Hierarchically structured poly(lactic acid) nanofibers by organic–inorganic nanohybridization strategy towards efficient PM removal and respiratory monitoring

Abstract

Despite the enormous potential in efficient removal of airborne PMs by biodegradable poly(lactic acid) (PLA) nanofiberous membranes (NFMs), current manufacturing methods still have large function gaps in providing reliable control over the fiber microstructure, membrane morphology or electret properties. Herein, the concept of organic–inorganic nanohybridization, strategically involving the combined electrospinning of PLA/TiO2 and electrospray of ZIF-8 nanodielectrics, was conceived to engender PLA NFMs (PLA/TIO@ZIF) featuring largely promoted electroactivity and surface activity, as exemplified by the increased dielectric constant and surface potential (up to 3.47 and 8.5 kV, respectively). This conferred the PLA/TIO@ZIF NFMs remarkable triboelectric nanogenerator (TENG) properties, yielding the output voltage as high as 17.9 V at 10 N and 1 Hz, and output current of 39.6 nA as driven by the humanoid respiration. Given impressive in situ electret performance and charge regeneration capability, the PLA/TIO@ZIF NFMs enabled ultrahigh PM0.3 filtering properties (90.4 %, 175 Pa, 85 L/min), accompanied by increased resistance to humidity (92.1 % removal of PM0.3, RH90 %, 32 L/min). Moreover, perfect 100 % inhibition of E. coli and S. aureus was achieved for PLA/TIO@ZIF, arising mainly from the plentiful surface charges and ROS generation. It is envisioned that the hierarchically nanostructured NFMs, offering the exceptional function integration, are highly appealing for long-term air purification and self-powered respiratory monitoring.