Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: In this thesis the formation and properties of a polymer gel on and at a surface
are investigated. The gel under investigation is defined as a three-dimensional network
of macromolecules that form permanent links with one another and also with
confining planar surfaces. The precise location of the crosslinks on the wall or on
another macromolecule is not known prior to linking, and will differ from sample to
sample. However, once the crosslinks are formed, they are assumed to be permanent.
This random linking is the source of the disorder in the system, over which
a quenched average has to be taken. An existing model [9] of network formation,
with polymer-polymer crosslinks, is extended to incorporate a surface and polymersurface
crosslinks. Within the framework of replica theory, statistical averages and
physical properties of the system are calculated by means of a variational approach.
Macroscopic information, in terms of the free energy of deformation, is obtained by
using two different potentials to simulate the erosslinks mathematically. / AFRIKAANSE OPSOMMING: In hierdie tesis word die vorming en eienskappe van 'n polimeergel, wat teen 'n
oppervlak gevorm word, ondersoek. Die gel word gedefinieer as 'n drie-dimensionele
netwerk van makromolekules wat permanente bindings met mekaar, maar ook met
twee inperkende, platvlakke, vorm. Die presiese ligging van die bindings op die
muur en op ander makromolekules is nie vooraf bekend nie, en sal verskil van een
gel-monster tot die volgende. Sodra die konneksies egter gevorm is, word aanvaar
dat hulle permanent is. Die lukrake bindingsproses is die oorsprong van wanorde
in die sisteem, waaroor 'n wanorde-gemiddelde bereken moet word. 'n Bestaande
model [9]van netwerkvorming, met polimeer-polimeer bindings, word uitgebrei om 'n
oppervlakte en polimeer-oppervlak bindings in te sluit. Statistiese fisika gemiddeldes
en fisiese eienskappe van die sisteem word binne die raamwerk van replika-teorie en 'n
variasie benadering bereken. Makroskopiese inligting, in terme van die vrye energie
van vervorming, word verkry deur twee verskillende potensiale te gebruik om die
konneksies wiskundig voor te stel.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/53552 |
| Date | 03 1900 |
| Creators | Vandoolaeghe, Wendy Leigh |
| Contributors | Muller-Nedebock, K., Stellenbosch University. Faculty of Science. Dept. of Physics. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 84 p. : ill. |
| Rights | Stellenbosch University |
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