Dynamic cross-linked/conductive dual-network polyurethane for integrated EMI shielding, thermal management and motion sensing

In order to realize the multi-scenario application of flexible sensors, a multifunctional polyurethane with a dynamic reversible/conductive irreversible dual network structure (SHPU@CNT/Ag) was developed. Specifically, the self-developed amino-terminated triphenylboroxine (ATPB) and hydroxylated multi-walled carbon nanotubes (MWCNT-OH) were cross-linked with polyurethane prepolymer, and then mixed with Ag NPs to obtain SHPU@CNT/Ag. The rapid photothermal conversion of SHPU@CNT/Ag (67.8 °C in 5 min) promotes the reorganization of dynamic bonds, showing 93.6% of self-healing efficiency at 80 °C and 30% of humidity. On this basis, we fabricated a wearable flexible synthetic leather sensor by coating SHPU@CNT/Ag solution on the surface of nonwoven fabrics. The electromagnetic interference (EMI) shielding efficiency of the resulting SHPU@CNT/Ag synthetic leather sensor reaches 34.43 dB, and it can real-time monitor human movement signals during playing badminton, achieving an integrated construction of electromagnetic shielding protection, photothermal self-healing and motion sensing. It is noted that the SHPU@CNT/Ag synthetic leather sensor has excellent air permeability (11,321 mL/cm 2 ·h), abrasion resistance and antibacterial performance. This study provides a new way for the development of smart devices, showing broad application prospects in wearable electronics and medical rehabilitation.