Development and properties of biodegradable PBAT/PPy/ETTPBAT yarn strain sensors

Conventional flexible sensor substrates often suffer from critical limitations, such as non-biodegradability, restricted elastic strain ranges, and vulnerability of exposed conductive functional layers. The development of flexible wearable strain sensors with biodegradability, high ductility, broad elastic strain ranges, and reusability is imperative. Here, the epoxidized soybean oil (ESO)/tannic acid (TA)/triallyl isocyanurate (TAIC)/polybutylene adipate-co-terephthalate (PBAT) (ETTPBAT) fibers with significantly expanded elastic strain capability were synthesized via melt spinning and UV irradiation techniques, and the PBAT/polypyrrole (PPy)/ETTPBAT yarn strain sensors were fabricated via in-situ polymerization, twisting, and encapsulation processes. The effects of UV irradiation duration, polymerization time, and p -toluene sulfonic acid monohydrate ( p -TSA) dopant concentration on the mechanical properties, thermodynamic characteristics, sensing performance, and electrothermal conversion capabilities of the PBAT/PPy/ETTPBAT yarn strain sensors were systematically investigated. The prepared biodegradable PBAT-based strain sensors have stable sensing performance and larger elastic strain range, which is valuable for enhancing the performance and application of biodegradable polymer-based strain sensors.