X-RAY EVIDENCE FOR SHARP CHAIN FOLDS IN CRYSTALLINE LINEAR ALKANES

In this note a typical straightforward small-angle X-ray scattering (SAXS) example is presented of once-folded solution-crystallized paraffins having layer periodicities exactly one half the extended chain length. Moreover, the very good order in the stacking of layers is indicated by the presence of high-order reflections. n-C//1//9//8H//3//9//8 was crystallized from 0. 8 percent solution in toluene for 6 h at 81. 5 plus or minus 0. 2 degree C to obtain crystals with purely extended chains, and from 0. 01 percent solution in toluene for 1. 5 hours at 73. 2 plus or minus 0. 4 degree C for crystals with purely once folded chains.