Insight into hydrogen bonds and characterization of interlayer
spacing of hydrated graphene oxide
Received: 26 January 2018 /Accepted: 15 May 2018
Springer-Verlag GmbH Germany, part of Springer Nature 2018
The number of hydrogen bonds and detailed information on the interlayer spacing of graphene oxide (GO) confined water
molecules were calculated through experiments and molecular dynamics simulations. Experiments play a crucial role in the
modeling strategy and verification of the simulation results. The binding of GO and water molecules is essentially controlled by
hydrogen bond networks involving functional groups and water molecules confined in the GO layers. With the increase in the
water content, the clusters of water molecules are more evident. The water molecules bounding to GO layers are transformed to a
free state, making the removal of water molecules from the system difficult at low water contents. The diffuse behaviors of the
water molecules are more evident at high water contents. With an increase in the water content, the functional groups are
surrounded by fewer water molecules, and the distance between the functional groups and water molecules increases. As a
result, the water molecules adsorbed into the GO interlamination will enlarge the interlayer spacing. The interlayer spacing is also
affected by the number of GO layers. These results were confirmed by the calculations of number of hydrogen bonds, water state,
mean square displacement, radial distribution function, and interlayer spacing of hydrated GO.
Keywords Graphene oxide
Mean square displacement
Radial distribution function
Graphene has attracted attention for its outstanding mechani-
cal , optical, thermal , and electronic properties since it
was synthesized in 2004 . These properties make it emerge
as a promising material for novel applications in
supercapacitors , water treatment adsorbents ,
nanoelectronics devices , and energy-storage systems .
Graphene oxide (GO), an oxygen-rich layered material, is an
intermediate product obtained in the synthesis of graphene
from graphite by the Hummers’ method. In addition to being
a precursor of graphene, GO has potential applications in solar
cells, optoelectronics [8, 9], biomedical technologies, and
paper-like composite materials [10, 11]. After oxidation, GO
maintains the layered structure like graphite and has many
oxygen-containing functional groups on the basal planes and
edges, such as epoxy, hydroxyl, and carboxyl groups [12, 13].
Since these functional groups are hydrophilic, GO can easily
absorb water molecules and other polar solvent molecules into
the GO interlamination, and some water molecules always
existed in the interlayer chambers of GO, even after prolonged
drying . Thus, the strong binding between the functional
groups attached to the GO platelets and water molecules
makes it difficult to separate GO from a system.
Recent studies have shown that the macroscopic structure,
the electronic properties of GO platelets, and the behaviors of
water molecules are mainly influenced by the water content
[11, 13, 14]. Several studies have shown that the GO structure
and water behaviors are dependent upon the hydration level.
Buchsteiner et al.  measured the GO interlayer spacing,
which ranges from 7 to 11 Å based on the hydration level, by
X-ray diffraction and neutron scattering. The water molecules
in the interlamination are bounded to epoxy and hydroxyl
groups via hydrogen bonds at almost all hydration levels.
The hydration level in their experimental study is reprensented
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s00894-018-3679-7) contains supplementary
material, which is available to authorized users.
* Guorui Zhu
School of Chemical Engineering and Technology, Tianjin University,
Tianjin 300350, China
Journal of Molecular Modeling (2018) 24:137