Presence of Particles on Melt-Cut Mica Sheets

Abstract

We show the presence of numerous particles on mica surfaces melt-cut for use in the surface force apparatus (SFA). The particles, as observed by atomic force microscopy, are typically 20−25 nm in diameter and 2−3 nm high, and cover up to 0.05% of the surface area. They consist of solidified droplets of molten mica, scattered across the surfaces during the cutting of cleaved mica with a white-hot platinum wire. The particles adhere strongly to the mica surfaces in inert atmospheres but become mobile and disappear upon scanning under water and polar liquids. They seem to remain attached to the surfaces in nonpolar liquids. The particles appear to affect to a noticeable extent only experiments involving capillary condensation of water between mica surfaces.

Two-dimensional observation of drainage and layering transitions in confined liquids

“…after gluing them to the cylindrical lenses (which were still used in the previous setup) and in particular after the hot wire melt cut procedure [10]. This removes any possible contamination of the sur- faces with particles that are typically created by the hot wire cutting [11]. In addition, the second cleavage produces particularly thin and hence easily deformable mica sheets (thickness d B 1 mm).…”

Confined fluid and the fluid-solid transition: Evidence from absolute free energy calculations

“…Specifically, the confined phase is buried between two solid mica walls with just a few layers of material contained in this region, which has thus far made it impossible to directly observe the structure. Moreover, the discovery of platinum nanoparticles on the mica surfaces in some experiments 10,11 led to a reexamination of previously published results, with the conclusion that some experimental findings were potentially compromised 12 .…”

Density and Phase State of a Confined Nonpolar Fluid

“…Thus, we can observe changes in density that would occur with a phase transition. The muscovite mica substrates used in this experiment were cleaved to sheets with uniform thicknesses of 3-7 μm and cut with surgical scissors to avoid the possible influence of platinum particle contamination (which has been suggested to occur when the mica is cut with a superheated platinum wire) [33,34]. The mica was then silvered on the backside and glued onto cylindrical BaLF4 glass disks using refractive-index-matched EPON 1002F epoxy resin, resulting in cylinder radii ranging from 2 to 5 cm.…”