The interaction of gamma-glycidoxypropyltrimethoxysilane with oxidised aluminium substrates: The effect of drying temperature

The interaction of gamma -glycidoxypropyltrimethoxysilane (GPS) with oxidis ed aluminium substrates has been investigated in terms of the effect of the drying, or curing, temperature. Samples treated with aqueous solutions of GPS at concentrations of 1,4 and 8% v/v were cured at 25, 50, 93 and 120 de greesC. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to construct adsorption isother ms and determine the thicknesses of the various GPS coatings. A temperature effect induces subtle changes in the structure of the resulting films. The uptake of GPS is increasing with increasing concentration of CPS. The stru cture of the films changes at a threshold temperature between 50 to 93 degr eesC. XPS and ToF-SIMS data both indicate that the interaction of the GPS f ilm on aluminium is different for low and high temperatures drying regimes. Using the Beer-Lambert equation, it was found that increasing the curing t emperature leads to the variation of the thickness of silane films. This is interpreted in terms of changes in the crosslink density of the films and in their state of hydration and/or degradation.