Single molecule diffusion in polymeric systems

Sibanda, Charmaine (2019-04)

Thesis (MSc)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT : The dynamics of thin polymeric systems were studied in this research work using the diffusion of single fluorescent molecules observed by single molecule fluorescence microscopy. A wide field single fluorescence microscopy setup was designed together with a custom-built heating stage to study the nano-environments of two different polymeric systems and how these systems are affected by a change in temperature. The designed optical setup achieved a localization precision of 20 nm which further enabled the tracking of single molecules embedded in polymeric systems. The position trajectories of the single molecules in the polymer matrices are used to calculate the motion of the single molecules from which the diffusion coefficient data is extracted. The distribution of the diffusion coefficients is a consequence of the microscopic dynamics of the polymeric systems coupled to the probe molecules. The fluorescence intensity pattern analysis of the single molecules is also used as reporters of the nano-environment of thin polymeric films.

AFRIKAANSE OPSOMMING : Die dinamika van dun polimeerstelsels is bestudeer in hierdie navorsingswerk met behulp van die diffusie van enkele fluoreserende molekules waargeneem deur enkelmolekule fluoressensie mikroskopie. 'n Wye veld enkel fluoressensie mikroskopie opstelling tesame met 'n toepaslike monster verwarmingstoestel is ontwerp om die nanoomgewings van twee verskillende polimeerstelsels te bestudeer onder die geringste temperatuurverandering. Die optiese opstelling het 'n enkelmolekuul lokaliserings-presisie van 20 nm behaal. Hierdie aansienlike presisie het toegelaat dat die posisies van die enkele molekules in die polimeermatrikse gebruik word om die diffusiekoëffisient van die enkele molekules te bereken. Die verspreiding van die diffusie koëffisiënte is 'n gevolg van die mikroskopiese dinamika van die polimeerstelsels gekoppel aan die molekules. Die enkelmolekuul fluoressensie intensiteit word ook ontleed en daar word getoon dat daar ‘n definitiewe monster afhanklikeheid bestaan.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/106244
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