A nanofluidic ion regulation membrane with aligned cellulose nanofibers

• Published in: Science advances 2019-02, Vol.5 (2), p.eaau4238-eaau4238
• Main Authors: Li, Tian, Li, Sylvia Xin, Kong, Weiqing, Chen, Chaoji, Hitz, Emily, Jia, Chao, Dai, Jiaqi, Zhang, Xin, Briber, Robert, Siwy, Zuzanna, Reed, Mark, Hu, Liangbing
• Format: Article
• Language: English
• Subjects: Applied Physics; bio-inspired; charge transport; defects; energy storage (including batteries and capacitors); Engineering; MATERIALS SCIENCE; SciAdv r-articles; synthesis (novel materials); synthesis (scalable processing); synthesis (self-assembly)
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aau4238

The advancement of nanofluidic applications will require the identification of materials with high-conductivity nanoscale channels that can be readily obtained at massive scale. Inspired by the transpiration in mesostructured trees, we report a nanofluidic membrane consisting of densely packed cellulose nanofibers directly derived from wood. Numerous nanochannels are produced among an expansive array of one-dimensional cellulose nanofibers. The abundant functional groups of cellulose enable facile tuning of the surface charge density via chemical modification. The nanofiber-nanofiber spacing can also be tuned from ~2 to ~20 nm by structural engineering. The surface-charge-governed ionic transport region shows a high ionic conductivity plateau of ~2 mS cm (up to 10 mM). The nanofluidic membrane also exhibits excellent mechanical flexibility, demonstrating stable performance even when the membrane is folded 150°. Combining the inherent advantages of cellulose, this novel class of membrane offers an environmentally responsible strategy for flexible and printable nanofluidic applications.