Modification of the degree of liquid contact with a solid by control of surface and micro-channel capillary geometry
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorsPhillip G. Wapner, Wesley P. Hoffman
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Abstract
A method of modifying the apparent wettability (the area contacted by a liquid) of solids with liquids by controlling the surface geometry or the capillary geometry. This modification is possible by understanding the geometric relationship between the contact angle and the included angle of surface features. This same geometric relationship can be used to control entrance of a liquid into a capillary and the flow of more than one fluid in distinct streams through a capillary device.
Claims14
A transition included angle based method of predicting and controlling the wetting of a solid by a liquid comprising the steps of:
- providing a solid having a surface geometry,
- providing a liquid,
- placing the liquid in contact with the solid,
- measuring a transitional included angle formed between the solid and the liquid;
- and
- specifying the surface geometry of the solid at least in part based upon the transitional included angle to achieve a desired degree of wetting of the solid by the liquid.
A capillary device with a capillary path for carrying at least a first fluid and a second fluid in separate streams, the capillary path having at least one capillary cross-section;
- the capillary cross-section including at least one first angular portion with a first capillary included angle with a vortex and at least one second portion;
- the first fluid is a gas or a liquid with a first contact angle and a first transitional included angle;
- the second fluid is a liquid that has a second contact angle greater than 90 degrees and a second transitional included angle greater than the first transitional included angle;
- the first angular portion having an included angle less than the second transitional included angle of the second fluid and greater than the first transitional included angle of the first fluid such that the first fluid flows nearer the vortex than the second portion and the second fluid flows nearer the second portion than the vortex.
A transition included angle based method of predicting and controlling the degree of contact between the surface of the capillary path of at least one capillary tube and a liquid comprising the steps of:
- providing a capillary tube having a cross-sectional shape and an axial shape;
- providing a liquid having a transitional included angle with the solid;
- and
- designing the cross-sectional shape or the axial shape of the capillary tube at least in part based upon the transitional included angle in order to achieve a desired capillary action between the tube and the liquid when the liquid and solid are placed in contact.
A method of analytically assessing a degree of contact between a solid with a plurality of surface included angles, at least one of which is a known surface included angle, and a liquid having a transitional included angle by comparing the transitional included angle with at least one known surface included angle.
A method of analytically assessing a liquid, having a transitional included angle, entering into a capillary having at least one known capillary included angle by comparing the transitional included angle with at least one known capillary included angle.
Dependencies are inferred from the claim text.