Bioinspired tree-like electroactive poly(lactic acid) nanofibers with enhanced surface activity and interfacial polarization for intelligent health management

Abstract

Poly(lactic acid) (PLA)-based nanofibrous membranes (NFMs) have significant potential for use in biodegradable filters for air purification, but their application is often limited by relatively poor electret properties. Herein, tree-inspired gradient PLA (TG-PLA) nanofibers with biomimetic surfaces and remarkable electroactivity were fabricated by coaxial electrospinning of a unique core–shell structure. Importantly, the bioinspired structure conferred dramatic increase of dielectric constant for TG-PLA NFMs by 218 %, as well as enhanced in situ electret properties (over 3-fold rise of surface potential). The well-controlled morphological features and increased electroactivity contributed synergistically to distinct promotion of active PM-capturing performance, as exemplified by 99.25 % filtration of PM_0.3 at the airflow velocity of 32 L/min for TG-PLA2, largely surpassing the counterpart (only 89.63 %). Benefiting from the significantly increased electroactivity, TG-PLA2 exhibited superior energy harvesting performance and long-term stability (output voltage of 44.7 V, over 2000-second cycle test). Furthermore, a convolutional neural network (CNN) algorithm was developed to establish an intelligent respiratory recognition system, demonstrating high-accuracy diagnosis of multiple complex scenarios. The exceptional promotion in the surface activity and intrinsic electroactivity for PLA nanofibers is of enormous potential for environmental applications. Our bioinspired strategy can lead to a versatile platform that integrates with profound property improvements and scale-up feasibility for intelligent protective membranes.