A multi-scale layered helical structure composite using the co-dispersion of cellulose nanocrystals and the micro-nano Al sheets and its efficient near-infrared stealth performance.

ABSTRACT

To design flexible functional materials with high efficiency, light weight, less metal consumption, stable structure for the thermal infrared stealth materials is a great challenge. We hypothesized that the use of crystal materials with different sizes to design composites with a chiral layered helical structure, the layered structures can repeatedly reflect infrared ray. Here, we reported the novel multi-scale layered helical chiral structure composite by self-assembly using the co-dispersion of cellulose nanocrystals (CNC) and micro-nano Al sheets. A new stable interlocking supermolecular structure is formed between the positively charged metal sheet and the negatively charged CNC photonic crystals. Metal sheets and CNC organic crystals were hybridized at the molecular level and form the Pickering-like CNC-Al co-dispersion system. The metal sheets in CNC chiral helical layered structure greatly improve its near-infrared reflection and stealth camouflage. Surprisingly, the CNC/Al composite on the heated glass substrate enabled the temperature drop 23 °C, and made its emissivity in the range of 7-14 µm significantly reduce. The synergetic effect of the Al sheets and the CNCs helical structure greatly improved the thermal infrared reflection and heat insulation properties. It is expected to provide a chiral layered material for the infrared stealth, and pattern camouflage fields.