Fig. (2) Gel-to-liquid crystalline phase transition of the hydrocarbon chains of LPS R60 at different concentrations of DS176 (A) and DS347 (B) by Fourier-transform infrared spectroscopy. The peak position of the symmetric vibration of the methylene groups ν_s(CH₂) is plotted versus temperature. In the gel phase, the wavenumber values lie at 2850 cm^-1, in the liquid crystalline phase they are shifted to 2852.5 to 2853.0 cm^-1.