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Density functional theories and the structure of fluids near walls

Augousti, Andreas T. (1985) Density functional theories and the structure of fluids near walls. Doctor of Philosophy (PhD) thesis, University of Kent. (doi:10.22024/UniKent/01.02.94181) (KAR id:94181)

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The structure of fluids near walls is examined using density functional techniques. A brief introduction to the subject is given, followed by a mathematical derivation of some important basic results. A linear (Chap.3) and non-linear (Chap.4) density functional approximation for the thermodynamic potential is used to treat a model fluid comprised of hard spheres with embedded point ions or dipoles confined between two hard infinite planar walls. Results are obtained and compared for the charge and polarisation densities. Both theories produce oscillatory charge and polarisation density profiles, in agreement with results at a single wall from other workers. These results differ qualitatively with those given by earlier, continuum theories of the electrical double layer such as Debye-Huckel and Poisson-Boltzmann. A modified functional is introduced (Chap.5), and is used to treat a simple fluid of hard spheres. A single variable parameter of the theory is chosen to ensure thermodynamic consistency, and results for the number density are obtained. These results are in excellent agreement with results from Monte Carlo computer experiments, even up to unrealistically high fluid densities. The modified functional is further applied to a hard sphere fluid with attractive long-range interactions. This leads to wetting of the walls by vapour, a result also observed previously at a single wall. Finally,. a perturbation treatment is applied to experimental scattering data to give a potential of mean force for an aqueous dispersion of polystyrene spheres.

Item Type: Thesis (Doctor of Philosophy (PhD))
Thesis advisor: Rickayzen, Gerald
Thesis advisor: Richmond, Peter
DOI/Identification number: 10.22024/UniKent/01.02.94181
Additional information: This thesis has been digitised by EThOS, the British Library digitisation service, for purposes of preservation and dissemination. It was uploaded to KAR on 25 April 2022 in order to hold its content and record within University of Kent systems. It is available Open Access using a Creative Commons Attribution, Non-commercial, No Derivatives ( licence so that the thesis and its author, can benefit from opportunities for increased readership and citation. This was done in line with University of Kent policies ( If you feel that your rights are compromised by open access to this thesis, or if you would like more information about its availability, please contact us at and we will seriously consider your claim under the terms of our Take-Down Policy (
Uncontrolled keywords: Fluid structure
Subjects: Q Science > QC Physics
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
SWORD Depositor: SWORD Copy
Depositing User: SWORD Copy
Date Deposited: 24 Jun 2022 15:32 UTC
Last Modified: 20 Nov 2023 14:50 UTC
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