Moisture-induced buckle delamination of thin inorganic layers on a polymer substrate was studied. Moisture has been found to have a significant effect on the failure mode. Experimentally, an increase in the buckle width, height and the total buckle delamination length with time and humidity was observed. Moreover, a transition from straight to telephone-cord buckle pattern was taken place in a humid environment. Applying only a uniaxial compressive strain on the thin layers did not result in the transition from straight to telephone-cord. For a compliant substrate the transition from straight to telephone-cord buckle occurred at significantly higher ratio of residual strain over critical buckling strain than for a rigid substrate. A simple model for buckling was applied. Using the energy release rate, the interfacial toughness was investigated as a function of relative humidity. (c) 2007 Elsevier B.V. All rights reserved.