Abstract
Generally, the interface friction on solid surfaces is regarded as consistent with wetting behaviors, characterized by the contact angles. Here using molecular dynamics simulations, we find that even a small charge difference (≤0.36 e) causes a change in the friction coefficient of over an order of magnitude on two-dimensional material and lipid surfaces, despite similar contact angles. This large difference is confirmed by experimentally measuring interfacial friction of graphite and MoS2 contacting on water, using atomic force microscopy. The large variation in the friction coefficient is attributed to the different fluctuations of localized potential energy under inhomogeneous charge distribution. Our results help to understand the dynamics of two-dimensional materials and biomolecules, generally formed by atoms with small charge, including nanomaterials, such as nitrogen-doped graphene, hydrogen-terminated graphene, or MoS2, and molecular transport through cell membranes.
Highlights
The interface friction on solid surfaces is regarded as consistent with wetting behaviors, characterized by the contact angles
The microscopic friction is usually determined by measuring the contact angle[24,25,26,27,28,29,30,31,32,33,34]; a large contact angle indicating a hydrophobic surface is associated with low surface friction, and vice versa[35]
In this work, based on the molecular dynamics simulations, we unexpectedly reveal a change in the friction coefficient of over an order of magnitude within a small charge range (≤0.36 e) even for similar contact angles
Summary
The interface friction on solid surfaces is regarded as consistent with wetting behaviors, characterized by the contact angles. In this work, based on the molecular dynamics simulations, we unexpectedly reveal a change in the friction coefficient of over an order of magnitude within a small charge range (≤0.36 e) even for similar contact angles.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have