Bioinspired Disordered Aerogel for Omnidirectional Terahertz Response.

Abstract

The structural disorder of the black butterfly assists in capturing sunlight across a wider spectral and angular range, injecting infinite vitality for omnidirectional and stimuli-responsive wave-absorbing materials. Here, the disordered micro-pores responding to terahertz (THz) waves through electromagnetic simulations, and then prepared via ice templating technology are analyzed and optimized. The customized disordered aerogel makes possible perfect terahertz response property with incidence-angle-insensitive and ultra-broadband. Ti₃C₂T_x MXene/carboxymethyl cellulose aerogels realize excellent shielding effectiveness exceeding 70.32 dB and reflection loss of more than 43.02 dB over the frequency range of 0.3-1.5 THz. Tailoring the structural orientation of anisotropic aerogels functions as a versatile dynamic modulation approach along terahertz propagation direction. The porous structure with moderate conductivity gradually triggers the resonance effect of the cavity, approximating a resonance sphere (pore) and waveguide system (tube). Ultimately, gradient impedance aerogel is proposed integrating THz-infrared stealth, hydrophobicity, and mechanical strength. This inspired biomimetic structural strategy will also enable various terahertz applications such as terahertz imaging, line-of-sight telecommunication, information encryption, and space exploration.