title: Ultrafast viscous water flow through nanostrand-channelled graphene oxide membranes.
abstract: Pressure-driven ultrafiltration membranes are important in separation applications. Advanced filtration membranes with high permeance and enhanced rejection must be developed to meet rising worldwide demand. Here we report nanostrand-channelled graphene oxide ultrafiltration membranes with a network of nanochannels with a narrow size distribution (3-5 nm) and superior separation performance. This permeance offers a 10-fold enhancement without sacrificing the rejection rate compared with that of graphene oxide membranes, and is more than 100 times higher than that of commercial ultrafiltration membranes with similar rejection. The flow enhancement is attributed to the porous structure and significantly reduced channel length. An abnormal pressure-dependent separation behaviour is also reported, where the elastic deformation of nanochannels offers tunable permeation and rejection. The water flow through these hydrophilic graphene oxide nanochannels is identified as viscous. This nanostrand-channelling approach is also extendable to other laminate membranes, providing potential for accelerating separation and water-purification processes.
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310028, China.
authors.forename: Hubiao
authors.initials: H
authors.lastname: Huang
authors.affiliation: Applied Mechanics Laboratory, Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China.
authors.forename: Zhigong
authors.initials: Z
authors.lastname: Song
authors.affiliation: Applied Mechanics Laboratory, Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310028, China.
authors.forename: Li
authors.initials: L
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310028, China.
authors.forename: Yiyin
authors.initials: Y
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310028, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Ying
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310028, China.
authors.forename: Luwei
authors.initials: L
authors.lastname: Sun
authors.affiliation: Applied Mechanics Laboratory, Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310028, China.
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Peng