Controllable Coalescence Dynamics of Nanodroplets on Textured Surfaces Decorated with Well-Designed Wrinkled Nanostructures: A Molecular Dynamics Study

Abstract

The control of coalescence and motion of droplets play a significant role in advanced technology and our daily life, and one of the most important approaches is surface design. Here, the microtextured surfaces decorated with wrinkled substrates are designed and studied for coalescence behaviors. The simulation results show that the coalescence speed would be slower on such surfaces due to the downward movement of the droplets induced by the penetration of atoms into the grooves that delays their movement along the coalescence direction, which is considered as a restriction effect. With the increase of the angles and the interval distance of wrinkled structures, the coalescence time becomes longer and the coalescing process becomes unfavorable, resulting from the enhanced restriction effect. More importantly, a composite substrate possessing the original and sub-wrinkled structures has been designed to tune the coalescence dynamics. The results of this work may not only help shed light on understanding the coalescence behaviors on the wrinkled substrates but also propose a feasible method for controlling the liquid coalescence behavior, which is expected to provide some useful implications for practical applications.

Molecular Dynamics Simulation on the Wettability of Nanoscale Wrinkles: High Water Adhesion of Rose Petals

“…In this article, all-atom molecular dynamics simulations, which are widely utilized to study wetting phenomenon at the nanoscale, − and the umbrella sampling method were applied to investigate the (de)­wetting properties of nanoscale wrinkles. The results were compared to those of the nanoscale strips exhibiting excellent hydrophobicity.…”

Morphogenesis of Liquid Indium Microdroplets on Solid Molybdenum Surfaces during Solidification at Normal Pressure and under Vacuum Conditions

“…11,24,25 The surfaces and interfacial properties of the underlying substrate have a significant influence on this movement behavior and the shape evolution of metal droplets. 26,27 For applications, however, not only the surface of particles and droplets is important but also the interface to an underlying substrate. In this respect, studies are available on when In or Ga droplets wet a surface and what influence an oxide layer might have.…”

“…In addition, the geometry and kinematics of the droplets are of great importance for the technical application of low-melting metals. The local control of position, shape, or even movement of micro- or nanostructures made of In or Ga by self-organization processes can be realized by sophisticated surface modifications and open up new possibilities, e.g., for bottom-up structuring. ,, The surfaces and interfacial properties of the underlying substrate have a significant influence on this movement behavior and the shape evolution of metal droplets. , …”

Impact Dynamics of Nanodroplets on V-Shaped Substrates: Asymmetrical Behavior and Fast-Rebound Dynamics

“…5,8−17 Among these, the design of surface structures is the most commonly used method to tune the droplet dynamics. 18 Generally speaking, the control of the drop impact dynamics for application has two aspects. On the one hand, the prevention of rebound and deposition of the drops is sometimes important in some situations, such as coating or pesticide spraying on the surfaces of leaves.…”

“…The impact behavior of the drops on the solid substrate is a frequently studied phenomenon in fluid mechanics because of numerous industrial and daily applications ranging from spray coating, inkjet printing, , aeronautics, , to criminal forensics . During the impact process, there are two main stages, including spreading and retraction, and various outcomes of the drop, such as splash, deposition, and rebound, , which are highly determined by liquid properties (e.g., size, density, viscosity, surface tension), substrate properties (e.g., wettability, roughness, surface nano/microstructure, shape, elasticity, or porosity), and impact conditions (e.g., impact velocity, environment temperature and humidity, gas pressure, and so on). ,− Among these, the design of surface structures is the most commonly used method to tune the droplet dynamics . Generally speaking, the control of the drop impact dynamics for application has two aspects.…”