Characterization studies of aluminum oxide barrier coatings on polymeric substrates

Abstract

Articles you may be interested inFabrication of super-hydrophobic surfaces on aluminum alloy substrates by RF-sputtered polytetrafluoroethylene coatings AIP Advances 4, 031323 (2014); 10.1063/1.4868363 Low-temperature atomic layer deposition of Al2O3 on blown polyethylene films with plasma-treated surfaces J. Vac. Sci. Technol. A 31, 01A129 (2013); 10.1116/1.4768171 Nanotribological characterization of fluoropolymer thin films for biomedical micro/nanoelectromechanical system applications J. Vac. Sci. Technol. A 23, 804 (2005); 10.1116/1.1861939 Plasma polymerization and deposition of linear, cyclic and aromatic fluorocarbons on (100)-oriented single crystal silicon substratesAluminum coatings are widely used as oxygen and water barrier layers on food packaging materials to protect the product from contamination and to extend its shelf life. Thin layers of aluminum, of the order of a few tens of nanometers, are thermally evaporated onto polymeric web in high speed roll-to-roll vacuum metallizers. More recently, transparent barrier layers, based on silica or aluminum oxide, have been introduced to allow product visibility and provide retortable, sterilizable, or microwaveable packaging. In all cases, though, the barrier characteristics are critically dependent on both the structure and properties of the coating and the nature and surface properties of the polymer film substrate. This paper, therefore, reports on characterization trials of aluminum oxide (AlO x ) coatings deposited onto polyethylene terephthalate (PET) and biaxially oriented polypropylene (BOPP) film substrates. Coating structures and properties have been investigated by scanning electron microscopy and atomic force microscopy; the influence of process parameters on barrier levels has been determined; surface energies have been determined through contact angle measurements; and coating-to-substrate adhesion has been assessed using "pull-off" tests. The main findings of this study are that the barrier performance of AlO x coated PET and BOPP films strongly depends on the surface properties of the plain film and the aluminum oxide film growth. While AlO x coated PET films deliver consistent barrier results, BOPP reveals considerable variations, depending on the individual substrate.

Aluminum oxide barrier coatings on polymer films for food packaging applications

“…A 180 degree peel test was used in this investigation and the peel force values obtained are summarized in Table IV. In our previous work [31] we have shown that for AlOx coated BOPP very high peel force values where obtained, independent of the plasma treatment applied and also independent of the barrier performance, thus indicating that insufficient barrier properties are not related to poor adhesion. This was also found for the additional BOPP films investigated in this study.…”

“…These defects were originally assumed to be caused by micro-arcs appearing during corona treatment at the film production site [31]. However, with our more recent investigations we could exclude corona treatment as a potential source of the defects and now focus on the heat setting/thermo fixation applied to BOPP films after the orientation process in order to stabilize the film and prevent unintentional shrinkage.…”

Suspended Multiwall Carbon Nanotube‐Based Infrared Sensors via Roll‐to‐Roll Fabrication

“…Developments in the fi eld of R2R metal evaporation technique make the electrode deposition step R2R compatible as well. [ 35 ] The SEM analysis (Figure 2 b) revealed a uniform coating of the MWCNTs and the tubes were suspended across the top of the walls of the trenches with little evidence of any tubes entrained within the trenches. Multiwall tubes, being less fl exible than their single wall counterparts, increased the probability of suspension after the coating and drying steps.…”

Recent progress on non-thermal plasma technology for high barrier layer fabrication

“…Other technique for preparing aluminum oxide coating is ALD technique. Struller et al [210][211][212] prepared aluminum oxide coated BOPP and PET barrier films via reactive thermal evaporation using a highspeed R2R process. The metal aluminum wire was continuously evaporated via resistively heated evaporation [213], and the transparent aluminum oxide coating was formed when the O 2 was introduced into the aluminum vapor stream.…”