and inter-molecular HBs (i.e., HBs between functional groups of GO and the surrounding water or with functional groups of the other GO layer in the case of very short inter-layer distance). However, due to the tight confinement of water in-between the GO layers, the inter-molecular GO-water HBs are assumed to be the dominant kind of interactions at the GO/water interface, in particular when it comes to water diffusion. Therefore, we focus our analysis on these HBs. Figure summarizes the results, giving in panels (a-c) the number of HBs of type O ep , HO acc and HO don , as the percentage of the maximum possible number.