Design and theoretical simulations of nano check valve constructed of graphene sheets

The unidirectional flow of nanofluids holds paramount importance in numerous nanofluidic applications. However, there remains a void in the practical implementation of a nano check valve specifically designed for ensuring such unidirectional flow. In this work, a nano check valve consisting of a diaphragm and a valve seat is designed and its forward opening and reverse shutoff processes are investigated using molecular dynamic simulations. Additionally, the effects of the modified groups of the diaphragm of the nano check valve are studied. The results demonstrate that the nano check valve can be opened efficiently under a certain forward differential pressure. Besides the differential pressure, the interaction between diaphragm and water molecules contributes to the opening process. Conversely, the non-bonding interaction between diaphragm and the valve seat prevents the opening. The reverse shutoff simulations reveal that the reverse shutoff function can be achieved under the backward pressure even when the nano check valve is firstly opened. It is observed that the ratio of hydroxyl to hydrogen groups on the edge of diaphragm has a significantly effect on the opening pressure due to the non-bond interaction of diaphragm and water molecules. This suggests that the opening pressure of the nano check valve could be regulated by changing the modifier groups.