Using modified raw materials to fabricate electrospun, superhydrophobic poly(lactic acid) multiscale nanofibrous membranes for air-filtration applications

Abstract

Nanofiber filtration materials are of considerable interest owing to their excellent interception capability for particulate matter (PM). However, numerous obstacles, such as highly complex manufacturing techniques, a short service life, low efficiency, and poor uniformity, hinder the large-scale production and utilization of these materials. In this work, multiscale modified poly(lactic acid) nanofibrous membranes (diameters: ∼49.9 and ∼223.22 nm) were fabricated by attaching long-chain alkyl groups with low surface energy to raw materials via chemical grafting and subsequently using the modified poly(lactic acid) for needleless electrospinning. This modification method facilitates the stable preparation process required for large-scale production. The membranes have small pores (∼340 nm in diameter) with a narrow pore-size distribution, superhydrophobicity (water contact angle: 155°), relatively high tensile strength (20.36 MPa), high filtration efficiency (>98.500% for PM0.3), and low resistance (<0.032% of atmospheric pressure), and they can maintain a filtration efficiency above 90.000% after 50 blowback cycles. Moreover, for particles with a diameter of <0.3 μm, the composites exhibit an initial filtration efficiency of 99.995%, which only decreases to 98.000% after 10 washing cycles. Therefore, this work presents a promising solution for the large-scale production of high-efficiency air filters.