摘要：

Surface roughness has been defined in terms of the average height of the asperities, h; and the average angle of inclination of the faces of the asperities to the horizontal, φ. A quantitatively reproducible roughness was produced on paraffin surfaces and the apparent angles of contact made by water drops on these surfaces were measured. Conditions for the formation of reproducible contact angles on roughened surfaces have been stipulated. The advancing contact angle was found to increase with an increase in the angle of inclination, φ, while only a slight decrease, if any, was observed in the receding contact angle. Hysteresis was found to increase with an increase in the angle of inclination, φ, but to be relatively independent of the height, h. On the basis of the results obtained a mechanism for the advancement of water drops across roughened paraffin surfaces was proposed.

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