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Gerichtete MWCNT/ Polypyrrol Hybride als Material für anisotrope Aktuatoren
Citation Link: https://doi.org/10.15480/882.1378
Publikationstyp
Doctoral Thesis
Date Issued
2016-12
Sprache
German
Author(s)
Advisor
Referee
Title Granting Institution
Technische Universität Hamburg-Harburg
Place of Title Granting Institution
Hamburg
Examination Date
2016-07-05
TORE-DOI
First published in
Technisch wissenschaftliche Schriftenreihe;28
Number in series
28
Publisher
TUTECH INNOVATION GmbH
The present work describes the manufacturing of vertically and horizontally aligned
Multi Walled Carbon Nanotube (MWCNT)/ Polypyrrole Hybrids and their direction
dependent behavior when actuated. In these hybrids, the Polypyrrole component is
responsible for the actuation; already at very low potential differences and currents the
polymer can be oxidized and reduced reversibly. This redox-procedure is accompanied
by a diffusion of solvated ions from the surrounding electrolyte and therefore, the
volume of the polymer swells or contracts. Because Polypyrrole is active under
physiological conditions, a possible application for such Hybrids would be to use them
as micro-actuators for implantable micro-dosing systems, which has a working
principle very similar to that of a compressor.
In the described Hybrids, the MWCNTs take over the role as an incorporated electrode
and ensure an even distribution of charges. At the same time, they induce direction
dependent actuation (or anisotropy in actuation) owing to their high stiffness along
their main orientation direction and nanostructured shape. The contraction and
elongation in the direction parallel to the main MWCNT orientation is almost
completely deterred.
As a starting material for the manufacturing of the Hybrids, vertically aligned
MWCNTs produced via gas flow CVD processes are used. Through a mechanical
process, these vertically oriented MWCNTs can be transformed into horizontally
aligned Buckypapers by densification. In a subsequent electrochemical polymerization
process, each of these individual MWCNTs is coated with a very thin layer (~20 nm)
of Polypyrrole. The relative orientation of the MWCNTs is preserved throughout the
coating procedure. Apart from their actuation behaviour, the mechanical properties
viz., tensile and compression stiffness and the electro-chemical properties of these
composites are also investigated.
Multi Walled Carbon Nanotube (MWCNT)/ Polypyrrole Hybrids and their direction
dependent behavior when actuated. In these hybrids, the Polypyrrole component is
responsible for the actuation; already at very low potential differences and currents the
polymer can be oxidized and reduced reversibly. This redox-procedure is accompanied
by a diffusion of solvated ions from the surrounding electrolyte and therefore, the
volume of the polymer swells or contracts. Because Polypyrrole is active under
physiological conditions, a possible application for such Hybrids would be to use them
as micro-actuators for implantable micro-dosing systems, which has a working
principle very similar to that of a compressor.
In the described Hybrids, the MWCNTs take over the role as an incorporated electrode
and ensure an even distribution of charges. At the same time, they induce direction
dependent actuation (or anisotropy in actuation) owing to their high stiffness along
their main orientation direction and nanostructured shape. The contraction and
elongation in the direction parallel to the main MWCNT orientation is almost
completely deterred.
As a starting material for the manufacturing of the Hybrids, vertically aligned
MWCNTs produced via gas flow CVD processes are used. Through a mechanical
process, these vertically oriented MWCNTs can be transformed into horizontally
aligned Buckypapers by densification. In a subsequent electrochemical polymerization
process, each of these individual MWCNTs is coated with a very thin layer (~20 nm)
of Polypyrrole. The relative orientation of the MWCNTs is preserved throughout the
coating procedure. Apart from their actuation behaviour, the mechanical properties
viz., tensile and compression stiffness and the electro-chemical properties of these
composites are also investigated.
Subjects
Carbon Nanotubes
Polypyrrol
Aktuation
Nanostrukturierung
Elektropolymeristation
DDC Class
540: Chemie
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