Versatile nano-micro collagen fiber-based wearable electronics for health monitoring and thermal management

As a vital component of wearable electronics, flexible strain sensors have drawn vast attention due to their capabilities in capturing postures and monitoring various human activities. However, most emerging strain sensors suffer from insufficient strength and conductivity, small sensitivity, weak interference immunity, and deficient functions for some specific applications. Herein, nano-micro collagen fiber-based flexible strain sensors (PPy/SCB@PP-CFs) with integrated super-amphiphobic properties, flame-retardant properties, electromagnetic interference (EMI) shielding effectiveness, and photothermal conversion performances were nanoengineered by incorporating in situ polymerization with spraying and dipping approaches. The on-demand nano-micro-structural and functional design of PPy/SCB@PP-CFs ensures accuracy, stability, durability, universality, and multi-purpose speciality for multiduty applications, including superior tensile strength (59.9 MPa), conductivity (6.5 S m(-1)), flexibility, biocompatibility, super-amphiphobic properties (contact angle > 155 degrees), flame-retardant properties, and EMI shielding effectiveness (18.3 dB). Moreover, PPy/SCB@PP-CFs possessing strain sensing performance can be processed into smart wearable electronics for health monitoring, such as human pulse detection, micro-expression analysis, and joint movement monitoring. Interestingly, PPy/SCB@PP-CFs exhibited outstanding photothermal conversion capacity and thus can be employed for thermal management through effective regulation of human sub-ambient temperature at different temperatures and in different environments. Our proposed PPy/SCB@PP-CFs have great potential for applications in multidimensional wearable electronic devices, human-machine interfaces, and artificial intelligence, generating a versatile platform for developing high-performance sensors with on-demand properties.