Raman study of local ordering processes of solid n-alkanes

• Spontaneous separation of molecules occurs in binary mixtures of n-alkanes.
• The process of microphase separation takes minutes after quenching.
• Raman allows characterisation of the orientational ordering of n-alkanes in domains.

The microphase separation of n-alkanes with different chain length was investigated by Raman spectroscopy for binary mixture rapidly quenched from the melt. The process was observed as a function of time. The first several minutes after solidification were crucial for the demixing process. For a few weeks old sample the orientational order parameters and were calculated based on the analysis of polarized spectra recorded in the area of the formed domains. The measured values are significantly greater than zero (from 0.17 to 0.32), which indicates the mutual parallel arrangement of the molecules in the domains composed of n-alkanes of the same chain length.

Figure optionsDownload as PowerPoint slide