Smart coatings for carbon fibre reinforced polymer composites in space applications
Creators: name: Delkowski, Michal
Publisher: name: University of Surrey
Year: 2023

description: Ultra-high dimensional stability of composite and polymeric materials is essential for advanced applications, including automotive, aerospace and space industry. Especially for carbon-fibre reinforced polymers (CFRPs) which feature high strength to weight ratio, thereby easing mass budget requirements for heavier payloads. For many space missions, these must support precision apertures and finely calibrated scientific instruments. Satellites use CFRP for various components including support structures, optical benches, telescope tubes and parabolic reflectors. However, it is important that these materials withstand the harsh environments of space, such as thermal cycling in vacuum (from cryogenic to hot temperatures), mechanical loads, radiation and atomic oxygen (AO) in space, while simultaneously maintaining their structural integrity and material dimensionality.<br>
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description: While today’s ultra-high performance composites are able to exhibit a near-zero (even negative) coefficient of thermal expansion, the dimensional instabilities that result from moisture ingression and release remain the fundamental vulnerability of composite materials. This restricts many applications particularly for spacecraft and aircraft constructions, including tight liquid hydrogen composite tanks envisaged for “Zero Emission” aviation. In addition, when satellites reach the vacuum of space, outgassing process occurs from polymers, leading to volatile organic by-products which can impact optical instruments. These can result in clouding the lenses, affecting the optical performance of the missions. Polymer and composite materials are also susceptible to environmental instabilities, erosion, build-up of heat and electrostatic discharge from radiation and atomic oxygen environments.<br>
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description: This work addresses these issues by developing smart and space-qualifiable nano-barrier coatings for composite and polymeric materials. The nano-barrier consists of plasma enhanced superlattice structure with a density of ~3.18 [g/cm3] which is deposited by a unique custom-built system in one-process run, at room temperature, without vacuum interruption. The structure blends within the mechanical properties of the polymeric materials, thereby creating a single composite entity. The resulting enhanced composite features mechanical integrity and strength that is superior to the underlying material, while remaining impervious to distortions caused by moisture (CME~0), outgassing (CVCM = 0.000 %) and other environmental effects. Furthermore, a smart thermal management is realised by controlling the bandgap of nano-barrier structures, thereby facilitating the radiative cooling in space (with variable solar absorptivity, min. ΔαS=0.30). Finally, the production capability on 3-D models of Earth, Observation, Navigation and Science (ENS) missions such as the Sentinel-5 and for future space programmes like Next-Generation and Hybrid Synthetic Aperture Radars (SAR), Copernicus Extension, Earth Explorer and Science Cosmic Vision is demonstrated.<br>