D. Gidalevitz, O. Y. Mindyuk, P. A. Heiney, B. O. Ocko, M. L. Kurnaz and D. K. Schwartz, Langmuir 14, 2910 (1988).
We have studied the thermal melting of two disc-shaped molecules at the air-water interface. Brewster Angle Microscopy images of both compounds indicated first order phase transitions from a low temperature solid phase to a high temperature fluid phase. Grazing-incidence diffraction measurements provided corroborating evidence of reversible melting, in the form of Bragg peaks that vanished at high temperature and reappeared upon cooling. Furthermore, we observed that the diffraction peaks obtained upon re-cooling were substantially sharper than those obtained initially, and the domain sizes seen in Brewster Angle Microscopy were substantially larger, indicating an enhancement of crystalline domain size by thermal annealing.