A study of the ‘‘rotator’’ phase of 16-hydroxy–lithium–hexadecanoate

The high temperature crystalline modification of CH2OH(CH2)14COOLi was investigated by differential scanning colorimetry (DSC), x-ray diffraction, and IR spectroscopy. The results can be explained assuming that the all-trans chains undergo rotations around their long axes coupled with (small) deformations of torsion angles within the potential well of the trans state. No clear evidence of conformational disorder was found, at variance with what was observed for the rotator phases of the n-alkanes. This would support the view that, in such phases, the generation of conformational defects is associated with the translation of part of the chains in the long axis direction, unfeasible for the system under study since too costly for electrostatic reasons.