Figure 2: In situ measurement of bond scission dynamics
From: Direct mechanochemical cleavage of functional groups from graphene
(a) Relative friction force measurements as a function of cumulative tip dwell time for normal loads 25–225 nN, showing an increasing exponential decay rate with increasing normal load. (b) Reaction curve for 50 nN normal load showing the kinetics of bond scission follows an exponential decay typical of a first-order chemical reaction. At low loads, a contamination layer contributes an additional decay term. This contamination layer slowly resorbs over many hours (inset). The error bars are the s.d. of the friction force values for each AFM scan. (c) Reaction rate as a function of measured contact stress, showing an exponential dependence consistent with an atomic-by-atom stress-assisted reaction mechanism. The x axis error bars were calculated by propagating uncertainty values from the linear fit of tip contact radius measurements to the calculation of contact stress. The y axis error comes from the calculated uncertainty of the exponential fit to the data in a.
