Flexible and Lightweight Ni/MXene Decorated Polyurethane Sponge Composite with Sensitive Strain Sensing Performance for Ultrahigh Terahertz Absorption

Abstract

Flexible and lightweight terahertz (THz) absorbers with high absorption performance are urgently indispensable in the application of foreign substance examination, molecular identification and 6G communication. Herein, cost‐effective approaches of autocatalytic plating and dip‐coating with a series of surface grafting are proposed to construct nickel/Ti3C2Tx (Ni/MXene) decorated polyurethane sponge (PUS) composite. The resultant PUS‐Ni/MXene sample exhibits average THz absorption shielding effectiveness (SEA) and absorption proportion of 42.7 dB and 99.9% from 0.1 to 2.2 THz at a thickness of only 1 mm. The THz SEA can achieve 69.8 dB for PUS‐Ni/MXene sample with 8 mm thickness while the specific SE is over 65.8 (dB cm3 g−1), surpassing most absorbers. To better understand the propagation characteristics of THz waves, the electromagnetic interference SEs and electric field distributions are calculated through finite difference time domain simulation, and verified by experiments. Moreover, the foldable and electrical properties endow the PUS‐Ni/MXene composite with smart pressure sensitivity that is promising for strain monitoring. The optimized PUS‐Ni/MXene sensor exhibits high sensitivity under a relatively small strain. And the outstanding long‐term stability and durability are also proved by 1200 stretching–releasing cycles. The as‐prepared THz absorber with excellent pressure sensing performance demonstrates enormous potential in future military and civilian applications.

Lightweight MXene-Based Hybrid Aerogels with Ultrabroadband Terahertz Absorption and Anisotropic Strain Sensitivity

“…The THz EMI shielding effectiveness (SE) values are calculated using the following equations , E M I 0.25em S E T = prefix− 20 0.25em log ( E T E T 0 ) EMI 0.25em S E R = prefix− 10 0.25em log ( 1 − true( normalE normalR 2 normalE normalR 0 2 true) ) EMI 0.25em S E A = EMI 0.25em S E T − EMI S E R where EMI SE T , EMI SE R , and EMI SE A are the total EMI SE, reflection-based SE, and absorption-based SE, respectively; E T , E R , E T0 , and E R0 are the amplitudes of transmission, reflection, pristine transmission, and pristine reflection terahertz pulses for the samples, respectively. Considering the dispersion shown in Figure e, we average all the SE values over the 0.5–3 THz region and list the results in Figure S5a.…”

“…As usually studied in the language of electromagnetic interference (EMI), the absorption shielding effectiveness and absolute absorption of these composites have achieved remarkable values, 14,15,21−25 e.g., 42.7 dB and 99.9% between 0.1 and 2.2 THz for the reported 3D Ni/MXene decorated polyurethane sponge composites at 1 mm thickness. 21 Unfortunately, their structure, strength, and flexibility are still limited, owing to the weak interactions between rigid MXene flakes and the large pore/ wall size for broadband absorption, i.e., ∼100 μm. Herein, we report on lightweight Ti 3 C 2 T x /poly-(3-glycidoxypropyldimethoxymethylsilane) (PGPDMS) hybrid aerogels combining superior THz wave absorption with strain flexibility.…”

“…Naturally, the exploration of the MXene-based 3D network structure expands to THz, leading to a critical branch of the THz absorber, ranging from MXene to magnetic metal/MXene-based sponges/foams. As usually studied in the language of electromagnetic interference (EMI), the absorption shielding effectiveness and absolute absorption of these composites have achieved remarkable values, ,,− e.g., 42.7 dB and 99.9% between 0.1 and 2.2 THz for the reported 3D Ni/MXene decorated polyurethane sponge composites at 1 mm thickness . Unfortunately, their structure, strength, and flexibility are still limited, owing to the weak interactions between rigid MXene flakes and the large pore/wall size for broadband absorption, i.e., ∼100 μm.…”

3D Architectural MXene‐based Composite Films for Stealth Terahertz Electromagnetic Interference Shielding Performance

“…[24] MXenes are explored in EMI shielding applications, especially terahertz broadband shielding, due to their high electrical conductivity and intrinsic radiation absorption capacity. [8,11,[24][25][26][27][28] Due to their high electrical conductivity, MXenes exhibit multiple reflection mechanisms between layers and contribute to secondary interferences, which can be rectified by either structural design or composite strategies. [18] Various structural designs such as thin film, [4,11,19,29] solid pellet, [30] porous film, [31] foam, [7,8,32,33] sponge, [26,34] fabric, [35] aerogel, [36,37] membrane, [9,16,38] and paint [39] are explored for MXenes to attenuate electromagnetic interference.…”

Ti3C2Tx MXene‐Based Superhydrophobic Broadband Terahertz Absorber with Large Pore‐Size Foam Architecture

“…Our work ignites the research interest in MXenebased porous EM absorbers in terahertz and microwave bands. [31][32][33] For most of the applications, the capability to stay dry and self-cleaning is necessary for a porous absorber. Liquid, ice, and dust on the surface will almost inevitably change the impedance-matching condition thus increasing the EM reflection.…”