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@PHDTHESIS{Yan:61650,
author = {Yan, Linglong},
othercontributors = {Beginn, Uwe},
title = {{S}elf-assembly of sulfonated amphiphiles for channel-like
synthetic membranes},
address = {Aachen},
publisher = {Publikationsserver der RWTH Aachen University},
reportid = {RWTH-CONV-123290},
pages = {VI, 160 S. : Ill., graph. Darst.},
year = {2006},
note = {Prüfungsjahr: 2006. - Publikationsjahr: 2007; Aachen,
Techn. Hochsch., Diss., 2006},
abstract = {Self-assembly is one of the most useful techniques, which
provide a facile strategy to construct structure-defined
functional materials, such as ion-selective membranes.
Highly selective membranes can eventually form a basis to
replace some energy- or labor-intensive purificatiion
processes and can also simplify specific detection problems
in the fields of biochemical, medical and even environmental
analytical technology. In this dissertation, a series of
wedge-shaped sulfonic acid derivatives differing in
substitution pattern and molecular symmetry as well as in
the size of the cationic count-ions, were synthesized and
characterized to give a better understanding of the
self-assembly process. From the dependence of transition
temperatures and enthalpies on the cation diameter, it is
conclusive that the occurrence of mesophases of these
compounds is more ruled by the geometric shape of the
mesogen than by the ionic interactions between cation and
sulfonate anion. For example, the symmetrical substituted
alkali metal cationic sulfonates all exhibit columnar
mesophases either on melting from the crystalline phase or
on annealing at the proper temperature. The target molecule
with polymerizable groups was also found to exhibit a
hexagonal columnar mesophase between 115°C and 233°C, as
well as in semi-polar methacrylate solvents as the
concentration exceeded $70wt\%.$ Photo-curing this hexagonal
columnar mesophase results in a cross-linked polymer film
covalently embedded with the cylinders network. The
membranes with abundant sulfonate channels were obtained by
photo-initiated polymerization in the state of lyotropic
columnar mesophases without losing the ordered columnar
arrangements. The ion-transport measurements showed their
ability to transport small alkalic cations through the
channels. The ion transport rates exhibited a decreasing
tendency in the sequence of Lithium > Sodium > Potassium
cation. Since in a free solution Lithium cation diffuses
slower than sodium cation that diffuses slower than
potassium cation, this opposite result is indicative of the
transport through the supramolecular channels. It is
confirmed that the diffusion became controlled by
cation-sulfonate interactions during the transport through
the supramolecular channels. In the last part of the
dissertation, the sulfonated functional membranes with
orientated columnar channels were achieved and used as a
model system to investigate the mechanism of cation
transport through the supramolecular sulfonated channels.
Due to the possession of the geometrically defined
superstructure, the presented strategy of constructing the
channel-like functional membrane gives the potential to
modify or tune the performance of the membranes for further
application.},
cin = {154720 / 150000},
ddc = {540},
cid = {$I:(DE-82)154720_20140620$ / $I:(DE-82)150000_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-opus-18219},
url = {https://publications.rwth-aachen.de/record/61650},
}
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