Assessing micro- and nanoscale adhesion via liquid metal-based contact angle measurements in vacuum

Line Tension and Drop Size Dependence of Contact Angle at the Nanoscale

“…The apparent line tension is also influenced by the surface topography, on top of the other properties of the liquid, solid, and gaseous phases. In our previous work we extracted an S a value of 149.5 nm from AFM topography measurements on the surface of a similar stainless steel sample [23]. This relatively high surface roughness value might be responsible for the increased scattering of cos(θ) with the decreasing drop size in Figure 3b, according to the findings of Lin et al [31].…”

“…The straight lines were tangential to the two two-phase boundaries (liquid-solid and liquid-gas). Further information on the measurement method can be found in [23]. A more detailed analysis of the measurement results obtained is given in the next chapter.…”

“…Therefore, the measurements were performed within a maximum of ten minutes after the preparation of the sphere to keep this influence low. More details about the contact angle measurement technique and the influence of the oxide layer can be found in previous work [23]. In addition, the increasing influence of the oxide layer with longer measuring times must also be taken into account.…”

“…To address these issues, we have previously presented the use of a liquid metal as a liquid with a barely measurable evaporation rate [22] and demonstrated robotically assisted contact angle measurements in a scanning electron microscope (SEM) [23]. To address the issue of oxide layer growth on the liquid metal droplets, which would prevent them from being useful for contact angle measurements [24], our experiments take place in the low-oxygen vacuum atmosphere of an SEM chamber.…”

Probing Friction and Adhesion of Individual Nanoplastic Particles

“…To gain fundamental insight into the dynamic processes experienced by NPs within such environments, their adhesion and friction behavior, as well as their underlying material-specific physicochemical properties, must be systematically characterized. However, many established techniques that can be used to characterize larger plastic particles cannot be applied to NPs; ,− as a consequence, a methodological gap currently exists in regard to the comprehensive characterization of NPs …”