Reversible sequin fabrics as variable emittance surfaces. (February 2022) - Huisman, Frank
Highlights: Reversible sequin fabrics are demonstrated as variable emittance surfaces. Their emissivity can be reversibly adjusted in a dynamic range of 0.8. The reversible sequin fabrics are flexible, durable, scalable, and inexpensive. The surface temperature can be tuned by adjusting the sequins' pattern. Reversible sequin fabrics can be used for thermal camouflage, illusion, and messaging. Abstract: This study demonstrates, for the first time, the use of reversible sequin fabrics as inexpensive, scalable, and durable variable emittance surfaces. First, the spectral normal-hemispherical reflectance's of commercially available gold/black and silver/black reversible sequin fabrics were measured at room temperature for wavelength between 0.25 and 20 μm. The surface roughness and material composition of the sequins were also characterized. The dynamic range of the total hemispherical emittance of the gold/black sequin fabric at room temperature was found to be 0.8, exceeding the performance of other variable emittance surfaces reported to date. The use of reversible sequin fabrics for thermal management was demonstrated experimentally by achieving different equilibrium temperatures of the fabric exposed to simulated solar radiation by simply adjusting the sequin pattern. The experimental measurements were in good agreement with a first order transient thermal model. Finally, thermal infrared images were taken of the sequin fabrics to illustrate their capabilities for thermal camouflage, illusion, and messaging.