3. Increasing the amount of water from two to three layers has no significant effect on the number of HBs, in comparison with the difference between the cases of one and two water layers From this observation one could conclude that starting with two water layers the maximum number of HBs is formed with the GO layer. Additional water layers will essentially form HBs between water molecules. This finding is in line with the construction of the model, where a single water layer has been defined as that number of water molecules which approximately covers a GO layer.