Analysis of Contact Angle and Hysteresis Phenomenonn Patterned Substrate using Liquid/Vapor Coexistenceissipative Particle Dynamics Simulation
Date Issued
2008
Date
2008
Author(s)
Chen, Yan-Yu
Abstract
Wetting is an important phenomenon, and has been used widely in many engineering applications. The contact angle is often used to describe the degree of wetting. The defect of the surface might induce wide contact angle distribution, often called hysteresis. In this thesis, Multi-body Dissipative Particle Dynamics (MDPD), which can represent the van der Waals loop, is used to simulate the wetting phenomenon on ideal patterned substrates and to analyze the relation between simulated hysteresis and theoretical prediction or experimental observation.PD is similar to Molecular Dynamic (MD) while the MDPD is improved from DPD to model the liquid/vapor coexistence interface. Such improvement allows us to describe the thermodynamic system associated with the wetting phenomenon. An efficient implementation to reduce the particles for the base is introduced. Three contact angle measurement methods from discrete particles are implemented.or a liquid droplet on an ideal flat substrate, hysteresis will not occur. This assessment was verified in our wetting simulations, in which the same contact angle was reached with different initial liquid shapes. For a droplet on a patterned substrate, the advancing contact angle, receding contact angle, and many meta-stable states have been found in our simulations. We found that θw<130° has more hysteresis. When θw>130°, the hysteresis is limited to a range of 15°~30°.
Subjects
Dissipative Particle Dynamics (DPD)
Liquid/Vapor coexistence interface
Wetting phenomenon
Hysteresis
Hysteresis transition
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95521608-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):76a7d2bf6add4405daff84c8a4625a14