Zhang Tianmeng, Guo Ruyong, Ying Guobing, Lu Zhiyong, Peng Chao, Shen Mingxia, Zhang Jianfeng
College of Mechanics and Materials, Hohai University, Nanjing 211100, P. R. China.
Productivity Centre of Jiangsu Province, Nanjing 210042, China.
Mater Horiz. 2022 May 10;9(5):1536-1542. doi: 10.1039/d2mh00046f.
The development of multifunctional films with a high permeability has been of great concern for effective separation of complex aqueous contaminants, especially in the face of zero or near-zero release regulations. Inspired by the natural structure of sandy soils, polydopamine-wrapped/connected polypyrrole sub-micron spheres (PPSM) were closely packed onto a polypyrrole-coated bacterial cellulose (PBC) support, by which a new two-layered PBC/PPSM composite film formed with graded nanofluidic channels. Interestingly, after being soaked in complex water environments of ethanol, acids, bases, heat, cold and high salinity, or else bended/folded for more than 10 times, the structure and performance of this film still stayed the same, validating its high structural stability and flexibility. Even in a high salinity environment over seawater, this PBC/PPSM film exhibits a dye-separation capacity of almost 100% with a surprisingly superhigh water permeance over one thousand L h m bar, one or two magnitudes higher than that of the related films reported in the literature. Meanwhile, the ability for effective oil-water-separation was also validated. Besides the superhydrophilicity and underwater superoleophobicity, the synapse-like-structure-induced graded nanofluidic channels are also proposed to play a key role for rendering such an outstandingly comprehensive performance of the film by greatly overcoming fluid resistance and reducing permeation viscosity.
具有高渗透性的多功能薄膜的开发对于有效分离复杂的水性污染物至关重要，尤其是在面临零排放或接近零排放法规的情况下。受沙质土壤自然结构的启发，将聚多巴胺包裹/连接的聚吡咯亚微米球（PPSM）紧密堆积在聚吡咯涂层的细菌纤维素（PBC）载体上，由此形成了一种具有分级纳米流体通道的新型双层PBC/PPSM复合薄膜。有趣的是，在乙醇、酸、碱、热、冷和高盐度等复杂水环境中浸泡后，或者弯曲/折叠10次以上后，该薄膜的结构和性能仍保持不变，验证了其高结构稳定性和柔韧性。即使在比海水盐度更高的环境中，这种PBC/PPSM薄膜也表现出近100%的染料分离能力，水渗透率高达一千多L h m bar，比文献报道的相关薄膜高出一两个数量级。同时，其有效的油水分离能力也得到了验证。除了超亲水性和水下超疏油性外，还提出类似突触结构的分级纳米流体通道通过极大地克服流体阻力和降低渗透粘度，对赋予薄膜如此出色的综合性能起到关键作用。
