But Nickel has patience. After spending thousands and thousands hours in the laboratory, he finally mixed the paint he was looking for. He sent a can of it to Helmut Essen, a radiation physicist who runs the radar technology department at the Research Establishment for Applied Science (FGAN) near Bonn. Essen examined Nickel's paint and was surprised to learn that it works "and for all militarily relevant frequencies," he says.
Now, Craig Hawker and colleagues at the University of California, Santa Barbara, have come up with a synthetic version of the colour-changing structures in cuttlefish cells. They created self-assembling ellipsoid particles that act like Bragg reflectors using poly(styrene-b-2-vinylpyridine) diblock copolymers and surfactant coated gold nanoparticles.
POPULAR SCIENCE that an even more exotic skin is being tested on two stealth aircraft at the high-security Groom Lake air base in Nevada. The skin is derived from an electromagnetically conductive polyaniline-based radar-absorbent composite material. It is optically transparent except when electrically charged, much like the LCDs used in laptop computers.
What makes this new material attractive is that it can change brightness and color instantaneously. Photo-sensitive receptors, mounted on all sides of the plane, read the ambient light and color of the sky and ground. An onboard computer adjusts thebrightness, hue, and texture of the skin to match the sky above the plane or the terrain below it.
The system is also claimed to make the aircraft even stealthier. The electrically charged skin dissipates radar waves, reducing the range of detection
"We're also developing a nonlinear coating that would bend light a certain way," he continued. "This is playing with luminescence and fluorescence. If you can blur the edges, it makes it very difficult to focus on an object. It gives it sort of a shimmer, like you see sometimes with distant objects on a hot day." Chameleon-like color changes and blurry edges could "buy the pilot a couple of seconds," Curran said.
Low observable coatings render IR detection of an object more difficult. These coatings are multipurpose materials that may be tuned for specific missions, or used in standard configurations. For example, they may be designed solely for IR stealth (without compromising the radar cross section of the host), or for both IR and radar stealth simultaneously.
However, the general conclusion is that INTERMAT coatings can protect any object. Tanks, armoured vehicles, carriers, artillery, rocket launchers, radar & communication systems, trucks, helicopters and any naval vessel can be rendered virtually undetectable from the IR enemy devices like Thermal Viewers, FLIR systems, NVGs, weapon thermal - IR sensors, etc. working in the spectrums between 600-14.000 nm.
Full link to the downloadable PDF file that explains the entire experiment
We farted around with cholesteric coatings for a while - you can change the colors with a pulse and they stay changed until you reprogram them. You just can't get enough gamut yet. But if you could, it would make great chameleonics.
Also, even back in WW2, we "stealthed" planes by illuminating the wings during the daytime. If you match the sky's brightness with the wing lights, a spotter's eyes will edit out the plane details and you just don't see them at all. It doesn't even have to be that close.
Ain't stochastic filtering systems grand? They work great for a lot of real world biological systems like your sight and hearing, but they've got holes you can exploit.
reply to post by Astr0
I have a few articles on metamaterials that I'll share once I get onto my laptop, there's some quite interesting things you can do with them, especially negative index metamaterials.
I can only suspect that there may be have been tests done on aircraft using these but articles come and go which means that they could of gone black.
Conducting polymers are excellent microwave absorbers and they show technological advantage when compared with inorganic electromagnetic absorbing materials, being light weight, easily processable, and the ability of changing the electromagnetic properties with nature and amount of dopants, synthesis conditions, etc.
In this paper we report the synthesis, dielectric properties, and expected application of conducting composites based on polyaniline (PAN). Cyclohexanone soluble conducting PAN composites of microwave conductivity 12.5 S/m was synthesized by the in situ polymerization of aniline in the presence of emulsion grade polyvinyl chloride. The dielectric properties of the composites, especially the dielectric loss, conductivity, dielectric heating coefficient, absorption coefficient, and penetration depth, were studied using a HP8510 vector network analyzer.
The microwave absorption of the composites were studied at different frequency bands i.e, S, C, and X bands (2–12 GHz). The absorption coefficient was found to be higher than 200 m−1 and it can be used for making microwave absorbers in space applications. POLYM. COMPOS., 28:588–592, 2007. © 2007 Society of Plastics Engineers
We have wrapped metallic cylinders with strongly absorbing metamaterials. These resonant structures, which are patterned on flexible substrates, smoothly coat the cylinder and give it an electromagnetic response designed to minimize its radar cross section. We compare the normal-incidence, small-beam reflection coefficient with the measurement of the far-field bistatic radar cross section of the sample, using a quasi-planar THz wave with a beam diameter significantly larger than the sample dimensions. In this geometry we demonstrate a near-400-fold reduction of the radar cross section at the design frequency of 0.87 THz. In addition we discuss the effect of finite sample dimensions and the spatial dependence of the reflection spectrum of the metamaterial.
"Almost all radio receivers in the world are designed to eliminate random noise, so that they can clearly receive the signal they're looking for," Walton said. "Radio receivers could search for this radar signal and they wouldn't find it. It also won't interfere with TV, radio, or other communication signals."
-------------------------------------- Department of Defense Annual Report on Cooperative Agreements and Other Transactions Entered into During FY2001 Under 10 USC 2371 ---------------------------------------------------------------------------- Agreement Number: DAAH01-01-9-R001 Type of Agreement: Other Transaction for Prototype Title: Gravito - Electro Magnetic Superconductivity Experiment Awarding Office: US Army Aviation and Missile Command (AMCOM), AMSAM-AC-RD-BA Awardee: AC Gravity, LLD Effective Date: 25 Apr 2001 Completion Date: 25 Sep 2002 U.S. Government Dollars: $448,970 Non-Government Dollars: $ 0 Dollars Returned to Government Account: $ 0