Preparation of hierarchical structured nano-sized/porous poly(lactic acid) composite fibrous membranes for air filtration

• Published in: Applied surface science Vol. 356; pp. 1168 - 1179
• Main Authors: Wang, Zhe, Pan, Zhijuan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.11.2015
• Subjects: Electrospinning; Fibers; Filtration; Filtration performance; Hierarchical structure; Mass ratios; Membranes; Nanopore; Nanostructure; Particulate composites; Performance enhancement; Specific surface; Electrospinning; Nanopore; Filtration performance; Hierarchical structure
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.08.211

•Increasing nanopores on fiber surface will improve filtration performance.•Correlation between hierarchical structure and filtration performance was verified.•Nano-sized fibers were conducive to the increase of filtration efficiency.•Hierarchical structured filter media show high-performance fine particle filtration. Hierarchical structured nano-sized/porous poly(lactic acid) (PLA-N/PLA-P) composite fibrous membranes with excellent air filtration performance were prepared via an electrospinning technique. Firstly, PLA-P fibers with different morphology were fabricated by varying the relative humidity, and the nanopores on fiber surface played a key role in improving the specific surface area and filtration performance of the resultant membranes. Secondly, hierarchical structure of PLA-N/PLA-P interlaced structured membranes and PLA-N/PLA-P double-layer structured membranes with different mass ratios for further enhanced air filtration performance were also successfully prepared by combining PLA-N fibers with PLA-P fibers. Filtration tests by measuring the penetration of sodium chloride (NaCl) aerosol particles with a 260nm mass median diameter revealed that a moderate mass ratio of PLA-P fibers and PLA-N fibers contributed to improving the filtration performance of the hierarchical structured PLA-N/PLA-P composite membrane, and the double-layer structured PLA-N/PLA-P membrane possessed a higher filtration efficiency and quality factor than that of an interlaced structured PLA-N/PLA-P membrane with the same mass ratio. The as-prepared PLA-N/PLA-P double-layer structured membrane with a mass ratio of 1/5 showed a high filtration efficiency (99.999%) and a relatively low pressure drop (93.3Pa) at the face velocity of 5.3cm/s.