Structural and diffusional behavior of long cyclic paraffin C24H48 in the mesophase and isotropic liquid phase as studied by high field-gradient 1H NMR spectroscopy

The self-diffusion coefficients ( D ) of long cyclic paraffin C 24 H 48 with two transitions at 29 and 51 °C as observed in the DSC diagram are successfully measured within the temperature range from 30 to 70 °C by means of pulse field-gradient spin-echo 1 H NMR method, in order to elucidate the diffusional behavior of the paraffin in the mesophase in the range of 29–51 °C and in the isotropic liquid phase above 51 °C. From the experimental results, it was found that the D value increased with increase in temperature and there is an abrupt turn in the temperature dependence for the mesophase and isotropic liquid phase in the diffusion process.