The effect of plasma‐polymerised silicon hydride‐rich polyhydrogenmethylsiloxane on the adhesion of silicone elastomers

Abstract

BACKGROUND: Silicone elastomers have outstanding material properties including good thermal stability, low electrical conductivity, biocompatibility and resilient physical and chemical properties. These elastomers, however, exhibit relatively poor adhesion to stainless steel, and the use of a nanometre thick plasma‐polymerised primer layer as a means of enhancing this adhesion was investigated in this study. The primer coatings studied consisted of polyhydrogenmethylsiloxane (PHMS), tetraethyl orthosilicate (TEOS) and mixtures of these two liquid precursors. RESULTS: The plasma‐polymerised primer coatings were deposited onto stainless steel substrates using a PlasmaStream™ atmospheric pressure plasma jet system. Deposited coatings were examined using ellipsometry, contact angle measurements, optical profilometry, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy and scanning electron microscopy. The adhesion of silicone elastomers bonded to the primed and bare stainless steel surfaces was assessed using 45° adhesion strength measurements. Elastomer adhesion was correlated with surface energy, thickness and roughness. CONCLUSION: An up to 15‐fold increase in adhesive fracture energy was observed for silicone elastomers bonded to the primed versus untreated stainless steel. The highest adhesion was observed for a coating deposited from a PHMS‐to‐TEOS precursor molar ratio of 3 to 1. Copyright © 2009 Society of Chemical Industry

Evaluation of the anti-fouling properties of nm thick atmospheric plasma deposited coatings

“…The 2970 cm −1 peak is due to the absorption of the Si-O-CH 3 functional group [24]. The FTIR peaks further demonstrate that the precursor chemistry is retained in the plasma deposited coatings, as has been observed and reported previously [14].…”

“…It has also been demonstrated previously that the addition of TEOS (tetraethyl orthosilicate) into siloxanes can enhance the coating adhesion to steel substrates [14]. The precursor mixtures investigated were -FP with TEOS, FS with TEOS, TC with FP as well as TC with FS.…”

Electrical, Thermal and Optical Diagnostics of an Atmospheric Plasma Jet System

“…Both of which have not been reported before. These measurements allow the reported plasma processing outcome [12][13][14][15][16][17][18][19] to be revaluated in terms of discharge power and heat transfer. Outside the nozzle the gas temperature drops towards the surface to such a degree that allows heat sensitive treatment of polymeric and composite materials and many medical applications.…”

“…The working gas is injected between the needle electrodes and flows out through the quartz tube nozzle. A corona plasma discharge is produced whose visual morphology varies with gas flow [14,18]. The helium flow rate of 1-10 standard litres per minute (slm) is controlled using manual valved rotameters.…”

Adhesion Improvement between Epoxy and Stainless Steel Using a Silane Coupling Agent in an Atmospheric Plasma Process

“…[43] The deposition of polyhydrogenmethylsiloxane and tetraethyl orthosilicate on SS substrates improved the adhesion strength towards silicon elastomers. [44] The main goal of this study is to deposit a siloxane layer on a SS surface through DBD process. 3-Aminopropyltriethoxysiloxane (abbreviated as APS) was chosen as chemical precursor not only because it is one of the most used coupling agents for polymeric/inorganic composite but also because the presence of an amino group (NH 2 ) in its structure makes it particularly reactive in the formation of covalent bonds with the epoxy resin.…”