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@PHDTHESIS{July:17831,
author = {July, Christoph},
title = {{I}nfluence of a shear flow on colloidal depletion
interaction},
volume = {41},
school = {Heinrich-Heine-Universität Düsseldorf},
type = {Dr. (Univ.)},
address = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {PreJuSER-17831},
isbn = {978-3-89336-791-7},
series = {Schriften des Forschungszentrums Jülich.
Schlüsseltechnologien / Key Technologies},
pages = {V, 105, XVIII S.},
year = {2011},
note = {Record converted from JUWEL: 18.07.2013;
Heinrich-Heine-Universität Düsseldorf, Diss., 2011},
abstract = {In this work colloidal depletion interactions are studied
in a quiescent state and under shear flow by means of total
internal reflection microscopy (TIRM). Depletion
interactions are very weak, entropy driven forces [1], which
arise when two or more colloidal particle species are mixed.
The first theoretical studies were done by Asakura and
Oosawa [2, 3]. The interest in depletion forces is driven by
the fact that they are able to influence phase behaviour and
self organisation of synthetic and natural colloidal systems
[4]. In general, depletion forces are so small that they are
difficult to measure by conventional methods such as atomic
force microscopy (AFM) [5, 6] or optical tweezers [7]. TIRM
is one of the most sensitive methods to probe depletion
interactions in colloidal systems [8–10]. This thesis
starts with an overview of the fundamental forces acting on
a colloid close to a wall (chapter 2). Electrostatic
interactions, gravitation, van der Waals forces, and a
simple depletion theory are derived for a colloidal sphere
in the vicinity of a surface. These theoretical foundations
are used as models to fit experimental potentials. Chapter 3
introduces the experimental methods used in this thesis and
provides an illustration of the nature of evanescent
illumination. The TIRM setup is explained in detail in
conjunction with the data evaluation. Sample preparation,
measurements of the properties of the used samples, as well
as advantages and drawbacks of the employed experimental
systems are further discussed in chapter 3. Methods for
characterizing samples and cleaning procedures are
discussed. In chapter 4, where the results of the thesis are
presented, first experiments suggest that using standard
TIRM methods result in artifacts when applying a shear flow
and trapping the probe particle with optical tweezers at the
same time. A significant advancement of this thesis is the
modification of the setup in order to remove the unwanted
influence of the tweezers when shearing the sample. [...]},
cin = {ICS-3},
ddc = {500},
cid = {I:(DE-Juel1)ICS-3-20110106},
pnm = {BioSoft: Makromolekulare Systeme und biologische
Informationsverarbeitung},
pid = {G:(DE-Juel1)FUEK505},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
url = {https://juser.fz-juelich.de/record/17831},
}