University of California

The rôle of surface tension and contact angle in the performance of spray liquids


Walter Ebeling

Author Affiliations

Walter Ebeling was Assistant Entomologist in the Experiment Station.

Publication Information

Hilgardia 12(11):665-698. DOI:10.3733/hilg.v12n11p665. November 1939.

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The wetting and spreading properties of spray liquids have been defined by Martin (16)4 as follows:


Wetting properties are defined by the ability of the liquid to form a persistent liquid-solid interface when excess of liquid is drained from the surface and are assessed by the receding contact angle. Perfect wetting results when this angle is zero. (Cos ?r ? 1.)


Spreading properties are defined by the ability of the liquid to form a persistent liquid-solid interface solely by surface activity over the plain solid surface, and are a function of the advancing contact angle.

Both wetting and spreading are functions of the contact angle, in one case the receding5 angle, and in the other case the advancing angle.

In the course of experimental work on the insecticidal efficiency of various aqueous solutions the writer has become interested in the spreading and penetrating properties of the liquids as indicated by their advancing contact angle.

Literature Cited

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Ebeling W. 1939. The rôle of surface tension and contact angle in the performance of spray liquids. Hilgardia 12(11):665-698. DOI:10.3733/hilg.v12n11p665
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