Behavior of polar liquids in the interplane space of
graphite oxide
(GO) and its related materials is of great interest due to the promising
opportunity for using graphene oxide membranes as filters for liquid
separation and purification. The main purpose of the present study
is to investigate the phase state of water, ethanol, methanol, and
acetonitrile in the interplane space of GO with different synthetic
prehistory, namely, Brodie and Hummers materials. Molecular mobility
data of the intercalated substances were obtained by analyzing the
continuous-wave X-band electron paramagnetic resonance spectra of
spin probe TEMPO located in the interplane space of GO. It was shown
that all liquids under study can exist inside GO in the form of three
fractions with different molecular mobilities. The relative amount
of the most mobile liquid-like fraction in Hummers’ GO (H-GO)
is several times larger than in Brodie’s GO (B-GO), and it
reversibly increases with increasing temperature. An intriguing fact
is that the molecular mobility of the liquid-like intercalated acetonitrile
was found to be significantly lower than that of intercalated water
and alcohols, whereas the viscosity of bulk acetonitrile was much
lower than that of bulk water, methanol, and ethanol.