Graphite oxides: hydratation and solvation - Alexandr V. Talysin - 8 décembre 2014

Alexandr V. Talyzin - Department of Physics, Umeå University, Sweden

Lundi 8 décembre 2014 à 14 h

IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris

Salle de conférence, 4e étage, Tour 22-23, Salle 1

Abstract

I will present very broad review of our research on graphite and graphene oxides. During last 5 years we published a set of studies about structural properties of graphite oxides (GO) which appeared to be strongly depended on particular method used for GO synthesis. Graphite oxide is layered hydrophilic material which easily absorbs polar solvents. The change of hydration/solvation state of GO’s was studied both under variations of pressure and temperature. Brodie GO exhibits phase transitions connected to insertion/deinsertion of solvent monolayer  upon variations of temperature or pressure. In contrast, Hummers GO shows gradual  expansion of lattice in liquid alcohols upon temperature lowering with insertion of at least 3-4 monolayers into interlayers of GO structure. The swelling properties of graphite oxides showed a lot of
similarities to some clay minerals. This similarity was further demonstrated in our experiments as we discovered that certain synthetic clays (Na-hectorite) exhibits pressure driven water layer insertion. Therefore, pressure induced solvent insertion is likely to be very general phenomena typical for layered hydrophilic materials. Finally, solvation and hydration of thin membranes prepared from graphene oxide solutions will be briefly reviewed. The multilayered graphene oxide membranes exhibited some unique properties which are different from precursor graphite oxides and make them promising for various applications: e.g. separation of liquid and gas mixtures, protective coatings etc.