Establishing Nanoscale Heterogeneity with Nanoscale Force Measurements

Abstract

Establishing the presence or absence of nanoscale compositional heterogeneity with nanoscale resolution is becoming instrumental for the development of many fields of science. Force versus distance measurements and parameters directly or indirectly derived from these profiles can be potentially employed for this purpose with sophisticated instruments such as the atomic force microscope (AFM). On the other hand, standards are necessary to reproducibly and conclusively support hypothesis from experimental data and these standards are still emerging. Here, we define a set of standards for providing data originating from atomic force measurements to be employed to compare between sample properties, parameters, or, more generally, compositional heterogeneity. We show that reporting the mean and standard deviation only might lead to inconsistent conclusions. The fundamental principle behind our investigation deals with the very definition of reproducibility and repeatability in terms of accuracy and precision, and we establish general criteria to ensure that these hold without the need of restricting assumptions.

Water wettability of graphene: interplay between the interfacial water structure and the electronic structure

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Direct Measurement of the Magnitude of the van der Waals Interaction of Single and Multilayer Graphene

“…The force reconstruction also consisted of 100 data points per sample and per experiment. We have previously demonstrated 43 that this results in robust mean and standard deviation values for this type of experiment including reproducibility and repeatability.…”

Surface and Bulk Effects in Photochemical Reactions and Photomechanical Effects in Dynamic Molecular Crystals

“…Figure 5e shows the variation of the average FAD as a function of the exposure time. Since it is well known that the tip radius R significantly affects the interaction between the tip and the sample surface, R was monitored in situ throughout the experiment using the critical amplitude method 60 that accounts for the apparent changes in R. The progressively different and statistically significant average of multiple measurements provided evidence that the changes in FAD are not experimental artifacts 61 and that the absolute value of the adhesion force increases with exposure time (the negative sign is related to the attractive nature of the force). The surface energy γ calculated using Eq.…”