Molecular Orientation in the Physical-Vapour-Deposited Thin Films of Calcium Stearate

Molecular orientation of the physical-vapor deposited thin films of calcium stearate was observed by a transmission electron microscopy. We found that the thin films consisting of the long chain molecules normal to the substrate can be formed either by decreasing the deposition rate or by increasing the temperature of substrate. This means that the normally-oriented thin films of the long chain compounds can be achieved by the physical-vapor-deposition at a very low deposition rate. The observations of the step morphologies showed that the growth of normally-orientated calcium stearate films occurred by a spiral growth mechanism and by a birth and spread mechanism at lower and higher supersaturations, respectively.