In the present work FT IR and solid-state NMR spectroscopic techniques are employed to examine the conformational order and mobility of alkyl chain segments chemically attached to solid surfaces. The influence of the different solid supports, pressure, surface coverage, synthetic routes and solvents over the wider temperature range on the conformational order of the alkyl chains have been examined. Inspection of the FT IR data for the C30 SAMs reveals that the solid substrate plays a vital role for the actual conformational state of the attached alkyl chains. On investigating commercial DiamondBond-18 phases, it is found that alkyl chains tethered to the graphite layer, exhibit a higher conformational order than those in conventional column materials. A comparative study reveals that C18 alkyl modified silica gels with higher surface coverage exhibit a higher conformational order compared to one with lower surface coverage. It was found that the C18 phases and solvents interact significantly, resulting in pronounced changes of the alkyl chain conformational order. A decrease in the conformational disorder is found on application of pressure to the stationary phase materials. The results derived from the present studies state that these aforementioned parameters have a strong influence on the conformational order and mobility of alkyl chains tethered to the inorganic metal oxides.
|Versandkostenfrei innerhalb Deutschlands|
Wollen auch Sie Ihre Dissertation veröffentlichen?