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UM E-Theses Collection (澳門大學電子學位論文庫)

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Title

Computational modeling of nanodroplet electrowetting on single-plate coplanar electrodes

English Abstract

Electrowetting-on-dielectric (EWOD) is a popular mechanism to control the spreading of a liquid droplet on a planar dielectric coated electrode. The technique has been used successfully in digital microfluidics (DMF) and has profound applications in many biotechnological areas. Hence, increasing our understanding on the electrowetting behavior of controlled droplet will greatly help the development of a more efficient and reliable DMF technique. In this thesis, we performed molecular dynamics (MD) simulation of water nanodroplet on a computational EWOD system. Our system included a hydrophobic surface and coplanar electrodes simulated by a pair of oppositely charged array of ions. The design of the system aims to generate non-uniform electric fields as those generated in real EWOD experiments. By varying the strength of the electrode-induced field, variations in contact angle of the droplet, hydrogen bonding and diffusion coefficient of the water molecules are disclosed in this study. Our main findings are: 1) nanodroplet displays asymmetric electrowetting in contact angle measurement; 2) water molecules and the entire droplet are slightly positively biased; 3) more water hydrogen bonds are maintained in the positive side, in both the first and second hydration layer to the surface; 4) water diffusion is higher in parallel to the surface than the normal direction.

Issue date

2017.

Author

Chan, Hoi Kei

Faculty

Faculty of Science and Technology

Department

Department of Computer and Information Science

Degree

M.Sc.

Subject

Microdroplets

Microfluidics

Molecular dynamics

Supervisor

Siu, Weng In

Mak, Pui-In

Files In This Item

Full-text (Intranet only)

Location
1/F Zone C
Library URL
991005803529706306