Evidence for Why Tri(ethylene oxide) Functionalized Si–C Linked Monolayers on Si(111) Have Inferior Protein Antifouling Properties Relative to the Equivalent Alkanethiol Monolayers Assembled on Gold

High quality methoxy-terminated monolayers containing a tri(ethylene oxide) moiety were formed on Si(111)–H surfaces in thermal hydrosilylation reactions. X-ray photoelectron spectroscopy, contact angle, and X-ray reflectivity measurements suggested that the suboptimal protein anti-fouling properties of these Si–C linked monolayers were due to a reduced lateral packing density of the chains resulting in a disordered layer with insufficient internal and external hydrophilicity.