Emulsion-engineered polylactide-based polyurethane/MXene films for high-performance flexible and biointegrated wearable sensors

Designing soft conductive polymeric materials with mechanical resilience and low filler loading remains a challenge in wearable electronics. This work presents a strategy based on sustainable precursors for fabricating flexible, conductive films from polylactide (PLA)-based polyurethane (PU) and delaminated MXene (Ti₃C₂T_x) through emulsion-assisted processing. Using virgin PLA as a controlled model feedstock, the polymer was depolymerized into hydroxyl-terminated oligomers via microwave-assisted alcohol-acidolysis and employed as polyol precursors for PU synthesis. Emulsification of PLA-PU and MXene with poly(vinyl alcohol) (PVA) as a compatibilizer yielded hybrid films with superior MXene dispersion and lower percolation thresholds (≤10 wt %) compared to solution-cast films (≥40 wt %). The 6:4 and 7:3 PLA-PU/MXene/PVA films offered an optimal balance of tensile strength and flexibility. The films exhibited sensitive, reproducible responses to macro- (finger bending) and micro-strains (vocal/laryngeal vibrations). The study advances PLA upcycling into high-performance electronic materials derived from biocompatible precursors for next-generation health monitoring and bio-integrated systems.