MIGRATION AND GROWTH-MECHANISM OF LONG-CHAIN MOLECULES ON THE SURFACE OF SOLID SUBSTRATES

When a long chain compound, calcium stearate ((CH3(CH2)16CO2)2Ca), is evaporated on the substrates of KCl, mica and amorphous carbon film, it forms either slender or planar crystals depending on the deposition conditions, in which molecules arrange parallel or perpendicular to the surface. By thermal treatment after deposition, the island crystals coalesce with each other to grow larger and then take the molecular orientation normal to the surface. Their dependence on the annealing temperature and the elapsing time reveals the mechanism of crystal growth and surface migration of molecules.