Etching and Deposition Mechanism of an Alcohol Plasma on Polycarbonate and Poly(Methyl Methacrylate): An Adhesion Promotion Mechanism for Plasma Deposited a:SiO_xC_yH_z Coating

Abstract

Favourable properties of polycarbonate have led to it replacing glass in many applications; however it does require a protective coating. Plasma deposited protective coatings of amorphous SiOxCyHz have, however, shown marginal adhesion to polycarbonate. This study has shown that plasma pre‐treatments using vapours from the alcohol family improved the coating adhesion on two types of polycarbonate. It is suggested that these plasmas both etch the polycarbonate and deposit a thin plasma polymer layer. It was previously reported that a similar adhesion improvement was obtained on PMMA, however under shorter treatment times. The variation has been linked to the difference in etch rates of the two polymers. This has led to an improved understanding of the etching mechanism of both polymers when exposed to radicals.

Influence of Tetramethyldisiloxane‐Oxygen Mixtures on the Physical Properties of Microwave PECVD Coatings and Subsequent Post‐Plasma Reactions

“…However, under these plasma deposition conditions the coatings were found to be incompatible with some plastic substrates, such as PMMA and PC. [27,48] Coatings deposited at low oxygen concentrations, whilst initially mechanically compliant with the surface, underwent considerable post-plasma reactions, which rendered them less compliant and resulted in coating failure. An alternative must be found wherein mechanically matched, stable coatings can be deposited.…”

Evaluation of polymer hydrophobic recovery behavior following H2O plasma processing

“…Polymers find extensive use in many important modern industries, including automotive, biomedical, environmental, and laboratory applications . Often, however, the properties of the polymer surface, including surface tension and surface functionality, are incompatible with the intended application, thereby limiting their utility.…”

“…Often, however, the properties of the polymer surface, including surface tension and surface functionality, are incompatible with the intended application, thereby limiting their utility. Among the most common issues, adhesive failure and delamination are resulting from interface incompatibility, wetting and fouling issues arising from undesirable surface tension or surface functionality, and surface instability causing the polymer surface to denature or degrade . Each of these issues can be mitigated by surface modification processes, including exposure to ultraviolet radiation, flame treatment, and plasma surface modification .…”

Chemical seeding via propanol plasma pretreatment for improving adhesion and properties of PECVD siloxane coatings on polymers

“…This forms an activated interlayer between the substrate and the coating, with instances of this interlayer being cited elsewhere in pretreatment and adhesions studies . Hall et al previously hypothesised that this interlayer is the primary cause of improved adhesion. It has also been shown that propanol plasma pretreatment processes change the surface properties of the substrate and that a post‐plasma treatment can affect the structure and properties of the coatings .…”

“…When depositing these siloxane coatings, it is critical to maximise the adhesion of the coating to the plastic substrate and to this end a treatment of the substrate is often employed . For siloxane coatings, a pretreatment using the vapours from propanol were previously applied to strengthen the adhesion of the coatings, the propanol plasma was shown to both etch and deposit a thin carbon‐based layer .…”