Condensed liquid behavior on hydrophobic micro/nano-structured surfaces is a subject with multiple practical applications, but remains poorly understood. In particular, the loss of superhydrophobicity of hydrophobic micro/nanostructures during condensation, even when the same surface shows water-repellant characteristics when exposed to air, requires intensive investigation to improve and apply...

We present an experimental study of the tunable anisotropic wetting behavior of chemically patterned anisotropic surfaces. Asymmetric glycerol droplet shapes, arising from patterns of alternating hydrophilic (pristine SiO2) and hydrophobic (fluoroalkylsilane self-assembled monolayers) stripes with dimensions in the low-micrometer range, are investigated in relation to stripe widths. Owing to th...

A novel computational fluid dynamics and molecular kinetic theory (CFD-MK) method was developed to simulate the impingement of a nanodroplet onto a solid surface. A numerical solution of the Navier–Stokes equation using a volume-of-fluid (VOF) technique was used to model nanodroplet deformation. Dynamic contact angle during droplet impact was obtained by molecular kinetic theory. This dynamic c...

The numerical simulation of dynamic wetting processes is of interest for a vast variety of industrial processes, where practical experiments are costly and timeconsuming. In these simulations, the dynamic contact angle is a key parameter, but the modeling of its behavior is poorly understood so far. In this article, we simulate droplet impact on a dry flat surface by using two different contact...

The purpose of this research is to establish a self-alignment technique for microparts assembly using liquid surface tension. The factors that influence alignment performance are examined and ways of performance improvement are discussed experimentally and theoretically. First, the relationship between the alignment accuracy and the behavior of the micropart and the water droplet is examined in...

We examine the evolution of an Ising ferromagnet endowed with zero-temperature single spin-flip dynamics. A large droplet of one phase in the sea of the opposite phase eventually disappears. An interesting behavior occurs in the intermediate regime when the droplet is still very large compared to the lattice spacing, but already very small compared to the initial size. In this regime the shape ...

Surfaces may be rendered superhydrophobic by engineering the surface morphology to control the extent of the liquid-air interface and by the use of low-surface-energy coatings. The droplet state on a superhydrophobic surface under static and dynamic conditions may be explained in terms of the relative magnitudes of the wetting and antiwetting pressures acting at the liquid-air interface on the ...

A Phase Doppler Particle Analyzer (PDPA) system is employed to measure the two-phase mist flow behavior including flow velocity field, droplet size distribution, droplet dynamics, and turbulence characteristics. Based on the droplet measurements made through PDPA, a projected profile describing how the air-mist coolant jet flow spreads and eventually blends into the hot main flow is proposed. T...

Controlling droplet dynamics via wettability or movement at the nanoscale is a significant goal of nanotechnology. By performing molecular dynamics simulations, we study the wettability and spontaneous coalescence of Cu droplets confined in two carbon walls. We first focus on one drop in the two-wall confinement to reveal confinement effects on wettability and detaching behavior of metallic dro...

Contact angle hysteresis of a macroscopic droplet on a heterogeneous but flat substrate is studied using the interface displacement model. First, the apparent contact angle of a droplet on a heterogeneous surface under the condition of constant volume is considered. By assuming a cylindrical liquid-vapor surface (meniscus) and minimizing the total free energy, we derive an equation for the appa...