Variable Emittance Materials Based on Conducting Polymers for Spacecraft Thermal Control

Chandrasekhar, Prasanna; Zay, Brian J.; McQueeney, T.; Ross, David; Lovas, Andre; Ponappan, Rengasamy; Gerhart, Charlotte; Swanson, Theodore D.; Kauder, Lonny R.; Douglas, D.; Peters, Wanda; Birur, Gajanana C.

doi:10.1063/1.1541290

Cited by 9 publications

(15 citation statements)

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“…Figure shows the CV of a typical V‐E skin incorporating a poly(aniline) (PANI)‐based CP matrix and the optimized IonEl, between the voltages used to generate the extreme IR‐light and IR‐dark states, which are (−)1.0 and (+)0.5 V, respectively (in 2‐electrode mode). We have described this behavior in our earlier communications . Very briefly, at −1.0 V, the CP is in its completely reduced, nonconductive, IR‐transparent and substantially visible–NIR‐transparent, leuco‐emeraldine form.…”

Section: Resultsmentioning

confidence: 83%

“…They are also increasingly inadequate for the greater thermal control needs of modern, energy‐intensive, large spacecraft. These latter include future manned missions where multiple coolant loops interface to crew quarters on one end and external radiators (e.g., louvers) on the other …”

Section: Introductionmentioning

confidence: 99%

“…Another, important property of thermal control materials is their solar absorptance, α(s), which is an absorptance that is integrated specifically over the solar spectrum, with predominant contributions in the 0.3–1.5 µm spectral region. It again varies from 0 to 1, with low values indicating low absorption of solar radiation.…”

Section: Introductionmentioning

confidence: 99%

“…The benchmark ε variation is that set by mechanical louvers, 0.15–0.55 (Δε ca. 0.4) . Additionally, in an ideal thermal control material, α(s) should remain constantly low, preferably <0.4, while ε is concomitantly varied from about 0.1 to 0.8, as needed, with Δε > 0.4.…”

Section: Introductionmentioning

confidence: 99%

“…Several years ago, we described an IR electrochromics system, an offshoot of a military IR camouflage technology, with some promise for space application, which used poly(aniline)‐based CPs and unique dopants that imparted enhanced IR electrochromism, and presented a number of advantages over other CP‐based electrochromic systems . This system, however, had a number of drawbacks that eventually prevented its successful implementation in space.…”

Section: Introductionmentioning

confidence: 99%

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Variable‐emittance infrared electrochromic skins combining unique conducting polymers, ionic liquid electrolytes, microporous polymer membranes, and semiconductor/polymer coatings, for spacecraft thermal control

Chandrasekhar

Zay

Lawrence

et al. 2014

J of Applied Polymer Sci

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Variable emittance (e) is a property vital for the increasing needs in thermal control of future microspacecraft. This article describes fabrication, function, and performance of thin-film, flexible, variable-emittance (V-E) electrochromic skins that use a conducting polymer/-Au/-microporous membrane (CP/Au/mP) base, and a new, unique ionic liquid electrolyte (IonEl). Poly(aniline-codiphenyl amine) with a long-chain polymeric dopant is used as the CP. A unique, patented device design yields no barrier between the active, electrochromic CP surface and the external environment, except for a thin, infrared-transparent semiconductor/polymer film that lowers solar absorptance [a(s)] and protects from atomic-O/far-UV. Use of the IonEl requires special activation methods. Data presented show tailorable e variations from 0.19 to 0.90, De values of >0.50 (which is the highest reported thus far for any functional V-E material, to our knowledge), a(s) < 0.35, and nearly indefinite cyclability. Extended space durability testing, including calorimetric thermal vacuum and continuous light/dark cycling over >7 months under space conditions (<10 25 Pa vacuum, far-UV), show excellent durability. Other data show resistance to solar wind, atomic-O, electrostatic discharge, and micrometeoroids. These lightweight, inexpensive, advanced polymeric materials represent the only technology that can work with micro-(<20 kg) and nano-(<2 kg) spacecraft, thus eventually allowing for much greater flexibility in their design and potentially "democratizing" the entire space industry, for example, allowing small firms to launch their own, dedicated satellites. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40850.

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Section: Resultsmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Variable‐emittance infrared electrochromic skins combining unique conducting polymers, ionic liquid electrolytes, microporous polymer membranes, and semiconductor/polymer coatings, for spacecraft thermal control

Chandrasekhar

Zay

Lawrence

et al. 2014

J of Applied Polymer Sci

Self Cite

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Advanced Passive Thermal Control Materials and Devices for Spacecraft: A Review

et al. 2022

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In recent planetary exploration space missions, spacecraft are exposed to severe thermal environments that are sometimes more extreme than those experienced in earth orbits. The development of advanced thermal control materials and devices together with reliable and accurate measurements of their thermophysical properties are needed for the development of systems designed to meet the engineering challenges associated with these space missions. We provide a comprehensive review of the state-of-the-art advanced passive thermal control materials and devices that are available for space applications, specifically, variable emissivity thermal control materials and microelectromechanical systems (MEMS), radiofrequency (RF)-transparent and/or tunable solar absorptivity and total hemispherical emissivity thermal control materials, and a passive re-deployable radiator with advanced materials and insulation. Prior to our in-depth review of these thermal control materials, we briefly summarize the thermal environments surrounding spacecraft, the characteristics of thermophysical properties for spacecraft materials that differ from those of materials for ground use, and the significance of solar absorptivity and total hemispherical emissivity for passive thermal control in space. In all four topics of materials and devices, the following subjects are overviewed: the basic principle of passive thermal control techniques in space, the measurement of thermophysical properties of those novel materials, simulation and/or on-orbit verification thermal performance tests, degradation tests in space environments, and some aspects of the implementation of the above-described materials and devices in actual space missions.

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Achieving variable infrared emissivity modulation regions of poly(aniline) films:the effect of film surface morphology on the optical tunability

Zhang

Wang

et al. 2021

Dyes and Pigments

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Variable Emittance Materials Based on Conducting Polymers for Spacecraft Thermal Control

Cited by 9 publications

References 0 publications

Variable‐emittance infrared electrochromic skins combining unique conducting polymers, ionic liquid electrolytes, microporous polymer membranes, and semiconductor/polymer coatings, for spacecraft thermal control

Variable‐emittance infrared electrochromic skins combining unique conducting polymers, ionic liquid electrolytes, microporous polymer membranes, and semiconductor/polymer coatings, for spacecraft thermal control

Advanced Passive Thermal Control Materials and Devices for Spacecraft: A Review

Achieving variable infrared emissivity modulation regions of poly(aniline) films:the effect of film surface morphology on the optical tunability

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