A Graphene Surface Force Balance

Abstract

We report a method for transferring graphene, grown by chemical vapor deposition, which produces ultraflat graphene surfaces (root-mean-square roughness of 0.19 nm) free from polymer residues over macroscopic areas (>1 cm2). The critical step in preparing such surfaces involves the use of an intermediate mica template, which itself is atomically smooth. We demonstrate the compatibility of these model surfaces with the surface force balance, opening up the possibility of measuring normal and lateral forces, including friction and adhesion, between two graphene sheets either in contact or across a liquid medium. The conductivity of the graphene surfaces allows forces to be measured while controlling the surface potential. This new apparatus, the graphene surface force balance, is expected to be of importance to the future understanding of graphene in applications from lubrication to electrochemical energy storage systems.

Lithium-ion battery electrolyte mobility at nano-confined graphene interfaces

“…The high-quality FECO ( Fig. 1b ) and Raman data indicate an excellent quality of graphene SFA disks prepared using this method compared with direct-transfer methods 18 . In this work similar results with identical conclusions were obtained with both graphene topographies (on EB-PVDed and sputtered iridium), although a higher resolution could be obtained using the smoother graphene (see comparison of FECO from rough and smooth graphene surfaces in Supplementary Fig.…”

Mechanisms of Electrotunable Friction in Friction Force Microscopy Experiments with Ionic Liquids

“…8,9,10,11 Experiments on electrotunable friction with surface force apparatus (SFA) are on the way. 7,12,13 Room Temperature Ionic Liquids (RTILs) have recently attracted considerable interest as lubricants due to their unique physical properties, in particular low vapor pressure, wide electrochemical stability window and the virtually unlimited variety of RTILs and their mixtures. 14,15,16,17 The interaction of RTILs with confining surfaces induces fascinating structural and dynamical features; to list some: layering, overscreening and crowding, 16,18 a discrete multi-valued friction behavior as a function of the load and the number of the confined ionic layers ("quantized friction"), 19 nanoscale capillary freezing of RTILs confined between metallic surfaces, 20 as well as electrotunable friction.…”

Graphene levitation and orientation control using a magnetic field

“…Different forces on graphene have been studied such as van der Waals force, electrostatic surface forces, gravity force, buoyancy force, and Brownian movement force. [51][52][53] Previous studies show that these forces are much larger than gravity. 53 For simplicity, we consider the sum of the above mentioned forces as the total resistance force in the amount of 20 times gravity.…”

“…53 For simplicity, we consider the sum of the above mentioned forces as the total resistance force in the amount of 20 times gravity. [51][52][53] Figure 10 shows the s m induced by the magnetic field as a function of initial angle with different x distances. The gray region indicates the torque s R induced by the resistance force in liquid.…”