Linoleic acid (LIA)/octadecylsilane(ODS) bilayers anchored through the silane moiety to the surface of a Ge internal reflection element (IRE) have been constructed using self-assembly techniques and the kinetics for their formation followed using attenuated total reflection infrared spectroscopy (ATR-IRS). Evidence that the acid layer is well-packed was obtained from the acid-base properties of the bilayer extracted from ATR-IRS measurements in aqueous solutions of different pH, yielding an effective pK(a) in the high-pH region of approximately 8.5.