Self-assembled monolayers of a series of linear thiols containing a 1-thiaoligo(ethylene oxide) (TOEO) moiety, i.e., HS(EO)(x)R (where R = C10H21, EO = -CH2CH2O-, and x = 4-8), were prepared on polycrystalline gold and characterized by visible spectroscopic ellipsometry (SE), infrared spectroscopic ellipsometry, and surface plasmon resonance. The TOEO segment was found to adopt a 7/2 helical structure oriented normal to the substrate for x = 5-7. Different structures were found for the other compounds in this series. When x = 4, the TOEO segment adopts a predominantly trans-extended conformation, whereas when x = 8, the TOEO appears to be disordered with some helical conformation. Monolayer thicknesses determined by SE are consistent with these structural changes. The significant increase in disorder with extension of the hydrophilic segment by two ethylene oxide units from 6 to 8 is potentially valuable for protein reconstitution in supported hybrid bilayer constructs.