Organisation and melting of solution grown truncated lozenge polyethylene single crystals

Morphological features and the melting behaviour of truncated lozenge crystals have been studied. For the crystals investigated, the heights of the (110) and the (200) sectors were measured to be 14.5 and 12.7 nm, respectively, using atomic force microscopy (AFM) in contact and non-contact mode. Moreover, melting temperatures of 123°C for the (110) sector and of 120°C for the (200) sector have been measured using real-time AFM during annealing experiments. Applying atomic force acoustic microscopy and the n-alkane decoration technique, no difference in the surface fold organisation of (110) and (200) sectors could be detected. For similar stem lengths, variations in stem tilt angle within the sectors might cause the thickness difference observed. However, a very high tilt angle difference above 20° is required. More likely, a shorter stem length within the (200) sector may cause its lower melting temperature.