Interlayer spacing of multilayer graphene oxide: Influences of oxygen-containing group density, thickness, temperature and strain

Multilayer graphene oxide (GO) has shown promising applications in ion sieving, gas separation and water purification. However, accurate control of interlayer spacing is still the bottleneck of practical application. In this paper, molecular dynamic simulations have been conducted to reveal the effects of oxygen-containing group density, thickness, temperature and applied strain on the interlayer spacing of multilayer GO sheets systematically. It is found that the interlayer spacing of multilayer GO is positively correlated with oxygen-containing group density and temperature. The interlayer spacing between the outer layer and the secondary outer layer are smaller than these between the inner layers. The distance between inner layers change little with the thickness. When the oxygen-containing group density is below 20%, the interlayer spacing decreases slightly with the increasing strains, while it reaches 30%, the interlayer space decreases first and then recovers at a turning point with an applied strain of 6% owing to the breakage of C-C bond in epoxy groups. Our results would provide a guidance for interlayer spacing controlling and separation membrane designing.