Surface-Bound Alkyl Monolayers: Electrochemical and Structural Characterization

: Two substrates that are amenable to analogous silane chemistry provided the basis for characterizing alkylsilane layers formed by octadecyltrichlorosilane (OTS) and dimethyloctadecylchlorosilane (DMOCS) reactions. Electrochemical analysis of the capacitance was used to measure an apparent thickness, d(A), and the degree of surface coverage, 0, for deposited silane layers on Si/SiO2 electrodes. Elemental analysis was performed to determine the carbon load resulting from comparable silane reactions on glass bead substrates. Glass bead substrates were also examined by FTIR spectroscopy to evaluate the hydrocarbon incorporation and hydration of surface silanol groups. A semiquantitative measure of hydrocarbon deposition was derived from FTIR spectra and shown to correlate well with the electrochemical and analytical data over a defined range.