  Active research in nanotechnology contemplates the use of nanomaterials for
engineering applications. However, a primary challenge is understanding the
effects of nanomaterial properties on industrial device performance and
translating unique nanoscale properties to the macroscale. One emerging example
is graphene oxide (GO) membranes for separation processes. Thus, here we
investigate how individual GO properties can impact layered GO characteristics
and water permeability. GO chemistry and morphology were controlled with
easy-to-implement photo-reduction and sonication techniques and were
quantitatively correlated offering a valuable tool to speed up the
characterization process. For example, one could perform chemical analysis and
concurrently obtain morphology information or vice versa. Chemical GO
modification allows for fine control of GO oxidation state and GO laminate
nanoarchitecture enabling controlled synthesis of a GO architectural laminate
(GOAL). The GOAL can be considered as the selective layer of the membrane
created by interconnected sub-nanometer channels, characterized by a length and
a height (i.e., GO spacing), through which water molecules permeate. Water
permeability was measured for eight GOAL characterized by different GO
chemistry and morphology, and indicate that GO nanochannel height dictates
water transport. The simulations indicate a no-slip Darcy-like water transport
regime inside the GOAL due to the presence of basal oxygen functionalities. The
experimental and simulation evidence presented in this letter help create a
clearer picture of water transport in GO and can be used to rationally design
more effective and efficient GO membranes.
