Atomistic calculations of fold defects in polymers: 1. Polyethylene

Semiempirical atomistic calculations of the conformations and energies of fold defects in polyethylene are reported. The calculations were carried out in different approximations: in a ‘single’ chain, in crystalline surroundings and in a crystal surface. The problem of finding an appropriate reference structure is discussed. The calculation of fold surfaces yields the surprising result that—in agreement with experimental results but in contrast to other atomistic calculations in the literature—the diagonal fold is more favoured than the b-axis fold.