AN EXAMINATION OF THE NUCLEATION KINETICS OF N-ALKANES IN THE HOMOLOGOUS SERIES C13H28 TO C32H66, AND THEIR RELATIONSHIP TO STRUCTURAL TYPE, ASSOCIATED WITH CRYSTALLIZATION FROM STAGNANT MELTS

Differential thermal analysis is used to examine the kinetics of nucle ation associated with the melt phase crystallization of n-alkanes in t he homologous series C13H28 to C32H66. Crystallization studies from st agnant melt samples reveal a direct correlation between structural typ e and nucleation behavior, notably demonstrating an alternating behavi or between the even and odd carbon number homologues which decreases i n extent as a function of increasing chain length, This effect is mirr ored in calculations of the lattice energies based on the crystallogra phic structures with greater lattice stability being found far the eve n carbon number n-alkanes which crystallize in the triclinic crystal s tructure. The data are consistent viith a heterogeneous nucleation mec hanism associated with preferential nucleation at the free surface of the sample associated with surface freezing.