This is the pre-peer reviewed version of the following article: Mei, S., Mehmood, M.Q., Hussain, S., Huang, K., Ling, X., Siew, S.Y., Liu, H., Teng, J., Danner, A. and Qiu, C.‐W. (2016), Flat Helical Nanosieves. Adv. Funct. Mater., 26: 5255-5262. doi:10.1002/adfm.201601345, which has been published in final form at https://doi.org/10.1002/adfm.201601345. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.