Deformation induced absorption band-tunable smart CNTs/Ti3C2Tx-WPU electromagnetic wave absorbing aerogel

• Published in: Carbon (New York) 2024-04, Vol.223, p.119023, Article 119023
• Main Authors: Kong, Luo, Zhang, Guiqin, Cui, Haodong, Qi, Jun, Wang, Tong, Xu, Hailong
• Format: Article
• Language: English
• Subjects: Aerogel; CNTs; Electromagnetic wave absorbing material; Ti3C2Tx
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2024.119023

Intelligent devices and multi-functional integrated electromagnetic functional materials have been widely concerned, and it's really matter to develop intelligently adjustable electromagnetic wave (EMW) absorbing materials. However, MXene Ti3C2Tx-based aerogel with adjustable strain and EMW absorption properties have rarely been reported. We use Water-borne polyurethane (WPU) as a binder to connect CNTs/Ti3C2Tx absorbent into CNTs/Ti3C2Tx-WPU aerogel with high resilience. The bidirectional freeze-drying method results in the periodic structure of the aerogel. Under external stress, when the critical buckling load is reached, the aerogel will buckle, resulting in the reduction of layer spacing and contact resistance. Due to the threshold effect caused by compression, the conductivity increases, which significantly affects the dielectric loss and EMW absorption properties. Meanwhile, when the applied stress is removed, the shape of aerogel can recover, indicating the aerogel has excellent elasticity. We selected the aerogel with a mass fraction of 0.2 wt% for compression to research its mechanical and dielectric properties. With 42% compression stain, the minimum reflection loss of the sample reached −68.2 dB. At 50% maximum compression stain, the CNTs/Ti3C2Tx-WPU aerogel can be cycled at least 100 times and keep structure stable. With the increase of stress, the EMW absorption band shifts to the high-frequency. When the stress is removed, absorption band returns to its original position. It provides an effective avenue to explore electromagnetic absorbers with intelligent response. [Display omitted] •We use Water-borne polyurethane (WPU) as a binder to connect CNTs/Ti3C2Tx absorbent into CNTs/Ti3C2Tx-WPU aerogel with high resilience. The bidirectional freeze-drying method results in the periodic structure of the aerogel. The layered periodic CNTs/Ti3C2Tx-WPU aerogels obtained by bidirectional freeze-drying showed high resilience.•When subjected to certain stress, CNTs/Ti3C2Tx-WPU aerogel showed good resilient cycle stability (100 cycles at 50% compression) with sensor characteristics. It showes good elastic cycle stability (100 cycles at 50% compression) under certain strain with sensor characteristics.•With the increase of compression strain, reflection loss and effective absorption band move to the high-frequency region and the decrease of corresponding thickness, which realizes intelligent regulation of electromagnetic parameters and effective absorption