United States of America As Represented by the Secretary of the Air Force

Phillip G Wapner

Wesley P Hoffman

Steven P Jones

Alexander N Pechenik

Gregory J Price

Alex Lobovsky

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 enhance two-phase fluid separation during phase transformation as well as measure dynamic contact angles.

Self-clearing vents based on droplet expulsion

Modification of the degree of liquid contact with a solid by control of surface and micro-channel capillary geometry

New fluid separation devices and absorption materials are disclosed. Hollow fibers with an axial capillary slit act as very high efficiency absorption materials, as well as high-surface-area fluid separation devices. The hollow fibers with an axial capillary slit are constructed to preferentially absorb or repel different fluids and arranged to maximize that action over a plurality of fibers to separate different fluids. These separation devices can also function as injection devices and very effective micro-reactors.

Fibers with axial capillary slit that enhances adsorption, absorption and separation

In the present invention, a technique is described for manufacturing microtube devices which have peripheral geometries that are not uniform along the tube or device axis. These geometries may exist in only one location on the periphery of the microtube device or geometries may be repeated either uniformly or non-uniformly with micron or sub-micron precision along the tube or device axis. The preferred manufacturing process involves forming a complex mandrel, ie., (one, for example, that can not be formed by extrusion or pultrusion under constant processing conditions) and giving it at least one metallic and/or nonmetallic coating by any of a variety of techniques. The complex mandrel can then be removed by appropriate chemical or physical means that do not adversely affect the coating(s) desired for the wall. The result is a microtube structure having an axial profile duplicating that on the mandrel from which it was formed.

Microtubes with axially variable geometries and method of manufacturing same

Provided are methods for fabricating fluid separation devices with precisely-sized, shaped microscopic capillaries that can separate one immiscible fluid from another on the basis of different separation characteristics. In particular, the method comprises the steps of fabricating a first set of capillaries having a first separation characteristic and a second set of capillaries having a second separation characteristic, incorporating one end of all of the capillaries into an inlet face, incorporating the second end of the first set of capillaries into a first outlet face, and incorporating the second end of the second set of capillaries into a second outlet face. Preferably, the first set of capillaries is hydrophillic and the second set of capillaries is hydrophobic.

Method of manufacture of separation devices

There are provided methods for fabricating devices for admitting air to a closed container while preventing passage of a water-based fluid therethrough. These devices comprise a plurality of hydrophobic capillaries or a hydrophobic reticulated microporous material. The devices comprising hydrophobic capillaries are fabricated by a variety of techniques, such as those employing extrusion, pultrusion, fugitive mandrel removal or a combination of these techniques. The devices comprising hydrophobic reticulated microporous material are fabricated by techniques such as foaming, sintering, template replication, incorporation of sacrificial particles or a combination of these techniques.

Air-admittance device and method for making same

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.

A liquid to solid material surface contact angle measurement system operating by way of detecting a transition in the behavior of a liquid sample with the solid material in a changing angular confinement environment along with use of a mathematical algorithm to then determine contact angle. Measurement of the angle at which the tested liquid transitions between apparent wetting and apparent non-wetting behavior, regardless of whether the liquid and solid material are truly classified as wetting or non-wetting, provides a measurement from which disclosed mathematical algorithms can predict the surface wetting characteristics of the liquid on the solid material. Automated performance of the confinement environment measurement and examples are included.

Liquid to solid angle of contact measurement

There are provided methods for fabricating baby bottle nipples which mimic the function of the human breast nipple. In the human breast nipple, milk is delivered to the baby through 15-25 fluid-delivery capillaries called lactiferous ducts. These ducts are 2-4 centimeters in length and 500-900 microns in diameter. Baby bottle nipples fabricated in accordance with the methods of this invention have the common feature of at least one hydrophilic fluid delivery passage. In one embodiment, the fluid delivery passage is a microtube. In another embodiment, the fluid delivery passage is a microchannel. In yet another embodiment, the fluid delivery passage comprises a porous reticulated foam with interconnected pores. In each of these embodiments, the fluid delivery passage has at least one dimension in the range of 1-2000 microns.

Method of manufacture of baby-feeding nipple

Carbon matrix composites fabricated by a rapid and low-cost process incorporating in-situ polymerization of wetting monomers

This invention is a rapid low-cost technique for manufacturing thick high-performance carbon and ceramic composites in the form of uniformly densified near-net shaped structures. This is accomplished by impregnating composite preforms with low-viscosity wetting monomers which undergo polymerization followed by pyrolysis reactions in the preform ultimately creating ceramic and/or carbon matrices. Since the monomers possess low-molecular-weight they have low viscosities. Thus, if they wet the fiber and partially-densified preform they can easily impregnate even the smallest pores. Once inside the preforms, polymerization of the monomers is then initiated, resulting in a liquid matrix-precursor of the high molecular weight needed to produce a superior matrix (upon pyrolysis) with high efficiency.

Baby bottle nipples which mimic the function of the human breast nipple are provided. In the human breast nipple, milk is delivered to the baby through 15-25 fluid-delivery capillaries called lactiferous ducts. These ducts are 2-4 centimeters in length and 500-900 microns in diameter. Baby bottle nipples fabricated in accordance with the methods of this invention have the common feature of at least one hydrophilic fluid delivery passage. In one embodiment, the fluid delivery passage is a microtube. In another embodiment, the fluid delivery passage is a microchannel. In yet another embodiment, the fluid delivery passage comprises a porous reticulated foam with interconnected pores. In each of these embodiments, the fluid delivery passage has at least one dimension in the range of 1-2000 microns.

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Palmdale, CA, United States of America

Phillip G Wapner