Adhesion of Thin CVD Films on Pulsed Plasma Pre-Treated Polypropylene

Abstract

The adhesion of thin CVD films on polyolefins is often critical due to the low surface free energy of the polymers. In this study, injection moulded PP samples are produced and investigated. The samples are treated in very well-characterized pulsed plasmas before a HMDSO-based coating is applied. The resulting bond strength is analyzed using pull-off tests. The fractured interfaces are characterized with XPS. Oxygen and argon plasma pre-treatments of the PP samples result in a bond strength improvement by a factor of about 2. Comparing oxygen and argon pre-treatments at equal ion fluences to the surface, it can be shown that the bond strength between CVD-coating and polymer is similar.

PEALD of SiO2 and Al2O3 Thin Films on Polypropylene: Investigations of the Film Growth at the Interface, Stress, and Gas Barrier Properties of Dyads

“…As it is known that a certain degree of surface conditioning, in terms of plasma cleaning/etching or by applying a substrate bias, can have a strong influence on the adhesion between the oxide thin film and the polymer substrate, the adhesion between the SiO 2 and Al 2 O 3 and the PP foil with and without pretreatment was investigated. There exist reports in the literature on the investigation of the adhesive strength of metallized and metal oxide thin films, such as Al or TiO 2 , on PP. , In addition, oxygen plasma pretreatment has been recently used to enhance the barrier properties of alumina films on PET against water vapor .…”

“…This finding is in agreement with the literature, where a pretreatment caused an even stronger increase in adhesion forces. 45 For the Al 2 O 3 thin films grown from DMAD, the pretreatment was found to have only little influence on the adhesive strength of the coatings. Although the film grown without pretreatment exhibits a strength of 0.84 MPa, the pretreated samples exhibit a value of 0.92 MPa.…”

Decoupling of ion‐ and photon‐activation mechanisms in polymer surfaces exposed to low‐temperature plasmas

“…Plasma and ion beam pre‐treatments are very common techniques to optimize the surface properties of polymers, to reach for example, a low roughness or to adjust a high or low surface energy. This technology is very important for the packaging, biomedical, or automotive industry, because it determines the interface of a subsequent coating on that polymer . For example, the adhesion of a layer deposited on top of a polymer can be substantially enhanced compared to the adhesion to a polymer substrate without any surface conditioning .…”

“…This technology is very important for the packaging, biomedical, or automotive industry, because it determines the interface of a subsequent coating on that polymer . For example, the adhesion of a layer deposited on top of a polymer can be substantially enhanced compared to the adhesion to a polymer substrate without any surface conditioning . The treatment of polymer surfaces by plasmas corresponds basically to simultaneous etching and functionalization processes caused by incident energetic ions and by the irradiation with UV and VUV photons from the plasma volume.…”

Spectroscopic and Microscopic Investigations of Degradation Processes in Polymer Surface‐Near Regions During the Deposition of SiOx Films

“…Especially, the deposition of silicon oxide (SiO x ) with a thickness of few tens of nanometer is of great interest, since such films are optically transparent and achieve a significant improvement of barrier performance against permeation of gases (e.g., O 2 ) and vapors (e.g., H 2 O) by several orders of magnitude . Nevertheless, SiO x barrier coatings on aliphatic polyolefins like polypropylene tends to show weak adhesion . During exposure to an oxygen containing plasma including reactive oxygen species, polymer chains of aliphatic polymers may be degraded and low molecular weight oxidized material (LMWOM) or a weak‐boundary layer might be the result .…”