Conformational order indicators for perdeuterated alkyl chain systems are identified in the Raman spectra of nonadecane-d40, polyethylene-d4, and stearic acid-d35. Six spectral indicators are identified: I[va(CD2)2196]/ I[va(CD2)2172], I[v(C-C)G]/I[v(C-C) T], I[vs(CD3)]/I[va(CD 2)2172], I[vs(CD2)]/I[v a(CD2)2172], and the full width at half-maximum (fwhm) and frequency of the vs(CD2) mode. Among these indicators, the ratio of I[va-(CD2)2196]/ I[va(CD2)2172] is considered a primary indicator of conformational order, since it responds to alkyl chain conformational changes in a manner similar to the I[va(CH 2)]/I[vs(CH2)] primary indicator for hydrogenated systems. Other indicators are correlated to this primary indicator to derive a better understanding of the effect of structural attributes on conformational order in perdeuterated alkyl chain systems. These Raman spectral order indicators are applicable to any perdeuterated alkyl-containing system including lipids, biological membranes, alkylsilane-based chromatographic stationary phases, and self-assembled monolayers.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry