Zuo Fenglei, Zhang Shichao, Liu Hui, Fong Hao, Yin Xia, Yu Jianyong, Ding Bin
Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai, 201620, China.
Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China.
Small. 2017 Dec;13(46). doi: 10.1002/smll.201702139. Epub 2017 Oct 17.
The filtration performance and light transmittance of nanofiber air filters are restricted by their thick fiber diameter, large pore size, and substrate dependence, which can be solved by constructing substrate-free fibrous membranes with true nanoscale diameters and ultrathin thicknesses, however, it has proven to be extremely challenging. Herein, a roust approach is presented to create free-standing polyurethane (PU) nanofiber/nets air filters composed of bonded nanofibers and 2D nanonets for particular matter (PM) capture via combining electrospinning/netting technique and facile peel off process from designed substrates. This strategy causes widely distributed Steiner-tree structured nanonets with diameters of ≈20 nm and bonded scaffold nanofibers to assemble into ultrathin membranes with small pore size, high porosity, and robust mechanical strength on a large scale based on ionic liquid inspiration and surface structure optimization of receiver substrates. As a consequence, the resulting free-standing PU nanofiber/nets filters exhibit high PM removal efficiency of >99.00% and PM removal efficiency of >99.73%, maintaining high light transmittance of ≈70% and low pressure drop of 28 Pa; even achieve >99.97% removal efficiency with ≈40% transmittance for PM filtration, and robust purification capacity for real smoke PM , making them promising high-efficiency and transparent filtration materials for various filtration and separation applications.
纳米纤维空气过滤器的过滤性能和透光率受到其较粗的纤维直径、较大的孔径以及对基材的依赖性的限制，通过构建具有真正纳米级直径和超薄厚度的无基材纤维膜可以解决这些问题，然而，这已被证明极具挑战性。在此，提出了一种稳健的方法，通过将静电纺丝/编织技术与从设计的基材上轻松剥离的过程相结合，制备出由粘结纳米纤维和二维纳米网组成的独立式聚氨酯（PU）纳米纤维/网空气过滤器，用于捕获颗粒物（PM）。基于离子液体的启发和接收基材的表面结构优化，这种策略使直径约为20 nm的广泛分布的斯坦纳树状结构纳米网和粘结的支架纳米纤维大规模组装成具有小孔径、高孔隙率和强大机械强度的超薄膜。结果，所得的独立式PU纳米纤维/网过滤器对PM的去除效率高达>99.00%，对PM₂.₅的去除效率高达>99.73%，保持约70%的高透光率和28 Pa的低压降；甚至在PM过滤时，透光率约为40%时，去除效率>99.97%，对实际烟雾PM具有强大的净化能力，使其成为各种过滤和分离应用中极具潜力的高效透明过滤材料。
