin atomic layer deposited (ALD) Al2O3 coatings are efficient barriers against gases and vapors. Al2O3 coatings are, however, brittle and straining them generates defects that impair barrier properties. Flexibility of ALD-grown Al2O3 coatings on biopolymer substrates can be improved by separating thinner Al2O3 layers with inorganic–organic alucone layers. The number and size of defects were smaller for these nanolaminates compared to the thick Al2O3 films after straining, and hence straining deteriorated the oxygen barrier properties less when applied to the laminates than when applied to the Al2O3 coatings.

► Al2O3, alucone and five-layer nanolaminates were deposited on biopolymers.
► Straining of Al2O3 coating generated defects that impaired barrier properties.
► Nanolaminates with thin Al2O3 layers and alucone were less sensitive to straining.