Abstract
Thin films of aminopropyltriethoxysilane (APS) have been deposited on grit-blasted aluminium and dried at four different temperatures: room temperature (RT), 50, 93 and 120°C respectively. These specimens were prepared in order to assess the occurrence of the three important reactions known to take place when using silanes as films and/or primers: hydrolysis in the absence of water, condensation with the substrate, i.e. covalent bond formation and crosslinking or self-condensation. Analyses performed using X-ray photoelectron spectroscopy (XPS) indicate that the films reduce in thickness with temperature and that the type of silicon bonding changes mostly above 50°C. Time of flight secondary ion mass spectrometry (ToF-SIMS) reveals that covalent bonding of APS on aluminium occurs at all temperatures used in this study as well as showing that the films are close to being fully hydrolysed. It is also possible to assess the presence of crosslinking within the films.