Flexible thermoplastic polyurethane/MXene foams for compressible electromagnetic interference shielding

It is always a great challenge for flexible and wearable electronics to achieve excellent electromagnetic inter-ference (EMI) shielding with good compressibility and flexibility at low filler content. Thus, TPU foam (TF) was prepared by salt following a sacrificial template method, then MXene nanosheets wrapped TF (TPU@PDA/ MXene foam referred to as TPMF) was successfully fabricated using vacuum-assisted impregnation with microporous elastic TF skeletons as a substrate and polydopamine (PDA) as a binder. Benefiting from the suc-cessful three-dimensional (3D) conductive network, this foam realized a significant conductivity of 290.8 S/m and an outstanding electromagnetic interference shielding effectiveness (EMI SE) of 72.2 dB in X-band at 0.66 vol % MXene loading and 2 mm TPMF thickness. It is a remarkable fact that the SE of TPMF was reduced from 72.2 dB to 48.4 dB with no protection after compression strain of 100 cycles at 50%, far exceeding the commercial standards of EMI shielding. This work proposes a simple and economical fabrication method of highly-efficient EMI shielding composites. The prepared shielding materials may be potentially applied in wearable smart de-vices and aerospace equipment.

Automated summary

A TPU foam (TF) was prepared by salt and then a MXene nanosheet wrapped TF (TPU@PDA/MXene foam referred to as TPMF) was successfully fabricated. This foam exhibited good conductivity and outstanding electromagnetic interference shielding effectiveness (EMI SE), making it suitable for wearable smart devices and aerospace equipment.