HIGH-RESOLUTION ELECTRON-MICROSCOPY OF MOLECULAR-CRYSTALS .4. PARAFFINS AND THEIR SOLID-SOLUTIONS

Lattice images of dislocations, growth boundaries and surface structur e, of the n-paraffin series have been obtained by high resolution elec tron microscopy. The crystals were grown so that the chain axes of the paraffin molecules were normal to the incident beam enabling distorti on created by chain end interactions to be resolved. Solid solutions o f paraffins within four carbon units in length, crystallized without e utectic segregation, irrespective of the even or odd numbers of carbon in the chains. However, for paraffins separated by only one or two ca rbon units there was lattice exfoliation at the crystal boundaries, wh ich we have interpreted as evidence for an interblock structure with s egregation of the minor component to the crystal boundaries.