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(Color online) Typical spectrum of a decylated surface, referred to the hydrogenated surface. polarization. Notice the sharp negative peak at (SiH loss) superimposed on a broad positive contribution (broadening of the remaining SiH), the positive bands at and [estimated H/decyl substitution ]. Inset: AFM picture of the decylated surface.
(a) Scheme of the variable-temperature cell used for the FTIR experiments and (b) scheme of the temperature sequence used for investigating the thermal stability of the organic layers. The arrows indicate the times when the spectra were recorded.
Typical IR spectra ( polarization) recorded at after successive heating of a catalytically decylated surface to increasing temperatures for durations of , under argon/hydrogen atmosphere. (a) The common reference for all spectra is the freshly grafted surface at . (b) For each spectrum, the reference spectrum is the one taken after heating at the preceding temperature (differential presentation). (c) Zoom on the spectrum. Spectrum of the fresh monolayer (dotted curves) compared with the loss (solid curves) for decyl (, multiplied by ) and ethyl (, multiplied by ) monolayers.
Loss of alkyl chains as a function of the heating temperature under reducing atmosphere: (a) quantitative data from the intensity of the band, for a surface decylated by the catalytic method, compared with theoretical expectation, using a reaction rate of the form , with and , and 50° temperature steps of a duration of (Ref. 4) or (present work). The lines are smooth curves drawn through the points; (b) normalized data (from the area of the band) for a surface modified using different chain lengths (, , , ). Note the improved stability of the ethylated surface.
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