Kevlar nanofibrous aerogel-based 3-layer tandem cloak enables highly efficient and long-lasting infrared stealth

Abstract

The control of thermal radiation features of objects for the purpose of infrared stealth has aroused extensive research interests in recent years, however, long-term and highly efficient infrared stealth for hot object under sunlight is still a giant challenge. Herein, a Kevlar nanofibrous aerogel-based 3-layer tandem cloak for long-term restraining of the thermal emission was proposed. The top layer was fabricated by magnetron sputtering silver (Ag) on the upper side of Kevlar nanofibrous aerogel film (Ag|KNA), demonstrating high thermal resistance (8.68 K·W−1), low infrared emissivity (0.12) and high optical reflectivity (0.87). The middle layer was realized by incorporating of phase change paraffin wax (PW) into KNA film (KNA/PW), showing phase change enthalpy of 162 J·g−1. The bottom layer was fabricated by sputtering Ag on the lower patterned side of KNA film (PKNA|Ag), illustrating low infrared transmittance (close to zero), high thermal reflectivity (0.94) and high thermal resistance (10.42 K·W−1). Then flexible tandem cloak was constructed via stacking these aerogel-based top, middle and bottom layers in sequence, showing long-term (up to 12 h), high-efficiency (radiation temperature difference less than 1 °C) hiding of thermo-model targets under heating and sunshining simultaneously. This work provides a promising strategy for designing more practical tandem cloak for infrared stealth applications.