Tsuneo Tanaka

Relation between gloss and wetting of a matte surface

The angular distribution of light reflected from a blackened aluminum matte plate was studied as a function of illumination for several degrees of castor-oil wetting. The results were compared with a theory based on geometrical optics and simple models of the matte surface. The theory and the experiment agree and provide an understanding of the effect of the underlying surface on its glossiness.

Bubble volume method for the measurement of dynamic surface tension of surfactant solutions

Abstract This paper concerns a buble volume method derived from the maximum bubble pressure method for measurement of surface tension of liquids. This new, simple method is based on a steady-state expansion of a single air bubble formed on the bubble tip turned upward in liquid until detachment from the tip; through measurement of the detached bubble volume, the liquid surface tension is obtained. The empirical relationship between the volume and the expanding time obtained for several pure liquids and aqueous solutions was found to be very similar to that between the drop weight (or volume) and the dropping time obtained by the drop weight technique. The analytical treatment of the experimental data gives the dynamic surface tension of C12E5 (dodecyl pentaethylene glycol) solutions. Evaluation with the adsorption equation for surface dilatation showed that the dynamic surface tension obeys diffusion-controlled adsorption kinetics as expected.