Measuring adhesion on rough surfaces using atomic force microscopy with a liquid probe

Abstract

We present a procedure to perform and interpret pull-off force measurements during the jump-off-contact process between a liquid drop and rough surfaces using a conventional atomic force microscope. In this method, a micrometric liquid mercury drop is attached to an AFM tipless cantilever to measure the force required to pull this drop off a rough surface. We test the method with two surfaces: a square array of nanometer-sized peaks commonly used for the determination of AFM tip sharpness and a multi-scaled rough diamond surface containing sub-micrometer protrusions. Measurements are carried out in a nitrogen atmosphere to avoid water capillary interactions. We obtain information about the average force of adhesion between a single peak or protrusion and the liquid drop. This procedure could provide useful microscopic information to improve our understanding of wetting phenomena on rough surfaces. 813

Quantifying Surface Wetting Properties Using Droplet Probe Atomic Force Microscopy

“…With this droplet probe AFM technique, we were also able to map local wetting variations due to the presence of micro/nanotextures and observed fast pinning-depinning dynamics as the droplet detached from the surface. Previously, droplet probe AFM was used to study various interfacial problems, − but its significance as a surface characterization tool remains underappreciated.…”

Atomic Force Microscopy Investigation of the In Situ‐Formed Oxide Layer at the Interface of Al2O3−C/Steel Melt in Terms of Adhesion Force and Roughness in a Model System

“…Drop Probe-AFM (CP-AFM): Drop probe measurements were done using the method described in detail by Escobar et al [27] Small microsized mercury droplets were used as CPs on stiff cantilevers (AIOAl-TL C, 22.13 N m À1 ). For four of the finger test samples, force spectroscopy measurements were realized on four different locations on each sample; each 2D map consisted of 256 force distance curves.…”

“…To simulate the interaction between the melt and the in situ layer, a small mercury droplet was attached onto the cantilever as model melt using Escobar's method [27] instead of the CP. The adhesive forces were measured using the same procedure as for CP AFM.…”

“…A special case is the drop probe method: For liquid metal capillary interactions, Escobar et al show how small microsized mercury droplets can be attached to the cantilever instead of a CP and how to interpret the force spectroscopy data. [27] Another property that is usually connected to adhesive interactions is wettability, which describes the tendency of a solid to form a common interface with a liquid that comes into contact with it. [22] The characteristic value to describe wetting is the material-specific contact angle, often measured via sessile drop measurements.…”

Estimation of rolling work of adhesion at the nanoscale with soft probing using optical tweezers

“…The work of adhesion estimated in this work is signicantly smaller than that reported for similar surfaces performed at large forces using AFM where 50 mJ m À2 are oen reported. 11,34 Our work appears to be a case of so probing of the surface by the optical tweezers. One can use this mode of so probing to study interaction between protein coated particles on specic surfaces and ascertain the interaction energy which cannot be performed in any other way.…”