KR20070106787A - Reflective electroactive particles - Google Patents

Abstract

This invention features an electroactive microcapsule comprising a shell and a mixture inside the shell, wherein the mixture comprising an oil; a plurality of metal particles; and a plurality of electrically non-conducting particles and wherein the plurality of metal particles and the plurality of electrically non-conducting particles have opposite charges.

Description

Reflective Electroactive Particles {REFLECTIVE ELECTROACTIVE PARTICLES}

FIELD OF THE INVENTION The present invention relates to electroactive particles capable of reflecting ultraviolet (UV), infrared, microwave and / or radio frequency, more specifically, as if the object is immediately adjacent to the detector using electromagnetic radiation. A reflective electroactive particle for making an adaptive camouflage structure that can be dynamically adjusted to disguise the appearance of an object to be visible.

The viability of objects such as military personnel, vehicles, equipment and structures in the battlefield environment is directly related to the ability of countermeasures to address all identified or unidentified threats to the object. An important countermeasure against a threat to an object is to disguise it, making it difficult for the enemy to detect its existence. Traditionally, indigenous paint camouflage has been used to reduce visible detection of objects by detectors using visible light. Modern war environments use many other proven methods of detection, such as radar and infrared emission detectors, which are not addressed by current paint camouflage countermeasures. In addition, the time required to frequently change indigenous paint camouflage for various battlefield environments hinders or delays the deployment of military assets required for a given combat situation.

In order to reduce the ability of an enemy to detect military objects, the camouflage can (1) be incorporated into military objects without interfering with them to perform their mission or intended use, and (2) Reduce the detection of military objects by (3) dynamically adapting to a wide range of changing battlefield environments (eg, night, day or rain), movement, and multiple geographic locations and environments within a given battlefield, (4) It is desirable to be able to quickly reconfigure or vary in various patterns to accommodate a wide variety of geographical environments, and (5) to be deployed at acceptable costs. Improved camouflage can provide some of the above desired features and important tactical advantages in use.

Summary of the Invention

Herein, detectors using visible, ultraviolet, infrared, microwave, and / or radio frequency are used to disguise the appearance of an object such that military personnel, vehicles, equipment, and structures appear to be their immediate surroundings. Adaptive gastrointestinal structures that can be adjusted dynamically are disclosed. The adaptive camouflage structure of the present invention can provide a wide viewing angle and can be easily incorporated as an integral part of the object. One feature of the adaptive camouflage structure of the present invention is that it can incorporate multiple incident radiation schemes into one device, reducing cost, weight and installation complexity. Another feature of the adaptive camouflage structure of the present invention is that the camouflage pattern generated on the reflective layer of the camouflage structure is stable and can be maintained without power. A further feature of the adaptive gastrointestinal constructs of the present invention is that the gastrointestinal patterns can be retained for a long time until they are changed or reconstructed by the new electric field pattern.

In a first aspect, the present invention includes a shell and a mixture comprising oil inside a shell, a plurality of metal particles and a plurality of electrically nonconductive particles, wherein the plurality of metal particles and the plurality of electrically nonconductive particles are opposite charges. It is characterized by having an electrically active microcapsules.

As a second aspect, the invention includes a coating of electrically nonconductive particles and a reflective material, the coating covering a portion of the electrically nonconductive particles, wherein the reflective material is an infrared reflective material, a radar reflective material, a microwave reflective material, UV And electroactive particles selected from the group consisting of reflective materials and combinations thereof.

In a third aspect, the present invention provides an electroactive microcapsule comprising a shell and a mixture comprising a plurality of flakes of an oil and a polymer inside the shell, the metal layer coated on one of the flat surfaces of each flake. It features.

In some embodiments of interest, about 25% to 75% of each of the electroactive particles in the first reflective layer reflects visible light and the remaining 75% to 25% of the particles do not reflect visible light. In another embodiment of interest, about 25% to 75% of each of the electroactive particles in the second reflective layer reflects infrared, radio frequency, microwave, ultraviolet, or combinations thereof, and the remaining 75% to 25% of the particles It does not reflect infrared rays, radio frequencies, microwaves, ultraviolet rays, or a combination thereof. In a further embodiment of interest, about 25% to 75% of each of the electroactive particles in the third reflective layer reflects infrared, radio frequency, microwave, ultraviolet, or a combination thereof and the remaining 75% to 25% of the particles. Does not reflect infrared, radio frequency, microwave, ultraviolet or combinations thereof.

Other features and advantages of the invention will be apparent from the following description and claims of particular embodiments thereof.

The above and other features of the present invention and the above and other advantages are apparent from the following more detailed description of specific embodiments of the present invention as shown in the accompanying drawings, in which like reference characters designate different drawings. It means the same part throughout. The drawings are not necessarily drawn to scale, emphasis instead being placed upon illustrating the principles of the invention.

1 is a schematic cross-sectional view of one embodiment of an adaptive camouflage structure comprising two reflective layers and two adjustable voltage pattern intermediate layers, wherein the top reflective layer reflects visible light and the bottom reflective layer reflects infrared light.

FIG. 2 is a schematic of one embodiment of an adaptive camouflage structure comprising three reflective layers and three adjustable voltage pattern intermediate layers, the upper reflective layer reflecting visible light, the intermediate reflective layer reflecting infrared light, and the bottom reflective layer reflecting radio frequency Section.

3 is a schematic cross-sectional view cut through the axis of a disk of one embodiment of a rotating disk for producing electroactive dichroic beads from two different curable liquid materials.

4 is a schematic side view of one embodiment of a double barrel nozzle for producing electroactive dichroic beads from two different curable liquid materials having opposite charges.

5 is a schematic perspective view of one embodiment of a rotating disk for producing electroactive dichroic beads from two different curable liquid materials having opposite charges.

6 is a schematic side view of one embodiment of an assembly of three rotating disks for producing electroactive multicolor split beads from different curable liquid materials.

7 is a schematic cross-sectional view cut through the axis of a rotating disk and an embodiment of a coating apparatus for producing electrically active beads.

8 is a schematic side view of one embodiment of a double barrel nozzle and coating apparatus for making electrically active beads.

9 illustrates a schematic representation of one embodiment of an adaptive camouflage structure comprising three reflective layers and one adjustable voltage pattern intermediate layer, the upper reflective layer reflecting visible light, the intermediate reflective layer reflecting infrared light, and the bottom reflective layer reflecting radio frequency. Section.

Detailed Description of the Preferred Embodiments

The improved adaptive gastrointestinal structures described herein can have two or more layers that include a plurality of electroactive particles that each layer can be selectively oriented to provide the desired image. Images provided by different layers may cover different regions of the electromagnetic spectrum, such as visible light, infrared light, ultraviolet light, microwaves and / or radio frequencies. In some embodiments, the images of the different layers can be individually selected by applying a suitable electric field by the adjustable voltage pattern interlayer. The electroactive particles can be embedded in a suitable binder that is transparent to one or more regions of the electromagnetic spectrum reflected by the electroactive particles and allows rotation of the electroactive particles in the layer. When oriented, the electroactive particles of each layer together provide a selected image to the observer or detector.

1 illustrates one embodiment of the two-layer adaptive camouflage structure of the present invention for disguising an object 50 such as military personnel, vehicles, equipment, and structures. The adaptive camouflage structure of FIG. 1 includes a first reflective layer 3 with a first host material and a second reflective layer 13 with a second host material, wherein each of the first and second reflective layers rotates in each host material. It further comprises a plurality of electroactive particles 60 and 61, possibly embedded or dispersed. The electroactive particles 60 and 61 can be, precisely or generally, in the form of spheres, beads, ovals, cylinders, discs, flakes or combinations thereof. The electroactive particles of the first reflecting layer may reflect visible light 1 coming from the environment of the object, for example, and the electroactive particles of the second reflecting layer may reflect infrared light 11 coming from the surrounding environment of the object. have. The first host material is transparent to both visible and infrared light, and the second host material is transparent to infrared light. If a material allows at least a portion of a particular area of the electromagnetic spectrum to pass through the material, then it is transparent to that area of the electromagnetic spectrum. In some embodiments, the electroactive particles 60 and 61 are exactly or generally in the form of spheres, beads, ovals, cylinders or combinations thereof, wherein the first host material and the second host material are each independently Polycarbonate, polyester, polyamide (such as nylon), polysiloxane (such as silicone and crosslinked silicone), polyethylene, and polypropylene. In some embodiments, electroactive particles 60 and 61 comprise flakes dispersed in a host fluid contained within a cavity of each host material. Suitable host fluids for dispersing the electrically active flakes may have a volume resistivity of at least 10 ⁹ ohm-cm, as measured by ASTM D 257-93. Some non-limiting examples of suitable host fluids include tetrafluorodibromoethane, tetrachloroethylene, trifluorochloroethylene, silicone oils, fluorinated oils, fluorosilicone oils, pneumatic liquid crystal fluids, hydrocarbons (e.g. paraffin liquids). , Toluene, xylene, octane, decane, tetradecane, decalin and kerosene), oils such as linseed oil, soybean oil, tung oil and olive oil, and combinations thereof. The first host material may or may not be the same as the second host material. Electroactive flakes and host fluids are described in US Pat. No. 6,665,042, which is incorporated herein by reference. The reflected visible light 2 may constitute a selected visible image suitable for disguising the object 50 to reduce the risk of being detected by visible light detectors such as human eyes, telescopes and electronic cameras. Likewise, the reflected infrared rays 12 are selected infrared rays suitable for disguising the object 50 to reduce the risk of being detected by an infrared imaging system such as FLIR (Forward Surveillance Infrared) operating at a wavelength of 1 to 20 μm. You can compose the image.

One skilled in the art can modify the first reflective layer 3 to be able to reflect radiation other than visible light such as ultraviolet, infrared, microwave or radio frequency. Likewise, one skilled in the art can modify the second reflective layer 13 to reflect other radiation than infrared, such as visible, ultraviolet, microwave or radio frequency. In some embodiments of interest, the second reflective layer 13 contains electroactive particles that can reflect ultraviolet, infrared, microwave, radio frequency, or a combination thereof. Thus, this reflective layer can optionally be used as an infrared reflective layer, radar reflective layer, UV reflective layer or microwave reflective layer.

Optionally, an adhesive layer can be applied on the outer surface of the second reflective layer 13 to mount with adhesive the two-layer adaptive camouflage structure on the surface of the object. Any suitable adhesive material known in the art can be used for this purpose. Non-limiting examples of suitable adhesive materials include phenol-formaldehyde resins, polychloroprene, urea-formaldehyde adhesives, nitrile rubber-phenol adhesives, epoxy resin adhesives, nitrile rubber-epoxy film adhesives, nylon-epoxy film adhesives, isocyanate based adhesives. , Hot melt adhesives, cyanoacrylate adhesives, anaerobic adhesives, silicone adhesives, high temperature resistant adhesives, acrylate adhesives toughened with hypalone, bismaleimide based adhesives, and acrylate based or methacrylate based adhesives . The number average molecular weight of the polymeric adhesive material can vary from 1000 to 10,000,000 Daltons. Alternatively, the two-layer adaptive camouflage structure can be mounted on the surface of the object using any conventional mechanical fasteners such as screws, nails, bolts and nuts, hook-loop fasteners and hook-hook fasteners.

Both visible and infrared images can be adjusted by independently applying the appropriate voltage pattern to each of the visible light reflecting layer 3 and the infrared reflecting layer 13 by means of the adjustable voltage pattern intermediate layer 40. Each adjustable voltage pattern intermediate layer 40 may overlie the surface 30 of the object 50 and / or at an interface between adjacent layers. The adjustable voltage pattern interlayer can be formed from a conductive material that is effectively transparent to visible light. Non-limiting examples of transparent conductive materials include transparent conductive oxides such as indium tin oxide, zinc oxide, tin oxide, indium oxide, cadmium oxide, gallium oxide, copper oxide, and combinations thereof; Thin metal coatings such as gold, silver and copper having a thickness in the range from 0.1 μm to 0.5 nm; Nanoparticles of a conductive material such as carbon nanotubes and gold coated silver nanoparticles; Transparent conductive films or stripes formed from transparent conductive ITO inks using ITO microparticles; Translucent conductive pastes using needle-shaped ITO particles; Transparent conductive ITO pastes using organic indium and tin compounds; Transparent conductive Au-Ag inks using gold coated silver nanoparticles; And transparent conductive carbon inks using carbon micro particles. All transparent conductive inks and pastes are available from Sumitomo Metal Mining (Tokyo, Japan).

2 illustrates one embodiment of a three layer adaptive camouflage structure for disguising an object 50. The adaptive camouflage structure of FIG. 2 includes a first reflective layer 3 with a first host material, a second reflective layer 13 with a second host material, and a third reflective layer 23 with a third host material, Wherein the first, second and third reflective layers each further comprise a plurality of electroactive particles 60, 61 and 62 rotatably embedded or dispersed in each host material. Optionally, an adhesive layer may be applied on the outer surface of the third reflective layer to mount the adhesive with a three layer adaptive camouflage structure on the surface of the object. Any suitable adhesive material may be used for this purpose. Alternatively, the three-layer adaptive camouflage structure can be mounted on the surface of the object using any conventional mechanical fasteners such as screws, nails, bolts and nuts, hook-loop fasteners and hook-hook fasteners.

 In some embodiments, the electroactive particles of the first reflective layer can reflect visible light 1 coming from the surrounding environment of the object, for example, and the electroactive particles of the second reflective layer come from the surrounding environment of the object, for example. The infrared rays 11 can be reflected and the electroactive particles of the third reflective layer can reflect the radio frequency 21 coming from the environment of the object. In further embodiments, the first host material is transparent to visible, infrared and radio frequencies, the second host material is transparent to infrared and radio frequencies, and the third host material is transparent to radio frequencies. In other embodiments, the electroactive particles 60, 61, and 62 are exactly or generally in the form of spheres, beads, ovals, cylinders, or a combination thereof, the first host material, the second host The material and the third host material are each independently a polymeric material selected from the group consisting of polycarbonates, polyesters, polyamides such as nylon, polysiloxanes such as silicones and crosslinked silicones, polyethylene, and polypropylene to be. In another embodiment, the electroactive particles are in the form of flakes dispersed in a host fluid contained within the cavity of each host material. The reflected visible light 2 may constitute a selected visible image suitable for disguising the object 50 to reduce the risk of being detected by the visible detector. Likewise, reflected infrared ray 12 may constitute a selected infrared image suitable for disguising object 50 to reduce the risk of being detected by an infrared imaging system. Likewise, the reflected radio frequency 22 may constitute a selected radar image suitable for disguising the object 50 to reduce the risk of being detected by the radar detector. The visible, infrared and radar images can be adjusted by independently applying a suitable voltage pattern to each of the visible light reflecting layer 3, the infrared reflecting layer 13 and the radar reflecting layer 23 by means of the adjustable voltage pattern intermediate layer 40. Each adjustable voltage pattern intermediate layer 40 may overlie the surface 30 of the object 50 and / or at an interface between two adjacent layers. One skilled in the art can modify the first reflective layer 3 to reflect radiation other than visible light such as ultraviolet, infrared, microwave or radio frequency or combinations thereof. Likewise, one skilled in the art can modify the second reflective layer 13 to reflect other radiation than infrared, such as visible, ultraviolet, microwave or radio frequency. Likewise, one skilled in the art can modify the third reflective layer 23 to reflect radiation other than radio frequency such as visible light, ultraviolet light, microwave or infrared light.

The visible light reflecting layer 3 may comprise a host material that is sufficiently transparent to visible light to allow at least a portion of the visible spectrum to pass through. Optionally, the host material of the visible light reflecting layer 3 may be sufficiently transparent to at least another region of the electromagnetic spectrum such as infrared, radio frequency, microwave and ultraviolet. Non-limiting examples of suitable host materials for the visible light reflecting layer include polycarbonates, polyesters, polyamides such as nylon, polysiloxanes such as silicones and crosslinked silicones, polyethylene, and polypropylene. Many electroactive particles that reflect visible light are embedded in the host material. Some non-limiting examples of electroactive particles that reflect visible light include dichroic beads or cylinders, multicolor split beads or cylinders, polymer liquid crystals and polymer birefringent flakes, and microencapsulated ink beads.

In some embodiments of interest, the visible light reflecting layer may comprise a host material and a plurality of dichroic beads or cylinders and / or multicolor split beads or cylinders rotatably embedded in the host material. Dichroic beads and multicolored divided beads are generally spherical or elliptical particles having a size generally ranging from about 10 μm to about 1 mm. In other embodiments of interest, the electroactive particles in the visible light reflecting layer of the adaptive camouflage structure generally comprise spherical dichroic beads. Each dichroic bead has two generally equally sized hemispheres with contrasting colors (eg black and white, red and white, etc.). The two colored hemispheres may have two different zeta potentials because of the different materials used to achieve optical anisotropy. Because of the difference in zeta potential, each dichroic bead has an opposite charge such that each exhibits electrical anisotropy corresponding to optical anisotropy. When a voltage is applied to one dichroic bead in the visible light reflecting layer, the dichroic bead rotates to present one color hemisphere to the viewer depending on the polarity of the applied voltage. When voltage is applied to all dichroic beads by an adjustable voltage pattern interlayer 40 adjacent to the visible light reflecting layer, the dichroic beads jointly form the selected visible image by rotating each bead independently to provide one color. The visible image stays in place for a long time without power, until a new voltage pattern is applied.

Dichroic beads can be prepared by conventional techniques known in the art. For example, dichroic beads can be prepared by sputtering a light reflective material, such as titanium oxide, on one hemisphere of the beads comprising black polyethylene. Alternatively, dichroic beads can be prepared by coating by evaporation with an inorganic colored material such as indium on one hemisphere of white glass beads having a diameter of about 10 μm to 1 mm. Alternatively, the dichroic beads are nonconductive black materials (e.g. graphite, titanium nitride, and combinations of magnesium fluoride and aluminum) on one hemisphere of glass beads loaded with a lot of white pigments (e.g. titanium oxide) in a vacuum evaporation chamber. It can be prepared by coating a layer of. The dichroic beads also form dichroic fibers by (a) coextrusion a semicircular layer of polyethylene with a white pigment added with a semicircular black layer of magnetite containing polyethylene, and (b) dichroic fibers obtained in a range of 10 μm to about 10 mm. Chopping with fine dichroic particles, (c) mixing the dichroic particles with clay or anti-agglomerate, and (d) heating the mixture with a liquid at about 120 ° C. to spheroidize the dichroic particles and then cooling and solidifying with dichroic beads. Can be prepared by.

Many other methods, such as those known in the art, can also be used to make dichroic beads or multicolor split beads. Non-limiting examples of apparatus suitable for performing suitable methods include the elements shown in FIGS. 3-6. Referring to FIG. 3, both sides 64 of a rotating disk in which the first colored curable liquid material 66 and the second colored curable liquid material 67 are evenly rotated about the shaft 63, ( 65 is applied by means of delivery (not shown). Colored curable liquid materials 66, 67 may include colored liquids and molten liquids such as molten carnauba wax and molten polyethylene. Because of the centrifugal force the first and second colored curable liquid materials 66, 67 flow towards the periphery of the disk 62, where they merge at the edges to form a dichroic stream 68, which is unstable Eventually it is broken and becomes a bi-color bead 69. When the liquids 66 and 67 flow to the edge of the disk 62 at the same speed, this technique produces dichroic beads having the same size colored hemispheres. Dichroic beads can be solidified by cooling at room temperature or cooling can be accelerated by allowing the dichroic beads to pass through a cooling zone containing cold liquid nitrogen or CO ₂ vapor (not shown). The dichroic beads 69 produced in this way generally have a diameter of about 5 to about 200 μm, depending on the rotational speed of the rotating disk 62 and the viscoelastic properties of the molten liquid.

4 and 5, dipole moments are implanted by combining two differently colored curable liquid materials 93 and 94 in a double barrel nozzle 91 or on a rotating disk 100. Other methods of generating dichroic beads 99 and 101 with are shown. Liquid materials 93 and 94 are filled by anode 95 and cathode 96 and combined by electrostatic attraction at the exit of the double barrel nozzle or at the rim of the rotating disk, thereby dichroic beads 99 and 101 respectively. ) And they all have injected dipole moments.

In another embodiment of interest, the electroactive particles in the visible light reflecting layer of the adaptive camouflage structure comprise multicolored split beads. Referring to FIG. 6, multicolor split beads can be made by using an assembly 71 of three rotating disks. Curable liquid materials colored in different colors are introduced on each side of each of the three rotating disks 72, 73, 74, which rotate uniformly around the common shaft 75 by means of delivery (not shown). Can be. The colored curable liquid materials combine at the edge of the disk to form a multicolored split stream which is unstable and eventually breaks up into multicolored split beads. Optionally, the colored curable liquid materials may each be filled independently by an anode and / or a cathode.

The manufacture and addressing or orientation of dichroic beads or cylinders and multicolored split beads or cylinders is described in U.S. Pat. , 5,922,268, 5,919,409, 5,917,646, 5,904,790, 5,894,367, 5,891,479, 5,815,306, 5,808,593, 5,777,782, 5,767,826, 5,760,761, 5,751,268, 5,717,515, 5,717,5 5,717,514, 5,717,514,5,717,514 It is incorporated herein by reference.

In another embodiment of interest, the electroactive particles in the visible light reflecting layer of the adaptive camouflage structure comprise microencapsulated ink beads. Each microencapsulated ink bead is a generally spherical microcapsule containing positively charged particles and negatively charged particles suspended in a clear liquid such as an oil, where the positively charged particles and negatively charged particles can reflect and / or absorb visible light. In some embodiments, both positively charged particles and negatively charged particles are colored. In another embodiment, each microencapsulated ink bead contains positively charged white particles and negatively charged black particles, all of which are suspended in oil in the beads. Thus, when a negative electric field is applied to such microencapsulated ink beads, negatively charged black particles migrate to the bottom of the microencapsulated ink beads and are hidden therein, while positively charged white particles move to the top of the microencapsulated ink beads There, the viewer can reflect visible white light. This process can be reversed by applying a positive electric field, in which case negatively charged black particles move to the top of the microencapsulated ink beads and absorb visible light there. Microencapsulated ink beads can be prepared by many conventional encapsulation techniques, such as those disclosed in US Pat. No. 6,067,185, which is incorporated herein by reference.

Many suitable procedures for microencapsulation are described in detail in the following two documents, which are incorporated herein by reference: Microencapsulation, Processes and Applications, I. Edited by I.E. Vandegaer, Plenum Press, New York, New York (1974); And Gutcho, Microcapsules and Microencapsulation Techniques, Nuyes Data Corp., Park Ridge, New Jersey (1976). Encapsulation methods fall into several general categories, namely interfacial polymerization, in situ polymerization, physical methods such as coextrusion and other phase separation methods, in-liquid curing, simple / complex coacervation, All can be applied to form electrically active beads for reflecting visible or other electromagnetic radiation. In one embodiment of making the microencapsulated ink beads, an oil phase comprising a mixture of positively charged particles, negatively charged particles, oil, and sebacoyl chloride (obtained from Aldrich) is subjected to a high speed such as 200-500 rpm at room temperature. It is dispersed in water with stirring to form a dispersion of oil droplets containing particles and dicarboxylic acid dichloride. Then, by adding an aqueous diamine solution to this dispersion, it reacts with the dicarboxylic acid dichloride at the interface between the droplets and the surrounding aqueous medium to form a polyamide shell around each droplet to form microencapsulated ink beads. Non-limiting examples of suitable dicarboxylic acid dichlorides include malonyl chloride, succinyl chloride, glutaryl chloride, adipyl chloride, pimeloyl chloride, subveroyl chloride, azeolaoyl chloride, sebacoyl chloride and terephthalo Monochloride chloride. Non-limiting examples of suitable diamines include 1,10-diaminodecane, 1,8-diaminooctane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1, 4-diaminobutane, 1,3-diaminopropane, 1,2-diaminoethane and 1,4-benzenediamine. Likewise, polyurea shells are used to convert dicarboxylic acid dichlorides into oil soluble diisocyanates such as methylene diphenyl diisocyanate, 1,6-hexamethylene diisocyanate, 1,5-naphthalene diisocyanate and 2,4-toluene diisocyanate. It can be formed by replacing. Similarly, the polyester shell is used to prepare diamines for ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decane It can be formed by replacing with a water-soluble diol such as diol and hydroquinone. Likewise, polyurethane shells can be formed by reacting water soluble diols with oil soluble diisocyanates. More detailed descriptions of the manufacture and application of microencapsulated ink beads are provided in US Pat. As incorporated herein by reference.

In another embodiment of interest, the electroactive particles of the visible light reflecting layer of the adaptive camouflage structure include liquid crystal polymer electroactive flakes or birefringent polymer electroactive flakes. Electroactive flakes can be prepared from liquid crystalline polymer materials such as pneumatic liquid crystalline polymer materials and cholesteric liquid crystalline polymer materials. In addition, electroactive flakes can be prepared from birefringent polymers having no liquid crystalline properties. Electroactive flakes can be prepared by casting a solvent-free film comprising a liquid crystal polymer or a birefringent polymer on a silicon substrate at elevated temperatures. Subsequently, liquid nitrogen is poured onto the silicon substrate to crush the cast film to obtain electroactive flakes. The size range of the electroactive flakes is 0.1 to 500 μm. The size of the electroactive flakes can be further reduced by conventional milling methods such as ball mills, sand mills and hammer mills.

The electroactive flakes can be dispersed in host fluids contained in the cavities throughout the host material in the visible light reflecting layer of the adaptive gastrointestinal structure. Alternatively, the electroactive flakes can be dispersed in a host fluid contained in microcapsules having a shell that is transparent to visible light. The preparation and application of liquid crystal polymers or birefringent polymer flakes is disclosed in US Pat. No. 6,665,042, which is incorporated herein by reference.

In general, the visible light reflecting layer reflects visible light from the sky and the surrounding environment into the visible light detector, thereby making the camouflaged object appear to be the surrounding environment. In some embodiments of interest, the visible light reflecting layer can be prepared by embedding a plurality of said visible reflecting electroactive particles in a host material such as crosslinked silicone, followed by curing and immersion in an oil such as silicone oil. The host material absorbs the oil and expands. The expansion process produces an oil filled microcavity that retains visible reflective electroactive particles. Visible light reflective electroactive particles can rotate within these cavities when a voltage is applied. The angle of rotation can be adjusted by the strength of the electric field. To overcome the adhesion between the visible reflective electroactive particles and the cavity walls, an electric field higher than the electrical threshold is applied before they rotate. This provides a stable visible image in the visible light reflecting layer, which remains until it is changed by the application of another electric field. The electrical signal applied in this way allows the various selected images to be placed on the visible light reflecting layer as desired.

The infrared reflecting layer 13 may comprise a host material that is sufficiently transparent to infrared light to allow at least a portion of the infrared spectrum to pass through. Optionally, the host material for the infrared reflecting layer 13 is sufficiently transparent to other electromagnetic radiation such as radio frequency, microwaves, ultraviolet light and combinations thereof to allow at least some of the other electromagnetic radiation to pass through. Non-limiting examples of suitable host materials for the infrared reflective layer 13 include polycarbonates, polyesters, polyamides such as nylon, polysiloxanes such as silicones and crosslinked silicones, polyethylene, polypropylene, and conductive Polymers such as polyaniline, polypyrrole, polythiophene, poly (p-phenylene), polyacetylene, poly (p-phenylenevinylene) and combinations thereof. A plurality of infrared reflective electroactive particles reflecting at least a portion of the infrared spectrum are embedded in the host material. The infrared reflective electroactive particles may be precisely or generally in the form of spheres, ovals, cylinders, discs, flakes, microcapsules or combinations thereof.

In some embodiments, the infrared reflective electroactive particles comprise infrared reflective electroactive beads or cylinders. Infrared reflective electroactive beads can be prepared by coating at least a portion of each of the anisotropic beads having a diameter of 10 μm to 1 mm with an infrared reflecting material. Similarly, infrared reflective electroactive cylinders can be made by coating at least a portion of each of the electrically anisotropic cylinders with an infrared reflective material. Electrically anisotropic beads or cylinders may be prepared in the same or similar manner as described above for dichroic beads or cylinders or multicolor split beads or cylinders.

The infrared reflectance of a material is its ability to reflect infrared light. Materials with high infrared reflectance generally reflect strongly, while materials with low infrared reflectance generally reflect very little. Thermally warm objects can be made colder in infrared detectors by using a material with a high infrared reflectance, causing their surface to reflect background infrared light. In general, the reflectivity of a material increases with increasing electron mobility of the material. In general, good electrical conductors with high electron mobility, such as metals, are highly reflective with an infrared reflectance greater than 50%. Non-limiting examples of good infrared reflecting materials (ie, materials having infrared reflectance greater than 50%) include metals and metal oxides. Poor electrical conductors such as glass and organic materials are generally very poor reflectors with low infrared reflectance (ie less than 50% infrared reflectance). In general, the sky and the surrounding environment of an object are thermally colder than objects camouflaged in the infrared region. The infrared reflecting layer 13 of the present invention reflects the lower level of infrared light from the sky and the surrounding environment into the infrared detector, while at the same time reflecting the infrared of the object away from the infrared detector, as if it is thermally cooler and the surrounding environment. By making it visible, it shields the temperature of the object.

Non-limiting specific examples of making infrared reflective electroactive beads or cylinders include infrared non-conductive materials such as metals and metal oxides, and non-conductive materials such as glass and organic materials (e.g. polyethylene) having an infrared reflectance of less than 50%. Coating on at least a portion of the bead or cylinder comprising. Beads are generally spherical or oval. Beads or cylinders have a size ranging from about 10 μm to about 1 mm. Non-limiting examples of suitable metals include aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, Silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium and lead, and metal alloys. Non-limiting examples of suitable metal oxides include indium oxide, tin oxide, indium tin oxide, cadmium stannate (Cd ₂ SnO ₄ ), copper doped cadmium stannate, stannic oxide and fluorine doped tin oxide. Since the nonmetallic and infrared reflective materials have different zeta potentials, the beads or cylinders obtained must exhibit electrical anisotropy and therefore be electrically active. Alternatively, infrared reflective electroactive beads can be prepared by coating by evaporation with an infrared reflective material on one hemisphere of glass beads having a low infrared reflectance of about 10 μm to 1 mm in diameter. The beads thus obtained must exhibit electrical anisotropy because the glass and infrared reflecting materials have different zeta potentials and therefore must be electrically active. Alternatively, infrared reflective electroactive beads or cylinders can be prepared by coating a material having a low infrared reflectance on at least a portion of a pre-coated metallized bead or cylinder having a high infrared reflectance.

The coating of beads or cylinders may be carried out in any manner conventional for the application of the particular coating material to be used, for example by liquid coating, fluidized bed coating, spraying, rotary atomization, monomer atomization / polymerization, deposition, sputter deposition, or the like. , Can be achieved. Optionally, the beads can be floated by acoustic levitation or by well known fluidized bed techniques.

In another embodiment of interest, the infrared reflective electroactive particles of the infrared reflective layer 13 comprise infrared reflective electroactive microcapsules. Each infrared reflective electroactive microcapsule contains a shell, an oil or liquid carrier in the shell, and a large number of two different kinds of particles having opposite charges or polarities dispersed in the liquid carrier. The first particles are a number of particles of electrically conductive material such as metals and metal oxides. The second particle is a large number of particles of electrically nonconductive material such as various glass and organic materials. The electrically conductive particles and the electrically nonconductive particles may be exactly or generally in the form of irregular shapes, spheres, beads, ovals, cylinders, disks, flakes or a combination thereof. Infrared reflective electrically active microcapsules are generally spherical or elliptical. In some embodiments, electrically conductive particles capable of reflecting infrared light are positively charged, and electrically nonconductive particles that do not reflect infrared light are negatively charged. When a negative electric field is applied to these infrared reflective electroactive microcapsules, the negatively charged non-reflective particles migrate to the bottom of the infrared reflective electroactive microcapsules and are hidden there, while the positively charged infrared reflective particles It can travel to the top of infrared reflective electrically active microcapsules and reflect infrared light therein. This process can be reversed by applying a positive electric field, in which case negatively charged particles move to the top of the infrared reflective electroactive microcapsules and absorb infrared radiation there.

In one embodiment of making infrared reflective microcapsules, an oil phase comprising a mixture of electrically conductive particles, electrically nonconductive particles, oil, and dicarboxylic acids such as sebacoyl chloride (obtained from Aldrich) is prepared at room temperature. It is dispersed in water with stirring at a high speed such as 500 rpm to form a dispersion of oil droplets containing particles and dicarboxylic acid dichloride. Aqueous diamine solution is then added to this dispersion, which reacts with the dicarboxylic acid dichloride at the interface between the droplets and the surrounding aqueous medium to form a polyamide shell around each droplet to form microencapsulated ink beads. Likewise, polyurea shells can be formed by replacing dicarboxylic acid dichlorides with diisocyanates that react with diamines. Likewise, polyester shells can be formed by replacing diamines with diols that react with dicarboxylic acid dichlorides. Similarly, polyurethane shells can be formed by reacting diols with diisocyanates. Non-limiting examples of suitable oil or liquid carriers for the oil phase are straight chain, branched chain and cycloaliphatic hydrocarbons such as petroleum oil, naphtha, ligroin, hexane, pentane, heptane, octane, isododecane, isononane and cyclo Hexane; Aromatic hydrocarbons such as benzene, toluene and xylene; Halocarbon liquids such as 1,1,2-trichloro-1,2,2-trifluoroethane, trichloromonofluoromethane and carbon tetrachloride; And isoparaffinic hydrocarbons such as various Isopar ™ carrier liquids (Exxon Company, Houston, Tex.) And Norpar ™ carrier liquids ( ExxonMobile Chemical, Houston, Texas, USA. The size of the infrared reflective electroactive microcapsules can vary from 1 to 1000 μm.

In some embodiments, the infrared reflective electrically conductive particles comprise aluminum, gold, silver, indium oxide, tin oxide, indium tin oxide, cadmium stannate (Cd ₂ SnO ₄ ), copper doped cadmium stannate, stannic tin and fluorine doped oxidant. Particles of metals and metal oxides, such as tin. In another embodiment of interest, the size of the metal particles ranges from 1 nm to 1 μm. Infrared reflective metal particles can be prepared according to methods known in the art, such as metal salt reduction, metal evaporation, surfactant stabilized metal dispersion, and methods disclosed in US Pat. , All of which are incorporated herein by reference. In a further embodiment of interest, the infrared non-reflective particles are particles of glass or organic materials such as plastics and elastomers. Metal loading in infrared reflective electroactive microcapsules can range from 0.01 to 5.0 g per 100 ml of oil.

In another embodiment of interest, the infrared reflective electroactive particles of the infrared reflective layer 13 comprise infrared reflective electroactive microcapsules. Each infrared reflective electroactive microcapsule contains a shell, an oil or liquid carrier in the shell, and a plurality of infrared reflective flakes dispersed in the liquid carrier. Infrared reflective electrically active microcapsules are generally spherical or elliptical. Infrared reflective flakes can be prepared by casting a solvent-free film comprising a liquid crystal polymer or a birefringent polymer on a silicon substrate at elevated temperatures. The outer surface of the cast film is then irradiated with infrared reflective metals such as aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium , Ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium and lead, and metal alloys. The metal coating can be applied with any conventional coating apparatus. Non-limiting examples of suitable coating apparatuses include chemical vapor deposition systems such as plasma enhanced CVD systems, model PD-200D (available from SAMCO, Sunnyvale, Calif.), PECVD systems, model NPE-4000 ( Nano-master (available from Austin, Texas), Ultra-High Vacuum CVD Process System, Model UHV-CVD-5000 (tech-back industries) Tek-Vac Industries (available from Brentwood, NY); Sputtering systems such as sputter coaters, models NSC 4000 and 3000 (available from Nano-Master (Austin, Texas, USA)) and Explorer® (EXPLORER ™) 14 Magnetron Sputtering System, Discovery DISCOVERY® 18 DC / RF Research Magnetron Sputter Deposition System, Discovery 24 Multi-Cathode DC / RF Magnetron Sputter System System, and Bench Top Turbo IV High Vacuum Deposition System (all of which are available from Denton Vacuum, Moorestown, NJ); Gas evaporation reactors such as those described in US Pat. No. 4,871,790, which is incorporated herein by reference; Klabundle-style static reactor; And a rotary reactor of Torrovap ™ design (available from Torrovap Industries, McHam, Ontario, Canada). Liquid nitrogen is then poured over the silicon substrate to crush the metallized coating into a plurality of electrically active infrared reflective flakes. The electrically active infrared reflective flakes can be dispersed in oil and then converted to microcapsules according to the encapsulation technique described above.

Optionally, surfactants may be used to promote dispersion of infrared reflective flakes, electrically conductive particles or electrically nonconductive particles in oil. Non-limiting examples of suitable surfactants for infrared reflective flakes and electrically conductive particles include epoxide terminated polyisobutylenes such as Actipol ™ E6, E16 and E23 (Amoco Chemical Co. (Amoco Chemical Co.) (available from Chicago, Illinois); Commercial oil additives such as Lubrizol ™ 6401 and Lubrizol 6418 (available from The Lubrizol Corporation, Wycliffe, Ohio), Amoco® 9250 (available from AMOCO Petroleum Additives Company, Naperville, Ill.), And Oloa® (OLOA ™) (succinimide Low molecular weight polyisobutylene (available from Chevron Chemical Company, San Francisco, Calif.) Attached to the diamine head group via a bond; and hydrocarbon compatible superdispersants, such as Solspers®. (Solsperse ™) 17,000 (available from ICI Americas Inc., Wilmington, Delaware) Generally, the concentration of surfactant is based on total fluids. In the range 0.001 to 10.0 g / 100 mL.

Optionally, a charge director or charge control agent may be used to control the charge of the infrared reflective flakes, electrically conductive particles, or electrically nonconductive particles. The charge director can impart a positive or negative charge to the particles or flakes. Non-limiting examples of suitable positive charge directors include organic acid metal salts consisting of polyvalent metal ions and organic anions that are counter ions. Non-limiting examples of suitable metal ions include Ba (II), Ca (II), Mn (II), Zn (II), Zr (IV), Cu (II), Al (III), Cr (III), Fe (II), Fe (III), Sb (III), Bi (III), Co (II), La (III), Pb (II), Mg (II), Mo (III), Ni (II), Ag (I), Sr (II), Sn (IV), V (V), Y (III) and Ti (IV). Non-limiting examples of suitable organic anions are aliphatic or aromatic carboxylic acids or sulfonic acids, preferably fatty acids such as stearic acid, behenic acid, neodecanoic acid, diisopropylsalicylic acid, abietic acid, naphthenic acid, octanoic acid Carboxylates or sulfonates derived from lauric acid, deoxidation, and the like. In some embodiments, the positive charge director is a metal carboxylate (soap) described in US Pat. No. 3,411,936, comprising alkaline earth metal and heavy metal salts of cycloaliphatic acids, including fatty acids containing at least 6-7 carbons and naphthenic acid. This document is incorporated herein by reference. In another embodiment, the positive charge director is a polyvalent metal soap of zirconium and aluminum. In a further embodiment, the positive charge director is zirconium soap (zirconium HEX-CEM) of octanoic acid (Mooney Chemicals, Cleveland, Ohio). Non-limiting examples of suitable negative charge directors include polymers or copolymers of nitrogen-containing monomers, quaternary ammonium block copolymers, lecithin, basic metal petronates, such as basic barium petronates, basic calcium petronates and basic sodium petronates, metals Naphthenate compounds, and polyisobutylene succinimide, available as OLOA ™ 1200 (Chevron Oronite Company LLC, Houston, TX), and others. And so on. Non-limiting examples of nitrogen-containing monomers include (meth) acrylates with aliphatic amino groups, vinyl monomers with nitrogen-containing heterocyclic rings, cyclic amide monomers with N-vinyl substituents, (meth) acrylamides, nitrogen-containing groups Aromatic substituted ethylenic monomers, nitrogen-containing vinyl ether monomers, and the like. In some embodiments, the negative charge directors are lecithin, basic metal petronates, and polyisobutylene succinimide. The charge director level depends on many factors, including the chemical composition of the dispersion and the particle size of the electrically active infrared reflective particles or flakes. One skilled in the art knows how to adjust the level of charge director based on the parameters described to achieve the desired result for their particular application.

In some embodiments of interest, the infrared reflecting layer 13 may be prepared by embedding a plurality of said infrared reflecting electroactive particles in a host material such as crosslinked silicone, followed by curing and immersion in an oil such as silicone oil. The host material absorbs the oil and expands. The expansion process produces an oil filled microcavity that retains infrared reflective electroactive particles. Infrared reflective electroactive particles can rotate within these cavities when a voltage is applied. The angle of rotation can be adjusted by the strength of the electric field. To overcome the adhesion between the infrared reflective electroactive particles and the cavity walls, an electric field higher than the electrical threshold is applied before they rotate. The application of this electric field provides a stable image which remains on the infrared reflecting layer 13 until it is changed by the application of another magnetic field. The electrical signal applied in this way allows the selected image to be placed on the infrared reflecting layer 13 as desired.

In general, good electrical conductors, such as metals, have high radio frequency reflectivity. Non-limiting examples of preferred radar reflective materials include metals such as aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium Ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium and lead, and metal alloys. Poor electrical conductors, such as various glass and organic materials, have little electron mobility and thus low radio frequency reflectivity. The radar reflector layer will reflect lower levels of radio frequency coming from the sky and the surrounding environment into the radar detector and at the same time reflect all other radio frequencies away from the radar detector, making the camouflaged object appear to be the surrounding environment.

The radar reflecting layer 23 may comprise a host material that is sufficiently transparent to radio frequencies to allow at least a portion of the radio frequency spectrum to pass through. Optionally, the host material for the radar reflecting layer may be sufficiently transparent to one or more other electromagnetic radiations such as infrared, microwaves and ultraviolet light. Non-limiting examples of suitable host materials for the radar reflective layer include polycarbonates, polyesters, polyamides (such as nylon), polysiloxanes (such as silicones and crosslinked silicones), polyethylene, polypropylene, and conductive polymers, such as Polyaniline, polypyrrole, polythiophene, poly (p-phenylene), polyacetylene, poly (p-phenylenevinylene) and combinations thereof. A number of radar reflective electroactive particles are embedded in the host material that can reflect at least a portion of the radio frequency spectrum. In some embodiments of interest, the radar reflective electroactive particles comprise radar reflective beads or cylinders. Radar reflective beads can be prepared by coating electrically anisotropic beads having a diameter of 10 μm to 1 mm with a radar reflective material. Similarly, radar reflective cylinders can be made by coating an electrically anisotropic cylinder with a radar reflective material. Electrically anisotropic beads or cylinders may be prepared in the same or similar manner as described above for dichroic beads or cylinders or multicolor split beads or cylinders.

Since metal is a good infrared reflecting material and also a radar reflecting material, the infrared reflecting microcapsules containing metal particles or flakes can be used as radar reflecting electrically active microcapsules for reflecting radio frequencies. In some embodiments of interest, the radar reflective electroactive particles in the radar reflective layer 23 comprise radar reflective electroactive microcapsules.

In some embodiments of interest, the radar reflective layer 23 can be prepared by embedding a plurality of the radar reflective electroactive particles in a host material such as crosslinked silicone, and then curing and immersing in an oil such as silicone oil. The host material absorbs the oil and expands. The expansion process produces an oil filled microcavity that retains radar reflective electroactive particles. Radar reflective electroactive particles can rotate within these cavities when a voltage is applied. The angle of rotation can be adjusted by the strength of the electric field. To overcome the adhesion between the radar reflective electroactive particles and the cavity walls, an electric field higher than the electrical threshold is applied before they rotate. The application of this electric field provides a stable image that remains in the radar reflecting layer 23 until it is changed by the application of another electric field. The electrical signal applied in this way allows the selected image to be placed on the radar reflecting layer 23 as desired.

In some embodiments of interest, one of the layers of the adaptive camouflage structure can include a UV reflecting layer. The UV reflecting layer may comprise a host material that is sufficiently transparent to ultraviolet light to allow at least a portion of the UV spectrum to pass through. Optionally, the host material for the UV reflecting layer can be sufficiently transparent to one or more other electromagnetic radiations, such as infrared, microwaves, and radio frequencies. Non-limiting examples of suitable host materials for the UV reflective layer include polycarbonates, polyesters, polyamides such as nylon, polysiloxanes such as silicones and crosslinked silicones, polyethylene, polypropylene, and conductive polymers, such as Polyaniline, polypyrrole, polythiophene, poly (p-phenylene), polyacetylene, poly (p-phenylenevinylene) and combinations thereof. A number of UV reflective electroactive particles are embedded within the host material that can reflect at least a portion of the UV spectrum. In some embodiments of interest, the UV reflective electroactive particles comprise UV reflective electroactive beads or cylinders. UV reflective electroactive beads can be prepared by coating electrically anisotropic beads having a diameter of 10 μm to 1 mm with a UV reflective material. Likewise, UV reflective electroactive cylinders can be prepared by coating the electrically anisotropic cylinder with a UV reflective material. Electrically anisotropic beads or cylinders may be prepared in the same or similar manner as described above for dichroic beads or cylinders or multicolor split beads or cylinders.

In general, good electrical conductors, such as metals, have high UV reflectance. Non-limiting examples of good UV reflecting materials include metals such as aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium Ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium and lead, and metal alloys. Poor electrical conductors, such as various glass and organic materials, have little electron mobility and thus low UV reflectivity. In general, the UV reflecting layer can reflect lower levels of ultraviolet light from the sky and the surrounding environment into the UV detector, while at the same time reflecting all other ultraviolet light away from the UV detector, making the camouflaged object appear to be the surrounding environment. .

Since the metal is a good infrared reflecting material and also a UV reflecting material, the infrared reflecting microcapsules containing metal particles or flakes can be used as UV reflecting microcapsules for reflecting ultraviolet light. In some embodiments of interest, the UV reflective electroactive particles in the UV reflective layer comprise UV reflective electroactive microcapsules.

In some embodiments of interest, a UV reflecting layer can be prepared by embedding a plurality of said UV reflecting electroactive particles in a host material such as crosslinked silicone, followed by curing and immersion in an oil such as silicone oil. The host material absorbs the oil and expands. The expansion process produces an oil filled microcavity that retains the UV reflective electroactive particles. UV reflective electroactive particles can rotate within these cavities when a voltage is applied. The angle of rotation can be adjusted by the strength of the electric field. To overcome the adhesion between the UV reflective electroactive particles and the cavity walls, an electric field above the electrical threshold is applied before they rotate. The application of this electric field provides a stable image that remains in the UV reflecting layer until it is changed by the application of another electric field. The electrical signal applied in this way allows the selected image to be placed on the UV reflecting layer as desired.

In some embodiments of interest, one of the layers of the adaptive camouflage structure of the present invention may comprise a microwave reflective layer. The microwave reflective layer may comprise a host material that is sufficiently transparent to microwaves to allow at least a portion of the microwave spectrum to pass through. Optionally, the host material for the microwave reflective layer may be sufficiently transparent to one or more other electromagnetic radiations such as infrared, UV and radio frequencies. Non-limiting examples of suitable host materials for the microwave reflective layer include polycarbonates, polyesters, polyamides such as nylon, polysiloxanes such as silicones and crosslinked silicones, polyethylene, polypropylene, and conductive polymers, such as Polyaniline, polypyrrole, polythiophene, poly (p-phenylene), polyacetylene, poly (p-phenylenevinylene) and combinations thereof. A number of microwave reflective electroactive particles are embedded within the host material that can reflect at least a portion of the microwave spectrum. In some embodiments, the microwave reflective electroactive particles comprise microwave reflective electroactive beads or cylinders. Microwave reflective electroactive beads can be prepared by coating electroisotropic beads having a diameter of 10 μm to 1 mm with a microwave reflective material. Likewise, microwave reflective electroactive cylinders can be prepared by coating an electrically anisotropic cylinder with a microwave reflective material. Electrically anisotropic beads or cylinders may be prepared in the same or similar manner as described above for dichroic beads or cylinders or multicolor split beads or cylinders.

In general, good electrical conductors, such as metals, have high microwave reflectivity. Non-limiting examples of preferred microwave reflective materials include metals such as aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium Ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium and lead, and metal alloys. Poor electrical conductors such as various glass and organic materials have little electron mobility and thus low microwave reflectivity. In general, the microwave reflective layer will reflect lower levels of microwaves from the sky and the surrounding environment into the microwave detector, thereby making the camouflaged object appear to be the surrounding environment.

Since the metal is a good infrared reflecting material and also a microwave reflecting material, the infrared reflecting microcapsules containing metal particles or flakes can be used as microwave reflecting microcapsules for reflecting microwaves. In some embodiments of interest, the microwave reflective electroactive particles in the microwave reflective layer comprise microwave reflective microcapsules.

In some embodiments of interest, the microwave reflective layer can be prepared by embedding a plurality of said microwave reflective electroactive particles in a host material such as crosslinked silicone, and then curing and immersing in an oil such as silicone oil. The host material absorbs the oil and expands. The expansion process produces an oil filled microcavity containing microwave reflective electroactive particles. Microwave reflective electroactive particles can rotate within these cavities when a voltage is applied. The angle of rotation can be adjusted by the strength of the electric field. To overcome the adhesion between the microwave reflective electroactive particles and the cavity walls, an electric field higher than the electrical threshold is applied before they rotate. The application of this electric field provides a stable image that remains in the microwave reflecting layer until it is changed by the application of another electric field. The electrical signal applied in this way allows the selected image to be placed on the microwave reflective layer as desired.

7 illustrates a unique but non-limiting method of making infrared reflective beads, radar reflective beads, UV reflective beads or microwave reflective beads. Two curable liquid materials 106 and 107 are applied by the delivery means (not shown) to the opposite sides 104, 105 of the rotating disk 102 which rotate evenly around the shaft 103. . The curable liquid materials 106, 107 may each independently comprise a molten liquid such as molten carnauba wax and molten polyethylene. Because of the centrifugal force, the curable liquid materials 106, 107 flow toward the periphery of the disk 102, where they merge at the edges to form the liquid stream 108, which is unstable and eventually breaks up to become the beads 109. The beads may be solidified by cooling at room temperature or the cooling may be accelerated by passing the liquid beads through a cooling zone containing cold liquid nitrogen vapor (not shown). In some embodiments, one of the curable liquid materials may further comprise particles or flakes comprising an infrared reflecting material, a radar reflecting material, a UV reflecting material or a microwave reflecting material. Thus, each of the beads 109 has one hemisphere containing particles or flakes of infrared reflective material, such as aluminum, radar reflective material, UV reflective material or microwave reflective material, and the other hemisphere that does not contain them.

In other embodiments, the curable liquid materials 106 and 107 are the same. Reflective beads 109 are used for coating the solidified beads using a coating device 81 which emits microdroplets or vapors 83 of reflective material 82 on one hemisphere of each solidified bead. By coating with a reflective material 82, such as a UV reflective material and a microwave reflective material. Non-limiting examples of coating apparatuses include those described in gas evaporation reactors, for example US Pat. No. 4,871,790, which is incorporated herein by reference; Clavand-style static reactor; And a rotary reactor of Torosham® design (available from Toroham Industries, McHam, Ontario, Canada); Chemical vapor deposition systems such as plasma enhanced CVD systems, model PD-200D (available from Samco (Sunnyvale, Calif.)), PECVD system, model NPE-4000 (available from Nano-Master (Austin, Texas, USA) ), Ultra-high bakeum CVD process system, model UHV-CVD-5000 (available from Tek-Back Industries, Brentwood, NY); Sputtering systems such as sputter coaters, models NSC 4000 and 3000 (available from Nano-Master (Austin, TX)) and Explorer® 14 Magnetron Sputtering System, Discovery® 18 DC / RF Research Magnetron Sputter Deposition System, Discovery® 24 Multi-cathode DC / RF Magnetron Sputter System, and Benchtop Turbo IV High Vaccum Deposition System (all of which are available from Denton Baccum, Moorestown, NJ) ).

8 illustrates another unique but non-limiting method of making infrared reflective beads, radar reflective beads, UV reflective beads or microwave reflective beads. Two curable liquid materials 106 and 107 are applied to the opposite sides of the double barrel nozzle 91 by delivery means (not shown). The curable liquid materials 106, 107 may each independently comprise a molten liquid such as molten carnauba wax and molten polyethylene. The curable liquid materials 106 and 107 are filled by the anode 95 and the cathode 96 to join the beads 120 having a dipole moment injected and joined by electrostatic attraction at the outlet of the double barrel nozzle 91. Form. In some embodiments, one of the curable liquid materials may further comprise particles or flakes comprising an infrared reflecting material, a radar reflecting material, a UV reflecting material or a microwave reflecting material. Thus, each of the beads 120 has one hemisphere containing particles or flakes of infrared reflective material, such as aluminum, radar reflective material, UV reflective material or microwave reflective material, and the other hemisphere that does not contain them. In other embodiments, the curable liquid materials 106 and 107 are the same. Reflective beads 120 use infrared reflecting material, radar reflecting material using coating device 81 which emits solidified beads onto microspheres or vapor 83 of reflective material 82 on one hemisphere of each solidified bead. By coating with a reflective material 82, such as a UV reflective material and a microwave reflective material. Non-limiting examples of coating apparatus include chemical vapor deposition systems and sputtering systems such as those described above.

The desired camouflage image of each reflective layer of the adaptive gastrointestinal construct of the present invention can be determined by one or a combination of methods known in the art. These methods range from pre-programmed images to actively changing images generated by sensors that monitor changes in indigenous environments, for example, due to vehicle motion or changing light conditions. Some of the conventional methods of determining the desired image are disclosed in US Pat. Nos. 6,682,879, 6,342,290 and 5,307,162, all of which are incorporated herein by reference.

Once desired, a desired camouflage image of each reflective layer of the adaptive camouflage structure of the present invention is selected. The desired camouflage image of the reflective layer of the adaptive camouflage structure can be generated using adjustable voltage pattern interlayers adjacent to the reflective layer to adjust the camouflage image reflected by the layer. Each adjustable voltage pattern intermediate layer is a conventional addressing scheme, such as the oblique electric field electrode type of US Patent 5,717,515, a multithreshold addressing system of US Patent 5,739,801, a dual vector field addressing system of US Patent 6,690,350, and US Pat. 6,504,524 and 6,445,489, various addressing systems such as conventional addressing schemes, all of which are incorporated herein by reference.

In some interesting embodiments, each adjustable voltage pattern interlayer includes an active matrix addressing scheme. The active matrix addressing scheme divides each reflective layer into an array of micro cells defined by columns and rows. Each cell represents one pixel and typically contains one thin film transistor for each cell. Each thin film transistor regulates the voltage applied to at least one reflective electroactive particle to adjust their orientation to reflect a particular radiation such as visible light, ultraviolet light, infrared light, microwave and / or radio frequency. In some embodiments, the active matrix addressing scheme regulates the voltage of each cell by the following procedure:

(1) The selected voltage is applied to the gates of one selected row (e.g., the first row) of the active matrix, while the unselected voltage is applied to the gates of all other rows.

(2) A data voltage is simultaneously applied to all the electrodes of each column to charge each pixel of the selected row to the desired voltage.

(3) Charges the selected voltage applied to the gates of the selected row to an unselected voltage.

(4) Repeat steps 1 to 3 for each subsequent row until all rows are selected and the pixels are charged to the desired voltage.

In another interesting embodiment, the addressing scheme includes two electrode assemblies located on each side of the reflective layer containing reflective electroactive particles. Both electrode assemblies are made of optically transparent conductors with very high reflectivity. Divide each electrode assembly into rectangular regions. Rectangular areas are separated by high reflectivity partition walls, which may be made of glass or other substrate materials. Both electrode assemblies can be connected to a power source. Within each rectangular area are located bus bars which can be individually addressed. The electrode busbar of one electrode is located parallel to it directly above the electrode busbar of the other electrode. The voltage at each individual busbar can be set using active matrix addressing electronics. Thus, each rectangular area can be addressed separately. Such electrode forms are described in US Pat. No. 6,492,967, which is incorporated herein by reference.

In a further embodiment of interest, each reflective layer of the adaptive camouflage structure of the present invention may be addressed separately from the other reflective layer by one of the addressing schemes. In a further embodiment of interest, if the reflective electroactive particles of the different layers of the adaptive gastrointestinal structure have different rotational thresholds, a single addressing scheme can be used to adjust all the reflective layers of the adaptive gastrointestinal structure. 9, visible light reflective electroactive particles 60 begin to rotate in visible light reflecting layer 3 only when high voltage V ₁ is applied, and infrared reflecting light in infrared reflecting layer 13 when medium voltage V _{2 is} applied. If the electroactive particles 61 begin to rotate and the radar reflective electroactive particles 62 in the radar reflecting layer 23 begin to rotate upon application of low voltage V ₃ , addressing the reflective electroactive particles of all three layers. An adjustable voltage pattern interlayer 40 can be used that includes a single addressing scheme. For example, application of high voltage V ₁ will cause the reflective electroactive particles 60, 61, and 62 of all three layers to rotate. Application of the intermediate voltage V ₂ will cause the infrared reflective electroactive particles 61 and the radar reflective electroactive particles 62 to rotate. Application of low voltage V ₃ will cause only the radar reflective electroactive particles 62 to rotate. Thus, the continuous application of high addressing voltage, medium addressing voltage and low addressing voltage can rotate all three layers of reflective electroactive particles as desired.

The above embodiments are intended to be illustrative and not restrictive. Further embodiments are within the scope of the following claims. While the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes may be made in appearance and detail without departing from the spirit and scope of the invention.

Claims (44)

An electroactive microcapsule comprising a shell and a mixture comprising oil in the shell, a plurality of metal particles and a plurality of electrically nonconductive particles, wherein the plurality of metal particles and the plurality of electrically nonconductive particles have opposite charges. . The electroactive microcapsule according to claim 1, wherein the oil is selected from the group consisting of straight chain, branched chain and cycloaliphatic hydrocarbons, aromatic hydrocarbons, halocarbon liquids and isoparaffinic hydrocarbons. The electroactive microcapsule of claim 1, wherein the concentration of the plurality of metal particles is in the range of 0.01 to 5.0 g of metal particles per 100 ml of oil. The method of claim 1, wherein the metal particles are aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium Electricity, which is a particle of a metal selected from the group consisting of silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium, lead and combinations thereof Active microcapsules. The electroactive microcapsule of claim 1, wherein the metal particles are generally in the form of spheres, beads, ovals, cylinders, disks, flakes or combinations thereof. The electroactive microcapsule of claim 1, wherein the electrically nonconductive particles are particles of an electrically nonconductive material selected from the group consisting of glass and organic materials. The electroactive microcapsules of claim 1, wherein the electrically nonconductive particles are generally in the form of spheres, beads, ovals, cylinders, discs, flakes or combinations thereof. 2. The electroactive microcapsule of claim 1, wherein the metal particles are positively charged and the electrically nonconductive particles are negatively charged. The electroactive microcapsule of claim 1, wherein the metal particles are negatively charged and the electrically nonconductive particles are positively charged. The electroactive microcapsule of claim 1, wherein the shell comprises a polymer derived from diamine and dicarboxylic acid dichloride. The diamine according to claim 10, wherein the diamine is 1,10-diaminodecane, 1,8-diaminooctane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1, An electrically active microcapsule selected from the group consisting of 4-diaminobutane, 1,3-diaminopropane, 1,2-diaminoethane and 1,4-benzenediamine. The dicarboxylic acid dichloride according to claim 10, wherein the dicarboxylic acid dichloride is malonyl chloride, succinyl chloride, glutaryl chloride, adipyl chloride, pimeloyl chloride, subveroyl chloride, azeolaoyl chloride, sebacoyl chloride and terephthalo An electrically active microcapsule selected from the group consisting of monochloride. The electroactive microcapsule of claim 1, wherein the shell comprises a polymer derived from diisocyanate and diamine or diol. The method of claim 13, wherein the diamine is 1,10-diaminodecane, 1,8-diaminooctane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1, Electroactive microcapsules selected from the group consisting of 4-diaminobutane, 1,3-diaminopropane, 1,2-diaminoethane and 1,4-benzenediamine. The method of claim 13, wherein the diol is ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decane Electroactive microcapsules selected from the group consisting of diols and hydroquinones. The electroactive microcapsule according to claim 13, wherein the diisocyanate is selected from the group consisting of methylene diphenyl diisocyanate, 1,6-hexamethylene diisocyanate, 1,5-naphthalene diisocyanate and 2,4-toluene diisocyanate. The electroactive microcapsule of claim 1, wherein the shell comprises a polymer derived from diol and dicarboxylic acid dichloride. 18. The process of claim 17, wherein the diol is ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decane Electroactive microcapsules selected from the group consisting of diols and hydroquinones. 18. The dicarboxylic acid dichloride of claim 17 wherein the dicarboxylic acid dichloride is malonyl chloride, succinyl chloride, glutaryl chloride, adipyl chloride, pimeloyl chloride, subveroyl chloride, azeolayl chloride, sebacoyl chloride and terephthalo An electrically active microcapsule selected from the group consisting of monochloride. The electroactive microcapsule of claim 1, wherein the mixture further comprises a positive charge director, a negative charge director, or a combination thereof. The electroactive microcapsule of claim 1, wherein the mixture further comprises a surfactant. The method of claim 21 wherein the surfactant is selected from the group consisting of epoxide terminated polyisobutylene, commercial oil additives, low molecular weight polyisobutylene attached to diamine head groups via succinimide linkages, and hydrocarbon compatible superdispersants. Electroactive microcapsules. A coating of electrically nonconductive particles and a reflective material, the coating covering a portion of the electrically nonconductive particle, the reflective material being an infrared reflective material, a radar reflective material, a microwave reflective material, a UV reflective material, and combinations thereof Electroactive particles selected from the group consisting of. The electroactive particle of claim 23, wherein the coating generally covers half of the electrically nonconductive particle. The electroactive particles of claim 23, wherein the electroactive particles are generally in the form of beads or cylinders. The electroactive particle of claim 23, wherein the electrically nonconductive particle comprises a glass or an organic material. The method of claim 23, wherein the reflective material is aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium Electricity comprising a metal selected from the group consisting of silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium, lead and combinations thereof Active particles. An electroactive microcapsule comprising a shell and a mixture comprising a plurality of flakes of oil and polymer inside the shell, the metal layer coated on one of the flat surfaces of each flake. 29. The process of claim 28 wherein the metal is aluminum, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, Electroactive microcapsules selected from the group consisting of silver, cadmium, indium, tin, antimony, lanthanum, gadolinium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium, lead, and combinations thereof. 29. The electrically active microcapsule of claim 28, wherein the oil is selected from the group consisting of straight chain, branched chain and cycloaliphatic hydrocarbons, aromatic hydrocarbons, halocarbon liquids and isoparaffinic hydrocarbons. The electroactive microcapsule of claim 28, wherein the polymer comprises a liquid crystal polymer or a birefringent polymer. 29. The electrically active microcapsule of claim 28, wherein the shell comprises a polymer derived from diamine and dicarboxylic acid dichloride. 33. The composition of claim 32 wherein the diamine is 1,10-diaminodecane, 1,8-diaminooctane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1, Electroactive microcapsules selected from the group consisting of 4-diaminobutane, 1,3-diaminopropane, 1,2-diaminoethane and 1,4-benzenediamine. The dicarboxylic acid dichloride according to claim 32, wherein the dicarboxylic acid dichloride is selected from malonyl chloride, succinyl chloride, glutaryl chloride, adipyl chloride, pimeloyl chloride, subveroyl chloride, azeolaoyl chloride, sebacoyl chloride and terephthalo An electrically active microcapsule selected from the group consisting of monochloride. 29. The electrically active microcapsule of claim 28, wherein the shell comprises a polymer derived from diisocyanate and diamine or diol. 36. The compound of claim 35, wherein the diamine is 1,10-diaminodecane, 1,8-diaminooctane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1, Electroactive microcapsules selected from the group consisting of 4-diaminobutane, 1,3-diaminopropane, 1,2-diaminoethane and 1,4-benzenediamine. The method of claim 35, wherein the diol is ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decane Electroactive microcapsules selected from the group consisting of diols and hydroquinones. 36. The electrically active microcapsule according to claim 35, wherein the diisocyanate is selected from the group consisting of methylene diphenyl diisocyanate, 1,6-hexamethylene diisocyanate, 1,5-naphthalene diisocyanate and 2,4-toluene diisocyanate. 29. The electrically active microcapsule of claim 28, wherein the shell comprises a polymer derived from diol and dicarboxylic acid dichloride. 40. The process of claim 39 wherein the diol is ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decane Electroactive microcapsules selected from the group consisting of diols and hydroquinones. 40. The dicarboxylic acid dichloride according to claim 39, wherein the dicarboxylic acid dichloride is malonyl chloride, succinyl chloride, glutaryl chloride, adipyl chloride, pimeloyl chloride, subveroyl chloride, azeolayl chloride, sebacoyl chloride and terephthalo An electrically active microcapsule selected from the group consisting of monochloride. The electroactive microcapsule of claim 28, wherein the mixture further comprises a positive charge director, a negative charge director, or a combination thereof. The electroactive microcapsule of claim 28, wherein the mixture further comprises a surfactant. 44. The surfactant of claim 43, wherein the surfactant is selected from the group consisting of epoxide terminated polyisobutylene, commercial oil additives, low molecular weight polyisobutylene attached to diamine head groups via succinimide linkages, and hydrocarbon compatible superdispersants. Electroactive microcapsules.

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