Evidence of covalent bond formation at the silane–metal interface during plasma polymerization of bis-1,2-(triethoxysilyl)ethane (BTSE) on aluminium

Silane and silane-like films were deposited from bis-1,2-(triethoxysilyl)ethane by vacuum and atmospheric plasma onto aluminium. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used for probing the aluminium/plasma polymer film interface. An AlOSi+ fragment was identified at nominal mass m/z =70.9539amu, indicating a strong chemical interaction (formation of a covalent bond) at the substrate/film interface. Until now, this strong silane–aluminium interaction has never been observed in plasma polymer BTSE films. Ageing tests in an ultrasonic water bath combined with X-ray photoelectron spectroscopy measurements allowed to indirectly confirm good adhesion, and therefore the formation of a chemical bond at the interface.