Low contact angles with water may be obtained on the surfaces of chemically reactive metals by a process involving chemical cleaning with powerful oxidizing acids, followed by electropolishing to restore smoothness to the etched specimens. By using highly refined handling techniques, contact angles in the range, 0-11°, were obtained on aluminum, brass, copper, magnesium, nickel, stainless steel and zinc. The low contact angles are considered a good indication that organic contamination was virtually absent from the electropolished surfaces. The possibility of spurious inorganic contamination, apart from the normal oxide film, also was considered, and, in the case of copper electropolished in phosphoric acid, the residual phosphate on the surface was estimated by coulometric reduction and shown to be much less than a monolayer. The preparatory technique used in this study is applicable to a wide variety of metals and alloys and serves to demonstrate experimentally the inherent water wettability of clean metal surfaces. It also provides a means of preparing clean, smooth substrates on ^which fatty acids or other compounds may be deposited and their behavior observed in determining wettability and adhesion. Mechanical polishing, followed by exhaustive rinsing with hot or cold redistilled organic solvents, was not effective in producing low contact angles on metal surfaces.

A technique is described for coulometric reduction of films on copper and other electropositive metals which utilizes a granular electrode for rapid and thorough pre ‐electrolysis of electrolyte to remove dissolved oxygen and traces of plateable cations. The sensitivity of the method has been thereby increased, and as little as a quarter of a monolayer of a reducible film can be detected readily. Results are reported for reversible cell potentials, overpotential as a function of pH and current density, and the effect of oxygen in the electrolyte, for the reduction of films of cuprous oxide, and for reduction of hydrogen ions at a copper surface. Data are also reported on the reduction of thick films of cuprous oxide formed at 125°C, and the usefulness of the coulometric method in providing information about the topography of reducible surface films is demonstrated. Other films studied included cuprous sulfide, cupric oxide, and cupric hydrogen phosphate, occurring alone or as mixed films. The effectiveness of various preparatory and rinsing techniques in eliminating phosphate contamination from copper surfaces electropolished in o‐phosphoric acid has been evaluated. With the most favorable technique, the residual phosphate appears to be much less than a monolayer.

Thermal diffusion coefficients have been measured for a series of binary mixtures of paraffin hydrocarbons and of paraffin hydrocarbons with benzene. The temperature dependence of the thermal diffusion coefficient is shown to be small. The results are correlated quite satisfactorily by assuming that the mobility of a molecule is inversely proportional to the product of the molecular mass and molecular cross section in the direction of flow.

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The electrical resistivity and thermoelectric power of the organic semiconductor tetrathiotetracene (TTT) and its chloride, bromide, iodide, and thiocyanate salts are reported as a function of temperature. The ion–radical salts, of nearly 1:1 stoichiometry, were discovered to be highly conducting organic semiconductors and have resistivity values at room temperature ranging from 2.3 × 103 Ω·cm for TTT–chloride to 0.71 Ω·cm for TTT–iodide. The sign of the Seebeck coefficient of TTT–chloride corresponds to an n-type semiconductor, while for TTT and the other salts it indicates p-type behavior. Infrared absorption spectra of the solids, uv–visible spectra of solutions, preliminary x-ray powder patterns and density measurements are correlated with electrical properties. The influence of constitution of the ion–radical salts on the electrical resistivity and possible mechanisms of conduction are discussed.