  The laminated structure of graphene oxide (GO) confers unique interactions
with water molecules which may be utilised in a range of applications that
require materials with tuneable hygroscopic properties. Precise roles of the
expandable interlayer spacing and functional groups in GO laminates are not
fully understood till date. Herein, we report experimental and theoretical
study on the adsorption and desorption behaviour of water in GO laminates as a
function of relative pressure. We have observed that GO imparts excellent water
uptake capacity of up to 0.58 gram of water per gram of GO (g g-1), which is
much higher than silica gel a conventional desiccant material. More
interestingly, the adsorption and desorption kinetics of GO is one order of
magnitude higher than silica gel. The observed extraordinary
adsorption/desorption rate can be attributed to the high capillary pressure in
GO laminates as well as micro meter sized tunnel like wrinkles located at the
surface.
