A Systematic Study of the Adhesive Properties of a Plasma Polymerised Primer Bonded Siloxane Elastomer to Stainless Steel

摘要

In this study the use of a plasma polymerised primer layer as a means of enhancing the adhesion of siloxane polymers to steel is investigated. The primer layer consisted of a mixture of tetraethoxysilane(TEOS)andpolyhydrogenmethyl siloxane. This liquid mixture was nebulized into helium atmospheric pressure plasma formed using the PlasmaStream? system. The resulting primer coatings were characterised using x-ray photoelectron spectroscopy (XPS), Fourier Transform infra red spectroscopy, optical profilometer, scanning electron microscope, water contact angle, and spectroscopic ellipsometry. The adhesion of the siloxane elastomer was accessed using 45° peel strength measurements. This study investigated the effect of plasma jet to substrate distance on primer performance. Increased coating oxidation is observed at higher jet orifice to substrate distances. Enhanced adhesion was observed for small jet to substrate distances and also on ground steel surfaces, compared with those that had been polished. The effect of the thickness of the primer layer on adhesive strength was studied for coatings with thickness in the range 100 to 450 nm. Silicones bonded to primer layer with lower thickness exhibited superior adhesion.