The Maximum Spreading Factor for Polymer Nanodroplets Impacting a Hydrophobic Solid Surface

Wang, Yibo; Wang, Xiaodong; Yang, Yan‐Ru; Chen, Min

doi:10.1021/acs.jpcc.9b02053

Cited by 49 publications

(52 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All simulations are implemented by the large-scale atomic/molecular massively parallel simulation (LAMMPS) package. MD simulations have been widely used for investigating the maximum spreading factor of low-viscosity nanodroplets, such as water and argon (Li et al 2015(Li et al , 2017Wang et al 2019Wang et al , 2020a. Figure 1 shows the schematics of simulated systems for a water and an argon nanodroplet impacting a smooth platinum substrate.…”

Section: Simulation Methodsmentioning

confidence: 99%

“…The maximum spreading diameter is commonly normalized as the maximum spreading factor, β max = D max /D 0 , where D 0 is the initial droplet diameter. To accurately predict β max , the impact dynamics of droplets have been continuously studied theoretically (Madejski 1976;Pasandideh-Fard et al 1996;Kim & Chun 2001;Clanet et al 2004;Bartolo, Josserand & Bonn 2005;Ukiwe & Kwok 2005;Attané, Girard & Morin 2007;Li, Zhang & Chen 2015;Wildeman et al 2016;Wang et al 2019, 2020b, Du et al 2021, experimentally (Clanet et al 2004;Ukiwe & Kwok 2005;Kannan & Sivakumar 2008;Vaikuntanathan, Kannan & Sivakumar 2010;Antonini, Amirfazli & Marengo 2012) and numerically (Li et al 2015;Wildeman et al 2016;Wang et al 2019Wang et al , 2020b.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, the mesh-free MD simulations are regarded as a direct approach to study the nanoscale flow by tracking motions of individual atoms by solving Newton's motion equations without setting complex boundary conditions (Koishi, Yasuoka & Zeng 2017;Xie et al 2018). The MD simulations have been adopted in studies of the impact of low-viscosity nanodroplets, especially on evaluation of the maximum spreading factor (Li et al 2015;Li, Li & Chen 2017;Wang et al 2019Wang et al , 2020a. Recently, three scale effects have been discovered for nanodroplet impact.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Scaling laws of the maximum spreading factor for impact of nanodroplets on solid surfaces

Wang

Zhang

et al. 2022

J. Fluid Mech.

Self Cite

View full text Add to dashboard Cite

This study investigates the dynamics of low-viscosity nanodroplets impacting surfaces with static contact angles from θ = 73° to 180° via molecular dynamics (MD) simulations. Two typical morphologies of impacting nanodroplets are observed at the maximum spreading state, a Hertz-ball-like in a low-Weber-number range and a thin-film-like in a high-Weber-number range. Only inertial and capillary forces dominate the impact for the former, whereas viscous force also becomes dominant for the latter. Regardless of morphologies at the maximum spreading state, the ratio of spreading time to contact time always remains constant on an ideal superhydrophobic surface with θ = 180°. With the help of different kinematic approximations of the spreading time and scaling laws of the contact time, scaling laws of the maximum spreading factor ${\beta _{max}}\sim W{e^{1/5}}$ in the low-Weber-number range (capillary regime) and ${\beta _{max}}\sim W{e^{2/3}}R{e^{ - 1/3}}$ (or ${\beta _{max}}\sim W{e^{1/2}}O{h^{1/3}}$ ) in the high-Weber-number range (cross-over regime) are obtained. Here, We, Re, and Oh are the Weber number, Reynolds number, and Ohnesorge number, respectively. Although the scaling laws are proposed only for the ideal superhydrophobic surface, they are tested valid for θ over 73° owing to the ignorable zero-velocity spreading effect. Furthermore, combining the two scaling laws leads to an impact number, $W{e^{3/10}}O{h^{1/3}} = 2.1$ . This impact number can be used to determine whether viscous force is ignorable for impacting nanodroplets, thereby distinguishing the capillary regime from the cross-over regime.

show abstract

Section: Simulation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Scaling laws of the maximum spreading factor for impact of nanodroplets on solid surfaces

Wang

Zhang

et al. 2022

J. Fluid Mech.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The mechanisms of spreading, break-up, bouncing, and other behaviors of nanodroplets are discussed via MD [15][16][17][18][19]. Chen et al simulated polymer nanodroplets impinging on a solid surface and found that the viscous dissipation of water nanodroplets stemmed from the velocity gradients in both the impinging and spreading directions [20]. Song et al investigated the deformation behaviors of water nanodroplets in an electric field and observed the deformation hysteresis phenomenon.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation on Behaviors of Water Nanodroplets Impinging on Moving Surfaces

2022

View full text Add to dashboard Cite

Droplets impinging on solid surfaces is a common phenomenon. However, the motion of surfaces remarkably influences the dynamical behaviors of droplets, and related research is scarce. Dynamical behaviors of water nanodroplets impinging on translation and vibrating solid copper surfaces were investigated via molecular dynamics (MD) simulation. The dynamical characteristics of water nanodroplets with various Weber numbers were studied at four translation velocities, four vibration amplitudes, and five vibration periods of the surface. The results show that when water nanodroplets impinge on translation surfaces, water molecules not only move along the surfaces but also rotate around the centroid of the water nanodroplet at the relative sliding stage. Water nanodroplets spread twice in the direction perpendicular to the relative sliding under a higher surface translation velocity. Additionally, a formula for water nanodroplets velocity in the translation direction was developed. Water nanodroplets with a larger Weber number experience a heavier friction force. For cases wherein water nanodroplets impinge on vibration surfaces, the increase in amplitudes impedes the spread of water nanodroplets, while the vibration periods promote it. Moreover, the short-period vibration makes water nanodroplets bounce off the surface.

show abstract

“…25−32 Li 23 experimentally studied two droplets impacting a solid surface and identified different coalescence mechanisms based on the comparison between the theoretical and experimental spread lengths. Wang et al 24 studied the impact of nanodroplets on a solid surface and developed a new model to estimate the maximum spreading factor. They also numerically studied a double droplet impact on a moving liquid and analyzed the asymmetric heat transfer characteristics.…”

Section: Introductionmentioning

confidence: 99%

Coalescence, Spreading, and Rebound of Two Water Droplets with Different Temperatures on a Superhydrophobic Surface

Chang

et al. 2019

ACS Omega

View full text Add to dashboard Cite

This paper studied the coalescence, spreading, and rebound of two droplets with different temperatures on a superhydrophobic surface. When the temperature of the impacting droplet was the same as that of the stationary droplet, there was a large deformation of both droplets before the coalescence and the energy dissipation was also large. The coalescence happened at the time close to the maximum spreading. When the temperature of the impacting droplet increased, the deformation of both droplets became smaller before the coalescence and the coalescence happened at or even before the droplets started to spread. The energy dissipation and loss in the later situation is less than those in the previous case. The rebounding characteristics of the merged droplets were also found to be dependent on the temperature. There is an optimum temperature at which the merged droplets can rebound for more times due to the balance of energy loss and also the interaction of the merged droplets with the underlying superhydrophobic substrate. These findings may help further the fundamental understanding of droplet collision on a superhydrophobic surfaces and also offer an alternative strategy to remove droplets from the underlying surfaces for different industrial applications, including condensation heat transfer in steam power plants and phase-change-based thermal management systems.

show abstract

The Maximum Spreading Factor for Polymer Nanodroplets Impacting a Hydrophobic Solid Surface

Cited by 49 publications

References 35 publications

Scaling laws of the maximum spreading factor for impact of nanodroplets on solid surfaces

Scaling laws of the maximum spreading factor for impact of nanodroplets on solid surfaces

Molecular Dynamics Simulation on Behaviors of Water Nanodroplets Impinging on Moving Surfaces

Coalescence, Spreading, and Rebound of Two Water Droplets with Different Temperatures on a Superhydrophobic Surface

Contact Info

Product

Resources

About