Electrostatic Self-Assembly Induced Nest-Like MXene Networks on Fabric for Ultra-Broadband Flexible Absorption.

Advancement of next-generation information technologies is driving the increasing integration of millimeter-wave and terahertz (THz) communication, detection, and artificial intelligence technologies, thereby creating a demand for multifunctional absorbing materials to address complex electromagnetic interference. In this study, a flexible WPU-MXene@FC composite fabric with ultra-broadband absorption, superhydrophobicity, and excellent durability is developed. The base fabric (FC) is modified via surface plasma treatment to introduce positively charged active sites on fibers. Driven by electrostatic interaction, negatively charged MXene is self-assembled with modified FC. The electrostatic interactions process induces a "nest-like" structure on fibers, building construct MXene multiple loss paths. Waterborne polyurethane (WPU) is finally coated to endow the FC with MXene oxidation protection, superhydrophobicity, and stability. Results show that a 1.8 mm-thick WPU-MXene@FC achieves an effective absorption bandwidth spanning 25.3-1200 GHz. Within 0.2-1.0 THz, the reflection loss (RL) value is below -30 dB, reaching a minimum of -45.2 dB. After 500 bending cycles, its RL remains below -30 dB. The WPU-MXene@FC exhibits superhydrophobicity (contact angle 151.3°, sliding angle 1.2°), excellent air permeability, and flexibility. This multifunctional FC has important applications in wearable devices, communications, and provides strong support for the development of lightweight stealth structures and flexible electromagnetic camouflage.