Electro-osmotic Flow through Nanochannel with Different Surface Charge Configurations: A Molecular Dynamics Simulation

In the present study it is observed that alternate patterning of charged and neutral stripes on the surface of the graphene nanochannel lowers the water permeance and electro-osmotic flow velocity. However, for any charge configurations water permeance and electro-osmotic velocity through the nanochannel increase as surface charge density (σ) increases from 0.005 Cm^−2 to 0.025 Cm^−2 . With the further increase in σ, water permeance and electro-osmotic velocity through the nanochannel gradually decrease. Here factors like number of counter ions near the surface of the nanochannel, specific interactions between the wall and the water molecule/ion species play significant role in determining the flow behavior. These factors also influence the slip velocity of water molecules near the surface.