Disclosed is a container comprising a thermoplastic wall defining an inner cavity. The wall supports a SiOx composite barrier coating or layer arranged between the wall and the inner cavity, wherein x is 1.8-2.4. High-resolution X-ray photoelectron spectroscopy (XPS) shows that one interface exists between the composite barrier coating or layer and the wall or a substrate. In one aspect, the interface has O3-Si-C covalent bonds accounting for at least 1 mol% of the proportion of O3-Si-C covalent bonds and SiO4 bonds. In another respect, the interface has chemical shift of Si 2p with the bond energy (eV) lower than the bond energy of SiO4 bonds. The result is a closely attached composite barrier coating or layer having high degree of adhesion with the substrate. The invention also provides a method of applying the composite barrier coating or layer.
