An electron diffraction study of the structure of thin films of normal paraffins

Abstract

Abstract Thin films of the normal paraffins tetracosane (C24H30), triacontane (C30H62) and tetratriacontane (C34H70) have been examined by electron diffraction when deposited on stainless steel, copper or collodion. Both the reflexion and the transmission techniques have been employed. The results of rubbing the films have been ascertained, and the orientations observed have been explained in terms of the crystal structure of the normal paraffins. Films of the three paraffins have been heated upon stainless steel and upon copper surfaces, and curves derived relating the temperature at which the ordered film structure breaks down, to the film thickness. These results suggest that this temperature corresponds in the case of a monolayer to a transition of the film structure from a condensed to an expanded type.