Electronic Theses and Dissertations

Identifier

759

Date

2012

Document Type

Thesis

Degree Name

Master of Science

Major

Physics

Concentration

Computational Physics

Committee Chair

Mohamed Laradji

Committee Member

Sanjay Mishra

Committee Member

Muhammad Jahan

Abstract

A Nano ElectroMechanical System (NEMS) is theoretically introduced, through a Dissipative Particle Dynamics simulation model, as a new and novel approach to the issue of nano-pumps. The design features a nanoscale planar slit pore filled with solvent and a grafted polymer brush on the inner face of the lower plane (substrate). The polymer brush is susceptible to the influence of an external driving field, with an intensity modulated by a three phase square wave. The brush couples to the external field directly through fundamental forces, while a secondary coupling transfers momentum to the solvent through hydrodynamic interactions. The result is net solvent velocity along a preferred direction, over many oscillation cycles, while the grafted brush remains anchored in place. This study explores the net solvent response as a function of grafting density, field intensity, fluid viscosity and polymer chain length. Simulation data is presented which suggests that solvent flow is maximized for moderate grafting densities due to an optimal saturation of solvent particles within the polymer brush, near their interface, in conjunction with adequate surface area provided by the collection of polymer segments near the brush boundary. This exchange is necessary to ensure proper hydrodynamic coupling.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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