“Suminagashi” Used in Studies on Monolayers

Abstract

We have tried to develop one of the downstreams of Langmuir-Blodgett methods by using the dyer's technics known as “suminagashi” (“nagashi” means “to let flow”). This kind of work was originally investigated scientifically by Torahiko Terada. A drop of Chinese ink (“sumi”) attached xo a glass rod was spread on the surface of aqueous cadmium chloride solution and a thin film was formed after several times of spreading. In the center of the film of ink, a weighed quantity of a solution of arachic acid in benzene was dropped, and the film was transferred to graph paper by blotting. The film was composed of two parts, which were the ink film and a white region where the ink film had been pushed away by the surface pressure of the arachic acid molecules. The area of this white part which was occupied by arachic acid molecules, was measured by counting sections of the grid on the paper. The method was also applicable for stu dying the spreadability of enamel proteins prepared from porcine enamel samples at early stage of development. Perfluoroalkyl polyether transferred on a section paper by the “suminagashi” was found to be detected by ESCA spectrometry.