Influence of argon plasma on the deposition of Al2O3 film onto the PET surfaces by atomic layer deposition

In this paper, polyethyleneterephthalate (PET) films with and without plasma pretreatment were modified by atomic layer deposition (ALD) and plasma-assisted atomic layer deposition (PA-ALD). It demonstrates that the Al2O3 films are successfully deposited onto the surface of PET films. The cracks formed on the deposited Al2O3 films in the ALD, plasma pretreated ALD, and PA-ALD were attributed to the energetic ion bombardment in plasmas. The surface wettability in terms of water contact angle shows that the deposited Al2O3 layer can enhance the wetting property of modified PET surface. Further characterizations of the Al2O3 films suggest that the elevated density of hydroxyl -OH group improve the initial growth of ALD deposition. Chemical composition of the Al2O3-coated PET film was characterized by X-ray photoelectron spectroscopy, which shows that the content of C 1s reduces with the growing of O 1s in the Al2O3-coated PET films, and the introduction of plasma in the ALD process helps the normal growth of Al2O3 on PET in PA-ALD.