Barrier Properties Of Thin Films Research Articles

Preparation of High-barrier Polyethylene Terephthalate bottle by Microwave Plasma Enhanced Chemical Vapor Deposition

In this work, we reported the investigation of diamond-like carbon (DLC) coating on the inner surface of polyethylene terephthalate (PET) bottles by Microwave Plasma Enhanced Chemical Vapor Deposition to improve their barrier properties. We used 2.45 GHz microwave to generate plasma, acetylene (C2H2) and argon (Ar) were used as monomer gas and diluted gas. The effects of plasma process parameters on deposition uniformity and barrier properties of thin films were studied in detail. In addition, we designed a new antenna shape to improve the uniformity of film deposition. We analyzed the microstructure and morphology of the DLC coating by atom force microscope (AFM). Fourier transform infrared spectroscope (FTIR) and Raman spectroscope were employed to investigate chemical composition and bonding structure. The deposition rate was obtained by Step Profiler. For the barrier properties, we measured the oxygen transmission rate (OTR) of the PET bottle coated with DLC film. It is noted that the uniformity of film deposition is affected by the process parameters and antenna shape, after optimizing the process parameters and antenna shape, the barrier property of PET bottles is improved obviously.

A combinatorial approach to enhance barrier properties of thin films on polymers: Seeding and capping of PECVD thin films by PEALD

A combinatorial approach to deposit gas barrier layers (GBLs) on polyethylene terephthalate (PET) by means of plasma‐enhanced chemical vapor deposition (PECVD) and plasma‐enhanced atomic layer deposition (PEALD) is presented. Thin films of SiOx and SiOxCyHz obtained from PECVD were grown either subsequently on a PEALD seeding layer (SiO2) or were capped by ultrathin PEALD films of Al2O3 or SiO2. To study the impact of PEALD layers on the overall GBL performance, PECVD coatings with high macro defect densities and low barrier efficiency with regard to the oxygen transmission rate (OTR) were chosen. PEALD seeding layers demonstrated the ability to influence the subsequent PECVD growth in terms of the lower macro defect density (9 macro‐defects mm−2) and improved barrier performance (OTR = 0.8 cm3 m−2 day−1), while the PEALD capping‐route produced GBLs free of macro‐defects.

Barrier SiO2-like coatings for archaeological artefacts preservation

Thin film chemical vapour deposition technique has been used for more than 50 years. Introducing organo-silicones as precursors, e.g. hexamethyldisiloxane (HMDSO) or tetraethyl orthosilicate (TEOS), brought new possibilities to this method. Barrier properties of thin films have become an important issue, especially for army and emergency services as well as for food and drink manufacturers. Our work is focused on protective HMDSO thin films for encapsulating cleaned archaeological artefacts, preventing the corrosion from destroying these historical items.Thin films are deposited via plasma enhanced chemical vapour deposition (PECVD) technique using low pressure capacitively coupled pasma in flow regime. Oxygen transmission rate (OTR) measurement was chosen as the most important one for characterization of barrier properties of deposited thin films. Lowest OTR reached for 50 nm thin film thickness was 120 cm3 m-2 atm-1 day-1. Samples were also analyzed by Fourier Transform Infrared spectrometry (FTIR) to determine their composition. Optical emission spectra and thin film thickness were measured during the deposition process. We optimized the deposition parameters for barrier layers by implementation of pulsed mode of plasma and argon plasma pre-treatment into the process.