The dynamic wetting properties of atomic force microscopy (AFM) tips are of much concern in many AFM-related measurement, fabrication, and manipulation applications. In this study, the wetting properties of silicon and silicon nitride AFM tips are investigated through dynamic contact angle measurement using a nano-Wilhelmy balance based method. This is done by capillary force measurement during...

Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) coupled with the Young-Laplace equation is a recently developed equation of state (EOS) that successfully presents not only the capillary condensation but also the pore critical phenomena. The development of this new EOS allows further investigation of the heats involved in condensation. Compared to the conventional approaches, the ...

We developed a novel method for fabrication of glass micromodels with varying depth (2.5-D) with no additional complexity over the 2-D micromodels' fabrication. Compared to a 2-D micromodel, the 2.5-D micromodel can better represent the 3-D features of multi-phase flow in real porous media, as demonstrated in this paper with three different examples. Physically realistic capillary snap-off and ...

The capillary levelling of cylindrical holes in viscous polystyrene films was studied using atomic force microscopy as well as quantitative analytical scaling arguments based on thin film theory and self-similarity. The relaxation of the holes was shown to consist of two different time regimes: an early regime where opposing sides of the hole do not interact, and a late regime where the hole is...

simultaneous capillary dominated displacement of the wetting and non-wetting phases are processes of interest in many disciplines including modeling of the penetration of polluting liquids in hydrology or the secondary migration in petroleum reservoir engineering. percolation models and in particular invasion percolation is well suited to characterize the slow immiscible displacement of two flu...

The interaction between energetically asymmetric hydrophilic and hydrophobic surfaces has fundamental and practical importance in both industrial and natural colloidal systems. The interaction forces between a hydrophilic silica sphere and a silanated, hydrophobic glass plate in N-methyl-2-pyrrolidone (NMP)-water binary mixtures were measured using atomic force microscopy (AFM). A strong and lo...

Micro-stereolithography ( SL) is capable of fabrication of highly complex three-dimensional (3D) microstructures by selectively photo-induced polymerization from the monomer resin. However, during the evaporative drying of structures from liquid resin, the 3D microstructures often collapse due to the capillary force. In this work, a theoretical model is developed to analyze the deflection and a...

The humidity present in ambient atmosphere affects the adhesion of small particles by causing capillary bridge formation between the particle and the surface. Even in moderate relative humidities this, usually attractive, force can have a significant effect on adhesion behaviour of micro and sub-micro particles. We have directly measured the pull-off forces of initially adhered oxide particles ...

The influence of sliding velocity on the adhesion force in a nanometer-sized contact was investigated with a novel atomic force microscope experimental setup that allows measuring adhesion forces while the probe is sliding at continuous and constant velocities. For hydrophobic surfaces, the adhesion forces (mainly van der Waals forces) remain constant, whereas for hydrophilic surfaces, adhesion...

We analytically determine the lateral capillary force acting on a spherical colloid trapped at an interface of arbitrary shape. Our calculations, which are valid for colloids that are small with respect to the capillary length, take into account surface tension, pressure and gravity. We relate the force acting on the colloid to the shape of the liquid interface prior to colloid deposition. Our ...