Studies on Monolayer Fluidity of Coordination Polymers Based on Their Surface Flow Patterns

Abstract

Differences were examined in two-dimensional fluidity between monolayers composed of N, N'-disubstituted dithiooxamides on pure water and that on an aqueous copper (II) sulfate. solution. The rotating cylinder method with licopodium powder developed by H. E. Ries Jr., was employed. On pure water a surface flow pattern was observed which was suggestive of a macroscopic slip in the monolayer similar to that in a three-dimensional crystal (refer Fig.3-a). This might mean that the monolayer are in a pseudo-crystalline state with. a longrange order and a rather weaker molecular interaction. On an aqueous copper (II) sulfate solution, the licopodium powder lines drew smoothly curved lines without break, as if they were on a stretched expandable rubber film. This suggests that the molecules composing the monolayer are combined each other through coordination bonds to copper ions, that is, the intermolecular force is rather strong and results in a' short-range order (refer Fig.3-b). These techniques of direct observation of fluidity, plasticity, and viscoelasticity are widely applicable and useful for process control of manufactureing the multilayer films.